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 <common/common.h>
  27 #include <common/defaults.h>
  28 #include <common/compat/endian.h>
  29 #include <common/utils.h>
  30
  31 #include "index.h"
  32
  33 /*
  34  * Create the index file associated with a trace file.
  35  *
  36  * Return allocated struct lttng_index_file, NULL on error.
  37  */
  38 struct lttng_index_file *lttng_index_file_create(const char *path_name,
  39                 char *stream_name, int uid, int gid,
  40                 uint64_t size, uint64_t count, uint32_t major, uint32_t minor)
  41 {
  42         struct lttng_index_file *index_file;
  43         int ret, fd = -1;
  44         ssize_t size_ret;
  45         struct ctf_packet_index_file_hdr hdr;
  46         char fullpath[PATH_MAX];
  47         uint32_t element_len = ctf_packet_index_len(major, minor);
  48
  49         index_file = zmalloc(sizeof(*index_file));
  50         if (!index_file) {
  51                 PERROR("allocating lttng_index_file");
  52                 goto error;
  53         }
  54
  55         ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR,
  56                         path_name);
  57         if (ret < 0) {
  58                 PERROR("snprintf index path");
  59                 goto error;
  60         }
  61
  62         /* Create index directory if necessary. */
  63         ret = utils_mkdir(fullpath, S_IRWXU | S_IRWXG, uid, gid);
  64         if (ret < 0) {
  65                 if (errno != EEXIST) {
  66                         PERROR("Index trace directory creation error");
  67                         goto error;
  68                 }
  69         }
  70
  71         /*
  72          * For tracefile rotation. We need to unlink the old
  73          * file if present to synchronize with the tail of the
  74          * live viewer which could be working on this same file.
  75          * By doing so, any reference to the old index file
  76          * stays valid even if we re-create a new file with the
  77          * same name afterwards.
  78          */
  79         ret = utils_unlink_stream_file(fullpath, stream_name, size, count, uid,
  80                         gid, DEFAULT_INDEX_FILE_SUFFIX);
  81         if (ret < 0 && errno != ENOENT) {
  82                 goto error;
  83         }
  84         ret = utils_create_stream_file(fullpath, stream_name, size, count, uid,
  85                         gid, DEFAULT_INDEX_FILE_SUFFIX);
  86         if (ret < 0) {
  87                 goto error;
  88         }
  89         fd = ret;
  90
  91         hdr.magic = htobe32(CTF_INDEX_MAGIC);
  92         hdr.index_major = htobe32(major);
  93         hdr.index_minor = htobe32(minor);
  94         hdr.packet_index_len = htobe32(element_len);
  95
  96         size_ret = lttng_write(fd, &hdr, sizeof(hdr));
  97         if (size_ret < sizeof(hdr)) {
  98                 PERROR("write index header");
  99                 goto error;
 100         }
 101         index_file->fd = fd;
 102         index_file->major = major;
 103         index_file->minor = minor;
 104         index_file->element_len = element_len;
 105         urcu_ref_init(&index_file->ref);
 106
 107         return index_file;
 108
 109 error:
 110         if (fd >= 0) {
 111                 int close_ret;
 112
 113                 close_ret = close(fd);
 114                 if (close_ret < 0) {
 115                         PERROR("close index fd");
 116                 }
 117         }
 118         free(index_file);
 119         return NULL;
 120 }
 121
 122 /*
 123  * Write index values to the given index file.
 124  *
 125  * Return 0 on success, -1 on error.
 126  */
 127 int lttng_index_file_write(const struct lttng_index_file *index_file,
 128                 const struct ctf_packet_index *element)
 129 {
 130         int fd;
 131         size_t len;
 132         ssize_t ret;
 133
 134         assert(index_file);
 135         assert(element);
 136
 137         fd = index_file->fd;
 138         len = index_file->element_len;
 139
 140         if (fd < 0) {
 141                 goto error;
 142         }
 143
 144         ret = lttng_write(fd, element, len);
 145         if (ret < len) {
 146                 PERROR("writing index file");
 147                 goto error;
 148         }
 149         return 0;
 150
 151 error:
 152         return -1;
 153 }
 154
 155 /*
 156  * Read index values from the given index file.
 157  *
 158  * Return 0 on success, -1 on error.
 159  */
 160 int lttng_index_file_read(const struct lttng_index_file *index_file,
 161                 struct ctf_packet_index *element)
 162 {
 163         ssize_t ret;
 164         int fd = index_file->fd;
 165         size_t len = index_file->element_len;
 166
 167         assert(element);
 168
 169         if (fd < 0) {
 170                 goto error;
 171         }
 172
 173         ret = lttng_read(fd, element, len);
 174         if (ret < len) {
 175                 PERROR("read index file");
 176                 goto error;
 177         }
 178         return 0;
 179
 180 error:
 181         return -1;
 182 }
 183
 184 /*
 185  * Open index file using a given path, channel name and tracefile count.
 186  *
 187  * Return allocated struct lttng_index_file, NULL on error.
 188  */
 189 struct lttng_index_file *lttng_index_file_open(const char *path_name,
 190                 const char *channel_name, uint64_t tracefile_count,
 191                 uint64_t tracefile_count_current)
 192 {
 193         struct lttng_index_file *index_file;
 194         int ret, read_fd;
 195         ssize_t read_len;
 196         char fullpath[PATH_MAX];
 197         struct ctf_packet_index_file_hdr hdr;
 198         uint32_t major, minor, element_len;
 199
 200         assert(path_name);
 201         assert(channel_name);
 202
 203         index_file = zmalloc(sizeof(*index_file));
 204         if (!index_file) {
 205                 PERROR("allocating lttng_index_file");
 206                 goto error;
 207         }
 208
 209         if (tracefile_count > 0) {
 210                 ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR "/%s_%"
 211                                 PRIu64 DEFAULT_INDEX_FILE_SUFFIX, path_name,
 212                                 channel_name, tracefile_count_current);
 213         } else {
 214                 ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR "/%s"
 215                                 DEFAULT_INDEX_FILE_SUFFIX, path_name, channel_name);
 216         }
 217         if (ret < 0) {
 218                 PERROR("snprintf index path");
 219                 goto error;
 220         }
 221
 222         DBG("Index opening file %s in read only", fullpath);
 223         read_fd = open(fullpath, O_RDONLY);
 224         if (read_fd < 0) {
 225                 PERROR("opening index in read-only");
 226                 goto error;
 227         }
 228
 229         read_len = lttng_read(read_fd, &hdr, sizeof(hdr));
 230         if (read_len < 0) {
 231                 PERROR("Reading index header");
 232                 goto error_close;
 233         }
 234
 235         if (be32toh(hdr.magic) != CTF_INDEX_MAGIC) {
 236                 ERR("Invalid header magic");
 237                 goto error_close;
 238         }
 239         major = be32toh(hdr.index_major);
 240         minor = be32toh(hdr.index_minor);
 241         element_len = be32toh(hdr.packet_index_len);
 242
 243         if (major != CTF_INDEX_MAJOR) {
 244                 ERR("Invalid header version");
 245                 goto error_close;
 246         }
 247         if (element_len > sizeof(struct ctf_packet_index)) {
 248                 ERR("Index element length too long");
 249                 goto error_close;
 250         }
 251
 252         index_file->fd = read_fd;
 253         index_file->major = major;
 254         index_file->minor = minor;
 255         index_file->element_len = element_len;
 256         urcu_ref_init(&index_file->ref);
 257
 258         return index_file;
 259
 260 error_close:
 261         if (read_fd >= 0) {
 262                 int close_ret;
 263
 264                 close_ret = close(read_fd);
 265                 if (close_ret < 0) {
 266                         PERROR("close read fd %d", read_fd);
 267                 }
 268         }
 269
 270 error:
 271         free(index_file);
 272         return NULL;
 273 }
 274
 275 void lttng_index_file_get(struct lttng_index_file *index_file)
 276 {
 277         urcu_ref_get(&index_file->ref);
 278 }
 279
 280 static void lttng_index_file_release(struct urcu_ref *ref)
 281 {
 282         struct lttng_index_file *index_file = caa_container_of(ref,
 283                         struct lttng_index_file, ref);
 284
 285         if (close(index_file->fd)) {
 286                 PERROR("close index fd");
 287         }
 288         free(index_file);
 289 }
 290
 291 void lttng_index_file_put(struct lttng_index_file *index_file)
 292 {
 293         urcu_ref_put(&index_file->ref, lttng_index_file_release);
 294 }