src/lxc/log.c

   1 /*
   2  * lxc: linux Container library
   3  *
   4  * (C) Copyright IBM Corp. 2007, 2008
   5  *
   6  * Authors:
   7  * Cedric Le Goater <legoater@free.fr>
   8  *
   9  * This library is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2.1 of the License, or (at your option) any later version.
  13  *
  14  * This library is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with this library; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  22  */
  23 #include <stdio.h>
  24 #include <errno.h>
  25 #include <limits.h>
  26 #include <unistd.h>
  27 #include <sys/types.h>
  28 #include <sys/stat.h>
  29 #include <string.h>
  30
  31 #define __USE_GNU /* for *_CLOEXEC */
  32
  33 #include <fcntl.h>
  34 #include <stdlib.h>
  35
  36 #include <lxc/log.h>
  37
  38 #define LXC_LOG_PREFIX_SIZE     32
  39 #define LXC_LOG_BUFFER_SIZE     512
  40
  41 int lxc_log_fd = 2;
  42 static char log_prefix[LXC_LOG_PREFIX_SIZE] = "lxc";
  43
  44 lxc_log_define(lxc_log, lxc);
  45
  46 /*---------------------------------------------------------------------------*/
  47 static int log_append_logfile(const struct lxc_log_appender *appender,
  48                               struct lxc_log_event *event)
  49 {
  50         char buffer[LXC_LOG_BUFFER_SIZE];
  51         int n;
  52
  53         if (lxc_log_fd == -1)
  54                 return 0;
  55
  56         n = snprintf(buffer, sizeof(buffer),
  57                      "%15s %10ld.%03ld %-8s %s - ",
  58                      log_prefix,
  59                      event->timestamp.tv_sec,
  60                      event->timestamp.tv_usec / 1000,
  61                      lxc_log_priority_to_string(event->priority),
  62                      event->category);
  63
  64         n += vsnprintf(buffer + n, sizeof(buffer) - n, event->fmt,
  65                        *event->vap);
  66
  67         if (n >= sizeof(buffer) - 1) {
  68                 WARN("truncated next event from %d to %zd bytes", n,
  69                      sizeof(buffer));
  70                 n = sizeof(buffer) - 1;
  71         }
  72
  73         buffer[n] = '\n';
  74
  75         return write(lxc_log_fd, buffer, n + 1);
  76 }
  77
  78 static struct lxc_log_appender log_appender_logfile = {
  79         .name           = "logfile",
  80         .append         = log_append_logfile,
  81         .next           = NULL,
  82 };
  83
  84 static struct lxc_log_category log_root = {
  85         .name           = "root",
  86         .priority       = LXC_LOG_PRIORITY_ERROR,
  87         .appender       = NULL,
  88         .parent         = NULL,
  89 };
  90
  91 struct lxc_log_category lxc_log_category_lxc = {
  92         .name           = "lxc",
  93         .priority       = LXC_LOG_PRIORITY_ERROR,
  94         .appender       = &log_appender_logfile,
  95         .parent         = &log_root
  96 };
  97
  98 /*---------------------------------------------------------------------------*/
  99 extern void lxc_log_setprefix(const char *prefix)
 100 {
 101         strncpy(log_prefix, prefix, sizeof(log_prefix));
 102         log_prefix[sizeof(log_prefix) - 1] = 0;
 103 }
 104
 105 /*---------------------------------------------------------------------------*/
 106 static int log_open(const char *name)
 107 {
 108         int fd;
 109         int newfd;
 110
 111         fd = open(name, O_CREAT | O_WRONLY | O_APPEND | O_CLOEXEC, 0666);
 112         if (fd == -1) {
 113                 ERROR("failed to open log file \"%s\" : %s", name,
 114                       strerror(errno));
 115                 return -1;
 116         }
 117
 118         if (fd > 2)
 119                 return fd;
 120
 121         newfd = fcntl(fd, F_DUPFD_CLOEXEC, 3);
 122         if (newfd == -1)
 123                 ERROR("failed to dup log fd %d : %s", fd, strerror(errno));
 124
 125         close(fd);
 126         return newfd;
 127 }
 128
 129 /*---------------------------------------------------------------------------*/
 130 extern int lxc_log_init(const char *file, const char *priority,
 131                         const char *prefix)
 132 {
 133         int lxc_priority = LXC_LOG_PRIORITY_ERROR;
 134
 135         if (priority) {
 136                 lxc_priority = lxc_log_priority_to_int(priority);
 137
 138                 if (lxc_priority == LXC_LOG_PRIORITY_NOTSET) {
 139                         ERROR("invalid log priority %s", priority);
 140                         return -1;
 141                 }
 142         }
 143
 144         lxc_log_category_lxc.priority = lxc_priority;
 145
 146         if (prefix)
 147                 lxc_log_setprefix(prefix);
 148
 149         if (file) {
 150                 int fd;
 151
 152                 fd = log_open(file);
 153                 if (fd == -1) {
 154                         ERROR("failed to initialize log service");
 155                         return -1;
 156                 }
 157
 158                 lxc_log_fd = fd;
 159         }
 160
 161         return 0;
 162 }