log.c

linux写的基于epoll技术的通信服务器

/* -------------------------------------------------------------------------
 * log.c - htun logging functions
  * -------------------------------------------------------------------------
 */

#include <stdio.h>
#include <unistd.h>
#include <semaphore.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <time.h>
#include <pthread.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#include "log.h"


/* Allows printf()-like interface to file descriptors without the
 * complications that arise from mixing stdio and low level calls 
 * FIXME: Needs date and time before logfile entries.
 */
int lprintf( log_t *log, unsigned int level, char *fmt, ... ) {
    int fd;
    int rc;
    va_list ap;
    time_t now;
    char date[50];
    static char line[LOGLINE_MAX];
    static char threadnum[10];
    int cnt;
    static char *levels[6] = { "[(bad)] ", 
                               "[debug] ", 
                               "[info ] ", 
                               "[warn ] ", 
                               "[error] ", 
                               "[fatal] " };

    if(!log) return -1;

    /* If this is debug info, and we're not logging it, return */
    if( !(log->flags&LOG_DEBUG) && level == DEBUG ) return 0;

    fd=log->fd;

    /* Prepare the date string   日期*/
    if( !(log->flags&LOG_NODATE) ) {
        now=time(NULL);
        strcpy(date,ctime(&now));
        date[strlen(date)-6]=' ';
        date[strlen(date)-5]='\0';
    }

    /*线程号*/
    if( !(log->flags&LOG_NOTID) ) {
        sprintf(threadnum, "(%lu) ", pthread_self());
    }

    cnt = snprintf(line, sizeof(line), "%s%s%s",
                   log->flags&LOG_NODATE ? "" : date,
                   log->flags&LOG_NOLVL  ? "" : 
                       (level > FATAL ? levels[0] : levels[level]),
                   log->flags&LOG_NOTID  ? "" : threadnum);

    va_start(ap, fmt);
    vsnprintf(line+cnt, sizeof(line)-cnt, fmt, ap);    /*如果输入的日志过长会自动截取*/
    va_end(ap);

    line[sizeof(line)-1] = '\0';

    if( !(log->flags&LOG_NOLF) ) {
        /*chomp(line);*/
        /*strcpy(line+strlen(line), "\n");*/
    }
        
    sem_wait(&log->sem);         /*用信号实现同步*/
    rc = write(fd, line, strlen(line));
    sem_post(&log->sem);

    if( !rc ) errno = 0;
    return rc;
}

log_t *log_open( char *fname, int flags ) {
    log_t *log = malloc(sizeof(log_t));

    if(!log) {
        fprintf(stderr, "log_open: Unable to malloc()");
        goto log_open_a;
    }
    log->flags=flags;
    if( !strcmp(fname,"-") ) {
        log->fd = 2;
    } else {
        log->fd = open(fname, O_WRONLY|O_CREAT|O_NOCTTY | 
                (flags&LOG_TRUNC ? O_TRUNC : O_APPEND) , 0666);
                
    }
    if( log->fd == -1 ) {
        fprintf(stderr, "log_open: Opening logfile %s: %s", 
                fname, strerror(errno));
        goto log_open_b;
    }
    if( sem_init(&log->sem, 0, 1) == -1 ) {
        fprintf(stderr, "log_open: Could not initialize log semaphore.");
        goto log_open_c;
    }
    return log;

log_open_c:
    close(log->fd);
log_open_b:
    free(log);
log_open_a:
    return NULL;
}

void log_close( log_t *log ) {
    sem_wait(&log->sem);
    sem_destroy(&log->sem);
    close(log->fd);
    free(log);
    return;
}