libc-top-half/musl/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 #if defined(__wasilibc_unmodified_upstream) || defined(_REENTRANT)
  10 #include <pthread.h>
  11 #endif
  12 #include <errno.h>
  13 #include <fcntl.h>
  14 #include "lock.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
  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 #if defined(__wasilibc_unmodified_upstream) || defined(_REENTRANT)
  43         int cs;
  44         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
  45 #endif
  46         LOCK(lock);
  47         close(log_fd);
  48         log_fd = -1;
  49         UNLOCK(lock);
  50 #if defined(__wasilibc_unmodified_upstream) || defined(_REENTRANT)
  51         pthread_setcancelstate(cs, 0);
  52 #endif
  53 }
  54
  55 static void __openlog()
  56 {
  57         log_fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0);
  58         if (log_fd >= 0) connect(log_fd, (void *)&log_addr, sizeof log_addr);
  59 }
  60
  61 void openlog(const char *ident, int opt, int facility)
  62 {
  63 #if defined(__wasilibc_unmodified_upstream) || defined(_REENTRANT)
  64         int cs;
  65         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
  66 #endif
  67         LOCK(lock);
  68
  69         if (ident) {
  70                 size_t n = strnlen(ident, sizeof log_ident - 1);
  71                 memcpy(log_ident, ident, n);
  72                 log_ident[n] = 0;
  73         } else {
  74                 log_ident[0] = 0;
  75         }
  76         log_opt = opt;
  77         log_facility = facility;
  78
  79         if ((opt & LOG_NDELAY) && log_fd<0) __openlog();
  80
  81         UNLOCK(lock);
  82 #if defined(__wasilibc_unmodified_upstream) || defined(_REENTRANT)
  83         pthread_setcancelstate(cs, 0);
  84 #endif
  85 }
  86
  87 static int is_lost_conn(int e)
  88 {
  89         return e==ECONNREFUSED || e==ECONNRESET || e==ENOTCONN || e==EPIPE;
  90 }
  91
  92 static void _vsyslog(int priority, const char *message, va_list ap)
  93 {
  94         char timebuf[16];
  95         time_t now;
  96         struct tm tm;
  97         char buf[1024];
  98         int errno_save = errno;
  99         int pid;
 100         int l, l2;
 101         int hlen;
 102         int fd;
 103
 104         if (log_fd < 0) __openlog();
 105
 106         if (!(priority & LOG_FACMASK)) priority |= log_facility;
 107
 108         now = time(NULL);
 109         gmtime_r(&now, &tm);
 110         strftime(timebuf, sizeof timebuf, "%b %e %T", &tm);
 111
 112         pid = (log_opt & LOG_PID) ? getpid() : 0;
 113         l = snprintf(buf, sizeof buf, "<%d>%s %n%s%s%.0d%s: ",
 114                 priority, timebuf, &hlen, log_ident, "["+!pid, pid, "]"+!pid);
 115         errno = errno_save;
 116         l2 = vsnprintf(buf+l, sizeof buf - l, message, ap);
 117         if (l2 >= 0) {
 118                 if (l2 >= sizeof buf - l) l = sizeof buf - 1;
 119                 else l += l2;
 120                 if (buf[l-1] != '\n') buf[l++] = '\n';
 121                 if (send(log_fd, buf, l, 0) < 0 && (!is_lost_conn(errno)
 122                     || connect(log_fd, (void *)&log_addr, sizeof log_addr) < 0
 123                     || send(log_fd, buf, l, 0) < 0)
 124                     && (log_opt & LOG_CONS)) {
 125                         fd = open("/dev/console", O_WRONLY|O_NOCTTY|O_CLOEXEC);
 126                         if (fd >= 0) {
 127                                 dprintf(fd, "%.*s", l-hlen, buf+hlen);
 128                                 close(fd);
 129                         }
 130                 }
 131                 if (log_opt & LOG_PERROR) dprintf(2, "%.*s", l-hlen, buf+hlen);
 132         }
 133 }
 134
 135 static void __vsyslog(int priority, const char *message, va_list ap)
 136 {
 137 #if defined(__wasilibc_unmodified_upstream) || defined(_REENTRANT)
 138         int cs;
 139 #endif
 140         if (!(log_mask & LOG_MASK(priority&7)) || (priority&~0x3ff)) return;
 141 #if defined(__wasilibc_unmodified_upstream) || defined(_REENTRANT)
 142         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
 143 #endif
 144         LOCK(lock);
 145         _vsyslog(priority, message, ap);
 146         UNLOCK(lock);
 147 #if defined(__wasilibc_unmodified_upstream) || defined(_REENTRANT)
 148         pthread_setcancelstate(cs, 0);
 149 #endif
 150 }
 151
 152 void syslog(int priority, const char *message, ...)
 153 {
 154         va_list ap;
 155         va_start(ap, message);
 156         __vsyslog(priority, message, ap);
 157         va_end(ap);
 158 }
 159
 160 weak_alias(__vsyslog, vsyslog);