log.c

   1 /*-*- Mode: C; c-basic-offset: 8 -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2010 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU General Public License as published by
  10   the Free Software Foundation; either version 2 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <stdarg.h>
  23 #include <stdio.h>
  24 #include <errno.h>
  25 #include <unistd.h>
  26 #include <fcntl.h>
  27 #include <sys/socket.h>
  28 #include <sys/un.h>
  29
  30 #include "log.h"
  31 #include "util.h"
  32 #include "macro.h"
  33
  34 extern char * __progname;
  35
  36 #define SYSLOG_TIMEOUT_USEC (5*USEC_PER_SEC)
  37 #define LOG_BUFFER_MAX 1024
  38
  39 static LogTarget log_target = LOG_TARGET_CONSOLE;
  40 static int log_max_level = LOG_DEBUG;
  41
  42 static int syslog_fd = -1;
  43 static int kmsg_fd = -1;
  44
  45 void log_close_kmsg(void) {
  46
  47         if (kmsg_fd >= 0) {
  48                 close_nointr(kmsg_fd);
  49                 kmsg_fd = -1;
  50         }
  51 }
  52
  53 int log_open_kmsg(void) {
  54
  55         if (log_target != LOG_TARGET_KMSG) {
  56                 log_close_kmsg();
  57                 return 0;
  58         }
  59
  60         if (kmsg_fd >= 0)
  61                 return 0;
  62
  63         if ((kmsg_fd = open("/dev/kmsg", O_WRONLY|O_NOCTTY|O_CLOEXEC)) < 0)
  64                 return -errno;
  65
  66         return 0;
  67 }
  68
  69 void log_close_syslog(void) {
  70
  71         if (syslog_fd >= 0) {
  72                 close_nointr(syslog_fd);
  73                 syslog_fd = -1;
  74         }
  75 }
  76
  77 int log_open_syslog(void) {
  78         union {
  79                 struct sockaddr sa;
  80                 struct sockaddr_un un;
  81         } sa;
  82         struct timeval tv;
  83         int r;
  84
  85         if (log_target != LOG_TARGET_SYSLOG) {
  86                 log_close_syslog();
  87                 return 0;
  88         }
  89
  90         if (syslog_fd >= 0)
  91                 return 0;
  92
  93         if ((syslog_fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0)) < 0)
  94                 return -errno;
  95
  96         /* Make sure we don't block for more than 5s when talking to
  97          * syslog */
  98         timeval_store(&tv, SYSLOG_TIMEOUT_USEC);
  99         if (setsockopt(syslog_fd, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv)) < 0) {
 100                 r = -errno;
 101                 log_close_syslog();
 102                 return r;
 103         }
 104
 105         zero(sa);
 106         sa.un.sun_family = AF_UNIX;
 107         strncpy(sa.un.sun_path, "/dev/log", sizeof(sa.un.sun_path));
 108
 109         if (connect(syslog_fd, &sa.sa, sizeof(sa)) < 0) {
 110                 r = -errno;
 111                 log_close_syslog();
 112                 return -errno;
 113         }
 114
 115         return 0;
 116 }
 117
 118 void log_set_target(LogTarget target) {
 119         assert(target >= 0);
 120         assert(target < _LOG_TARGET_MAX);
 121
 122         log_target = target;
 123 }
 124
 125 void log_set_max_level(int level) {
 126         assert((level & LOG_PRIMASK) == level);
 127
 128         log_max_level = level;
 129 }
 130
 131 static void write_to_console(
 132         int level,
 133         const char*file,
 134         int line,
 135         const char *func,
 136         const char *format,
 137         va_list ap) {
 138
 139         const char *prefix, *suffix;
 140
 141         if (LOG_PRI(level) <= LOG_ERR) {
 142                 prefix = "\x1B[1;31m";
 143                 suffix = "\x1B[0m";
 144         } else {
 145                 prefix = "";
 146                 suffix = "";
 147         }
 148
 149         fprintf(stderr, "(%s:%u) %s", file, line, prefix);
 150         vfprintf(stderr, format, ap);
 151         fprintf(stderr, "%s\n", suffix);
 152 }
 153
 154 static int write_to_syslog(
 155         int level,
 156         const char*file,
 157         int line,
 158         const char *func,
 159         const char *format,
 160         va_list ap) {
 161
 162         char header_priority[16], header_time[64], header_pid[16];
 163         char buffer[LOG_BUFFER_MAX];
 164         struct iovec iovec[5];
 165         struct msghdr msghdr;
 166         time_t t;
 167         struct tm *tm;
 168
 169         if (syslog_fd < 0)
 170                 return -EIO;
 171
 172         snprintf(header_priority, sizeof(header_priority), "<%i>", LOG_MAKEPRI(LOG_DAEMON, LOG_PRI(level)));
 173         char_array_0(header_priority);
 174
 175         t = (time_t) (now(CLOCK_REALTIME) / USEC_PER_SEC);
 176         if (!(tm = localtime(&t)))
 177                 return -EINVAL;
 178
 179         if (strftime(header_time, sizeof(header_time), "%h %e %T ", tm) <= 0)
 180                 return -EINVAL;
 181
 182         snprintf(header_pid, sizeof(header_pid), "[%llu]: ", (unsigned long long) getpid());
 183         char_array_0(header_pid);
 184
 185         vsnprintf(buffer, sizeof(buffer), format, ap);
 186         char_array_0(buffer);
 187
 188         zero(iovec);
 189         IOVEC_SET_STRING(iovec[0], header_priority);
 190         IOVEC_SET_STRING(iovec[1], header_time);
 191         IOVEC_SET_STRING(iovec[2], file_name_from_path(__progname));
 192         IOVEC_SET_STRING(iovec[3], header_pid);
 193         IOVEC_SET_STRING(iovec[4], buffer);
 194
 195         zero(msghdr);
 196         msghdr.msg_iov = iovec;
 197         msghdr.msg_iovlen = ELEMENTSOF(iovec);
 198
 199         if (sendmsg(syslog_fd, &msghdr, 0) < 0)
 200                 return -errno;
 201
 202         return 0;
 203 }
 204
 205 static int write_to_kmsg(
 206         int level,
 207         const char*file,
 208         int line,
 209         const char *func,
 210         const char *format,
 211         va_list ap) {
 212
 213         char header_priority[16], header_pid[16];
 214         char buffer[LOG_BUFFER_MAX];
 215         struct iovec iovec[5];
 216
 217         if (kmsg_fd < 0)
 218                 return -EIO;
 219
 220         snprintf(header_priority, sizeof(header_priority), "<%i>", LOG_PRI(level));
 221         char_array_0(header_priority);
 222
 223         snprintf(header_pid, sizeof(header_pid), "[%llu]: ", (unsigned long long) getpid());
 224         char_array_0(header_pid);
 225
 226         vsnprintf(buffer, sizeof(buffer), format, ap);
 227         char_array_0(buffer);
 228
 229         zero(iovec);
 230         IOVEC_SET_STRING(iovec[0], header_priority);
 231         IOVEC_SET_STRING(iovec[1], file_name_from_path(__progname));
 232         IOVEC_SET_STRING(iovec[2], header_pid);
 233         IOVEC_SET_STRING(iovec[3], buffer);
 234         IOVEC_SET_STRING(iovec[4], (char*) "\n");
 235
 236         if (writev(kmsg_fd, iovec, ELEMENTSOF(iovec)) < 0)
 237                 return -errno;
 238
 239         return 0;
 240 }
 241
 242 void log_meta(
 243         int level,
 244         const char*file,
 245         int line,
 246         const char *func,
 247         const char *format, ...) {
 248
 249         va_list ap;
 250         bool written;
 251         int saved_errno;
 252
 253         if (LOG_PRI(level) > log_max_level)
 254                 return;
 255
 256         saved_errno = errno;
 257         written = false;
 258
 259         if (log_target == LOG_TARGET_KMSG) {
 260                 va_start(ap, format);
 261                 written = write_to_kmsg(level, file, line, func, format, ap) >= 0;
 262                 va_end(ap);
 263         } else if (log_target == LOG_TARGET_SYSLOG) {
 264                 va_start(ap, format);
 265                 written = write_to_syslog(level, file, line, func, format, ap) >= 0;
 266                 va_end(ap);
 267         }
 268
 269         if (!written) {
 270                 va_start(ap, format);
 271                 write_to_console(level, file, line, func, format, ap);
 272                 va_end(ap);
 273         }
 274
 275         errno = saved_errno;
 276 }