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 #include "fork_impl.h"
  16
  17 static volatile int lock[1];
  18 static char log_ident[32];
  19 static int log_opt;
  20 static int log_facility = LOG_USER;
  21 static int log_mask = 0xff;
  22 static int log_fd = -1;
  23 volatile int *const __syslog_lockptr = lock;
  24
  25 int setlogmask(int maskpri)
  26 {
  27         LOCK(lock);
  28         int ret = log_mask;
  29         if (maskpri) log_mask = maskpri;
  30         UNLOCK(lock);
  31         return ret;
  32 }
  33
  34 static const struct {
  35         short sun_family;
  36         char sun_path[9];
  37 } log_addr = {
  38         AF_UNIX,
  39         "/dev/log"
  40 };
  41
  42 void closelog(void)
  43 {
  44 #if defined(__wasilibc_unmodified_upstream) || defined(_REENTRANT)
  45         int cs;
  46         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
  47 #endif
  48         LOCK(lock);
  49         close(log_fd);
  50         log_fd = -1;
  51         UNLOCK(lock);
  52 #if defined(__wasilibc_unmodified_upstream) || defined(_REENTRANT)
  53         pthread_setcancelstate(cs, 0);
  54 #endif
  55 }
  56
  57 static void __openlog()
  58 {
  59         log_fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0);
  60         if (log_fd >= 0) connect(log_fd, (void *)&log_addr, sizeof log_addr);
  61 }
  62
  63 void openlog(const char *ident, int opt, int facility)
  64 {
  65 #if defined(__wasilibc_unmodified_upstream) || defined(_REENTRANT)
  66         int cs;
  67         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
  68 #endif
  69         LOCK(lock);
  70
  71         if (ident) {
  72                 size_t n = strnlen(ident, sizeof log_ident - 1);
  73                 memcpy(log_ident, ident, n);
  74                 log_ident[n] = 0;
  75         } else {
  76                 log_ident[0] = 0;
  77         }
  78         log_opt = opt;
  79         log_facility = facility;
  80
  81         if ((opt & LOG_NDELAY) && log_fd<0) __openlog();
  82
  83         UNLOCK(lock);
  84 #if defined(__wasilibc_unmodified_upstream) || defined(_REENTRANT)
  85         pthread_setcancelstate(cs, 0);
  86 #endif
  87 }
  88
  89 static int is_lost_conn(int e)
  90 {
  91         return e==ECONNREFUSED || e==ECONNRESET || e==ENOTCONN || e==EPIPE;
  92 }
  93
  94 static void _vsyslog(int priority, const char *message, va_list ap)
  95 {
  96         char timebuf[16];
  97         time_t now;
  98         struct tm tm;
  99         char buf[1024];
 100         int errno_save = errno;
 101         int pid;
 102         int l, l2;
 103         int hlen;
 104         int fd;
 105
 106         if (log_fd < 0) __openlog();
 107
 108         if (!(priority & LOG_FACMASK)) priority |= log_facility;
 109
 110         now = time(NULL);
 111         gmtime_r(&now, &tm);
 112         strftime(timebuf, sizeof timebuf, "%b %e %T", &tm);
 113
 114         pid = (log_opt & LOG_PID) ? getpid() : 0;
 115         l = snprintf(buf, sizeof buf, "<%d>%s %n%s%s%.0d%s: ",
 116                 priority, timebuf, &hlen, log_ident, "["+!pid, pid, "]"+!pid);
 117         errno = errno_save;
 118         l2 = vsnprintf(buf+l, sizeof buf - l, message, ap);
 119         if (l2 >= 0) {
 120                 if (l2 >= sizeof buf - l) l = sizeof buf - 1;
 121                 else l += l2;
 122                 if (buf[l-1] != '\n') buf[l++] = '\n';
 123                 if (send(log_fd, buf, l, 0) < 0 && (!is_lost_conn(errno)
 124                     || connect(log_fd, (void *)&log_addr, sizeof log_addr) < 0
 125                     || send(log_fd, buf, l, 0) < 0)
 126                     && (log_opt & LOG_CONS)) {
 127                         fd = open("/dev/console", O_WRONLY|O_NOCTTY|O_CLOEXEC);
 128                         if (fd >= 0) {
 129                                 dprintf(fd, "%.*s", l-hlen, buf+hlen);
 130                                 close(fd);
 131                         }
 132                 }
 133                 if (log_opt & LOG_PERROR) dprintf(2, "%.*s", l-hlen, buf+hlen);
 134         }
 135 }
 136
 137 static void __vsyslog(int priority, const char *message, va_list ap)
 138 {
 139 #if defined(__wasilibc_unmodified_upstream) || defined(_REENTRANT)
 140         int cs;
 141 #endif
 142         if (!(log_mask & LOG_MASK(priority&7)) || (priority&~0x3ff)) return;
 143 #if defined(__wasilibc_unmodified_upstream) || defined(_REENTRANT)
 144         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
 145 #endif
 146         LOCK(lock);
 147         _vsyslog(priority, message, ap);
 148         UNLOCK(lock);
 149 #if defined(__wasilibc_unmodified_upstream) || defined(_REENTRANT)
 150         pthread_setcancelstate(cs, 0);
 151 #endif
 152 }
 153
 154 void syslog(int priority, const char *message, ...)
 155 {
 156         va_list ap;
 157         va_start(ap, message);
 158         __vsyslog(priority, message, ap);
 159         va_end(ap);
 160 }
 161
 162 weak_alias(__vsyslog, vsyslog);