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 struct lttng_index_file *_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)
  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 uint32_t element_len = ctf_packet_index_len(index_major,
  53                         index_minor);
  54         const mode_t mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP;
  55         const bool acquired_reference = lttng_trace_chunk_get(chunk);
  56
  57         assert(acquired_reference);
  58
  59         index_file = zmalloc(sizeof(*index_file));
  60         if (!index_file) {
  61                 PERROR("Failed to allocate lttng_index_file");
  62                 goto error;
  63         }
  64
  65         index_file->trace_chunk = chunk;
  66         ret = snprintf(index_directory_path, sizeof(index_directory_path),
  67                         "%s/" DEFAULT_INDEX_DIR, channel_path);
  68         if (ret < 0 || ret >= sizeof(index_directory_path)) {
  69                 ERR("Failed to format index directory path");
  70                 goto error;
  71         }
  72
  73         ret = utils_stream_file_path(index_directory_path, stream_name,
  74                         stream_file_size, stream_file_index,
  75                         DEFAULT_INDEX_FILE_SUFFIX,
  76                         index_file_path, sizeof(index_file_path));
  77         if (ret) {
  78                 goto error;
  79         }
  80
  81         if (unlink_existing_file) {
  82                 /*
  83                  * For tracefile rotation. We need to unlink the old
  84                  * file if present to synchronize with the tail of the
  85                  * live viewer which could be working on this same file.
  86                  * By doing so, any reference to the old index file
  87                  * stays valid even if we re-create a new file with the
  88                  * same name afterwards.
  89                  */
  90                 chunk_status = lttng_trace_chunk_unlink_file(
  91                                 chunk, index_file_path);
  92                 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK &&
  93                                 !(chunk_status == LTTNG_TRACE_CHUNK_STATUS_ERROR &&
  94                                                 errno == ENOENT)) {
  95                         goto error;
  96                 }
  97         }
  98
  99         chunk_status = lttng_trace_chunk_open_file(chunk, index_file_path,
 100                         flags, mode, &fd);
 101         if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
 102                 goto error;
 103         }
 104
 105         ctf_packet_index_file_hdr_init(&hdr, index_major, index_minor);
 106         size_ret = lttng_write(fd, &hdr, sizeof(hdr));
 107         if (size_ret < sizeof(hdr)) {
 108                 PERROR("Failed to write index header");
 109                 goto error;
 110         }
 111         index_file->fd = fd;
 112         index_file->major = index_major;
 113         index_file->minor = index_minor;
 114         index_file->element_len = element_len;
 115         urcu_ref_init(&index_file->ref);
 116
 117         return index_file;
 118
 119 error:
 120         if (fd >= 0) {
 121                 ret = close(fd);
 122                 if (ret < 0) {
 123                         PERROR("Failed to close file descriptor of index file");
 124                 }
 125         }
 126         free(index_file);
 127         return NULL;
 128 }
 129
 130 struct lttng_index_file *lttng_index_file_create_from_trace_chunk(
 131                 struct lttng_trace_chunk *chunk,
 132                 const char *channel_path, const char *stream_name,
 133                 uint64_t stream_file_size, uint64_t stream_file_index,
 134                 uint32_t index_major, uint32_t index_minor,
 135                 bool unlink_existing_file)
 136 {
 137         return _lttng_index_file_create_from_trace_chunk(chunk, channel_path,
 138                         stream_name, stream_file_size, stream_file_index,
 139                         index_major, index_minor, unlink_existing_file,
 140                         WRITE_FILE_FLAGS);
 141 }
 142
 143 struct lttng_index_file *lttng_index_file_create_from_trace_chunk_read_only(
 144                 struct lttng_trace_chunk *chunk,
 145                 const char *channel_path, const char *stream_name,
 146                 uint64_t stream_file_size, uint64_t stream_file_index,
 147                 uint32_t index_major, uint32_t index_minor)
 148 {
 149         return _lttng_index_file_create_from_trace_chunk(chunk, channel_path,
 150                         stream_name, stream_file_size, stream_file_index,
 151                         index_major, index_minor, false,
 152                         READ_ONLY_FILE_FLAGS);
 153 }
 154
 155 /*
 156  * Write index values to the given index file.
 157  *
 158  * Return 0 on success, -1 on error.
 159  */
 160 int lttng_index_file_write(const struct lttng_index_file *index_file,
 161                 const struct ctf_packet_index *element)
 162 {
 163         int fd;
 164         size_t len;
 165         ssize_t ret;
 166
 167         assert(index_file);
 168         assert(element);
 169
 170         fd = index_file->fd;
 171         len = index_file->element_len;
 172
 173         if (fd < 0) {
 174                 goto error;
 175         }
 176
 177         ret = lttng_write(fd, element, len);
 178         if (ret < len) {
 179                 PERROR("writing index file");
 180                 goto error;
 181         }
 182         return 0;
 183
 184 error:
 185         return -1;
 186 }
 187
 188 /*
 189  * Read index values from the given index file.
 190  *
 191  * Return 0 on success, -1 on error.
 192  */
 193 int lttng_index_file_read(const struct lttng_index_file *index_file,
 194                 struct ctf_packet_index *element)
 195 {
 196         ssize_t ret;
 197         int fd = index_file->fd;
 198         size_t len = index_file->element_len;
 199
 200         assert(element);
 201
 202         if (fd < 0) {
 203                 goto error;
 204         }
 205
 206         ret = lttng_read(fd, element, len);
 207         if (ret < 0) {
 208                 PERROR("read index file");
 209                 goto error;
 210         }
 211         if (ret < len) {
 212                 ERR("lttng_read expected %zu, returned %zd", len, ret);
 213                 goto error;
 214         }
 215         return 0;
 216
 217 error:
 218         return -1;
 219 }
 220
 221 void lttng_index_file_get(struct lttng_index_file *index_file)
 222 {
 223         urcu_ref_get(&index_file->ref);
 224 }
 225
 226 static void lttng_index_file_release(struct urcu_ref *ref)
 227 {
 228         struct lttng_index_file *index_file = caa_container_of(ref,
 229                         struct lttng_index_file, ref);
 230
 231         if (close(index_file->fd)) {
 232                 PERROR("close index fd");
 233         }
 234         lttng_trace_chunk_put(index_file->trace_chunk);
 235         free(index_file);
 236 }
 237
 238 void lttng_index_file_put(struct lttng_index_file *index_file)
 239 {
 240         urcu_ref_put(&index_file->ref, lttng_index_file_release);
 241 }