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