src/common/index/index.c

   1 /*
   2  * Copyright (C) 2013 Julien Desfossez <jdesfossez@efficios.com>
   3  * Copyright (C) 2013 David Goulet <dgoulet@efficios.com>
   4  * Copyright (C) 2016 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * SPDX-License-Identifier: GPL-2.0-only
   7  *
   8  */
   9
  10 #define _LGPL_SOURCE
  11 #include <assert.h>
  12 #include <sys/stat.h>
  13 #include <sys/types.h>
  14 #include <fcntl.h>
  15
  16 #include <lttng/constant.h>
  17 #include <common/common.h>
  18 #include <common/defaults.h>
  19 #include <common/compat/endian.h>
  20 #include <common/utils.h>
  21
  22 #include "index.h"
  23
  24 #define WRITE_FILE_FLAGS        (O_WRONLY | O_CREAT | O_TRUNC)
  25 #define READ_ONLY_FILE_FLAGS    O_RDONLY
  26
  27 static enum lttng_trace_chunk_status _lttng_index_file_create_from_trace_chunk(
  28                 struct lttng_trace_chunk *chunk,
  29                 const char *channel_path, const char *stream_name,
  30                 uint64_t stream_file_size, uint64_t stream_file_index,
  31                 uint32_t index_major, uint32_t index_minor,
  32                 bool unlink_existing_file,
  33                 int flags, bool expect_no_file, struct lttng_index_file **file)
  34 {
  35         struct lttng_index_file *index_file;
  36         enum lttng_trace_chunk_status chunk_status;
  37         int ret;
  38         struct fs_handle *fs_handle = NULL;
  39         ssize_t size_ret;
  40         struct ctf_packet_index_file_hdr hdr;
  41         char index_directory_path[LTTNG_PATH_MAX];
  42         char index_file_path[LTTNG_PATH_MAX];
  43         const mode_t mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP;
  44         const bool acquired_reference = lttng_trace_chunk_get(chunk);
  45         const char *separator;
  46
  47         assert(acquired_reference);
  48
  49         index_file = zmalloc(sizeof(*index_file));
  50         if (!index_file) {
  51                 PERROR("Failed to allocate lttng_index_file");
  52                 chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
  53                 goto error;
  54         }
  55
  56         index_file->trace_chunk = chunk;
  57         if (channel_path[0] == '\0') {
  58                 separator = "";
  59         } else {
  60                 separator = "/";
  61         }
  62         ret = snprintf(index_directory_path, sizeof(index_directory_path),
  63                         "%s%s" DEFAULT_INDEX_DIR, channel_path, separator);
  64         if (ret < 0 || ret >= sizeof(index_directory_path)) {
  65                 ERR("Failed to format index directory path");
  66                 chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
  67                 goto error;
  68         }
  69
  70         ret = utils_stream_file_path(index_directory_path, stream_name,
  71                         stream_file_size, stream_file_index,
  72                         DEFAULT_INDEX_FILE_SUFFIX,
  73                         index_file_path, sizeof(index_file_path));
  74         if (ret) {
  75                 chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
  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_fs_handle(chunk, index_file_path,
  98                         flags, mode, &fs_handle, expect_no_file);
  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 = fs_handle_write(fs_handle, &hdr, sizeof(hdr));
 106                 if (size_ret < sizeof(hdr)) {
 107                         PERROR("Failed to write index header");
 108                         chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
 109                         goto error;
 110                 }
 111                 index_file->element_len = ctf_packet_index_len(index_major, index_minor);
 112         } else {
 113                 uint32_t element_len;
 114
 115                 size_ret = fs_handle_read(fs_handle, &hdr, sizeof(hdr));
 116                 if (size_ret < 0) {
 117                         PERROR("Failed to read index header");
 118                         chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
 119                         goto error;
 120                 }
 121                 if (be32toh(hdr.magic) != CTF_INDEX_MAGIC) {
 122                         ERR("Invalid header magic");
 123                         chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
 124                         goto error;
 125                 }
 126                 if (index_major != be32toh(hdr.index_major)) {
 127                         ERR("Index major number mismatch: %u, expect %u",
 128                                 be32toh(hdr.index_major), index_major);
 129                         chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
 130                         goto error;
 131                 }
 132                 if (index_minor != be32toh(hdr.index_minor)) {
 133                         ERR("Index minor number mismatch: %u, expect %u",
 134                                 be32toh(hdr.index_minor), index_minor);
 135                         chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
 136                         goto error;
 137                 }
 138                 element_len = be32toh(hdr.packet_index_len);
 139                 if (element_len > sizeof(struct ctf_packet_index)) {
 140                         ERR("Index element length too long");
 141                         chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
 142                         goto error;
 143                 }
 144                 index_file->element_len = element_len;
 145         }
 146         index_file->file = fs_handle;
 147         index_file->major = index_major;
 148         index_file->minor = index_minor;
 149         urcu_ref_init(&index_file->ref);
 150
 151         *file = index_file;
 152         return LTTNG_TRACE_CHUNK_STATUS_OK;
 153
 154 error:
 155         if (fs_handle) {
 156                 ret = fs_handle_close(fs_handle);
 157                 if (ret < 0) {
 158                         PERROR("Failed to close file descriptor of index file");
 159                 }
 160         }
 161         lttng_trace_chunk_put(chunk);
 162         free(index_file);
 163         return chunk_status;
 164 }
 165
 166 enum lttng_trace_chunk_status lttng_index_file_create_from_trace_chunk(
 167                 struct lttng_trace_chunk *chunk,
 168                 const char *channel_path, const char *stream_name,
 169                 uint64_t stream_file_size, uint64_t stream_file_index,
 170                 uint32_t index_major, uint32_t index_minor,
 171                 bool unlink_existing_file, struct lttng_index_file **file)
 172 {
 173         return _lttng_index_file_create_from_trace_chunk(chunk, channel_path,
 174                         stream_name, stream_file_size, stream_file_index,
 175                         index_major, index_minor, unlink_existing_file,
 176                         WRITE_FILE_FLAGS, false, file);
 177 }
 178
 179 enum lttng_trace_chunk_status lttng_index_file_create_from_trace_chunk_read_only(
 180                 struct lttng_trace_chunk *chunk,
 181                 const char *channel_path, const char *stream_name,
 182                 uint64_t stream_file_size, uint64_t stream_file_index,
 183                 uint32_t index_major, uint32_t index_minor,
 184                 bool expect_no_file, struct lttng_index_file **file)
 185 {
 186         return _lttng_index_file_create_from_trace_chunk(chunk, channel_path,
 187                         stream_name, stream_file_size, stream_file_index,
 188                         index_major, index_minor, false,
 189                         READ_ONLY_FILE_FLAGS, expect_no_file, file);
 190 }
 191
 192 /*
 193  * Write index values to the given index file.
 194  *
 195  * Return 0 on success, -1 on error.
 196  */
 197 int lttng_index_file_write(const struct lttng_index_file *index_file,
 198                 const struct ctf_packet_index *element)
 199 {
 200         ssize_t ret;
 201         const size_t len = index_file->element_len;;
 202
 203         assert(index_file);
 204         assert(element);
 205
 206         if (!index_file->file) {
 207                 goto error;
 208         }
 209
 210         ret = fs_handle_write(index_file->file, element, len);
 211         if (ret < len) {
 212                 PERROR("writing index file");
 213                 goto error;
 214         }
 215         return 0;
 216
 217 error:
 218         return -1;
 219 }
 220
 221 /*
 222  * Read index values from the given index file.
 223  *
 224  * Return 0 on success, -1 on error.
 225  */
 226 int lttng_index_file_read(const struct lttng_index_file *index_file,
 227                 struct ctf_packet_index *element)
 228 {
 229         ssize_t ret;
 230         const size_t len = index_file->element_len;
 231
 232         assert(element);
 233
 234         if (!index_file->file) {
 235                 goto error;
 236         }
 237
 238         ret = fs_handle_read(index_file->file, element, len);
 239         if (ret < 0) {
 240                 PERROR("read index file");
 241                 goto error;
 242         }
 243         if (ret < len) {
 244                 ERR("lttng_read expected %zu, returned %zd", len, ret);
 245                 goto error;
 246         }
 247         return 0;
 248
 249 error:
 250         return -1;
 251 }
 252
 253 void lttng_index_file_get(struct lttng_index_file *index_file)
 254 {
 255         urcu_ref_get(&index_file->ref);
 256 }
 257
 258 static void lttng_index_file_release(struct urcu_ref *ref)
 259 {
 260         struct lttng_index_file *index_file = caa_container_of(ref,
 261                         struct lttng_index_file, ref);
 262
 263         if (fs_handle_close(index_file->file)) {
 264                 PERROR("close index fd");
 265         }
 266         lttng_trace_chunk_put(index_file->trace_chunk);
 267         free(index_file);
 268 }
 269
 270 void lttng_index_file_put(struct lttng_index_file *index_file)
 271 {
 272         urcu_ref_put(&index_file->ref, lttng_index_file_release);
 273 }