src/common/index/index.cpp

   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 <sys/stat.h>
  12 #include <sys/types.h>
  13 #include <fcntl.h>
  14
  15 #include <lttng/constant.h>
  16 #include <common/common.hpp>
  17 #include <common/defaults.hpp>
  18 #include <common/compat/endian.hpp>
  19 #include <common/utils.hpp>
  20
  21 #include "index.hpp"
  22
  23 #define WRITE_FILE_FLAGS        (O_WRONLY | O_CREAT | O_TRUNC)
  24 #define READ_ONLY_FILE_FLAGS    O_RDONLY
  25
  26 static enum lttng_trace_chunk_status _lttng_index_file_create_from_trace_chunk(
  27                 struct lttng_trace_chunk *chunk,
  28                 const char *channel_path, const char *stream_name,
  29                 uint64_t stream_file_size, uint64_t stream_file_index,
  30                 uint32_t index_major, uint32_t index_minor,
  31                 bool unlink_existing_file,
  32                 int flags, bool expect_no_file, struct lttng_index_file **file)
  33 {
  34         struct lttng_index_file *index_file;
  35         enum lttng_trace_chunk_status chunk_status;
  36         int ret;
  37         struct fs_handle *fs_handle = NULL;
  38         ssize_t size_ret;
  39         struct ctf_packet_index_file_hdr hdr;
  40         char index_directory_path[LTTNG_PATH_MAX];
  41         char index_file_path[LTTNG_PATH_MAX];
  42         const mode_t mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP;
  43         const bool acquired_reference = lttng_trace_chunk_get(chunk);
  44         const char *separator;
  45
  46         LTTNG_ASSERT(acquired_reference);
  47
  48         index_file = zmalloc<lttng_index_file>();
  49         if (!index_file) {
  50                 PERROR("Failed to allocate lttng_index_file");
  51                 chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
  52                 goto error;
  53         }
  54
  55         index_file->trace_chunk = chunk;
  56         if (channel_path[0] == '\0') {
  57                 separator = "";
  58         } else {
  59                 separator = "/";
  60         }
  61         ret = snprintf(index_directory_path, sizeof(index_directory_path),
  62                         "%s%s" DEFAULT_INDEX_DIR, channel_path, separator);
  63         if (ret < 0 || ret >= sizeof(index_directory_path)) {
  64                 ERR("Failed to format index directory path");
  65                 chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
  66                 goto error;
  67         }
  68
  69         ret = utils_stream_file_path(index_directory_path, stream_name,
  70                         stream_file_size, stream_file_index,
  71                         DEFAULT_INDEX_FILE_SUFFIX,
  72                         index_file_path, sizeof(index_file_path));
  73         if (ret) {
  74                 chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
  75                 goto error;
  76         }
  77
  78         if (unlink_existing_file) {
  79                 /*
  80                  * For tracefile rotation. We need to unlink the old
  81                  * file if present to synchronize with the tail of the
  82                  * live viewer which could be working on this same file.
  83                  * By doing so, any reference to the old index file
  84                  * stays valid even if we re-create a new file with the
  85                  * same name afterwards.
  86                  */
  87                 chunk_status = (lttng_trace_chunk_status) lttng_trace_chunk_unlink_file(
  88                                 chunk, index_file_path);
  89                 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK &&
  90                                 !(chunk_status == LTTNG_TRACE_CHUNK_STATUS_ERROR &&
  91                                                 errno == ENOENT)) {
  92                         goto error;
  93                 }
  94         }
  95
  96         chunk_status = lttng_trace_chunk_open_fs_handle(chunk, index_file_path,
  97                         flags, mode, &fs_handle, expect_no_file);
  98         if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
  99                 goto error;
 100         }
 101
 102         if (flags == WRITE_FILE_FLAGS) {
 103                 ctf_packet_index_file_hdr_init(&hdr, index_major, index_minor);
 104                 size_ret = fs_handle_write(fs_handle, &hdr, sizeof(hdr));
 105                 if (size_ret < sizeof(hdr)) {
 106                         PERROR("Failed to write index header");
 107                         chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
 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 = fs_handle_read(fs_handle, &hdr, sizeof(hdr));
 115                 if (size_ret < 0) {
 116                         PERROR("Failed to read index header");
 117                         chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
 118                         goto error;
 119                 }
 120                 if (be32toh(hdr.magic) != CTF_INDEX_MAGIC) {
 121                         ERR("Invalid header magic");
 122                         chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
 123                         goto error;
 124                 }
 125                 if (index_major != be32toh(hdr.index_major)) {
 126                         ERR("Index major number mismatch: %u, expect %u",
 127                                 be32toh(hdr.index_major), index_major);
 128                         chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
 129                         goto error;
 130                 }
 131                 if (index_minor != be32toh(hdr.index_minor)) {
 132                         ERR("Index minor number mismatch: %u, expect %u",
 133                                 be32toh(hdr.index_minor), index_minor);
 134                         chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
 135                         goto error;
 136                 }
 137                 element_len = be32toh(hdr.packet_index_len);
 138                 if (element_len > sizeof(struct ctf_packet_index)) {
 139                         ERR("Index element length too long");
 140                         chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
 141                         goto error;
 142                 }
 143                 index_file->element_len = element_len;
 144         }
 145         index_file->file = fs_handle;
 146         index_file->major = index_major;
 147         index_file->minor = index_minor;
 148         urcu_ref_init(&index_file->ref);
 149
 150         *file = index_file;
 151         return LTTNG_TRACE_CHUNK_STATUS_OK;
 152
 153 error:
 154         if (fs_handle) {
 155                 ret = fs_handle_close(fs_handle);
 156                 if (ret < 0) {
 157                         PERROR("Failed to close file descriptor of index file");
 158                 }
 159         }
 160         lttng_trace_chunk_put(chunk);
 161         free(index_file);
 162         return chunk_status;
 163 }
 164
 165 enum lttng_trace_chunk_status lttng_index_file_create_from_trace_chunk(
 166                 struct lttng_trace_chunk *chunk,
 167                 const char *channel_path, const char *stream_name,
 168                 uint64_t stream_file_size, uint64_t stream_file_index,
 169                 uint32_t index_major, uint32_t index_minor,
 170                 bool unlink_existing_file, struct lttng_index_file **file)
 171 {
 172         return _lttng_index_file_create_from_trace_chunk(chunk, channel_path,
 173                         stream_name, stream_file_size, stream_file_index,
 174                         index_major, index_minor, unlink_existing_file,
 175                         WRITE_FILE_FLAGS, false, file);
 176 }
 177
 178 enum lttng_trace_chunk_status lttng_index_file_create_from_trace_chunk_read_only(
 179                 struct lttng_trace_chunk *chunk,
 180                 const char *channel_path, const char *stream_name,
 181                 uint64_t stream_file_size, uint64_t stream_file_index,
 182                 uint32_t index_major, uint32_t index_minor,
 183                 bool expect_no_file, struct lttng_index_file **file)
 184 {
 185         return _lttng_index_file_create_from_trace_chunk(chunk, channel_path,
 186                         stream_name, stream_file_size, stream_file_index,
 187                         index_major, index_minor, false,
 188                         READ_ONLY_FILE_FLAGS, expect_no_file, file);
 189 }
 190
 191 /*
 192  * Write index values to the given index file.
 193  *
 194  * Return 0 on success, -1 on error.
 195  */
 196 int lttng_index_file_write(const struct lttng_index_file *index_file,
 197                 const struct ctf_packet_index *element)
 198 {
 199         ssize_t ret;
 200         const size_t len = index_file->element_len;;
 201
 202         LTTNG_ASSERT(index_file);
 203         LTTNG_ASSERT(element);
 204
 205         if (!index_file->file) {
 206                 goto error;
 207         }
 208
 209         ret = fs_handle_write(index_file->file, element, len);
 210         if (ret < len) {
 211                 PERROR("writing index file");
 212                 goto error;
 213         }
 214         return 0;
 215
 216 error:
 217         return -1;
 218 }
 219
 220 /*
 221  * Read index values from the given index file.
 222  *
 223  * Return 0 on success, -1 on error.
 224  */
 225 int lttng_index_file_read(const struct lttng_index_file *index_file,
 226                 struct ctf_packet_index *element)
 227 {
 228         ssize_t ret;
 229         const size_t len = index_file->element_len;
 230
 231         LTTNG_ASSERT(element);
 232
 233         if (!index_file->file) {
 234                 goto error;
 235         }
 236
 237         ret = fs_handle_read(index_file->file, element, len);
 238         if (ret < 0) {
 239                 PERROR("read index file");
 240                 goto error;
 241         }
 242         if (ret < len) {
 243                 ERR("lttng_read expected %zu, returned %zd", len, ret);
 244                 goto error;
 245         }
 246         return 0;
 247
 248 error:
 249         return -1;
 250 }
 251
 252 void lttng_index_file_get(struct lttng_index_file *index_file)
 253 {
 254         urcu_ref_get(&index_file->ref);
 255 }
 256
 257 static void lttng_index_file_release(struct urcu_ref *ref)
 258 {
 259         struct lttng_index_file *index_file = caa_container_of(ref,
 260                         struct lttng_index_file, ref);
 261
 262         if (fs_handle_close(index_file->file)) {
 263                 PERROR("close index fd");
 264         }
 265         lttng_trace_chunk_put(index_file->trace_chunk);
 266         free(index_file);
 267 }
 268
 269 void lttng_index_file_put(struct lttng_index_file *index_file)
 270 {
 271         urcu_ref_put(&index_file->ref, lttng_index_file_release);
 272 }