src/common/index/index.c

   1 /*
   2  * Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
   3  *                      David Goulet <dgoulet@efficios.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License, version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  12  * more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along with
  15  * this program; if not, write to the Free Software Foundation, Inc., 51
  16  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #define _GNU_SOURCE
  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 fd on success, a negative value on error.
  37  */
  38 int index_create_file(char *path_name, char *stream_name, int uid, int gid,
  39                 uint64_t size, uint64_t count)
  40 {
  41         int ret, fd = -1;
  42         ssize_t size_ret;
  43         struct ctf_packet_index_file_hdr hdr;
  44         char fullpath[PATH_MAX];
  45
  46         ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR,
  47                         path_name);
  48         if (ret < 0) {
  49                 PERROR("snprintf index path");
  50                 goto error;
  51         }
  52
  53         /* Create index directory if necessary. */
  54         ret = utils_mkdir(fullpath, S_IRWXU | S_IRWXG, uid, gid);
  55         if (ret < 0) {
  56                 if (ret != -EEXIST) {
  57                         PERROR("Index trace directory creation error");
  58                         goto error;
  59                 }
  60         }
  61
  62         /*
  63          * For tracefile rotation. We need to unlink the old
  64          * file if present to synchronize with the tail of the
  65          * live viewer which could be working on this same file.
  66          * By doing so, any reference to the old index file
  67          * stays valid even if we re-create a new file with the
  68          * same name afterwards.
  69          */
  70         ret = utils_unlink_stream_file(fullpath, stream_name, size, count, uid,
  71                         gid, DEFAULT_INDEX_FILE_SUFFIX);
  72         if (ret < 0 && errno != ENOENT) {
  73                 goto error;
  74         }
  75         ret = utils_create_stream_file(fullpath, stream_name, size, count, uid,
  76                         gid, DEFAULT_INDEX_FILE_SUFFIX);
  77         if (ret < 0) {
  78                 goto error;
  79         }
  80         fd = ret;
  81
  82         hdr.magic = htobe32(CTF_INDEX_MAGIC);
  83         hdr.index_major = htobe32(CTF_INDEX_MAJOR);
  84         hdr.index_minor = htobe32(CTF_INDEX_MINOR);
  85         hdr.packet_index_len = htobe32(sizeof(struct ctf_packet_index));
  86
  87         size_ret = lttng_write(fd, &hdr, sizeof(hdr));
  88         if (size_ret < sizeof(hdr)) {
  89                 PERROR("write index header");
  90                 ret = -1;
  91                 goto error;
  92         }
  93
  94         return fd;
  95
  96 error:
  97         if (fd >= 0) {
  98                 int close_ret;
  99
 100                 close_ret = close(fd);
 101                 if (close_ret < 0) {
 102                         PERROR("close index fd");
 103                 }
 104         }
 105         return ret;
 106 }
 107
 108 /*
 109  * Write index values to the given fd of size len.
 110  *
 111  * Return "len" on success or else < len on error. errno contains error
 112  * details.
 113  */
 114 ssize_t index_write(int fd, struct ctf_packet_index *index, size_t len)
 115 {
 116         ssize_t ret;
 117
 118         assert(index);
 119
 120         if (fd < 0) {
 121                 ret = -EINVAL;
 122                 goto error;
 123         }
 124
 125         ret = lttng_write(fd, index, len);
 126         if (ret < len) {
 127                 PERROR("writing index file");
 128         }
 129
 130 error:
 131         return ret;
 132 }
 133
 134 /*
 135  * Open index file using a given path, channel name and tracefile count.
 136  *
 137  * Return read only FD on success or else a negative value.
 138  */
 139 int index_open(const char *path_name, const char *channel_name,
 140                 uint64_t tracefile_count, uint64_t tracefile_count_current)
 141 {
 142         int ret, read_fd;
 143         ssize_t read_len;
 144         char fullpath[PATH_MAX];
 145         struct ctf_packet_index_file_hdr hdr;
 146
 147         assert(path_name);
 148         assert(channel_name);
 149
 150         if (tracefile_count > 0) {
 151                 ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR "/%s_%"
 152                                 PRIu64 DEFAULT_INDEX_FILE_SUFFIX, path_name,
 153                                 channel_name, tracefile_count_current);
 154         } else {
 155                 ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR "/%s"
 156                                 DEFAULT_INDEX_FILE_SUFFIX, path_name, channel_name);
 157         }
 158         if (ret < 0) {
 159                 PERROR("snprintf index path");
 160                 goto error;
 161         }
 162
 163         DBG("Index opening file %s in read only", fullpath);
 164         read_fd = open(fullpath, O_RDONLY);
 165         if (read_fd < 0) {
 166                 if (errno == ENOENT) {
 167                         ret = -ENOENT;
 168                 } else {
 169                         PERROR("opening index in read-only");
 170                 }
 171                 goto error;
 172         }
 173
 174         read_len = lttng_read(read_fd, &hdr, sizeof(hdr));
 175         if (read_len < 0) {
 176                 PERROR("Reading index header");
 177                 goto error_close;
 178         }
 179
 180         if (be32toh(hdr.magic) != CTF_INDEX_MAGIC) {
 181                 ERR("Invalid header magic");
 182                 goto error_close;
 183         }
 184         if (be32toh(hdr.index_major) != CTF_INDEX_MAJOR ||
 185                         be32toh(hdr.index_minor) != CTF_INDEX_MINOR) {
 186                 ERR("Invalid header version");
 187                 goto error_close;
 188         }
 189
 190         return read_fd;
 191
 192 error_close:
 193         if (read_fd >= 0) {
 194                 int close_ret;
 195
 196                 close_ret = close(read_fd);
 197                 if (close_ret < 0) {
 198                         PERROR("close read fd %d", read_fd);
 199                 }
 200         }
 201         ret = -1;
 202
 203 error:
 204         return ret;
 205 }