Add session configuration load capability to libconfig
[lttng-tools.git] / src / common / config / config.c
index e945a19fb94c9f940b4113d8aa188b6fd5150ffe..5e100a7ab6c9c6e66848f5010acc711ffba51b8d 100644 (file)
 
 #define _GNU_SOURCE
 #include <assert.h>
-#include <config.h>
 #include <ctype.h>
-#include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <inttypes.h>
+#include <dirent.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
 
 #include <common/defaults.h>
 #include <common/error.h>
 #include <common/macros.h>
 #include <common/utils.h>
+#include <common/config/config-session-internal.h>
+#include <lttng/lttng-error.h>
+#include <libxml/parser.h>
+#include <libxml/valid.h>
+#include <libxml/xmlschemas.h>
+#include <libxml/tree.h>
+#include <lttng/lttng.h>
+#include <lttng/snapshot.h>
 
 #include "config.h"
+#include "config-internal.h"
 
 struct handler_filter_args {
        const char* section;
@@ -37,12 +49,119 @@ struct handler_filter_args {
        void *user_data;
 };
 
+struct session_config_validation_ctx {
+       xmlSchemaParserCtxtPtr parser_ctx;
+       xmlSchemaPtr schema;
+       xmlSchemaValidCtxtPtr schema_validation_ctx;
+};
+
 const char * const config_str_yes = "yes";
 const char * const config_str_true = "true";
 const char * const config_str_on = "on";
 const char * const config_str_no = "no";
 const char * const config_str_false = "false";
 const char * const config_str_off = "off";
+const char * const config_xml_encoding = "UTF-8";
+const size_t config_xml_encoding_bytes_per_char = 2;   /* Size of the encoding's largest character */
+const char * const config_xml_indent_string = "\t";
+const char * const config_xml_true = "true";
+const char * const config_xml_false = "false";
+
+const char * const config_element_channel = "channel";
+const char * const config_element_channels = "channels";
+const char * const config_element_domain = "domain";
+const char * const config_element_domains = "domains";
+const char * const config_element_event = "event";
+const char * const config_element_events = "events";
+const char * const config_element_context = "context";
+const char * const config_element_contexts = "contexts";
+const char * const config_element_attributes = "attributes";
+const char * const config_element_exclusion = "exclusion";
+const char * const config_element_exclusions = "exclusions";
+const char * const config_element_function_attributes = "function_attributes";
+const char * const config_element_probe_attributes = "probe_attributes";
+const char * const config_element_symbol_name = "symbol_name";
+const char * const config_element_address = "address";
+const char * const config_element_offset = "offset";
+const char * const config_element_name = "name";
+const char * const config_element_enabled = "enabled";
+const char * const config_element_overwrite_mode = "overwrite_mode";
+const char * const config_element_subbuf_size = "subbuffer_size";
+const char * const config_element_num_subbuf = "subbuffer_count";
+const char * const config_element_switch_timer_interval = "switch_timer_interval";
+const char * const config_element_read_timer_interval = "read_timer_interval";
+const char * const config_element_output = "output";
+const char * const config_element_output_type = "output_type";
+const char * const config_element_tracefile_size = "tracefile_size";
+const char * const config_element_tracefile_count = "tracefile_count";
+const char * const config_element_live_timer_interval = "live_timer_interval";
+const char * const config_element_type = "type";
+const char * const config_element_buffer_type = "buffer_type";
+const char * const config_element_session = "session";
+const char * const config_element_sessions = "sessions";
+const char * const config_element_perf = "perf";
+const char * const config_element_config = "config";
+const char * const config_element_started = "started";
+const char * const config_element_snapshot_mode = "snapshot_mode";
+const char * const config_element_loglevel = "loglevel";
+const char * const config_element_loglevel_type = "loglevel_type";
+const char * const config_element_filter = "filter";
+const char * const config_element_snapshot_outputs = "snapshot_outputs";
+const char * const config_element_consumer_output = "consumer_output";
+const char * const config_element_destination = "destination";
+const char * const config_element_path = "path";
+const char * const config_element_net_output = "net_output";
+const char * const config_element_control_uri = "control_uri";
+const char * const config_element_data_uri = "data_uri";
+const char * const config_element_max_size = "max_size";
+
+const char * const config_domain_type_kernel = "KERNEL";
+const char * const config_domain_type_ust = "UST";
+const char * const config_domain_type_jul = "JUL";
+
+const char * const config_buffer_type_per_pid = "PER_PID";
+const char * const config_buffer_type_per_uid = "PER_UID";
+const char * const config_buffer_type_global = "GLOBAL";
+
+const char * const config_overwrite_mode_discard = "DISCARD";
+const char * const config_overwrite_mode_overwrite = "OVERWRITE";
+
+const char * const config_output_type_splice = "SPLICE";
+const char * const config_output_type_mmap = "MMAP";
+
+const char * const config_loglevel_type_all = "ALL";
+const char * const config_loglevel_type_range = "RANGE";
+const char * const config_loglevel_type_single = "SINGLE";
+
+const char * const config_event_type_all = "ALL";
+const char * const config_event_type_tracepoint = "TRACEPOINT";
+const char * const config_event_type_probe = "PROBE";
+const char * const config_event_type_function = "FUNCTION";
+const char * const config_event_type_function_entry = "FUNCTION_ENTRY";
+const char * const config_event_type_noop = "NOOP";
+const char * const config_event_type_syscall = "SYSCALL";
+const char * const config_event_type_kprobe = "KPROBE";
+const char * const config_event_type_kretprobe = "KRETPROBE";
+
+const char * const config_event_context_pid = "PID";
+const char * const config_event_context_procname = "PROCNAME";
+const char * const config_event_context_prio = "PRIO";
+const char * const config_event_context_nice = "NICE";
+const char * const config_event_context_vpid = "VPID";
+const char * const config_event_context_tid = "TID";
+const char * const config_event_context_vtid = "VTID";
+const char * const config_event_context_ppid = "PPID";
+const char * const config_event_context_vppid = "VPPID";
+const char * const config_event_context_pthread_id = "PTHREAD_ID";
+const char * const config_event_context_hostname = "HOSTNAME";
+const char * const config_event_context_ip = "IP";
+
+struct consumer_output {
+       int enabled;
+       char *path;
+       char *control_uri;
+       char *data_uri;
+};
 
 static int config_entry_handler_filter(struct handler_filter_args *args,
                const char *section, const char *name, const char *value)
@@ -171,3 +290,2208 @@ int config_parse_value(const char *value)
 end:
        return ret;
 }
+
+/*
+ * Returns a xmlChar string which must be released using xmlFree().
+ */
+static xmlChar *encode_string(const char *in_str)
+{
+       xmlChar *out_str = NULL;
+       xmlCharEncodingHandlerPtr handler;
+       int out_len, ret, in_len;
+
+       assert(in_str);
+
+       handler = xmlFindCharEncodingHandler(config_xml_encoding);
+       if (!handler) {
+               ERR("xmlFindCharEncodingHandler return NULL!. Configure issue!");
+               goto end;
+       }
+
+       in_len = strlen(in_str);
+       /*
+        * Add 1 byte for the NULL terminted character. The factor 2 here is
+        * because UTF-8 can be on two bytes so this fits the worst case for each
+        * bytes.
+        */
+       out_len = (in_len * 2) + 1;
+       out_str = xmlMalloc(out_len);
+       if (!out_str) {
+               goto end;
+       }
+
+       ret = handler->input(out_str, &out_len, (const xmlChar *) in_str, &in_len);
+       if (ret < 0) {
+               xmlFree(out_str);
+               out_str = NULL;
+               goto end;
+       }
+
+       /* out_len is now the size of out_str */
+       out_str[out_len] = '\0';
+end:
+       return out_str;
+}
+
+LTTNG_HIDDEN
+struct config_writer *config_writer_create(int fd_output)
+{
+       int ret;
+       struct config_writer *writer;
+       xmlOutputBufferPtr buffer;
+
+       writer = zmalloc(sizeof(struct config_writer));
+       if (!writer) {
+               PERROR("zmalloc config_writer_create");
+               goto end;
+       }
+
+       buffer = xmlOutputBufferCreateFd(fd_output, NULL);
+       if (!buffer) {
+               goto error_destroy;
+       }
+
+       writer->writer = xmlNewTextWriter(buffer);
+       ret = xmlTextWriterStartDocument(writer->writer, NULL,
+               config_xml_encoding, NULL);
+       if (ret < 0) {
+               goto error_destroy;
+       }
+
+       ret = xmlTextWriterSetIndentString(writer->writer,
+               BAD_CAST config_xml_indent_string);
+       if (ret)  {
+               goto error_destroy;
+       }
+
+       ret = xmlTextWriterSetIndent(writer->writer, 1);
+       if (ret)  {
+               goto error_destroy;
+       }
+
+end:
+       return writer;
+error_destroy:
+       config_writer_destroy(writer);
+       return NULL;
+}
+
+LTTNG_HIDDEN
+int config_writer_destroy(struct config_writer *writer)
+{
+       int ret = 0;
+
+       if (!writer) {
+               ret = -EINVAL;
+               goto end;
+       }
+
+       if (xmlTextWriterEndDocument(writer->writer) < 0) {
+               WARN("Could not close XML document");
+               ret = -EIO;
+       }
+
+       if (writer->writer) {
+               xmlFreeTextWriter(writer->writer);
+       }
+
+       free(writer);
+end:
+       return ret;
+}
+
+LTTNG_HIDDEN
+int config_writer_open_element(struct config_writer *writer,
+       const char *element_name)
+{
+       int ret;
+       xmlChar *encoded_element_name;
+
+       if (!writer || !writer->writer || !element_name || !element_name[0]) {
+               ret = -1;
+               goto end;
+       }
+
+       encoded_element_name = encode_string(element_name);
+       if (!encoded_element_name) {
+               ret = -1;
+               goto end;
+       }
+
+       ret = xmlTextWriterStartElement(writer->writer, encoded_element_name);
+       xmlFree(encoded_element_name);
+end:
+       return ret > 0 ? 0 : ret;
+}
+
+LTTNG_HIDDEN
+int config_writer_close_element(struct config_writer *writer)
+{
+       int ret;
+
+       if (!writer || !writer->writer) {
+               ret = -1;
+               goto end;
+       }
+
+       ret = xmlTextWriterEndElement(writer->writer);
+end:
+       return ret > 0 ? 0 : ret;
+}
+
+LTTNG_HIDDEN
+int config_writer_write_element_unsigned_int(struct config_writer *writer,
+               const char *element_name, uint64_t value)
+{
+       int ret;
+       xmlChar *encoded_element_name;
+
+       if (!writer || !writer->writer || !element_name || !element_name[0]) {
+               ret = -1;
+               goto end;
+       }
+
+       encoded_element_name = encode_string(element_name);
+       if (!encoded_element_name) {
+               ret = -1;
+               goto end;
+       }
+
+       ret = xmlTextWriterWriteFormatElement(writer->writer,
+               encoded_element_name, "%" PRIu64, value);
+       xmlFree(encoded_element_name);
+end:
+       return ret > 0 ? 0 : ret;
+}
+
+LTTNG_HIDDEN
+int config_writer_write_element_signed_int(struct config_writer *writer,
+               const char *element_name, int64_t value)
+{
+       int ret;
+       xmlChar *encoded_element_name;
+
+       if (!writer || !writer->writer || !element_name || !element_name[0]) {
+               ret = -1;
+               goto end;
+       }
+
+       encoded_element_name = encode_string(element_name);
+       if (!encoded_element_name) {
+               ret = -1;
+               goto end;
+       }
+
+       ret = xmlTextWriterWriteFormatElement(writer->writer,
+               encoded_element_name, "%" PRIi64, value);
+       xmlFree(encoded_element_name);
+end:
+       return ret > 0 ? 0 : ret;
+}
+
+LTTNG_HIDDEN
+int config_writer_write_element_bool(struct config_writer *writer,
+               const char *element_name, int value)
+{
+       return config_writer_write_element_string(writer, element_name,
+               value ? config_xml_true : config_xml_false);
+}
+
+LTTNG_HIDDEN
+int config_writer_write_element_string(struct config_writer *writer,
+               const char *element_name, const char *value)
+{
+       int ret;
+       xmlChar *encoded_element_name = NULL;
+       xmlChar *encoded_value = NULL;
+
+       if (!writer || !writer->writer || !element_name || !element_name[0] ||
+               !value) {
+               ret = -1;
+               goto end;
+       }
+
+       encoded_element_name = encode_string(element_name);
+       if (!encoded_element_name) {
+               ret = -1;
+               goto end;
+       }
+
+       encoded_value = encode_string(value);
+       if (!encoded_value) {
+               ret = -1;
+               goto end;
+       }
+
+       ret = xmlTextWriterWriteElement(writer->writer, encoded_element_name,
+                       encoded_value);
+end:
+       xmlFree(encoded_element_name);
+       xmlFree(encoded_value);
+       return ret > 0 ? 0 : ret;
+}
+
+static
+void xml_error_handler(void *ctx, const char *format, ...)
+{
+       char *errMsg;
+       va_list args;
+       int ret;
+
+       va_start(args, format);
+       ret = vasprintf(&errMsg, format, args);
+       if (ret == -1) {
+               ERR("String allocation failed in xml error handler");
+               return;
+       }
+       va_end(args);
+
+       fprintf(stderr, "XML Error: %s", errMsg);
+       free(errMsg);
+}
+
+static
+void fini_session_config_validation_ctx(
+       struct session_config_validation_ctx *ctx)
+{
+       if (ctx->parser_ctx) {
+               xmlSchemaFreeParserCtxt(ctx->parser_ctx);
+       }
+
+       if (ctx->schema) {
+               xmlSchemaFree(ctx->schema);
+       }
+
+       if (ctx->schema_validation_ctx) {
+               xmlSchemaFreeValidCtxt(ctx->schema_validation_ctx);
+       }
+
+       memset(ctx, 0, sizeof(struct session_config_validation_ctx));
+}
+
+static
+int init_session_config_validation_ctx(
+       struct session_config_validation_ctx *ctx)
+{
+       int ret;
+
+       ctx->parser_ctx = xmlSchemaNewParserCtxt(DEFAULT_SESSION_CONFIG_XSD_PATH);
+       if (!ctx->parser_ctx) {
+               ERR("XSD parser context creation failed");
+               ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+               goto end;
+       }
+       xmlSchemaSetParserErrors(ctx->parser_ctx, xml_error_handler,
+               xml_error_handler, NULL);
+
+       ctx->schema = xmlSchemaParse(ctx->parser_ctx);
+       if (!ctx->schema) {
+               ERR("XSD parsing failed");
+               ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+               goto end;
+       }
+
+       ctx->schema_validation_ctx = xmlSchemaNewValidCtxt(ctx->schema);
+       if (!ctx->schema_validation_ctx) {
+               ERR("XSD validation context creation failed");
+               ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+               goto end;
+       }
+
+       xmlSchemaSetValidErrors(ctx->schema_validation_ctx, xml_error_handler,
+                       xml_error_handler, NULL);
+       ret = 0;
+
+end:
+       if (ret) {
+               fini_session_config_validation_ctx(ctx);
+       }
+
+       return ret;
+}
+
+static
+int parse_uint(xmlChar *str, uint64_t *val)
+{
+       int ret;
+       char *endptr;
+
+       if (!str || !val) {
+               ret = -1;
+               goto end;
+       }
+
+       *val = strtoull((const char *) str, &endptr, 10);
+       if (!endptr || *endptr) {
+               ret = -1;
+       } else {
+               ret = 0;
+       }
+
+end:
+       return ret;
+}
+
+static
+int parse_int(xmlChar *str, int64_t *val)
+{
+       int ret;
+       char *endptr;
+
+       if (!str || !val) {
+               ret = -1;
+               goto end;
+       }
+
+       *val = strtoll((const char *) str, &endptr, 10);
+       if (!endptr || *endptr) {
+               ret = -1;
+       } else {
+               ret = 0;
+       }
+
+end:
+       return ret;
+}
+
+static
+int parse_bool(xmlChar *str, int *val)
+{
+       int ret = 0;
+
+       if (!str || !val) {
+               ret = -1;
+               goto end;
+       }
+
+       if (!strcmp((const char *) str, config_xml_true)) {
+               *val = 1;
+       } else if (!strcmp((const char *) str, config_xml_false)) {
+               *val = 0;
+       } else {
+               WARN("Invalid boolean value encoutered (%s).",
+                       (const char *) str);
+               ret = -1;
+       }
+end:
+       return ret;
+}
+
+static
+int get_domain_type(xmlChar *domain)
+{
+       int ret;
+
+       if (!domain) {
+               goto error;
+       }
+
+       if (!strcmp((char *) domain, config_domain_type_kernel)) {
+               ret = LTTNG_DOMAIN_KERNEL;
+       } else if (!strcmp((char *) domain, config_domain_type_ust)) {
+               ret = LTTNG_DOMAIN_UST;
+       } else if (!strcmp((char *) domain, config_domain_type_jul)) {
+               ret = LTTNG_DOMAIN_JUL;
+       } else {
+               goto error;
+       }
+
+       return ret;
+error:
+       return -1;
+}
+
+static
+int get_buffer_type(xmlChar *buffer_type)
+{
+       int ret;
+
+       if (!buffer_type) {
+               goto error;
+       }
+
+       if (!strcmp((char *) buffer_type, config_buffer_type_global)) {
+               ret = LTTNG_BUFFER_GLOBAL;
+       } else if (!strcmp((char *) buffer_type, config_buffer_type_per_uid)) {
+               ret = LTTNG_BUFFER_PER_UID;
+       } else if (!strcmp((char *) buffer_type, config_buffer_type_per_pid)) {
+               ret = LTTNG_BUFFER_PER_PID;
+       } else {
+               goto error;
+       }
+
+       return ret;
+error:
+       return -1;
+}
+
+static
+int get_overwrite_mode(xmlChar *overwrite_mode)
+{
+       int ret;
+
+       if (!overwrite_mode) {
+               goto error;
+       }
+
+       if (!strcmp((char *) overwrite_mode, config_overwrite_mode_overwrite)) {
+               ret = 1;
+       } else if (!strcmp((char *) overwrite_mode,
+               config_overwrite_mode_discard)) {
+               ret = 0;
+       } else {
+               goto error;
+       }
+
+       return ret;
+error:
+       return -1;
+}
+
+static
+int get_output_type(xmlChar *output_type)
+{
+       int ret;
+
+       if (!output_type) {
+               goto error;
+       }
+
+       if (!strcmp((char *) output_type, config_output_type_mmap)) {
+               ret = LTTNG_EVENT_MMAP;
+       } else if (!strcmp((char *) output_type, config_output_type_splice)) {
+               ret = LTTNG_EVENT_SPLICE;
+       } else {
+               goto error;
+       }
+
+       return ret;
+error:
+       return -1;
+}
+
+static
+int get_event_type(xmlChar *event_type)
+{
+       int ret;
+
+       if (!event_type) {
+               goto error;
+       }
+
+       if (!strcmp((char *) event_type, config_event_type_all)) {
+               ret = LTTNG_EVENT_ALL;
+       } else if (!strcmp((char *) event_type, config_event_type_tracepoint)) {
+               ret = LTTNG_EVENT_TRACEPOINT;
+       } else if (!strcmp((char *) event_type, config_event_type_probe)) {
+               ret = LTTNG_EVENT_PROBE;
+       } else if (!strcmp((char *) event_type, config_event_type_function)) {
+               ret = LTTNG_EVENT_FUNCTION;
+       } else if (!strcmp((char *) event_type,
+               config_event_type_function_entry)) {
+               ret = LTTNG_EVENT_FUNCTION_ENTRY;
+       } else if (!strcmp((char *) event_type, config_event_type_noop)) {
+               ret = LTTNG_EVENT_NOOP;
+       } else if (!strcmp((char *) event_type, config_event_type_syscall)) {
+               ret = LTTNG_EVENT_SYSCALL;
+       } else {
+               goto error;
+       }
+
+       return ret;
+error:
+       return -1;
+}
+
+static
+int get_loglevel_type(xmlChar *loglevel_type)
+{
+       int ret;
+
+       if (!loglevel_type) {
+               goto error;
+       }
+
+       if (!strcmp((char *) loglevel_type, config_loglevel_type_all)) {
+               ret = LTTNG_EVENT_LOGLEVEL_ALL;
+       } else if (!strcmp((char *) loglevel_type,
+               config_loglevel_type_range)) {
+               ret = LTTNG_EVENT_LOGLEVEL_RANGE;
+       } else if (!strcmp((char *) loglevel_type,
+               config_loglevel_type_single)) {
+               ret = LTTNG_EVENT_LOGLEVEL_SINGLE;
+       } else {
+               goto error;
+       }
+
+       return ret;
+error:
+       return -1;
+}
+
+/*
+ * Return the context type or -1 on error.
+ */
+static
+int get_context_type(xmlChar *context_type)
+{
+       int ret;
+
+       if (!context_type) {
+               goto error;
+       }
+
+       if (!strcmp((char *) context_type, config_event_context_pid)) {
+               ret = LTTNG_EVENT_CONTEXT_PID;
+       } else if (!strcmp((char *) context_type,
+               config_event_context_procname)) {
+               ret = LTTNG_EVENT_CONTEXT_PROCNAME;
+       } else if (!strcmp((char *) context_type,
+               config_event_context_prio)) {
+               ret = LTTNG_EVENT_CONTEXT_PRIO;
+       } else if (!strcmp((char *) context_type,
+               config_event_context_nice)) {
+               ret = LTTNG_EVENT_CONTEXT_NICE;
+       } else if (!strcmp((char *) context_type,
+               config_event_context_vpid)) {
+               ret = LTTNG_EVENT_CONTEXT_VPID;
+       } else if (!strcmp((char *) context_type,
+               config_event_context_tid)) {
+               ret = LTTNG_EVENT_CONTEXT_TID;
+       } else if (!strcmp((char *) context_type,
+               config_event_context_vtid)) {
+               ret = LTTNG_EVENT_CONTEXT_VTID;
+       } else if (!strcmp((char *) context_type,
+               config_event_context_ppid)) {
+               ret = LTTNG_EVENT_CONTEXT_PPID;
+       } else if (!strcmp((char *) context_type,
+               config_event_context_vppid)) {
+               ret = LTTNG_EVENT_CONTEXT_VPPID;
+       } else if (!strcmp((char *) context_type,
+               config_event_context_pthread_id)) {
+               ret = LTTNG_EVENT_CONTEXT_PTHREAD_ID;
+       } else if (!strcmp((char *) context_type,
+               config_event_context_hostname)) {
+               ret = LTTNG_EVENT_CONTEXT_HOSTNAME;
+       } else if (!strcmp((char *) context_type,
+               config_event_context_ip)) {
+               ret = LTTNG_EVENT_CONTEXT_IP;
+       } else {
+               goto error;
+       }
+
+       return ret;
+error:
+       return -1;
+}
+
+static
+int init_domain(xmlNodePtr domain_node, struct lttng_domain *domain)
+{
+       int ret;
+       xmlNodePtr node;
+
+       for (node = xmlFirstElementChild(domain_node); node;
+               node = xmlNextElementSibling(node)) {
+               if (!strcmp((const char *) node->name, config_element_type)) {
+                       /* domain type */
+                       xmlChar *node_content = xmlNodeGetContent(node);
+                       if (!node_content) {
+                               ret = -LTTNG_ERR_NOMEM;
+                               goto end;
+                       }
+
+                       ret = get_domain_type(node_content);
+                       free(node_content);
+                       if (ret < 0) {
+                               ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                               goto end;
+                       }
+
+                       domain->type = ret;
+               } else if (!strcmp((const char *) node->name,
+                       config_element_buffer_type)) {
+                       /* buffer type */
+                       xmlChar *node_content = xmlNodeGetContent(node);
+                       if (!node_content) {
+                               ret = -LTTNG_ERR_NOMEM;
+                               goto end;
+                       }
+
+                       ret = get_buffer_type(node_content);
+                       free(node_content);
+                       if (ret < 0) {
+                               ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                               goto end;
+                       }
+
+                       domain->buf_type = ret;
+               }
+       }
+       ret = 0;
+end:
+       return ret;
+}
+
+static
+int get_net_output_uris(xmlNodePtr net_output_node, char **control_uri,
+       char **data_uri)
+{
+       xmlNodePtr node;
+
+       for (node = xmlFirstElementChild(net_output_node); node;
+               node = xmlNextElementSibling(node)) {
+               if (!strcmp((const char *) node->name, config_element_control_uri)) {
+                       /* control_uri */
+                       *control_uri = (char *) xmlNodeGetContent(node);
+                       if (!*control_uri) {
+                               break;
+                       }
+               } else {
+                       /* data_uri */
+                       *data_uri = (char *) xmlNodeGetContent(node);
+                       if (!*data_uri) {
+                               break;
+                       }
+               }
+       }
+
+       return *control_uri || *data_uri ? 0 : -LTTNG_ERR_LOAD_INVALID_CONFIG;
+}
+
+static
+int process_consumer_output(xmlNodePtr consumer_output_node,
+       struct consumer_output *output)
+{
+       int ret;
+       xmlNodePtr node;
+
+       assert(output);
+
+       for (node = xmlFirstElementChild(consumer_output_node); node;
+                       node = xmlNextElementSibling(node)) {
+               if (!strcmp((const char *) node->name, config_element_enabled)) {
+                       xmlChar *enabled_str = xmlNodeGetContent(node);
+
+                       /* enabled */
+                       if (!enabled_str) {
+                               ret = -LTTNG_ERR_NOMEM;
+                               goto end;
+                       }
+
+                       ret = parse_bool(enabled_str, &output->enabled);
+                       free(enabled_str);
+                       if (ret) {
+                               goto end;
+                       }
+               } else {
+                       xmlNodePtr output_type_node;
+
+                       /* destination */
+                       output_type_node = xmlFirstElementChild(node);
+                       if (!output_type_node) {
+                               ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                               goto end;
+                       }
+
+                       if (!strcmp((const char *) output_type_node->name,
+                                       config_element_path)) {
+                               /* path */
+                               output->path = (char *) xmlNodeGetContent(output_type_node);
+                               if (!output->path) {
+                                       ret = -LTTNG_ERR_NOMEM;
+                                       goto end;
+                               }
+                       } else {
+                               /* net_output */
+                               ret = get_net_output_uris(output_type_node,
+                                               &output->control_uri, &output->data_uri);
+                               if (ret) {
+                                       goto end;
+                               }
+                       }
+               }
+       }
+       ret = 0;
+
+end:
+       if (ret) {
+               free(output->path);
+               free(output->control_uri);
+               free(output->data_uri);
+               memset(output, 0, sizeof(struct consumer_output));
+       }
+       return ret;
+}
+
+static
+int create_session_net_output(const char *name, struct lttng_domain *domain,
+       const char *control_uri, const char *data_uri)
+{
+       int ret;
+       struct lttng_handle *handle;
+       const char *uri = NULL;
+
+       assert(name);
+       assert(domain);
+
+       handle = lttng_create_handle(name, domain);
+       if (!handle) {
+               ret = -LTTNG_ERR_NOMEM;
+               goto end;
+       }
+
+       if (!control_uri || !data_uri) {
+               uri = control_uri ? control_uri : data_uri;
+               control_uri = uri;
+               data_uri = uri;
+       }
+
+       ret = lttng_set_consumer_url(handle, control_uri, data_uri);
+       lttng_destroy_handle(handle);
+end:
+       return ret;
+}
+
+static
+int create_snapshot_session(const char *session_name, xmlNodePtr output_node)
+{
+       int ret;
+       xmlNodePtr node = NULL;
+       xmlNodePtr snapshot_output_list_node;
+       xmlNodePtr snapshot_output_node;
+
+       assert(session_name);
+
+       ret = lttng_create_session_snapshot(session_name, NULL);
+       if (ret) {
+               goto end;
+       }
+
+       if (!output_node) {
+               goto end;
+       }
+
+       snapshot_output_list_node = xmlFirstElementChild(output_node);
+
+       /* Parse and create snapshot outputs */
+
+       for (snapshot_output_node =
+                       xmlFirstElementChild(snapshot_output_list_node);
+                       snapshot_output_node; snapshot_output_node =
+                       xmlNextElementSibling(snapshot_output_node)) {
+               char *name = NULL;
+               uint64_t max_size = UINT64_MAX;
+               struct consumer_output output = { 0 };
+               struct lttng_snapshot_output *snapshot_output = NULL;
+
+               for (node = xmlFirstElementChild(snapshot_output_node); node;
+                               node = xmlNextElementSibling(node)) {
+                       if (!strcmp((const char *) node->name,
+                               config_element_name)) {
+                               /* name */
+                               name = (char *) xmlNodeGetContent(node);
+                               if (!name) {
+                                       ret = -LTTNG_ERR_NOMEM;
+                                       goto error_snapshot_output;
+                               }
+                       } else if (!strcmp((const char *) node->name,
+                               config_element_max_size)) {
+                               xmlChar *content = xmlNodeGetContent(node);
+
+                               /* max_size */
+                               if (!content) {
+                                       ret = -LTTNG_ERR_NOMEM;
+                                       goto error_snapshot_output;
+                               }
+                               ret = parse_uint(content, &max_size);
+                               free(content);
+                               if (ret) {
+                                       ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                                       goto error_snapshot_output;
+                               }
+                       } else {
+                               /* consumer_output */
+                               ret = process_consumer_output(node, &output);
+                               if (ret) {
+                                       goto error_snapshot_output;
+                               }
+                       }
+               }
+
+               snapshot_output = lttng_snapshot_output_create();
+               if (!snapshot_output) {
+                       ret = -LTTNG_ERR_NOMEM;
+                       goto error_snapshot_output;
+               }
+
+               ret = lttng_snapshot_output_set_name(name, snapshot_output);
+               if (ret) {
+                       goto error_snapshot_output;
+               }
+
+               ret = lttng_snapshot_output_set_size(max_size, snapshot_output);
+               if (ret) {
+                       goto error_snapshot_output;
+               }
+
+               if (output.path) {
+                       ret = lttng_snapshot_output_set_ctrl_url(output.path,
+                                       snapshot_output);
+                       if (ret) {
+                               goto error_snapshot_output;
+                       }
+               } else {
+                       if (output.control_uri) {
+                               ret = lttng_snapshot_output_set_ctrl_url(output.control_uri,
+                                               snapshot_output);
+                               if (ret) {
+                                       goto error_snapshot_output;
+                               }
+                       }
+
+                       if (output.data_uri) {
+                               ret = lttng_snapshot_output_set_data_url(output.data_uri,
+                                               snapshot_output);
+                               if (ret) {
+                                       goto error_snapshot_output;
+                               }
+                       }
+               }
+
+               ret = lttng_snapshot_add_output(session_name, snapshot_output);
+error_snapshot_output:
+               free(name);
+               free(output.path);
+               free(output.control_uri);
+               free(output.data_uri);
+               lttng_snapshot_output_destroy(snapshot_output);
+               if (ret) {
+                       goto end;
+               }
+       }
+end:
+       return ret;
+}
+
+static
+int create_session(const char *name,
+       struct lttng_domain *kernel_domain,
+       struct lttng_domain *ust_domain,
+       struct lttng_domain *jul_domain,
+       xmlNodePtr output_node,
+       uint64_t live_timer_interval)
+{
+       int ret;
+       struct consumer_output output = { 0 };
+       xmlNodePtr consumer_output_node;
+
+       assert(name);
+       assert(kernel_domain);
+       assert(ust_domain);
+       assert(jul_domain);
+
+       if (output_node) {
+               consumer_output_node = xmlFirstElementChild(output_node);
+               if (!consumer_output_node) {
+                       ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                       goto end;
+               }
+
+               if (strcmp((const char *) consumer_output_node->name,
+                       config_element_consumer_output)) {
+                       WARN("Invalid output type, expected %s node",
+                               config_element_consumer_output);
+                       ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                       goto end;
+               }
+
+               ret = process_consumer_output(consumer_output_node, &output);
+               if (ret) {
+                       goto end;
+               }
+       }
+
+       if (live_timer_interval != UINT64_MAX &&
+               !output.control_uri && !output.data_uri) {
+               ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+               goto end;
+       }
+
+       if (output.control_uri || output.data_uri) {
+               int i;
+               struct lttng_domain *domain;
+               struct lttng_domain *domains[] =
+                       { kernel_domain, ust_domain, jul_domain };
+
+               /* network destination */
+               if (live_timer_interval && live_timer_interval != UINT64_MAX) {
+                       const char *url = output.control_uri ?
+                               output.control_uri : output.data_uri;
+
+                       /* URL has to be provided, even if we'll overwrite it after. */
+                       ret = lttng_create_session_live(name, url, live_timer_interval);
+               } else {
+                       ret = lttng_create_session(name, NULL);
+               }
+               if (ret) {
+                       goto end;
+               }
+
+               for (i = 0; i < (sizeof(domains) / sizeof(*domain)); i++) {
+                       domain = domains[i];
+                       if (!domain) {
+                               continue;
+                       }
+
+                       ret = create_session_net_output(name, domain, output.control_uri,
+                                       output.data_uri);
+                       if (ret) {
+                               goto end;
+                       }
+               }
+       } else {
+               /* either local output or no output */
+               ret = lttng_create_session(name, output.path);
+               if (ret) {
+                       goto end;
+               }
+       }
+end:
+       free(output.path);
+       free(output.control_uri);
+       free(output.data_uri);
+       return ret;
+}
+static
+int process_probe_attribute_node(xmlNodePtr probe_attribute_node,
+       struct lttng_event_probe_attr *attr)
+{
+       int ret;
+
+       assert(probe_attribute_node);
+       assert(attr);
+
+       if (!strcmp((const char *) probe_attribute_node->name,
+               config_element_address)) {
+               xmlChar *content;
+               uint64_t addr = 0;
+
+               /* addr */
+               content = xmlNodeGetContent(probe_attribute_node);
+               if (!content) {
+                       ret = -LTTNG_ERR_NOMEM;
+                       goto end;
+               }
+
+               ret = parse_uint(content, &addr);
+               free(content);
+               if (ret) {
+                       ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                       goto end;
+               }
+
+               attr->addr = addr;
+       } else if (!strcmp((const char *) probe_attribute_node->name,
+               config_element_offset)) {
+               xmlChar *content;
+               uint64_t offset = 0;
+
+               /* offset */
+               content = xmlNodeGetContent(probe_attribute_node);
+               if (!content) {
+                       ret = -LTTNG_ERR_NOMEM;
+                       goto end;
+               }
+
+               ret = parse_uint(content, &offset);
+               free(content);
+               if (ret) {
+                       ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                       goto end;
+               }
+
+               attr->offset = offset;
+       } else if (!strcmp((const char *) probe_attribute_node->name,
+               config_element_symbol_name)) {
+               xmlChar *content;
+               size_t name_len;
+
+               /* symbol_name */
+               content = xmlNodeGetContent(probe_attribute_node);
+               if (!content) {
+                       ret = -LTTNG_ERR_NOMEM;
+                       goto end;
+               }
+
+               name_len = strlen((char *) content);
+               if (name_len >= LTTNG_SYMBOL_NAME_LEN) {
+                       WARN("symbol_name too long.");
+                       ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                       free(content);
+                       goto end;
+               }
+
+               strncpy(attr->symbol_name, (const char *) content, name_len);
+               free(content);
+       }
+       ret = 0;
+end:
+       return ret;
+}
+
+static
+int process_event_node(xmlNodePtr event_node, struct lttng_handle *handle,
+       const char *channel_name)
+{
+       int ret, i;
+       xmlNodePtr node;
+       struct lttng_event event;
+       char **exclusions = NULL;
+       unsigned long exclusion_count = 0;
+       char *filter_expression = NULL;
+
+       assert(event_node);
+       assert(handle);
+       assert(channel_name);
+
+       memset(&event, 0, sizeof(event));
+
+       for (node = xmlFirstElementChild(event_node); node;
+               node = xmlNextElementSibling(node)) {
+               if (!strcmp((const char *) node->name, config_element_name)) {
+                       xmlChar *content;
+                       size_t name_len;
+
+                       /* name */
+                       content = xmlNodeGetContent(node);
+                       if (!content) {
+                               ret = -LTTNG_ERR_NOMEM;
+                               goto end;
+                       }
+
+                       name_len = strlen((char *) content);
+                       if (name_len >= LTTNG_SYMBOL_NAME_LEN) {
+                               WARN("Channel name too long.");
+                               ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                               free(content);
+                               goto end;
+                       }
+
+                       strncpy(event.name, (const char *) content, name_len);
+                       free(content);
+               } else if (!strcmp((const char *) node->name,
+                       config_element_enabled)) {
+                       xmlChar *content = xmlNodeGetContent(node);
+
+                       /* enabled */
+                       if (!content) {
+                               ret = -LTTNG_ERR_NOMEM;
+                               goto end;
+                       }
+
+                       ret = parse_bool(content, &event.enabled);
+                       free(content);
+                       if (ret) {
+                               ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                               goto end;
+                       }
+               } else if (!strcmp((const char *) node->name,
+                       config_element_type)) {
+                       xmlChar *content = xmlNodeGetContent(node);
+
+                       /* type */
+                       if (!content) {
+                               ret = -LTTNG_ERR_NOMEM;
+                               goto end;
+                       }
+
+                       ret = get_event_type(content);
+                       free(content);
+                       if (ret < 0) {
+                               ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                               goto end;
+                       }
+
+                       event.type = ret;
+               } else if (!strcmp((const char *) node->name,
+                       config_element_loglevel_type)) {
+                       xmlChar *content = xmlNodeGetContent(node);
+
+                       /* loglevel_type */
+                       if (!content) {
+                               ret = -LTTNG_ERR_NOMEM;
+                               goto end;
+                       }
+
+                       ret = get_loglevel_type(content);
+                       free(content);
+                       if (ret < 0) {
+                               ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                               goto end;
+                       }
+
+                       event.loglevel_type = ret;
+               } else if (!strcmp((const char *) node->name,
+                       config_element_loglevel)) {
+                       xmlChar *content;
+                       int64_t loglevel = 0;
+
+                       /* loglevel */
+                       content = xmlNodeGetContent(node);
+                       if (!content) {
+                               ret = -LTTNG_ERR_NOMEM;
+                               goto end;
+                       }
+
+                       ret = parse_int(content, &loglevel);
+                       free(content);
+                       if (ret) {
+                               ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                               goto end;
+                       }
+
+                       if (loglevel > INT_MAX || loglevel < INT_MIN) {
+                               WARN("loglevel out of range.");
+                               ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                               goto end;
+                       }
+
+                       event.loglevel = loglevel;
+               } else if (!strcmp((const char *) node->name,
+                       config_element_filter)) {
+                       xmlChar *content =
+                               xmlNodeGetContent(node);
+
+                       /* filter */
+                       if (!content) {
+                               ret = -LTTNG_ERR_NOMEM;
+                               goto end;
+                       }
+
+                       filter_expression = strdup((char *) content);
+                       free(content);
+                       if (!filter_expression) {
+                               ret = -LTTNG_ERR_NOMEM;
+                               goto end;
+                       }
+               } else if (!strcmp((const char *) node->name,
+                       config_element_exclusions)) {
+                       xmlNodePtr exclusion_node;
+                       int exclusion_index = 0;
+
+                       /* exclusions */
+                       if (exclusions) {
+                               /*
+                                * Exclusions has already been initialized,
+                                * invalid file.
+                                */
+                               ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                               goto end;
+                       }
+
+                       exclusion_count = xmlChildElementCount(node);
+                       if (!exclusion_count) {
+                               continue;
+                       }
+
+                       exclusions = zmalloc(exclusion_count * sizeof(char *));
+                       if (!exclusions) {
+                               exclusion_count = 0;
+                               ret = -LTTNG_ERR_NOMEM;
+                               goto end;
+                       }
+
+                       for (exclusion_node = xmlFirstElementChild(node); exclusion_node;
+                                       exclusion_node = xmlNextElementSibling(exclusion_node)) {
+                               xmlChar *content =
+                                       xmlNodeGetContent(exclusion_node);
+
+                               if (!content) {
+                                       ret = -LTTNG_ERR_NOMEM;
+                                       goto end;
+                               }
+
+                               exclusions[exclusion_index] = strdup((const char *) content);
+                               free(content);
+                               if (!exclusions[exclusion_index]) {
+                                       ret = -LTTNG_ERR_NOMEM;
+                                       goto end;
+                               }
+                               exclusion_index++;
+                       }
+
+                       event.exclusion = 1;
+               } else if (!strcmp((const char *) node->name,
+                       config_element_attributes)) {
+                       xmlNodePtr attribute_node = xmlFirstElementChild(node);
+
+                       /* attributes */
+                       if (!attribute_node) {
+                               ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                               goto end;
+                       }
+
+                       if (!strcmp((const char *) node->name,
+                                               config_element_probe_attributes)) {
+                               xmlNodePtr probe_attribute_node;
+
+                               /* probe_attributes */
+                               for (probe_attribute_node =
+                                       xmlFirstElementChild(attribute_node); probe_attribute_node;
+                                       probe_attribute_node = xmlNextElementSibling(
+                                                       probe_attribute_node)) {
+
+                                       ret = process_probe_attribute_node(probe_attribute_node,
+                                                       &event.attr.probe);
+                                       if (ret) {
+                                               goto end;
+                                       }
+                               }
+                       } else {
+                               size_t sym_len;
+                               xmlChar *content;
+                               xmlNodePtr symbol_node = xmlFirstElementChild(attribute_node);
+
+                               /* function_attributes */
+                               content = xmlNodeGetContent(symbol_node);
+                               if (!content) {
+                                       ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                                       goto end;
+                               }
+
+                               sym_len = strlen((char *) content);
+                               if (sym_len >= LTTNG_SYMBOL_NAME_LEN) {
+                                       WARN("Function name too long.");
+                                       ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                                       free(content);
+                                       goto end;
+                               }
+
+                               strncpy(event.attr.ftrace.symbol_name, (char *) content,
+                                               sym_len);
+                               free(content);
+                       }
+               }
+       }
+
+       ret = lttng_enable_event_with_exclusions(handle, &event, channel_name,
+                       filter_expression, exclusion_count, exclusions);
+end:
+       for (i = 0; i < exclusion_count; i++) {
+               free(exclusions[i]);
+       }
+
+       free(exclusions);
+       free(filter_expression);
+       return ret;
+}
+
+static
+int process_events_node(xmlNodePtr events_node, struct lttng_handle *handle,
+       const char *channel_name)
+{
+       int ret = 0;
+       xmlNodePtr node;
+
+       assert(events_node);
+       assert(handle);
+       assert(channel_name);
+
+       for (node = xmlFirstElementChild(events_node); node;
+               node = xmlNextElementSibling(node)) {
+               ret = process_event_node(node, handle, channel_name);
+               if (ret) {
+                       goto end;
+               }
+       }
+end:
+       return ret;
+}
+
+static
+int process_channel_attr_node(xmlNodePtr attr_node,
+               struct lttng_channel *channel, xmlNodePtr *contexts_node,
+               xmlNodePtr *events_node)
+{
+       int ret;
+
+       assert(attr_node);
+       assert(channel);
+       assert(contexts_node);
+       assert(events_node);
+
+       if (!strcmp((const char *) attr_node->name, config_element_name)) {
+               xmlChar *content;
+               size_t name_len;
+
+               /* name */
+               content = xmlNodeGetContent(attr_node);
+               if (!content) {
+                       ret = -LTTNG_ERR_NOMEM;
+                       goto end;
+               }
+
+               name_len = strlen((char *) content);
+               if (name_len >= LTTNG_SYMBOL_NAME_LEN) {
+                       WARN("Channel name too long.");
+                       ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                       free(content);
+                       goto end;
+               }
+
+               strncpy(channel->name, (const char *) content, name_len);
+               free(content);
+       } else if (!strcmp((const char *) attr_node->name,
+                       config_element_enabled)) {
+               xmlChar *content;
+               int enabled;
+
+               /* enabled */
+               content = xmlNodeGetContent(attr_node);
+               if (!content) {
+                       ret = -LTTNG_ERR_NOMEM;
+                       goto end;
+               }
+
+               ret = parse_bool(content, &enabled);
+               free(content);
+               if (ret) {
+                       ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                       goto end;
+               }
+
+               channel->enabled = enabled;
+       } else if (!strcmp((const char *) attr_node->name,
+                       config_element_overwrite_mode)) {
+               xmlChar *content;
+
+               /* overwrite_mode */
+               content = xmlNodeGetContent(attr_node);
+               if (!content) {
+                       ret = -LTTNG_ERR_NOMEM;
+                       goto end;
+               }
+
+               ret = get_overwrite_mode(content);
+               free(content);
+               if (ret < 0) {
+                       ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                       goto end;
+               }
+
+               channel->attr.overwrite = ret;
+       } else if (!strcmp((const char *) attr_node->name,
+                       config_element_subbuf_size)) {
+               xmlChar *content;
+
+               /* subbuffer_size */
+               content = xmlNodeGetContent(attr_node);
+               if (!content) {
+                       ret = -LTTNG_ERR_NOMEM;
+                       goto end;
+               }
+
+               ret = parse_uint(content, &channel->attr.subbuf_size);
+               free(content);
+               if (ret) {
+                       ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                       goto end;
+               }
+       } else if (!strcmp((const char *) attr_node->name,
+                       config_element_num_subbuf)) {
+               xmlChar *content;
+
+               /* subbuffer_count */
+               content = xmlNodeGetContent(attr_node);
+               if (!content) {
+                       ret = -LTTNG_ERR_NOMEM;
+                       goto end;
+               }
+
+               ret = parse_uint(content, &channel->attr.num_subbuf);
+               free(content);
+               if (ret) {
+                       ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                       goto end;
+               }
+       } else if (!strcmp((const char *) attr_node->name,
+                       config_element_switch_timer_interval)) {
+               xmlChar *content;
+               uint64_t switch_timer_interval = 0;
+
+               /* switch_timer_interval */
+               content = xmlNodeGetContent(attr_node);
+               if (!content) {
+                       ret = -LTTNG_ERR_NOMEM;
+                       goto end;
+               }
+
+               ret = parse_uint(content, &switch_timer_interval);
+               free(content);
+               if (ret) {
+                       ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                       goto end;
+               }
+
+               if (switch_timer_interval > UINT_MAX) {
+                       WARN("switch_timer_interval out of range.");
+                       ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                       goto end;
+               }
+
+               channel->attr.switch_timer_interval =
+                       switch_timer_interval;
+       } else if (!strcmp((const char *) attr_node->name,
+                       config_element_read_timer_interval)) {
+               xmlChar *content;
+               uint64_t read_timer_interval = 0;
+
+               /* read_timer_interval */
+               content = xmlNodeGetContent(attr_node);
+               if (!content) {
+                       ret = -LTTNG_ERR_NOMEM;
+                       goto end;
+               }
+
+               ret = parse_uint(content, &read_timer_interval);
+               free(content);
+               if (ret) {
+                       ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                       goto end;
+               }
+
+               if (read_timer_interval > UINT_MAX) {
+                       WARN("read_timer_interval out of range.");
+                       ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                       goto end;
+               }
+
+               channel->attr.read_timer_interval =
+                       read_timer_interval;
+       } else if (!strcmp((const char *) attr_node->name,
+                       config_element_output_type)) {
+               xmlChar *content;
+
+               /* output_type */
+               content = xmlNodeGetContent(attr_node);
+               if (!content) {
+                       ret = -LTTNG_ERR_NOMEM;
+                       goto end;
+               }
+
+               ret = get_output_type(content);
+               free(content);
+               if (ret < 0) {
+                       ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                       goto end;
+               }
+
+               channel->attr.output = ret;
+       } else if (!strcmp((const char *) attr_node->name,
+                       config_element_tracefile_size)) {
+               xmlChar *content;
+
+               /* tracefile_size */
+               content = xmlNodeGetContent(attr_node);
+               if (!content) {
+                       ret = -LTTNG_ERR_NOMEM;
+                       goto end;
+               }
+
+               ret = parse_uint(content, &channel->attr.tracefile_size);
+               free(content);
+               if (ret) {
+                       ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                       goto end;
+               }
+       } else if (!strcmp((const char *) attr_node->name,
+                       config_element_tracefile_count)) {
+               xmlChar *content;
+
+               /* tracefile_count */
+               content = xmlNodeGetContent(attr_node);
+               if (!content) {
+                       ret = -LTTNG_ERR_NOMEM;
+                       goto end;
+               }
+
+               ret = parse_uint(content, &channel->attr.tracefile_count);
+               free(content);
+               if (ret) {
+                       ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                       goto end;
+               }
+       } else if (!strcmp((const char *) attr_node->name,
+                       config_element_live_timer_interval)) {
+               xmlChar *content;
+               uint64_t live_timer_interval = 0;
+
+               /* live_timer_interval */
+               content = xmlNodeGetContent(attr_node);
+               if (!content) {
+                       ret = -LTTNG_ERR_NOMEM;
+                       goto end;
+               }
+
+               ret = parse_uint(content, &live_timer_interval);
+               free(content);
+               if (ret) {
+                       ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                       goto end;
+               }
+
+               if (live_timer_interval > UINT_MAX) {
+                       WARN("live_timer_interval out of range.");
+                       ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                       goto end;
+               }
+
+               channel->attr.live_timer_interval =
+                       live_timer_interval;
+       } else if (!strcmp((const char *) attr_node->name,
+                       config_element_events)) {
+               /* events */
+               *events_node = attr_node;
+       } else {
+               /* contexts */
+               *contexts_node = attr_node;
+       }
+       ret = 0;
+end:
+       return ret;
+}
+
+static
+int process_context_node(xmlNodePtr context_node,
+       struct lttng_handle *handle, const char *channel_name)
+{
+       int ret;
+       struct lttng_event_context context;
+       xmlNodePtr context_child_node = xmlFirstElementChild(context_node);
+
+       assert(handle);
+       assert(channel_name);
+
+       if (!context_child_node) {
+               ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+               goto end;
+       }
+
+       memset(&context, 0, sizeof(context));
+
+       if (!strcmp((const char *) context_child_node->name,
+               config_element_type)) {
+               /* type */
+               xmlChar *content = xmlNodeGetContent(context_child_node);
+               if (!content) {
+                       ret = -LTTNG_ERR_NOMEM;
+                       goto end;
+               }
+
+               ret = get_context_type(content);
+               free(content);
+               if (ret < 0) {
+                       ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                       goto end;
+               }
+
+               context.ctx = ret;
+       } else {
+               xmlNodePtr perf_attr_node;
+
+               /* perf */
+               context.ctx = LTTNG_EVENT_CONTEXT_PERF_COUNTER;
+               for (perf_attr_node = xmlFirstElementChild(context_child_node);
+                       perf_attr_node; perf_attr_node =
+                               xmlNextElementSibling(perf_attr_node)) {
+                       if (!strcmp((const char *) perf_attr_node->name,
+                               config_element_type)) {
+                               xmlChar *content;
+                               uint64_t type = 0;
+
+                               /* type */
+                               content = xmlNodeGetContent(perf_attr_node);
+                               if (!content) {
+                                       ret = -LTTNG_ERR_NOMEM;
+                                       goto end;
+                               }
+
+                               ret = parse_uint(content, &type);
+                               free(content);
+                               if (ret) {
+                                       ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                                       goto end;
+                               }
+
+                               if (type > UINT32_MAX) {
+                                       WARN("perf context type out of range.");
+                                       ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                                       goto end;
+                               }
+
+                               context.u.perf_counter.type = type;
+                       } else if (!strcmp((const char *) perf_attr_node->name,
+                               config_element_config)) {
+                               xmlChar *content;
+                               uint64_t config = 0;
+
+                               /* config */
+                               content = xmlNodeGetContent(perf_attr_node);
+                               if (!content) {
+                                       ret = -LTTNG_ERR_NOMEM;
+                                       goto end;
+                               }
+
+                               ret = parse_uint(content, &config);
+                               free(content);
+                               if (ret) {
+                                       ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                                       goto end;
+                               }
+
+                               context.u.perf_counter.config = config;
+                       } else if (!strcmp((const char *) perf_attr_node->name,
+                               config_element_name)) {
+                               xmlChar *content;
+                               size_t name_len;
+
+                               /* name */
+                               content = xmlNodeGetContent(perf_attr_node);
+                               if (!content) {
+                                       ret = -LTTNG_ERR_NOMEM;
+                                       goto end;
+                               }
+
+                               name_len = strlen((char *) content);
+                               if (name_len >= LTTNG_SYMBOL_NAME_LEN) {
+                                       WARN("perf context name too long.");
+                                       ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                                       free(content);
+                                       goto end;
+                               }
+
+                               strncpy(context.u.perf_counter.name, (const char *) content,
+                                               name_len);
+                               free(content);
+                       }
+               }
+       }
+
+       ret = lttng_add_context(handle, &context, NULL, channel_name);
+end:
+       return ret;
+}
+
+static
+int process_contexts_node(xmlNodePtr contexts_node,
+       struct lttng_handle *handle, const char *channel_name)
+{
+       int ret = 0;
+       xmlNodePtr context_node;
+
+       for (context_node = xmlFirstElementChild(contexts_node); context_node;
+                       context_node = xmlNextElementSibling(context_node)) {
+               ret = process_context_node(context_node, handle, channel_name);
+               if (ret) {
+                       goto end;
+               }
+       }
+end:
+       return ret;
+}
+
+static
+int process_domain_node(xmlNodePtr domain_node, const char *session_name)
+{
+       int ret;
+       struct lttng_domain domain = { 0 };
+       struct lttng_handle *handle = NULL;
+       xmlNodePtr channels_node = NULL;
+       xmlNodePtr node;
+
+       assert(session_name);
+
+       ret = init_domain(domain_node, &domain);
+       if (ret) {
+               goto end;
+       }
+
+       handle = lttng_create_handle(session_name, &domain);
+       if (!handle) {
+               ret = -LTTNG_ERR_NOMEM;
+               goto end;
+       }
+
+       /* get the channels node */
+       for (node = xmlFirstElementChild(domain_node); node;
+               node = xmlNextElementSibling(node)) {
+               if (!strcmp((const char *) node->name,
+                       config_element_channels)) {
+                       channels_node = node;
+                       break;
+               }
+       }
+
+       if (!channels_node) {
+               goto end;
+       }
+
+       /* create all channels */
+       for (node = xmlFirstElementChild(channels_node); node;
+               node = xmlNextElementSibling(node)) {
+               struct lttng_channel channel;
+               xmlNodePtr contexts_node = NULL;
+               xmlNodePtr events_node = NULL;
+               xmlNodePtr channel_attr_node;
+
+               memset(&channel, 0, sizeof(channel));
+               lttng_channel_set_default_attr(&domain, &channel.attr);
+
+               for (channel_attr_node = xmlFirstElementChild(node);
+                       channel_attr_node; channel_attr_node =
+                       xmlNextElementSibling(channel_attr_node)) {
+                       ret = process_channel_attr_node(channel_attr_node,
+                               &channel, &contexts_node, &events_node);
+                       if (ret) {
+                               goto end;
+                       }
+               }
+
+               ret = lttng_enable_channel(handle, &channel);
+               if (ret < 0) {
+                       goto end;
+               }
+
+               ret = process_events_node(events_node, handle, channel.name);
+               if (ret) {
+                       goto end;
+               }
+
+               ret = process_contexts_node(contexts_node, handle,
+                       channel.name);
+               if (ret) {
+                       goto end;
+               }
+       }
+end:
+       lttng_destroy_handle(handle);
+       return ret;
+}
+
+static
+int process_session_node(xmlNodePtr session_node, const char *session_name,
+               int override)
+{
+       int ret, started = -1, snapshot_mode = -1;
+       uint64_t live_timer_interval = UINT64_MAX;
+       char *name = NULL;
+       xmlNodePtr domains_node = NULL;
+       xmlNodePtr output_node = NULL;
+       xmlNodePtr node;
+       struct lttng_domain *kernel_domain = NULL;
+       struct lttng_domain *ust_domain = NULL;
+       struct lttng_domain *jul_domain = NULL;
+
+       for (node = xmlFirstElementChild(session_node); node;
+               node = xmlNextElementSibling(node)) {
+               if (!name && !strcmp((const char *) node->name,
+                       config_element_name)) {
+                       /* name */
+                       xmlChar *node_content = xmlNodeGetContent(node);
+                       if (!node_content) {
+                               ret = -LTTNG_ERR_NOMEM;
+                               goto end;
+                       }
+
+                       name = (char *) node_content;
+               } else if (!domains_node && !strcmp((const char *) node->name,
+                       config_element_domains)) {
+                       /* domains */
+                       domains_node = node;
+               } else if (started == -1 && !strcmp((const char *) node->name,
+                       config_element_started)) {
+                       /* started */
+                       xmlChar *node_content = xmlNodeGetContent(node);
+                       if (!node_content) {
+                               ret = -LTTNG_ERR_NOMEM;
+                               goto end;
+                       }
+
+                       ret = parse_bool(node_content, &started);
+                       free(node_content);
+                       if (ret) {
+                               ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                               goto end;
+                       }
+               } else if (!output_node && !strcmp((const char *) node->name,
+                       config_element_output)) {
+                       /* output */
+                       output_node = node;
+               } else {
+                       /* attributes, snapshot_mode or live_timer_interval */
+                       xmlNodePtr attributes_child =
+                               xmlFirstElementChild(node);
+
+                       if (!strcmp((const char *) attributes_child->name,
+                               config_element_snapshot_mode)) {
+                               /* snapshot_mode */
+                               xmlChar *snapshot_mode_content =
+                                       xmlNodeGetContent(attributes_child);
+                               if (!snapshot_mode_content) {
+                                       ret = -LTTNG_ERR_NOMEM;
+                                       goto end;
+                               }
+
+                               ret = parse_bool(snapshot_mode_content, &snapshot_mode);
+                               free(snapshot_mode_content);
+                               if (ret) {
+                                       ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                                       goto end;
+                               }
+                       } else {
+                               /* live_timer_interval */
+                               xmlChar *timer_interval_content =
+                                       xmlNodeGetContent(attributes_child);
+                               if (!timer_interval_content) {
+                                       ret = -LTTNG_ERR_NOMEM;
+                                       goto end;
+                               }
+
+                               ret = parse_uint(timer_interval_content, &live_timer_interval);
+                               free(timer_interval_content);
+                               if (ret) {
+                                       ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+                                       goto end;
+                               }
+                       }
+               }
+       }
+
+       if (!name) {
+               /* Mandatory attribute, as defined in the session XSD */
+               ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+               goto end;
+       }
+
+       if (session_name && strcmp(name, session_name)) {
+               /* This is not the session we are looking for */
+               ret = -LTTNG_ERR_LOAD_SESSION_NOT_FOUND;
+               goto end;
+       }
+
+       /* Init domains to create the session handles */
+       for (node = xmlFirstElementChild(domains_node); node;
+               node = xmlNextElementSibling(node)) {
+               struct lttng_domain *domain;
+
+               domain = zmalloc(sizeof(*domain));
+               if (!domain) {
+                       ret = -LTTNG_ERR_NOMEM;
+                       goto end;
+               }
+
+               ret = init_domain(node, domain);
+               if (ret) {
+                       goto domain_init_error;
+               }
+
+               switch (domain->type) {
+               case LTTNG_DOMAIN_KERNEL:
+                       kernel_domain = domain;
+                       break;
+               case LTTNG_DOMAIN_UST:
+                       ust_domain = domain;
+                       break;
+               case LTTNG_DOMAIN_JUL:
+                       jul_domain = domain;
+                       break;
+               default:
+                       WARN("Invalid domain type");
+                       goto domain_init_error;
+               }
+               continue;
+domain_init_error:
+               free(domain);
+               ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+               goto end;
+       }
+
+       if (override) {
+               /* Destroy session if it exists */
+               ret = lttng_destroy_session(name);
+               if (ret && ret != -LTTNG_ERR_SESS_NOT_FOUND) {
+                       ERR("Failed to destroy existing session.");
+                       goto end;
+               }
+       }
+
+       /* Create session type depending on output type */
+       if (snapshot_mode && snapshot_mode != -1) {
+               ret = create_snapshot_session(name, output_node);
+       } else if (live_timer_interval &&
+               live_timer_interval != UINT64_MAX) {
+               ret = create_session(name, kernel_domain, ust_domain, jul_domain,
+                               output_node, live_timer_interval);
+       } else {
+               /* regular session */
+               ret = create_session(name, kernel_domain, ust_domain, jul_domain,
+                               output_node, UINT64_MAX);
+       }
+
+       if (ret) {
+               goto end;
+       }
+
+       for (node = xmlFirstElementChild(domains_node); node;
+               node = xmlNextElementSibling(node)) {
+               ret = process_domain_node(node, name);
+               if (ret) {
+                       goto end;
+               }
+       }
+
+       if (started) {
+               ret = lttng_start_tracing(name);
+               if (ret) {
+                       goto end;
+               }
+       }
+end:
+       free(kernel_domain);
+       free(ust_domain);
+       free(jul_domain);
+       free(name);
+       return ret;
+}
+
+static
+int load_session_from_file(const char *path, const char *session_name,
+       struct session_config_validation_ctx *validation_ctx, int override)
+{
+       int ret, session_found = !session_name;
+       xmlDocPtr doc = NULL;
+       xmlNodePtr sessions_node;
+       xmlNodePtr session_node;
+       struct stat sb;
+
+       assert(path);
+       assert(validation_ctx);
+
+       ret = stat(path, &sb);
+       if (ret) {
+               ret = -LTTNG_ERR_LOAD_SESSION_NOENT;
+               goto end;
+       }
+
+       doc = xmlParseFile(path);
+       if (!doc) {
+               ret = -LTTNG_ERR_LOAD_IO_FAIL;
+               goto end;
+       }
+
+       ret = xmlSchemaValidateDoc(validation_ctx->schema_validation_ctx, doc);
+       if (ret) {
+               ERR("Session configuration file validation failed");
+               ret = -LTTNG_ERR_LOAD_INVALID_CONFIG;
+               goto end;
+       }
+
+       sessions_node = xmlDocGetRootElement(doc);
+       if (!sessions_node) {
+               goto end;
+       }
+
+       for (session_node = xmlFirstElementChild(sessions_node);
+               session_node; session_node =
+                       xmlNextElementSibling(session_node)) {
+               ret = process_session_node(session_node,
+                       session_name, override);
+               if (session_name && ret == 0) {
+                       /* Target session found and loaded */
+                       session_found = 1;
+                       break;
+               }
+       }
+end:
+       xmlFreeDoc(doc);
+       if (!ret) {
+               ret = session_found ? 0 : -LTTNG_ERR_LOAD_SESSION_NOT_FOUND;
+       }
+       return ret;
+}
+
+static
+int load_session_from_path(const char *path, const char *session_name,
+       struct session_config_validation_ctx *validation_ctx, int override)
+{
+       int ret, session_found = !session_name;
+       struct stat sb;
+       DIR *directory = NULL;
+
+       assert(path);
+       assert(validation_ctx);
+
+       ret = stat(path, &sb);
+       if (ret) {
+               ret = -LTTNG_ERR_LOAD_SESSION_NOENT;
+               goto end;
+       }
+       if (S_ISDIR(sb.st_mode)) {
+               struct dirent *entry;
+               struct dirent *result;
+               char *file_path = NULL;
+               size_t path_len = strlen(path);
+
+               if (path_len >= PATH_MAX) {
+                       ret = -LTTNG_ERR_INVALID;
+                       goto end;
+               }
+
+               entry = zmalloc(sizeof(*entry));
+               if (!entry) {
+                       ret = -LTTNG_ERR_NOMEM;
+                       goto end;
+               }
+
+               directory = opendir(path);
+               if (!directory) {
+                       ret = -LTTNG_ERR_LOAD_IO_FAIL;
+                       free(entry);
+                       goto end;
+               }
+
+               file_path = zmalloc(PATH_MAX);
+               if (!file_path) {
+                       ret = -LTTNG_ERR_NOMEM;
+                       free(entry);
+                       goto end;
+               }
+
+               strncpy(file_path, path, path_len);
+               if (file_path[path_len - 1] != '/') {
+                       file_path[path_len++] = '/';
+               }
+
+               /* Search for *.lttng files */
+               while (!readdir_r(directory, entry, &result) && result) {
+                       size_t file_name_len = strlen(result->d_name);
+
+                       if (file_name_len <=
+                               sizeof(DEFAULT_SESSION_CONFIG_FILE_EXTENSION)) {
+                               continue;
+                       }
+
+                       if (path_len + file_name_len > PATH_MAX) {
+                               continue;
+                       }
+
+                       if (strcmp(DEFAULT_SESSION_CONFIG_FILE_EXTENSION,
+                               result->d_name + file_name_len - sizeof(
+                               DEFAULT_SESSION_CONFIG_FILE_EXTENSION) + 1)) {
+                               continue;
+                       }
+
+                       strncpy(file_path + path_len, result->d_name, file_name_len);
+                       file_path[path_len + file_name_len] = '\0';
+
+                       ret = load_session_from_file(file_path, session_name,
+                               validation_ctx, override);
+                       if (session_name && !ret) {
+                               session_found = 1;
+                               break;
+                       }
+               }
+
+               free(entry);
+               free(file_path);
+       } else {
+               ret = load_session_from_file(path, session_name,
+                       validation_ctx, override);
+               if (ret) {
+                       goto end;
+               } else {
+                       session_found = 1;
+               }
+       }
+
+end:
+       if (directory) {
+               if (closedir(directory)) {
+                       PERROR("closedir");
+               }
+       }
+
+       if (!session_found) {
+               ret = -LTTNG_ERR_LOAD_SESSION_NOT_FOUND;
+       }
+
+       return ret;
+}
+
+LTTNG_HIDDEN
+int config_load_session(const char *path, const char *session_name,
+               int override)
+{
+       int ret;
+       struct session_config_validation_ctx validation_ctx = { 0 };
+
+       ret = init_session_config_validation_ctx(&validation_ctx);
+       if (ret) {
+               goto end;
+       }
+
+       if (!path) {
+               /* Try home path */
+               char *home_path = utils_get_home_dir();
+               if (home_path) {
+                       char *path;
+
+                       ret = asprintf(&path, DEFAULT_SESSION_HOME_CONFIGPATH,
+                               home_path);
+                       if (ret < 0) {
+                               goto end;
+                       }
+
+                       ret = load_session_from_path(path, NULL,
+                               &validation_ctx, 0);
+                       if (ret && ret != -LTTNG_ERR_LOAD_SESSION_NOENT) {
+                               free(path);
+                               goto end;
+                       }
+
+                       free(path);
+               }
+
+               /* Try system session configuration path */
+               ret = load_session_from_path(DEFAULT_SESSION_SYSTEM_CONFIGPATH, NULL,
+                               &validation_ctx, 0);
+               if (ret && ret != -LTTNG_ERR_LOAD_SESSION_NOENT) {
+                       goto end;
+               }
+       } else {
+               ret = access(path, F_OK);
+               if (ret < 0) {
+                       PERROR("access");
+                       switch (errno) {
+                       case ENOENT:
+                               ret = -LTTNG_ERR_INVALID;
+                               WARN("Session configuration path does not exist.");
+                               break;
+                       case EACCES:
+                               ret = -LTTNG_ERR_EPERM;
+                               break;
+                       default:
+                               ret = -LTTNG_ERR_UNK;
+                               break;
+                       }
+                       goto end;
+               }
+
+               ret = load_session_from_path(path, session_name,
+                       &validation_ctx, override);
+       }
+end:
+       fini_session_config_validation_ctx(&validation_ctx);
+       return ret;
+}
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