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/*
20140129
20241209 - reformated using clang-format
Jan Mojzis
Public domain.
*/
#include <unistd.h>
#include "blocking.h"
#include "open.h"
#include "channel.h"
/*
The 'channel_fork' function is used to create a new process.
Function creates 3 pipes from/to child:
fd[0] is pipe to childs standard input
fd[1] is pipe from childs standard output
fd[2] is pipe from childs error output
Function returns also childs PID.
*/
long long channel_fork(int fd[3]) {
int pi[2], pa[3], ch[3];
long long i, pid;
for (i = 0; i < 3; ++i) pa[i] = ch[i] = fd[i] = -1;
for (i = 0; i < 3; ++i) {
if (open_pipe(pi) == -1) goto cleanup;
pa[i] = pi[i ? 0 : 1];
ch[i] = pi[i ? 1 : 0];
}
pid = fork();
if (pid == -1) goto cleanup;
if (pid == 0) {
for (i = 0; i < 3; ++i) {
close(pa[i]);
close(i);
blocking_enable(ch[i]);
if (dup(ch[i]) != i) _exit(111);
}
return 0;
}
for (i = 0; i < 3; ++i) {
close(ch[i]);
fd[i] = pa[i];
}
return pid;
cleanup:
for (i = 0; i < 3; ++i) {
close(pa[i]);
close(ch[i]);
}
return -1;
}
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