/* CC0 license (public domain) - see LICENSE file for details */
+#include <ccan/closefrom/closefrom.h>
#include <ccan/pipecmd/pipecmd.h>
#include <ccan/noerr/noerr.h>
#include <stdlib.h>
#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;
+
+ if (!arr) {
+ errno = ENOMEM;
+ return -1;
+ }
+ ret = pipecmdarr(fd_tochild, fd_fromchild, fd_errfromchild, arr);
+ free_noerr(arr);
+ return ret;
+}
+
+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) {
- char **args = gather_args(cmd, ap);
-
- if (fd_tochild)
- close(tochild[1]);
- if (fd_fromchild)
- close(fromchild[0]);
- close(execfail[0]);
+ int i;
+ for (i = 0; i < num_child_close; i++)
+ close(child_close[i]);
// Child runs command.
- if (!args)
- err = ENOMEM;
- else {
- if (tochild[0] != STDIN_FILENO) {
- if (dup2(tochild[0], STDIN_FILENO) == -1)
- goto child_errno_fail;
- close(tochild[0]);
- }
- if (fromchild[1] != STDOUT_FILENO) {
- if (dup2(fromchild[1], STDOUT_FILENO) == -1)
- goto child_errno_fail;
- close(fromchild[1]);
- }
- execvp(cmd, args);
- child_errno_fail:
- err = errno;
+ if (tochild[0] != STDIN_FILENO) {
+ if (dup2(tochild[0], STDIN_FILENO) == -1)
+ goto child_errno_fail;
+ close(tochild[0]);
+ }
+ if (fromchild[1] != STDOUT_FILENO) {
+ if (dup2(fromchild[1], STDOUT_FILENO) == -1)
+ 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]);
+ }
+
+ /* Map execfail[1] to fd 3. */
+ if (execfail[1] != 3) {
+ if (dup2(execfail[1], 3) == -1)
+ goto child_errno_fail;
+ /* CLOEXEC is not shared by dup2, so copy the flags
+ * from execfail[1] to 3.
+ */
+ if (fcntl(3, F_SETFD, fcntl(execfail[1], F_GETFD)) < 0)
+ goto child_errno_fail;
+ close(execfail[1]);
+ execfail[1] = 3;
+ }
+
+ /* Make (fairly!) sure all other fds are closed. */
+ closefrom(4);
+
+ execvp(arr[0], arr);
+
+ child_errno_fail:
+ err = errno;
+ /* Gcc's warn-unused-result fail. */
+ if (write(execfail[1], &err, sizeof(err))) {
+ ;
}
- write(execfail[1], &err, sizeof(err));
exit(127);
}
- close(tochild[0]);
- close(fromchild[1]);
- close(execfail[1]);
+ int i;
+ for (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]);
waitpid(childpid, NULL, 0);
errno = err;
return -1;
}
- if (fd_tochild)
+ close(execfail[0]);
+ 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 (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;
projects / ccan / blobdiff