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#include <stdio.h><br /> #include <fcntl.h><br /> #include <stdlib.h><br /> #include <unistd.h><br /> #include <pwd.h><br /> #include <time.h><br /> #include <signal.h></p> <p>int daemon(int, int);<br /> char *daemon_log = "/u01/log/daemon.log";<br /> int add_log(char*, char*);<br /> void sig_handler(int);<br /> void restart_sleep(int);<br /> int is_daemon = 1;<br /> int is_root = 1;</p> <p>int main()<br /> {<br /> fprintf(stdout, "daemon start/n");<br /> int ret;<br /> //是否切换到普通用户<br /> if (!is_root) {<br /> if (getuid() == 0 || geteuid() == 0) {<br /> char *username = "flynetcn";<br /> struct passwd *pw;<br /> if ((pw = getpwnam(username)) == 0) {<br /> fprintf(stderr, "can't find the user %s/n", username);<br /> return 1;<br /> }<br /> if (setgid(pw->pw_gid) < 0 || setuid(pw->pw_uid) < 0) {<br /> fprintf(stderr, "failed to assume identity of user %s/n", username);<br /> return 1;<br /> }<br /> }<br /> }<br /> //防止僵死子进程<br /> struct sigaction sa, oldsa;<br /> sa.sa_handler = sig_handler;<br /> sigemptyset(&sa.sa_mask);<br /> sa.sa_flags = SA_RESTART;<br /> if (sigaction(SIGCHLD, &sa, &oldsa) == -1) {<br /> fprintf(stderr, "sigaction(SIGCHLD) error/n");<br /> return 1;<br /> }<br /> //切换到守护进程<br /> if (is_daemon) {<br /> ret = daemon(1, 0);<br /> if (ret == -1) {<br /> fprintf(stderr, "failed to daemon/n");<br /> return 1;<br /> }<br /> }</p> <p> /**<br /> * do something<br /> */<br /> int crontimers[3][2];<br /> //task 1<br /> crontimers[0][0] = 3;<br /> crontimers[0][1] = 6;<br /> //task 2<br /> crontimers[1][0] = -1;<br /> crontimers[1][1] = 6;<br /> //task 3<br /> crontimers[2][0] = -1;<br /> crontimers[2][1] = 36;<br /> //tasks comm<br /> char *croncomm[3];<br /> croncomm[0] = "echo task1 >> /dev/null 2>&1";<br /> croncomm[1] = "echo task2 >> /dev/null 2>&1";<br /> croncomm[2] = "echo task3 >> /dev/null 2>&1";<br /> char buf[1024];<br /> char tbuf[50];<br /> time_t timestamp;<br /> struct tm *now;<br /> int time_left;<br /> int cron_num;<br /> cron_num = sizeof(croncomm)/sizeof(char*);<br /> int hok, i;<br /> while (1) {<br /> timestamp = time(NULL);<br /> now = localtime(×tamp);<br /> strftime(tbuf, 30, "%Y-%m-%d %H:%M:%S", now);<br /> //<br /> sprintf(buf, "%s ------/n", tbuf);<br /> add_log(buf, daemon_log);<br /> for (i=0; i<cron_num; i++) {<br /> hok=0;<br /> sprintf(buf, "task %d :/n", i);<br /> add_log(buf, daemon_log);<br /> if (crontimers[i][0]==-1 || now->tm_hour==crontimers[i][0]) {<br /> hok = 1;<br /> add_log("hok/n", daemon_log);<br /> } else {<br /> continue;<br /> }<br /> if (crontimers[i][1]==now->tm_min && croncomm[i]) {<br /> add_log("mok/n", daemon_log);<br /> sprintf(buf, "run %s/n", croncomm[i]);<br /> add_log(buf, daemon_log);<br /> ret = fork();<br /> if (ret == 0) {<br /> system(croncomm[i]);<br /> exit(0);<br /> }<br /> }<br /> }<br /> timestamp = time(NULL);<br /> now = localtime(×tamp);<br /> time_left = 60 - now->tm_sec;<br /> restart_sleep(time_left);<br /> }<br /> /**<br /> * end<br /> */</p> <p>}</p> <p>int add_log(char *str, char *logfile)<br /> {<br /> FILE *fp;<br /> if ((fp = fopen(logfile, "a")) == NULL) {<br /> return -1;<br /> }<br /> if (!(*str) || fputs(str, fp)==EOF) {<br /> fclose(fp);<br /> return -1;<br /> }<br /> fflush(fp);<br /> fclose(fp);<br /> return 0;<br /> }</p> <p>int daemon(int nochdir, int noclose)<br /> {<br /> int fd, ret;<br /> ret = fork();<br /> switch (ret) {<br /> case -1: return -1;<br /> case 0: break;<br /> default: exit(0);<br /> }<br /> if (setsid() == -1)<br /> return -1;<br /> if (nochdir == 0) {<br /> if(chdir("/") != 0) {<br /> perror("chdir");<br /> return -1;<br /> }<br /> }<br /> if (noclose == 0 && (fd = open("/dev/null", O_RDWR, 0)) != -1) {<br /> if(dup2(fd, STDIN_FILENO) < 0) {<br /> perror("dup2 stdin");<br /> return -1;<br /> }<br /> if(dup2(fd, STDOUT_FILENO) < 0) {<br /> perror("dup2 stdout");<br /> return -1;<br /> }<br /> if(dup2(fd, STDERR_FILENO) < 0) {<br /> perror("dup2 stderr");<br /> return -1;<br /> }<br /> if (fd > STDERR_FILENO) {<br /> if(close(fd) < 0) {<br /> perror("close");<br /> return -1;<br /> }<br /> }<br /> }<br /> return 0;<br /> }</p> <p>void sig_handler(int sig)<br /> {<br /> if (sig == SIGCHLD) {<br /> int status;<br /> pid_t pid;<br /> pid = wait(&status);<br /> }<br /> }<br /> //防止被信号中断<br /> void restart_sleep(int sec)<br /> {<br /> int left;<br /> left = sec;<br /> while (left > 0) {<br /> left = sleep(left);<br /> }<br /> }
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