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#include <fcntl.h>
#include "stdio_impl.h"
#include "pthread_impl.h"
#include "syscall.h"
static void dummy_0()
{
}
weak_alias(dummy_0, __acquire_ptc);
weak_alias(dummy_0, __release_ptc);
pid_t __vfork(void);
FILE *popen(const char *cmd, const char *mode)
{
int p[2], op, i;
pid_t pid;
FILE *f;
sigset_t old;
const char *modes = "rw", *mi = strchr(modes, *mode);
if (mi) {
op = mi-modes;
} else {
errno = EINVAL;
return 0;
}
if (pipe2(p, O_CLOEXEC)) return NULL;
f = fdopen(p[op], mode);
if (!f) {
__syscall(SYS_close, p[0]);
__syscall(SYS_close, p[1]);
return NULL;
}
sigprocmask(SIG_BLOCK, SIGALL_SET, &old);
__acquire_ptc();
pid = __vfork();
if (pid) {
__release_ptc();
__syscall(SYS_close, p[1-op]);
sigprocmask(SIG_BLOCK, SIGALL_SET, &old);
if (pid < 0) {
fclose(f);
return 0;
}
f->pipe_pid = pid;
return f;
}
/* See notes in system.c for why this is needed. */
for (i=1; i<=8*__SYSCALL_SSLEN; i++) {
struct sigaction sa;
__libc_sigaction(i, 0, &sa);
if (sa.sa_handler!=SIG_IGN && sa.sa_handler!=SIG_DFL) {
sa.sa_handler = SIG_DFL;
__libc_sigaction(i, &sa, 0);
}
}
if (dup2(p[1-op], 1-op) < 0) _exit(127);
fcntl(1-op, F_SETFD, 0);
if (p[0] != 1-op) __syscall(SYS_close, p[0]);
if (p[1] != 1-op) __syscall(SYS_close, p[1]);
sigprocmask(SIG_SETMASK, &old, 0);
execl("/bin/sh", "sh", "-c", cmd, (char *)0);
_exit(127);
}
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