src/common/index/index.c

   1 /*
   2  * Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
   3  *                      David Goulet <dgoulet@efficios.com>
   4  *               2016 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License, version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along with
  16  * this program; if not, write to the Free Software Foundation, Inc., 51
  17  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #define _LGPL_SOURCE
  21 #include <assert.h>
  22 #include <sys/stat.h>
  23 #include <sys/types.h>
  24 #include <fcntl.h>
  25
  26 #include <lttng/constant.h>
  27 #include <common/common.h>
  28 #include <common/defaults.h>
  29 #include <common/compat/endian.h>
  30 #include <common/utils.h>
  31
  32 #include "index.h"
  33
  34 #define WRITE_FILE_FLAGS        (O_WRONLY | O_CREAT | O_TRUNC)
  35 #define READ_ONLY_FILE_FLAGS    O_RDONLY
  36
  37 static enum lttng_trace_chunk_status _lttng_index_file_create_from_trace_chunk(
  38                 struct lttng_trace_chunk *chunk,
  39                 const char *channel_path, const char *stream_name,
  40                 uint64_t stream_file_size, uint64_t stream_file_index,
  41                 uint32_t index_major, uint32_t index_minor,
  42                 bool unlink_existing_file,
  43                 int flags, bool expect_no_file, struct lttng_index_file **file)
  44 {
  45         struct lttng_index_file *index_file;
  46         enum lttng_trace_chunk_status chunk_status;
  47         int ret, fd = -1;
  48         ssize_t size_ret;
  49         struct ctf_packet_index_file_hdr hdr;
  50         char index_directory_path[LTTNG_PATH_MAX];
  51         char index_file_path[LTTNG_PATH_MAX];
  52         const mode_t mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP;
  53         const bool acquired_reference = lttng_trace_chunk_get(chunk);
  54         const char *separator;
  55
  56         assert(acquired_reference);
  57
  58         index_file = zmalloc(sizeof(*index_file));
  59         if (!index_file) {
  60                 PERROR("Failed to allocate lttng_index_file");
  61                 chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
  62                 goto error;
  63         }
  64
  65         index_file->trace_chunk = chunk;
  66         if (channel_path[0] == '\0') {
  67                 separator = "";
  68         } else {
  69                 separator = "/";
  70         }
  71         ret = snprintf(index_directory_path, sizeof(index_directory_path),
  72                         "%s%s" DEFAULT_INDEX_DIR, channel_path, separator);
  73         if (ret < 0 || ret >= sizeof(index_directory_path)) {
  74                 ERR("Failed to format index directory path");
  75                 chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
  76                 goto error;
  77         }
  78
  79         ret = utils_stream_file_path(index_directory_path, stream_name,
  80                         stream_file_size, stream_file_index,
  81                         DEFAULT_INDEX_FILE_SUFFIX,
  82                         index_file_path, sizeof(index_file_path));
  83         if (ret) {
  84                 chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
  85                 goto error;
  86         }
  87
  88         if (unlink_existing_file) {
  89                 /*
  90                  * For tracefile rotation. We need to unlink the old
  91                  * file if present to synchronize with the tail of the
  92                  * live viewer which could be working on this same file.
  93                  * By doing so, any reference to the old index file
  94                  * stays valid even if we re-create a new file with the
  95                  * same name afterwards.
  96                  */
  97                 chunk_status = lttng_trace_chunk_unlink_file(
  98                                 chunk, index_file_path);
  99                 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK &&
 100                                 !(chunk_status == LTTNG_TRACE_CHUNK_STATUS_ERROR &&
 101                                                 errno == ENOENT)) {
 102                         goto error;
 103                 }
 104         }
 105
 106         chunk_status = lttng_trace_chunk_open_file(chunk, index_file_path,
 107                         flags, mode, &fd, expect_no_file);
 108         if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
 109                 goto error;
 110         }
 111
 112         if (flags == WRITE_FILE_FLAGS) {
 113                 ctf_packet_index_file_hdr_init(&hdr, index_major, index_minor);
 114                 size_ret = lttng_write(fd, &hdr, sizeof(hdr));
 115                 if (size_ret < sizeof(hdr)) {
 116                         PERROR("Failed to write index header");
 117                         chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
 118                         goto error;
 119                 }
 120                 index_file->element_len = ctf_packet_index_len(index_major, index_minor);
 121         } else {
 122                 uint32_t element_len;
 123
 124                 size_ret = lttng_read(fd, &hdr, sizeof(hdr));
 125                 if (size_ret < 0) {
 126                         PERROR("Failed to read index header");
 127                         chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
 128                         goto error;
 129                 }
 130                 if (be32toh(hdr.magic) != CTF_INDEX_MAGIC) {
 131                         ERR("Invalid header magic");
 132                         chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
 133                         goto error;
 134                 }
 135                 if (index_major != be32toh(hdr.index_major)) {
 136                         ERR("Index major number mismatch: %u, expect %u",
 137                                 be32toh(hdr.index_major), index_major);
 138                         chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
 139                         goto error;
 140                 }
 141                 if (index_minor != be32toh(hdr.index_minor)) {
 142                         ERR("Index minor number mismatch: %u, expect %u",
 143                                 be32toh(hdr.index_minor), index_minor);
 144                         chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
 145                         goto error;
 146                 }
 147                 element_len = be32toh(hdr.packet_index_len);
 148                 if (element_len > sizeof(struct ctf_packet_index)) {
 149                         ERR("Index element length too long");
 150                         chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
 151                         goto error;
 152                 }
 153                 index_file->element_len = element_len;
 154         }
 155         index_file->fd = fd;
 156         index_file->major = index_major;
 157         index_file->minor = index_minor;
 158         urcu_ref_init(&index_file->ref);
 159
 160         *file = index_file;
 161         return LTTNG_TRACE_CHUNK_STATUS_OK;
 162
 163 error:
 164         if (fd >= 0) {
 165                 ret = close(fd);
 166                 if (ret < 0) {
 167                         PERROR("Failed to close file descriptor of index file");
 168                 }
 169         }
 170         lttng_trace_chunk_put(chunk);
 171         free(index_file);
 172         return chunk_status;
 173 }
 174
 175 enum lttng_trace_chunk_status lttng_index_file_create_from_trace_chunk(
 176                 struct lttng_trace_chunk *chunk,
 177                 const char *channel_path, const char *stream_name,
 178                 uint64_t stream_file_size, uint64_t stream_file_index,
 179                 uint32_t index_major, uint32_t index_minor,
 180                 bool unlink_existing_file, struct lttng_index_file **file)
 181 {
 182         return _lttng_index_file_create_from_trace_chunk(chunk, channel_path,
 183                         stream_name, stream_file_size, stream_file_index,
 184                         index_major, index_minor, unlink_existing_file,
 185                         WRITE_FILE_FLAGS, false, file);
 186 }
 187
 188 enum lttng_trace_chunk_status lttng_index_file_create_from_trace_chunk_read_only(
 189                 struct lttng_trace_chunk *chunk,
 190                 const char *channel_path, const char *stream_name,
 191                 uint64_t stream_file_size, uint64_t stream_file_index,
 192                 uint32_t index_major, uint32_t index_minor,
 193                 bool expect_no_file, struct lttng_index_file **file)
 194 {
 195         return _lttng_index_file_create_from_trace_chunk(chunk, channel_path,
 196                         stream_name, stream_file_size, stream_file_index,
 197                         index_major, index_minor, false,
 198                         READ_ONLY_FILE_FLAGS, expect_no_file, file);
 199 }
 200
 201 /*
 202  * Write index values to the given index file.
 203  *
 204  * Return 0 on success, -1 on error.
 205  */
 206 int lttng_index_file_write(const struct lttng_index_file *index_file,
 207                 const struct ctf_packet_index *element)
 208 {
 209         int fd;
 210         size_t len;
 211         ssize_t ret;
 212
 213         assert(index_file);
 214         assert(element);
 215
 216         fd = index_file->fd;
 217         len = index_file->element_len;
 218
 219         if (fd < 0) {
 220                 goto error;
 221         }
 222
 223         ret = lttng_write(fd, element, len);
 224         if (ret < len) {
 225                 PERROR("writing index file");
 226                 goto error;
 227         }
 228         return 0;
 229
 230 error:
 231         return -1;
 232 }
 233
 234 /*
 235  * Read index values from the given index file.
 236  *
 237  * Return 0 on success, -1 on error.
 238  */
 239 int lttng_index_file_read(const struct lttng_index_file *index_file,
 240                 struct ctf_packet_index *element)
 241 {
 242         ssize_t ret;
 243         int fd = index_file->fd;
 244         size_t len = index_file->element_len;
 245
 246         assert(element);
 247
 248         if (fd < 0) {
 249                 goto error;
 250         }
 251
 252         ret = lttng_read(fd, element, len);
 253         if (ret < 0) {
 254                 PERROR("read index file");
 255                 goto error;
 256         }
 257         if (ret < len) {
 258                 ERR("lttng_read expected %zu, returned %zd", len, ret);
 259                 goto error;
 260         }
 261         return 0;
 262
 263 error:
 264         return -1;
 265 }
 266
 267 void lttng_index_file_get(struct lttng_index_file *index_file)
 268 {
 269         urcu_ref_get(&index_file->ref);
 270 }
 271
 272 static void lttng_index_file_release(struct urcu_ref *ref)
 273 {
 274         struct lttng_index_file *index_file = caa_container_of(ref,
 275                         struct lttng_index_file, ref);
 276
 277         if (close(index_file->fd)) {
 278                 PERROR("close index fd");
 279         }
 280         lttng_trace_chunk_put(index_file->trace_chunk);
 281         free(index_file);
 282 }
 283
 284 void lttng_index_file_put(struct lttng_index_file *index_file)
 285 {
 286         urcu_ref_put(&index_file->ref, lttng_index_file_release);
 287 }