C 超过时间限制时终止进程
我已经为下面的代码工作了相当长的时间,但是我不能真正理解它。 任务是读取终端命令并每x秒运行一次;如果命令没有在等待时间内完成,我们希望终止进程,然后再次运行该命令。 任何帮助都将不胜感激。 我很确定我没有正确使用waitpid();我将如何使用waitpid来实现目标 此外,我将如何检测子进程中的错误?计划是在子进程中发生错误时终止父进程C 超过时间限制时终止进程,c,kill-process,waitpid,C,Kill Process,Waitpid,我已经为下面的代码工作了相当长的时间,但是我不能真正理解它。 任务是读取终端命令并每x秒运行一次;如果命令没有在等待时间内完成,我们希望终止进程,然后再次运行该命令。 任何帮助都将不胜感激。 我很确定我没有正确使用waitpid();我将如何使用waitpid来实现目标 此外,我将如何检测子进程中的错误?计划是在子进程中发生错误时终止父进程 #include <stdio.h> #include <stdlib.h> #include <unistd.h> #
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <string.h>
#include <signal.h>
#include <sys/wait.h>
/*
*
*/
int main(int argc, char** argv) {
int waitingTime;
if (argc < 3) {
printf("Invalid number of arguments provided. Please specify a command and exactly one parameter.");
return (EXIT_FAILURE);
}
// -n parameter specified? If so, set the waiting time.
if (argc == 5 && strcmp(argv[3], "-n") == 0) {
waitingTime = atoi(argv[4]);
} else {
waitingTime = 5; // Default waiting time.
}
char* cmd = (char*)malloc(sizeof(argv[1]));
cmd = argv[1];
char* param = (char*)malloc(sizeof(argv[2]));
param = argv[2];
// Print the read command and its param
printf("Command: %s, Parameter: %s, Interval: %d\n\n", cmd, param, waitingTime);
pid_t pid;
for (;;) {
// Declared here for scope
int secsWaited;
secsWaited = 0;
pid = fork();
if (pid == 0) {
pid = getpid();
printf("==============\n");
execlp(cmd, cmd, param, "/", (char *)NULL);
printf("Excec failed; killing the proccess.");
kill(pid, SIGKILL);
} else if (pid > 0) {
int status, code;
for (;;) {
code = waitpid(pid, &status, WNOHANG);
if (code == 0 && secsWaited >= waitingTime) {
kill(pid, SIGKILL);
printf("Child stopped");
break;
} else if (code == 0 && secsWaited < waitingTime) {
secsWaited++;
sleep(1);
} else {
break;
}
}
/*if (!WIFEXITED(status)) {
printf("Time exceeding, stopping child.");
// Get parent process id and kill it.
kill(getpid(), SIGKILL);
}*/
// Sleep for the specified time
sleep(waitingTime - secsWaited);
} else {
return (EXIT_FAILURE);
}
}
free(cmd);
free(param);
return (EXIT_SUCCESS);
}
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/*
*
*/
int main(int argc,字符**argv){
国际等待时间;
如果(argc<3){
printf(“提供的参数数量无效。请指定一个命令和一个参数。”);
返回(退出失败);
}
//指定了-n参数?如果是,请设置等待时间。
如果(argc==5&&strcmp(argv[3],“-n”)==0){
waitingTime=atoi(argv[4]);
}否则{
waitingTime=5;//默认等待时间。
}
char*cmd=(char*)malloc(sizeof(argv[1]);
cmd=argv[1];
char*param=(char*)malloc(sizeof(argv[2]);
param=argv[2];
//打印read命令及其参数
printf(“命令:%s,参数:%s,间隔:%d\n\n”,cmd,param,waitingTime);
pid_t pid;
对于(;){
//在此处声明范围
国际安全委员会;
secsWaited=0;
pid=fork();
如果(pid==0){
pid=getpid();
printf(“=========================\n”);
execlp(cmd,cmd,param,“/”,(char*)NULL);
printf(“EXEC失败;终止进程”);
kill(pid,SIGKILL);
}否则,如果(pid>0){
int状态,代码;
对于(;;){
代码=等待pid(pid和状态,WNOHANG);
如果(代码==0&&secsWaited>=waitingTime){
kill(pid,SIGKILL);
printf(“儿童停止”);
打破
}else if(代码==0&&secsWaited
您的逻辑有点太复杂(例如,有太多不同的睡眠
调用和if/else
梯形图逻辑)
另外,不需要malloc
字符串argv
它们可以直接使用
我已经对它进行了简化,并对其进行了一些重构,以使其能够正常工作[请原谅这种无缘无故的风格清理]:
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <string.h>
#include <signal.h>
#include <sys/wait.h>
/*
*
*/
int
main(int argc, char **argv)
{
int waitingTime;
if (argc < 3) {
printf("Invalid number of arguments provided. Please specify a command and exactly one parameter.");
return (EXIT_FAILURE);
}
// -n parameter specified? If so, set the waiting time.
if (argc == 5 && strcmp(argv[3], "-n") == 0) {
waitingTime = atoi(argv[4]);
}
else {
waitingTime = 5; // Default waiting time.
}
char *cmd = argv[1];
char *param = argv[2];
// Print the read command and its param
printf("Command: %s, Parameter: %s, Interval: %d\n\n",
cmd, param, waitingTime);
pid_t pid;
int code = -1;
int status;
int killflg = 1;
for (;;) {
// Declared here for scope
int secsWaited;
secsWaited = 0;
pid = fork();
// stop on fork failure
if (pid < 0) {
killflg = 1;
break;
}
// child process
if (pid == 0) {
pid = getpid();
printf("==============\n");
#if 0
execlp(cmd, cmd, param, "/", (char *) NULL);
#else
execlp(cmd, cmd, param, (char *) NULL);
#endif
printf("Excec failed; killing the proccess.");
// NOTE/BUG: this is the child so pid is zero, so killing it is wrong
#if 0
kill(pid, SIGKILL);
#else
exit(1);
#endif
}
killflg = 0;
for (;;) {
code = waitpid(pid, &status, WNOHANG);
if (code > 0)
break;
if (killflg)
continue;
secsWaited++;
sleep(1);
if (secsWaited >= waitingTime) {
printf("timeout\n");
kill(pid, SIGKILL);
killflg = 1;
}
}
if (! killflg)
break;
}
#if 0
free(cmd);
free(param);
#endif
if (killflg)
code = EXIT_FAILURE;
else
code = EXIT_SUCCESS;
return code;
}
旁注:我在这里使用了
usleep
,但是,尽管稍微复杂一点,但是使用nanosleep
被认为是更好的选择。您使用C的具体原因是什么?这样的任务更适合于shell编程或更高级别的编程语言,比如python。我被要求用C语言来完成,这不是我的主意。好吧,这很有意义,并帮助我理解相关的命令。然而,我还有一个问题:现在,程序将在一次迭代后停止;如果删除“if(!killflg)”处的断点,它将按预期工作。我是错过了什么,还是这只是一个误会?
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <string.h>
#include <signal.h>
#include <sys/wait.h>
#include <time.h>
double
tvgetf(void)
{
struct timespec ts;
double sec;
clock_gettime(CLOCK_REALTIME,&ts);
sec = ts.tv_nsec;
sec /= 1e9;
sec += ts.tv_sec;
return sec;
}
/*
*
*/
int
main(int argc, char **argv)
{
int waitingTime;
if (argc < 3) {
printf("Invalid number of arguments provided. Please specify a command and exactly one parameter.");
return (EXIT_FAILURE);
}
// -n parameter specified? If so, set the waiting time.
if (argc == 5 && strcmp(argv[3], "-n") == 0) {
waitingTime = atoi(argv[4]);
}
else {
waitingTime = 5; // Default waiting time.
}
char *cmd = argv[1];
char *param = argv[2];
// Print the read command and its param
printf("Command: %s, Parameter: %s, Interval: %d\n\n", cmd, param, waitingTime);
pid_t pid;
int code = -1;
int status;
int killflg = 1;
double todzero = tvgetf();
for (;;) {
// Declared here for scope
double todbeg = tvgetf();
double todelap;
pid = fork();
// stop on fork failure
if (pid < 0) {
killflg = 1;
break;
}
// child process
if (pid == 0) {
pid = getpid();
printf("============== (%.9f)\n",tvgetf() - todzero);
execlp(cmd, cmd, param, (char *) NULL);
printf("Excec failed; killing the proccess.");
exit(1);
}
killflg = 0;
for (;;) {
code = waitpid(pid, &status, WNOHANG);
if (code > 0)
break;
if (killflg)
continue;
usleep(1000);
todelap = tvgetf() - todbeg;
if (todelap >= waitingTime) {
printf("timeout\n");
kill(pid, SIGKILL);
killflg = 1;
}
}
// do _not_ wait -- we already timed out
if (killflg)
continue;
// get final elapsed time for this round and the amount of time
// remaining until the next interval
todelap = tvgetf() - todbeg;
useconds_t time_to_wait = ((double) waitingTime - todelap) * 1e6;
// wait until the next time period
if (time_to_wait > 0)
usleep(time_to_wait);
}
if (killflg)
code = EXIT_FAILURE;
else
code = EXIT_SUCCESS;
return code;
}