log.c

   1 #include <sys/types.h>
   2 #include <sys/stat.h>
   3 #include <fcntl.h>
   4 #include <unistd.h>
   5 #include <stdarg.h>
   6 #include <stdio.h>
   7 #include <string.h>
   8
   9 #include "log.h"
  10
  11 int log_fd = -1;
  12 int log_level = 6;
  13
  14 void log_init(void)
  15 {
  16         static const char *name = "/dev/__kmsg__";
  17         if (mknod(name, S_IFCHR | 0600, (1 << 8) | 11) == 0) {
  18                 log_fd = open(name, O_WRONLY);
  19                 fcntl(log_fd, F_SETFD, FD_CLOEXEC);
  20                 unlink(name);
  21         }
  22 }
  23
  24 #define LOG_BUF_MAX 512
  25 void log_write(int level, const char *fmt, ...)
  26 {
  27         char buf[LOG_BUF_MAX];
  28         va_list ap;
  29
  30         if (level > log_level) return;
  31         if (log_fd < 0) return;
  32
  33         va_start(ap, fmt);
  34         vsnprintf(buf, LOG_BUF_MAX, fmt, ap);
  35         buf[LOG_BUF_MAX - 1] = 0;
  36         va_end(ap);
  37         write(log_fd, buf, strlen(buf));
  38 }
  39