github.com/afumu/libc@v0.0.6/musl/src/misc/syslog.c (about)

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