simplify syslog, add vsyslog interface (nonstandard)

with datagram sockets, depending on fprintf not to flush the output
early was very fragile; the new version simply uses a small fixed-size
buffer. it could be updated to dynamic-allocate large buffers if
needed, but i can't envision any admin being happy about finding
64kb-long lines in their syslog...

diff --git a/src/misc/syslog.c b/src/misc/syslog.c
index de42ce2..0f75764 100644 (file)
--- a/src/misc/syslog.c
+++ b/src/misc/syslog.c
@@ -14,7 +14,7 @@ static const char *log_ident;
 static int log_opt;
 static int log_facility = LOG_USER;
 static int log_mask = 0xff;
-static FILE *log_f;
+static int log_fd = -1;
 
 int setlogmask(int maskpri)
 {
@@ -34,26 +34,21 @@ static const struct {
 void closelog(void)
 {
        LOCK(&lock);
-       if (log_f) fclose(log_f);
-       log_f = NULL;
+       close(log_fd);
+       log_fd = -1;
        UNLOCK(&lock);
 }
 
 static void __openlog(const char *ident, int opt, int facility)
 {
-       int fd;
-
        log_ident = ident;
        log_opt = opt;
        log_facility = facility;
 
-       if (!(opt & LOG_NDELAY) || log_f) return;
+       if (!(opt & LOG_NDELAY) || log_fd>=0) return;
 
-       fd = socket(AF_UNIX, SOCK_DGRAM, 0);
-       fcntl(fd, F_SETFD, FD_CLOEXEC);
-       if (connect(fd, (void *)&log_addr, sizeof(short) + sizeof "/dev/log") < 0)
-               close(fd);
-       else log_f = fdopen(fd, "wb");
+       log_fd = socket(AF_UNIX, SOCK_DGRAM, 0);
+       fcntl(log_fd, F_SETFD, FD_CLOEXEC);
 }
 
 void openlog(const char *ident, int opt, int facility)
@@ -63,42 +58,52 @@ void openlog(const char *ident, int opt, int facility)
        UNLOCK(&lock);
 }
 
-void syslog(int priority, const char *message, ...)
+void __vsyslog(int priority, const char *message, va_list ap)
 {
-       va_list ap;
        char timebuf[16];
        time_t now;
        struct tm tm;
-       //const char *fmt, *ident, *sep;
-       //int i;
+       char buf[256];
+       int pid;
+       int l, l2;
 
        if (!(log_mask & LOG_MASK(priority&7)) || (priority&~0x3ff)) return;
 
        LOCK(&lock);
 
-       if (!log_f) __openlog(log_ident, log_opt | LOG_NDELAY, log_facility);
-       if (!log_f) {
-               UNLOCK(&lock);
-               return;
+       if (log_fd < 0) {
+               __openlog(log_ident, log_opt | LOG_NDELAY, log_facility);
+               if (log_fd < 0) {
+                       UNLOCK(&lock);
+                       return;
+               }
        }
 
        now = time(NULL);
        gmtime_r(&now, &tm);
        strftime(timebuf, sizeof timebuf, "%b %e %T", &tm);
 
-       fprintf(log_f, "<%d>%s ", priority, timebuf);
-       if (log_ident) fprintf(log_f, "%s", log_ident);
-       if (log_opt & LOG_PID) fprintf(log_f, "[%d]", getpid());
-       if (log_ident) fprintf(log_f, ": ");
+       pid = (log_opt & LOG_PID) ? getpid() : 0;
+       l = snprintf(buf, sizeof buf, "<%d>%s %s%s%.0d%s: ",
+               priority, timebuf,
+               log_ident ? log_ident : "",
+               "["+!pid, pid, "]"+!pid);
+       l2 = vsnprintf(buf+l, sizeof buf - l, message, ap);
+       if (l2 >= 0) {
+               l += l2;
+               if (buf[l-1] != '\n') buf[l++] = '\n';
+               sendto(log_fd, buf, l, 0, (void *)&log_addr, 11);
+       }
+
+       UNLOCK(&lock);
+}
 
+void syslog(int priority, const char *message, ...)
+{
+       va_list ap;
        va_start(ap, message);
-       vfprintf(log_f, message, ap);
+       __vsyslog(priority, message, ap);
        va_end(ap);
-       fputc(0, log_f);
-       fflush(log_f);
-
-       // Note: LOG_CONS is not supported because it is annoying!!
-       // syslogd will send messages to console if it deems them appropriate!
-
-       UNLOCK(&lock);
 }
+
+weak_alias(__vsyslog, vsyslog);