从派生进程复制stdout和stderr到文件 [英] Duplicate stdout and stderr from fork process to files
本文介绍了从派生进程复制stdout和stderr到文件的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我需要将子流程的stdout
和stderr
复制到多个文件.
我知道我可以使用tee()
,但是我还没有找到示例.
现在,仅将所有内容打印到stdout和stderr.
怎么做?
I need to duplicate stdout
and stderr
of a child proccess to multiple files.
I understand that i can use tee()
, but I haven't found examples for that.
Now, it's only to print all to stdout and stderr.
How to do it?
pid_t childId = fork();
switch(childId){
case -1:
perror("fork() error!\n");
return;
case 0:
mysignal(SIGTTOU, SIG_DFL);
mysignal(SIGTTIN, SIG_DFL);
mysignal(SIGCHLD, SIG_DFL);
if(!background)
tcsetpgrp(cterm, getpid());
setpgid(0, 0);
if (isWriter) close(pipefd[0]);
if (isReader!=-1) {
close(0);
dup(oldChannelOut);
}
if(isWriter){
close(1);
dup(pipefd[1]);
}
//exec, if program is in current directory
execv(commandArgv[0], commandArgv);
int i = 0;
char buf[_POSIX_MAX_PATH];
while(path[i] != NULL){
buf[0] = '\0';
strcat(buf, path[i]);
if(path[i][ strlen(path[i])-1 ] != '/'){
buf[strlen(path[i])] = '/';
buf[strlen(path[i])+1] = '\0';
}
strcat(buf, commandArgv[0]);
execv(buf, commandArgv);
++i;
}
fprintf(stderr,"\"%s\": command not found\n",commandArgv[0]);
exit(1);
UPD::尝试修改后,不起作用.问题出在哪里?
UPD: After tried modify, dont work. Where is problem ?
fdout=open("1", O_APPEND | O_WRONLY | O_CREAT, S_IRUSR | S_IWUSR);
fderr=open("2",O_APPEND | O_WRONLY | O_CREAT, S_IRUSR | S_IWUSR);
...
case 0:
if (isReader!=-1) {
close(0);
dup(oldChannelOut);
}
dup2(fdout, 1);
dup2(fderr, 2);
close(fdout);
close(fderr);
exec....
default:
{
if(background) {
addJob(&jobListStartB,childId,commandArgv,BACKGROUND);
if (oldChannelOut != -1){
close(oldChannelOut);
oldChannelOut = -1;
}
}
else if(!background){
if (oldChannelOut != -1){
close(oldChannelOut);
oldChannelOut = -1;
}
}
推荐答案
使用tee
和splice
将数据从一个句柄写入多个其他句柄:
Using tee
and splice
to write data from a handle to multiple other handles:
// Needs at least two targets, sentinel is INVALID_HANDLE_VALUE
int push_to_all(int source, ssize_t count, ...) {
va_list vl;
va_start(vl, count);
int target = va_arg(vl, int), next = va_arg(vl, int);
count = tee(source, target, count, SPLICE_F_NONBLOCK);
if(count <= 0) { va_end(vl); return count; }
while((target = next, next = va_arg(vl, int)) > 0) {
tee(source, target, count, 0);
va_end(vl);
return splice(source, 0, target, 0, count, 0);
}
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