#include <unistd.h>
#include <fcntl.h>
+int pipecmd_preserve;
+
static char **gather_args(const char *arg0, va_list ap)
{
size_t n = 1;
arr[0] = (char *)arg0;
while ((arr[n++] = va_arg(ap, char *)) != NULL) {
- arr = realloc(arr, sizeof(char *) * (n + 1));
- if (!arr)
+ char **narr = realloc(arr, sizeof(char *) * (n + 1));
+ if (!narr) {
+ free(arr);
return NULL;
+ }
+ arr = narr;
}
return arr;
}
-pid_t pipecmdv(int *fd_fromchild, int *fd_tochild, const char *cmd, va_list ap)
+pid_t pipecmdv(int *fd_tochild, int *fd_fromchild, int *fd_errfromchild,
+ const char *cmd, va_list ap)
{
char **arr = gather_args(cmd, ap);
pid_t ret;
errno = ENOMEM;
return -1;
}
- ret = pipecmdarr(fd_fromchild, fd_tochild, arr);
+ ret = pipecmdarr(fd_tochild, fd_fromchild, fd_errfromchild, arr);
free_noerr(arr);
return ret;
}
-pid_t pipecmdarr(int *fd_fromchild, int *fd_tochild, char *const *arr)
+pid_t pipecmdarr(int *fd_tochild, int *fd_fromchild, int *fd_errfromchild,
+ char *const *arr)
{
- int tochild[2], fromchild[2], execfail[2];
+ int tochild[2], fromchild[2], errfromchild[2], execfail[2];
+ /* fds for parent to close */
+ int par_close[4], num_par_close = 0;
+ /* fds for child to close */
+ int child_close[4], num_child_close = 0;
pid_t childpid;
int err;
if (fd_tochild) {
- if (pipe(tochild) != 0)
+ if (fd_tochild == &pipecmd_preserve) {
+ tochild[0] = STDIN_FILENO;
+ } else if (pipe(tochild) == 0) {
+ par_close[num_par_close++] = tochild[0];
+ child_close[num_child_close++] = tochild[1];
+ } else
goto fail;
} else {
tochild[0] = open("/dev/null", O_RDONLY);
if (tochild[0] < 0)
goto fail;
+ par_close[num_par_close++] = tochild[0];
}
if (fd_fromchild) {
- if (pipe(fromchild) != 0)
- goto close_tochild_fail;
+ if (fd_fromchild == &pipecmd_preserve) {
+ fromchild[1] = STDOUT_FILENO;
+ } else if (pipe(fromchild) == 0) {
+ par_close[num_par_close++] = fromchild[1];
+ child_close[num_child_close++] = fromchild[0];
+ } else
+ goto fail;
} else {
fromchild[1] = open("/dev/null", O_WRONLY);
if (fromchild[1] < 0)
- goto close_tochild_fail;
+ goto fail;
+ par_close[num_par_close++] = fromchild[1];
+ }
+ if (fd_errfromchild) {
+ if (fd_errfromchild == &pipecmd_preserve) {
+ errfromchild[1] = STDERR_FILENO;
+ } else if (fd_errfromchild == fd_fromchild) {
+ errfromchild[0] = fromchild[0];
+ errfromchild[1] = fromchild[1];
+ } else if (pipe(errfromchild) == 0) {
+ par_close[num_par_close++] = errfromchild[1];
+ child_close[num_child_close++] = errfromchild[0];
+ } else
+ goto fail;
+ } else {
+ errfromchild[1] = open("/dev/null", O_WRONLY);
+ if (errfromchild[1] < 0)
+ goto fail;
+ par_close[num_par_close++] = errfromchild[1];
}
+
if (pipe(execfail) != 0)
- goto close_fromchild_fail;
+ goto fail;
+
+ par_close[num_par_close++] = execfail[1];
+ child_close[num_child_close++] = execfail[0];
if (fcntl(execfail[1], F_SETFD, fcntl(execfail[1], F_GETFD)
| FD_CLOEXEC) < 0)
- goto close_execfail_fail;
+ goto fail;
childpid = fork();
if (childpid < 0)
- goto close_execfail_fail;
+ goto fail;
if (childpid == 0) {
- if (fd_tochild)
- close(tochild[1]);
- if (fd_fromchild)
- close(fromchild[0]);
- close(execfail[0]);
+ for (int i = 0; i < num_child_close; i++)
+ close(child_close[i]);
// Child runs command.
if (tochild[0] != STDIN_FILENO) {
goto child_errno_fail;
close(fromchild[1]);
}
+ if (fd_errfromchild && fd_errfromchild == fd_fromchild) {
+ if (dup2(STDOUT_FILENO, STDERR_FILENO) == -1)
+ goto child_errno_fail;
+ } else if (errfromchild[1] != STDERR_FILENO) {
+ if (dup2(errfromchild[1], STDERR_FILENO) == -1)
+ goto child_errno_fail;
+ close(errfromchild[1]);
+ }
execvp(arr[0], arr);
child_errno_fail:
err = errno;
- write(execfail[1], &err, sizeof(err));
+ /* Gcc's warn-unused-result fail. */
+ if (write(execfail[1], &err, sizeof(err))) {
+ ;
+ }
exit(127);
}
- close(tochild[0]);
- close(fromchild[1]);
- close(execfail[1]);
+ for (int i = 0; i < num_par_close; i++)
+ close(par_close[i]);
+
/* Child will close this without writing on successful exec. */
if (read(execfail[0], &err, sizeof(err)) == sizeof(err)) {
close(execfail[0]);
return -1;
}
close(execfail[0]);
- if (fd_tochild)
+ if (fd_tochild && fd_tochild != &pipecmd_preserve)
*fd_tochild = tochild[1];
- if (fd_fromchild)
+ if (fd_fromchild && fd_fromchild != &pipecmd_preserve)
*fd_fromchild = fromchild[0];
+ if (fd_errfromchild && fd_errfromchild != &pipecmd_preserve)
+ *fd_errfromchild = errfromchild[0];
return childpid;
-close_execfail_fail:
- close_noerr(execfail[0]);
- close_noerr(execfail[1]);
-close_fromchild_fail:
- if (fd_fromchild)
- close_noerr(fromchild[0]);
- close_noerr(fromchild[1]);
-close_tochild_fail:
- close_noerr(tochild[0]);
- if (fd_tochild)
- close_noerr(tochild[1]);
fail:
+ for (int i = 0; i < num_par_close; i++)
+ close_noerr(par_close[i]);
return -1;
}
-pid_t pipecmd(int *fd_fromchild, int *fd_tochild, const char *cmd, ...)
+pid_t pipecmd(int *fd_tochild, int *fd_fromchild, int *fd_errfromchild,
+ const char *cmd, ...)
{
pid_t childpid;
va_list ap;
va_start(ap, cmd);
- childpid = pipecmdv(fd_fromchild, fd_tochild, cmd, ap);
+ childpid = pipecmdv(fd_tochild, fd_fromchild, fd_errfromchild, cmd, ap);
va_end(ap);
return childpid;