src/misc/syslog.c

   1 #include <stdarg.h>
   2 #include <sys/socket.h>
   3 #include <stdio.h>
   4 #include <unistd.h>
   5 #include <syslog.h>
   6 #include <time.h>
   7 #include <signal.h>
   8 #include <string.h>
   9 #include <pthread.h>
  10 #include <errno.h>
  11 #include <fcntl.h>
  12 #include "lock.h"
  13 #include "fork_impl.h"
  14 #include "locale_impl.h"
  15
  16 static volatile int lock[1];
  17 static char log_ident[32];
  18 static int log_opt;
  19 static int log_facility = LOG_USER;
  20 static int log_mask = 0xff;
  21 static int log_fd = -1;
  22 volatile int *const __syslog_lockptr = lock;
  23
  24 int setlogmask(int maskpri)
  25 {
  26         LOCK(lock);
  27         int ret = log_mask;
  28         if (maskpri) log_mask = maskpri;
  29         UNLOCK(lock);
  30         return ret;
  31 }
  32
  33 static const struct {
  34         short sun_family;
  35         char sun_path[9];
  36 } log_addr = {
  37         AF_UNIX,
  38         "/dev/log"
  39 };
  40
  41 void closelog(void)
  42 {
  43         int cs;
  44         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
  45         LOCK(lock);
  46         close(log_fd);
  47         log_fd = -1;
  48         UNLOCK(lock);
  49         pthread_setcancelstate(cs, 0);
  50 }
  51
  52 static void __openlog()
  53 {
  54         log_fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0);
  55         if (log_fd >= 0) connect(log_fd, (void *)&log_addr, sizeof log_addr);
  56 }
  57
  58 void openlog(const char *ident, int opt, int facility)
  59 {
  60         int cs;
  61         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
  62         LOCK(lock);
  63
  64         if (ident) {
  65                 size_t n = strnlen(ident, sizeof log_ident - 1);
  66                 memcpy(log_ident, ident, n);
  67                 log_ident[n] = 0;
  68         } else {
  69                 log_ident[0] = 0;
  70         }
  71         log_opt = opt;
  72         log_facility = facility;
  73
  74         if ((opt & LOG_NDELAY) && log_fd<0) __openlog();
  75
  76         UNLOCK(lock);
  77         pthread_setcancelstate(cs, 0);
  78 }
  79
  80 static int is_lost_conn(int e)
  81 {
  82         return e==ECONNREFUSED || e==ECONNRESET || e==ENOTCONN || e==EPIPE;
  83 }
  84
  85 static void _vsyslog(int priority, const char *message, va_list ap)
  86 {
  87         char timebuf[16];
  88         time_t now;
  89         struct tm tm;
  90         char buf[1024];
  91         int errno_save = errno;
  92         int pid;
  93         int l, l2;
  94         int hlen;
  95         int fd;
  96
  97         if (log_fd < 0) __openlog();
  98
  99         if (!(priority & LOG_FACMASK)) priority |= log_facility;
 100
 101         now = time(NULL);
 102         gmtime_r(&now, &tm);
 103         strftime_l(timebuf, sizeof timebuf, "%b %e %T", &tm, C_LOCALE);
 104
 105         pid = (log_opt & LOG_PID) ? getpid() : 0;
 106         l = snprintf(buf, sizeof buf, "<%d>%s %n%s%s%.0d%s: ",
 107                 priority, timebuf, &hlen, log_ident, "["+!pid, pid, "]"+!pid);
 108         errno = errno_save;
 109         l2 = vsnprintf(buf+l, sizeof buf - l, message, ap);
 110         if (l2 >= 0) {
 111                 if (l2 >= sizeof buf - l) l = sizeof buf - 1;
 112                 else l += l2;
 113                 if (buf[l-1] != '\n') buf[l++] = '\n';
 114                 if (send(log_fd, buf, l, 0) < 0 && (!is_lost_conn(errno)
 115                     || connect(log_fd, (void *)&log_addr, sizeof log_addr) < 0
 116                     || send(log_fd, buf, l, 0) < 0)
 117                     && (log_opt & LOG_CONS)) {
 118                         fd = open("/dev/console", O_WRONLY|O_NOCTTY|O_CLOEXEC);
 119                         if (fd >= 0) {
 120                                 dprintf(fd, "%.*s", l-hlen, buf+hlen);
 121                                 close(fd);
 122                         }
 123                 }
 124                 if (log_opt & LOG_PERROR) dprintf(2, "%.*s", l-hlen, buf+hlen);
 125         }
 126 }
 127
 128 static void __vsyslog(int priority, const char *message, va_list ap)
 129 {
 130         int cs;
 131         if (!(log_mask & LOG_MASK(priority&7)) || (priority&~0x3ff)) return;
 132         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
 133         LOCK(lock);
 134         _vsyslog(priority, message, ap);
 135         UNLOCK(lock);
 136         pthread_setcancelstate(cs, 0);
 137 }
 138
 139 void syslog(int priority, const char *message, ...)
 140 {
 141         va_list ap;
 142         va_start(ap, message);
 143         __vsyslog(priority, message, ap);
 144         va_end(ap);
 145 }
 146
 147 weak_alias(__vsyslog, vsyslog);