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#include <unistd.h>
#include <sys/types.h>
#include <assert.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <stdlib.h>
#include "exec.h"
static void close_pipe(int p[2]) {
if (p[0] >= 0)
close(p[0]);
if (p[1] >= 0)
close(p[1]);
}
struct stream* stream_exec(const char *args) {
struct stream *s = NULL;
int stdout_pipe[2];
int stdin_pipe[2];
pid_t pid;
s = malloc(sizeof(struct stream));
assert(s);
memset(s, 0, sizeof(struct stream));
if (pipe(stdin_pipe) < 0 || pipe(stdout_pipe) < 0) {
fprintf(stderr, "pipe(): %s\n", strerror(errno));
goto fail;
}
if ((pid = fork()) < 0) {
fprintf(stderr, "fork(): %s\n", strerror(errno));
goto fail;
} else if (pid == 0) {
close(stdin_pipe[1]);
close(stdout_pipe[0]);
if (dup2(stdin_pipe[0], 0) < 0 || dup2(stdout_pipe[1], 1) < 0) {
fprintf(stderr, "dup2(): %s\n", strerror(errno));
exit(1);
}
execl("/bin/sh", "/bin/sh", "-c", args, NULL);
fprintf(stderr, "exec(): %s\n", strerror(errno));
exit(1);
}
s->output_fd = stdin_pipe[1];
close(stdin_pipe[0]);
s->input_fd = stdout_pipe[0];
close(stdout_pipe[1]);
return s;
fail:
free(s);
close_pipe(stdout_pipe);
close_pipe(stdin_pipe);
return NULL;
}
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