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 struct lttng_index_file *lttng_index_file_create_from_trace_chunk(
  35                 struct lttng_trace_chunk *chunk,
  36                 const char *channel_path, char *stream_name,
  37                 uint64_t stream_file_size, uint64_t stream_count,
  38                 uint32_t index_major, uint32_t index_minor,
  39                 bool unlink_existing_file)
  40 {
  41         struct lttng_index_file *index_file;
  42         enum lttng_trace_chunk_status chunk_status;
  43         int ret, fd = -1;
  44         ssize_t size_ret;
  45         struct ctf_packet_index_file_hdr hdr;
  46         char index_directory_path[LTTNG_PATH_MAX];
  47         char index_file_path[LTTNG_PATH_MAX];
  48         const uint32_t element_len = ctf_packet_index_len(index_major,
  49                         index_minor);
  50         const int flags = O_WRONLY | O_CREAT | O_TRUNC;
  51         const mode_t mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP;
  52
  53         index_file = zmalloc(sizeof(*index_file));
  54         if (!index_file) {
  55                 PERROR("Failed to allocate lttng_index_file");
  56                 goto error;
  57         }
  58
  59         ret = snprintf(index_directory_path, sizeof(index_directory_path),
  60                         "%s/" DEFAULT_INDEX_DIR, channel_path);
  61         if (ret < 0 || ret >= sizeof(index_directory_path)) {
  62                 ERR("Failed to format index directory path");
  63                 goto error;
  64         }
  65
  66         ret = utils_stream_file_path(index_directory_path, stream_name,
  67                         stream_file_size, stream_count,
  68                         DEFAULT_INDEX_FILE_SUFFIX,
  69                         index_file_path, sizeof(index_file_path));
  70         if (ret) {
  71                 goto error;
  72         }
  73
  74         if (unlink_existing_file) {
  75                 /*
  76                  * For tracefile rotation. We need to unlink the old
  77                  * file if present to synchronize with the tail of the
  78                  * live viewer which could be working on this same file.
  79                  * By doing so, any reference to the old index file
  80                  * stays valid even if we re-create a new file with the
  81                  * same name afterwards.
  82                  */
  83                 chunk_status = lttng_trace_chunk_unlink_file(
  84                                 chunk, index_file_path);
  85                 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK &&
  86                                 !(chunk_status == LTTNG_TRACE_CHUNK_STATUS_ERROR &&
  87                                                 errno == ENOENT)) {
  88                         goto error;
  89                 }
  90         }
  91
  92         chunk_status = lttng_trace_chunk_open_file(chunk, index_file_path,
  93                         flags, mode, &fd);
  94         if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
  95                 goto error;
  96         }
  97
  98         ctf_packet_index_file_hdr_init(&hdr, index_major, index_minor);
  99         size_ret = lttng_write(fd, &hdr, sizeof(hdr));
 100         if (size_ret < sizeof(hdr)) {
 101                 PERROR("Failed to write index header");
 102                 goto error;
 103         }
 104         index_file->fd = fd;
 105         index_file->major = index_major;
 106         index_file->minor = index_minor;
 107         index_file->element_len = element_len;
 108         urcu_ref_init(&index_file->ref);
 109
 110         return index_file;
 111
 112 error:
 113         if (fd >= 0) {
 114                 ret = close(fd);
 115                 if (ret < 0) {
 116                         PERROR("Failed to close file descriptor of index file");
 117                 }
 118         }
 119         free(index_file);
 120         return NULL;
 121 }
 122
 123 /*
 124  * Write index values to the given index file.
 125  *
 126  * Return 0 on success, -1 on error.
 127  */
 128 int lttng_index_file_write(const struct lttng_index_file *index_file,
 129                 const struct ctf_packet_index *element)
 130 {
 131         int fd;
 132         size_t len;
 133         ssize_t ret;
 134
 135         assert(index_file);
 136         assert(element);
 137
 138         fd = index_file->fd;
 139         len = index_file->element_len;
 140
 141         if (fd < 0) {
 142                 goto error;
 143         }
 144
 145         ret = lttng_write(fd, element, len);
 146         if (ret < len) {
 147                 PERROR("writing index file");
 148                 goto error;
 149         }
 150         return 0;
 151
 152 error:
 153         return -1;
 154 }
 155
 156 /*
 157  * Read index values from the given index file.
 158  *
 159  * Return 0 on success, -1 on error.
 160  */
 161 int lttng_index_file_read(const struct lttng_index_file *index_file,
 162                 struct ctf_packet_index *element)
 163 {
 164         ssize_t ret;
 165         int fd = index_file->fd;
 166         size_t len = index_file->element_len;
 167
 168         assert(element);
 169
 170         if (fd < 0) {
 171                 goto error;
 172         }
 173
 174         ret = lttng_read(fd, element, len);
 175         if (ret < 0) {
 176                 PERROR("read index file");
 177                 goto error;
 178         }
 179         if (ret < len) {
 180                 ERR("lttng_read expected %zu, returned %zd", len, ret);
 181                 goto error;
 182         }
 183         return 0;
 184
 185 error:
 186         return -1;
 187 }
 188
 189 /*
 190  * Open index file using a given path, channel name and tracefile count.
 191  *
 192  * Return allocated struct lttng_index_file, NULL on error.
 193  */
 194 struct lttng_index_file *lttng_index_file_open(const char *path_name,
 195                 const char *channel_name, uint64_t tracefile_count,
 196                 uint64_t tracefile_count_current)
 197 {
 198         struct lttng_index_file *index_file;
 199         int ret, read_fd;
 200         ssize_t read_len;
 201         char fullpath[PATH_MAX];
 202         struct ctf_packet_index_file_hdr hdr;
 203         uint32_t major, minor, element_len;
 204
 205         assert(path_name);
 206         assert(channel_name);
 207
 208         index_file = zmalloc(sizeof(*index_file));
 209         if (!index_file) {
 210                 PERROR("allocating lttng_index_file");
 211                 goto error;
 212         }
 213
 214         if (tracefile_count > 0) {
 215                 ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR "/%s_%"
 216                                 PRIu64 DEFAULT_INDEX_FILE_SUFFIX, path_name,
 217                                 channel_name, tracefile_count_current);
 218         } else {
 219                 ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR "/%s"
 220                                 DEFAULT_INDEX_FILE_SUFFIX, path_name, channel_name);
 221         }
 222         if (ret < 0) {
 223                 PERROR("snprintf index path");
 224                 goto error;
 225         }
 226
 227         DBG("Index opening file %s in read only", fullpath);
 228         read_fd = open(fullpath, O_RDONLY);
 229         if (read_fd < 0) {
 230                 PERROR("opening index in read-only");
 231                 goto error;
 232         }
 233
 234         read_len = lttng_read(read_fd, &hdr, sizeof(hdr));
 235         if (read_len < 0) {
 236                 PERROR("Reading index header");
 237                 goto error_close;
 238         }
 239
 240         if (be32toh(hdr.magic) != CTF_INDEX_MAGIC) {
 241                 ERR("Invalid header magic");
 242                 goto error_close;
 243         }
 244         major = be32toh(hdr.index_major);
 245         minor = be32toh(hdr.index_minor);
 246         element_len = be32toh(hdr.packet_index_len);
 247
 248         if (major != CTF_INDEX_MAJOR) {
 249                 ERR("Invalid header version");
 250                 goto error_close;
 251         }
 252         if (element_len > sizeof(struct ctf_packet_index)) {
 253                 ERR("Index element length too long");
 254                 goto error_close;
 255         }
 256
 257         index_file->fd = read_fd;
 258         index_file->major = major;
 259         index_file->minor = minor;
 260         index_file->element_len = element_len;
 261         urcu_ref_init(&index_file->ref);
 262
 263         return index_file;
 264
 265 error_close:
 266         if (read_fd >= 0) {
 267                 int close_ret;
 268
 269                 close_ret = close(read_fd);
 270                 if (close_ret < 0) {
 271                         PERROR("close read fd %d", read_fd);
 272                 }
 273         }
 274
 275 error:
 276         free(index_file);
 277         return NULL;
 278 }
 279
 280 void lttng_index_file_get(struct lttng_index_file *index_file)
 281 {
 282         urcu_ref_get(&index_file->ref);
 283 }
 284
 285 static void lttng_index_file_release(struct urcu_ref *ref)
 286 {
 287         struct lttng_index_file *index_file = caa_container_of(ref,
 288                         struct lttng_index_file, ref);
 289
 290         if (close(index_file->fd)) {
 291                 PERROR("close index fd");
 292         }
 293         free(index_file);
 294 }
 295
 296 void lttng_index_file_put(struct lttng_index_file *index_file)
 297 {
 298         urcu_ref_put(&index_file->ref, lttng_index_file_release);
 299 }