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 mode_t mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP;
  53         const bool acquired_reference = lttng_trace_chunk_get(chunk);
  54
  55         assert(acquired_reference);
  56
  57         index_file = zmalloc(sizeof(*index_file));
  58         if (!index_file) {
  59                 PERROR("Failed to allocate lttng_index_file");
  60                 goto error;
  61         }
  62
  63         index_file->trace_chunk = chunk;
  64         ret = snprintf(index_directory_path, sizeof(index_directory_path),
  65                         "%s/" DEFAULT_INDEX_DIR, channel_path);
  66         if (ret < 0 || ret >= sizeof(index_directory_path)) {
  67                 ERR("Failed to format index directory path");
  68                 goto error;
  69         }
  70
  71         ret = utils_stream_file_path(index_directory_path, stream_name,
  72                         stream_file_size, stream_file_index,
  73                         DEFAULT_INDEX_FILE_SUFFIX,
  74                         index_file_path, sizeof(index_file_path));
  75         if (ret) {
  76                 goto error;
  77         }
  78
  79         if (unlink_existing_file) {
  80                 /*
  81                  * For tracefile rotation. We need to unlink the old
  82                  * file if present to synchronize with the tail of the
  83                  * live viewer which could be working on this same file.
  84                  * By doing so, any reference to the old index file
  85                  * stays valid even if we re-create a new file with the
  86                  * same name afterwards.
  87                  */
  88                 chunk_status = lttng_trace_chunk_unlink_file(
  89                                 chunk, index_file_path);
  90                 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK &&
  91                                 !(chunk_status == LTTNG_TRACE_CHUNK_STATUS_ERROR &&
  92                                                 errno == ENOENT)) {
  93                         goto error;
  94                 }
  95         }
  96
  97         chunk_status = lttng_trace_chunk_open_file(chunk, index_file_path,
  98                         flags, mode, &fd);
  99         if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
 100                 goto error;
 101         }
 102
 103         if (flags == WRITE_FILE_FLAGS) {
 104                 ctf_packet_index_file_hdr_init(&hdr, index_major, index_minor);
 105                 size_ret = lttng_write(fd, &hdr, sizeof(hdr));
 106                 if (size_ret < sizeof(hdr)) {
 107                         PERROR("Failed to write index header");
 108                         goto error;
 109                 }
 110                 index_file->element_len = ctf_packet_index_len(index_major, index_minor);
 111         } else {
 112                 uint32_t element_len;
 113
 114                 size_ret = lttng_read(fd, &hdr, sizeof(hdr));
 115                 if (size_ret < 0) {
 116                         PERROR("Failed to read index header");
 117                         goto error;
 118                 }
 119                 if (be32toh(hdr.magic) != CTF_INDEX_MAGIC) {
 120                         ERR("Invalid header magic");
 121                         goto error;
 122                 }
 123                 if (index_major != be32toh(hdr.index_major)) {
 124                         ERR("Index major number mismatch: %u, expect %u",
 125                                 be32toh(hdr.index_major), index_major);
 126                         goto error;
 127                 }
 128                 if (index_minor != be32toh(hdr.index_minor)) {
 129                         ERR("Index minor number mismatch: %u, expect %u",
 130                                 be32toh(hdr.index_minor), index_minor);
 131                         goto error;
 132                 }
 133                 element_len = be32toh(hdr.packet_index_len);
 134                 if (element_len > sizeof(struct ctf_packet_index)) {
 135                         ERR("Index element length too long");
 136                         goto error;
 137                 }
 138                 index_file->element_len = element_len;
 139         }
 140         index_file->fd = fd;
 141         index_file->major = index_major;
 142         index_file->minor = index_minor;
 143         urcu_ref_init(&index_file->ref);
 144
 145         return index_file;
 146
 147 error:
 148         if (fd >= 0) {
 149                 ret = close(fd);
 150                 if (ret < 0) {
 151                         PERROR("Failed to close file descriptor of index file");
 152                 }
 153         }
 154         lttng_trace_chunk_put(chunk);
 155         free(index_file);
 156         return NULL;
 157 }
 158
 159 struct lttng_index_file *lttng_index_file_create_from_trace_chunk(
 160                 struct lttng_trace_chunk *chunk,
 161                 const char *channel_path, const char *stream_name,
 162                 uint64_t stream_file_size, uint64_t stream_file_index,
 163                 uint32_t index_major, uint32_t index_minor,
 164                 bool unlink_existing_file)
 165 {
 166         return _lttng_index_file_create_from_trace_chunk(chunk, channel_path,
 167                         stream_name, stream_file_size, stream_file_index,
 168                         index_major, index_minor, unlink_existing_file,
 169                         WRITE_FILE_FLAGS);
 170 }
 171
 172 struct lttng_index_file *lttng_index_file_create_from_trace_chunk_read_only(
 173                 struct lttng_trace_chunk *chunk,
 174                 const char *channel_path, const char *stream_name,
 175                 uint64_t stream_file_size, uint64_t stream_file_index,
 176                 uint32_t index_major, uint32_t index_minor)
 177 {
 178         return _lttng_index_file_create_from_trace_chunk(chunk, channel_path,
 179                         stream_name, stream_file_size, stream_file_index,
 180                         index_major, index_minor, false,
 181                         READ_ONLY_FILE_FLAGS);
 182 }
 183
 184 /*
 185  * Write index values to the given index file.
 186  *
 187  * Return 0 on success, -1 on error.
 188  */
 189 int lttng_index_file_write(const struct lttng_index_file *index_file,
 190                 const struct ctf_packet_index *element)
 191 {
 192         int fd;
 193         size_t len;
 194         ssize_t ret;
 195
 196         assert(index_file);
 197         assert(element);
 198
 199         fd = index_file->fd;
 200         len = index_file->element_len;
 201
 202         if (fd < 0) {
 203                 goto error;
 204         }
 205
 206         ret = lttng_write(fd, element, len);
 207         if (ret < len) {
 208                 PERROR("writing index file");
 209                 goto error;
 210         }
 211         return 0;
 212
 213 error:
 214         return -1;
 215 }
 216
 217 /*
 218  * Read index values from the given index file.
 219  *
 220  * Return 0 on success, -1 on error.
 221  */
 222 int lttng_index_file_read(const struct lttng_index_file *index_file,
 223                 struct ctf_packet_index *element)
 224 {
 225         ssize_t ret;
 226         int fd = index_file->fd;
 227         size_t len = index_file->element_len;
 228
 229         assert(element);
 230
 231         if (fd < 0) {
 232                 goto error;
 233         }
 234
 235         ret = lttng_read(fd, element, len);
 236         if (ret < 0) {
 237                 PERROR("read index file");
 238                 goto error;
 239         }
 240         if (ret < len) {
 241                 ERR("lttng_read expected %zu, returned %zd", len, ret);
 242                 goto error;
 243         }
 244         return 0;
 245
 246 error:
 247         return -1;
 248 }
 249
 250 void lttng_index_file_get(struct lttng_index_file *index_file)
 251 {
 252         urcu_ref_get(&index_file->ref);
 253 }
 254
 255 static void lttng_index_file_release(struct urcu_ref *ref)
 256 {
 257         struct lttng_index_file *index_file = caa_container_of(ref,
 258                         struct lttng_index_file, ref);
 259
 260         if (close(index_file->fd)) {
 261                 PERROR("close index fd");
 262         }
 263         lttng_trace_chunk_put(index_file->trace_chunk);
 264         free(index_file);
 265 }
 266
 267 void lttng_index_file_put(struct lttng_index_file *index_file)
 268 {
 269         urcu_ref_put(&index_file->ref, lttng_index_file_release);
 270 }