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 #include <assert.h>
  21 #include <sys/stat.h>
  22 #include <sys/types.h>
  23 #include <fcntl.h>
  24
  25 #include <common/common.h>
  26 #include <common/defaults.h>
  27 #include <common/utils.h>
  28
  29 #include "index.h"
  30
  31 /*
  32  * Create the index file associated with a trace file.
  33  *
  34  * Return fd on success, a negative value on error.
  35  */
  36 int index_create_file(char *path_name, char *stream_name, int uid, int gid,
  37                 uint64_t size, uint64_t count)
  38 {
  39         int ret, fd = -1;
  40         ssize_t size_ret;
  41         struct ctf_packet_index_file_hdr hdr;
  42         char fullpath[PATH_MAX];
  43
  44         ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR,
  45                         path_name);
  46         if (ret < 0) {
  47                 PERROR("snprintf index path");
  48                 goto error;
  49         }
  50
  51         /* Create index directory if necessary. */
  52         ret = run_as_mkdir(fullpath, S_IRWXU | S_IRWXG, uid, gid);
  53         if (ret < 0) {
  54                 if (ret != -EEXIST) {
  55                         ERR("Index trace directory creation error");
  56                         goto error;
  57                 }
  58         }
  59
  60         ret = utils_create_stream_file(fullpath, stream_name, size, count, uid,
  61                         gid, DEFAULT_INDEX_FILE_SUFFIX);
  62         if (ret < 0) {
  63                 goto error;
  64         }
  65         fd = ret;
  66
  67         hdr.magic = htobe32(CTF_INDEX_MAGIC);
  68         hdr.index_major = htobe32(CTF_INDEX_MAJOR);
  69         hdr.index_minor = htobe32(CTF_INDEX_MINOR);
  70         hdr.packet_index_len = sizeof(struct ctf_packet_index);
  71
  72         size_ret = lttng_write(fd, &hdr, sizeof(hdr));
  73         if (size_ret < sizeof(hdr)) {
  74                 PERROR("write index header");
  75                 ret = -1;
  76                 goto error;
  77         }
  78
  79         return fd;
  80
  81 error:
  82         if (fd >= 0) {
  83                 int close_ret;
  84
  85                 close_ret = close(fd);
  86                 if (close_ret < 0) {
  87                         PERROR("close index fd");
  88                 }
  89         }
  90         return ret;
  91 }
  92
  93 /*
  94  * Write index values to the given fd of size len.
  95  *
  96  * Return "len" on success or else < len on error. errno contains error
  97  * details.
  98  */
  99 ssize_t index_write(int fd, struct ctf_packet_index *index, size_t len)
 100 {
 101         ssize_t ret;
 102
 103         assert(fd >= 0);
 104         assert(index);
 105
 106         ret = lttng_write(fd, index, len);
 107         if (ret < len) {
 108                 PERROR("writing index file");
 109         }
 110
 111         return ret;
 112 }
 113
 114 /*
 115  * Open index file using a given path, channel name and tracefile count.
 116  *
 117  * Return read only FD on success or else a negative value.
 118  */
 119 int index_open(const char *path_name, const char *channel_name,
 120                 uint64_t tracefile_count, uint64_t tracefile_count_current)
 121 {
 122         int ret, read_fd;
 123         ssize_t read_len;
 124         char fullpath[PATH_MAX];
 125         struct ctf_packet_index_file_hdr hdr;
 126
 127         assert(path_name);
 128         assert(channel_name);
 129
 130         if (tracefile_count > 0) {
 131                 ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR "/%s_%"
 132                                 PRIu64 DEFAULT_INDEX_FILE_SUFFIX, path_name,
 133                                 channel_name, tracefile_count_current);
 134         } else {
 135                 ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR "/%s"
 136                                 DEFAULT_INDEX_FILE_SUFFIX, path_name, channel_name);
 137         }
 138         if (ret < 0) {
 139                 PERROR("snprintf index path");
 140                 goto error;
 141         }
 142
 143         DBG("Index opening file %s in read only", fullpath);
 144         read_fd = open(fullpath, O_RDONLY);
 145         if (read_fd < 0) {
 146                 if (errno == ENOENT) {
 147                         ret = -ENOENT;
 148                 } else {
 149                         PERROR("opening index in read-only");
 150                 }
 151                 goto error;
 152         }
 153
 154         read_len = lttng_read(read_fd, &hdr, sizeof(hdr));
 155         if (read_len < 0) {
 156                 PERROR("Reading index header");
 157                 goto error_close;
 158         }
 159
 160         if (be32toh(hdr.magic) != CTF_INDEX_MAGIC) {
 161                 ERR("Invalid header magic");
 162                 goto error_close;
 163         }
 164         if (be32toh(hdr.index_major) != CTF_INDEX_MAJOR ||
 165                         be32toh(hdr.index_minor) != CTF_INDEX_MINOR) {
 166                 ERR("Invalid header version");
 167                 goto error_close;
 168         }
 169
 170         return read_fd;
 171
 172 error_close:
 173         if (read_fd >= 0) {
 174                 int close_ret;
 175
 176                 close_ret = close(read_fd);
 177                 if (close_ret < 0) {
 178                         PERROR("close read fd %d", read_fd);
 179                 }
 180         }
 181         ret = -1;
 182
 183 error:
 184         return ret;
 185 }