Add a "fork" of musl as //fusl.

fusl/src/misc/syslog.c

+#include <stdarg.h>
+#include <sys/socket.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <syslog.h>
+#include <time.h>
+#include <signal.h>
+#include <string.h>
+#include <pthread.h>
+#include <errno.h>
+#include <fcntl.h>
+#include "libc.h"
+
+static volatile int lock[2];
+static char log_ident[32];
+static int log_opt;
+static int log_facility = LOG_USER;
+static int log_mask = 0xff;
+static int log_fd = -1;
+
+int setlogmask(int maskpri)
+{
+        LOCK(lock);
+        int ret = log_mask;
+        if (maskpri) log_mask = maskpri;
+        UNLOCK(lock);
+        return ret;
+}
+
+static const struct {
+        short sun_family;
+        char sun_path[9];
+} log_addr = {
+        AF_UNIX,
+        "/dev/log"
+};
+
+void closelog(void)
+{
+        int cs;
+        pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
+        LOCK(lock);
+        close(log_fd);
+        log_fd = -1;
+        UNLOCK(lock);
+        pthread_setcancelstate(cs, 0);
+}
+
+static void __openlog()
+{
+        log_fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0);
+        if (log_fd >= 0) connect(log_fd, (void *)&log_addr, sizeof log_addr);
+}
+
+void openlog(const char *ident, int opt, int facility)
+{
+        int cs;
+        pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
+        LOCK(lock);
+
+        if (ident) {
+                size_t n = strnlen(ident, sizeof log_ident - 1);
+                memcpy(log_ident, ident, n);
+                log_ident[n] = 0;
+        } else {
+                log_ident[0] = 0;
+        }
+        log_opt = opt;
+        log_facility = facility;
+
+        if ((opt & LOG_NDELAY) && log_fd<0) __openlog();
+
+        UNLOCK(lock);
+        pthread_setcancelstate(cs, 0);
+}
+
+static int is_lost_conn(int e)
+{
+        return e==ECONNREFUSED || e==ECONNRESET || e==ENOTCONN || e==EPIPE;
+}
+
+static void _vsyslog(int priority, const char *message, va_list ap)
+{
+        char timebuf[16];
+        time_t now;
+        struct tm tm;
+        char buf[1024];
+        int errno_save = errno;
+        int pid;
+        int l, l2;
+        int hlen;
+        int fd;
+
+        if (log_fd < 0) __openlog();
+
+        if (!(priority & LOG_FACMASK)) priority |= log_facility;
+
+        now = time(NULL);
+        gmtime_r(&now, &tm);
+        strftime(timebuf, sizeof timebuf, "%b %e %T", &tm);
+
+        pid = (log_opt & LOG_PID) ? getpid() : 0;
+        l = snprintf(buf, sizeof buf, "<%d>%s %n%s%s%.0d%s: ",
+                priority, timebuf, &hlen, log_ident, "["+!pid, pid, "]"+!pid);
+        errno = errno_save;
+        l2 = vsnprintf(buf+l, sizeof buf - l, message, ap);
+        if (l2 >= 0) {
+                if (l2 >= sizeof buf - l) l = sizeof buf - 1;
+                else l += l2;
+                if (buf[l-1] != '\n') buf[l++] = '\n';
+                if (send(log_fd, buf, l, 0) < 0 && (!is_lost_conn(errno)
+                    || connect(log_fd, (void *)&log_addr, sizeof log_addr) < 0
+                    || send(log_fd, buf, l, 0) < 0)
+                    && (log_opt & LOG_CONS)) {
+                        fd = open("/dev/console", O_WRONLY|O_NOCTTY|O_CLOEXEC);
+                        if (fd >= 0) {
+                                dprintf(fd, "%.*s", l-hlen, buf+hlen);
+                                close(fd);
+                        }
+                }
+                if (log_opt & LOG_PERROR) dprintf(2, "%.*s", l-hlen, buf+hlen);
+        }
+}
+
+void __vsyslog(int priority, const char *message, va_list ap)
+{
+        int cs;
+        if (!(log_mask & LOG_MASK(priority&7)) || (priority&~0x3ff)) return;
+        pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
+        LOCK(lock);
+        _vsyslog(priority, message, ap);
+        UNLOCK(lock);
+        pthread_setcancelstate(cs, 0);
+}
+
+void syslog(int priority, const char *message, ...)
+{
+        va_list ap;
+        va_start(ap, message);
+        __vsyslog(priority, message, ap);
+        va_end(ap);
+}
+
+weak_alias(__vsyslog, vsyslog);