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