* libguile/posix.c (start_child): Close standard file descriptors only
after all of them have been dup2'd.
---
libguile/posix.c | 40 +++++++++++++++++++---------------------
1 file changed, 19 insertions(+), 21 deletions(-)
diff --git a/libguile/posix.c b/libguile/posix.c
index 3ab12b99e..148ebeb3d 100644
--- a/libguile/posix.c
+++ b/libguile/posix.c
@@ -1357,27 +1357,25 @@ start_child (const char *exec_file, char **exec_argv,
if (err == -1)
err = open ("/dev/null", O_WRONLY);
- if (in > 0)
- {
- if (out == 0)
- out = renumber_file_descriptor (out, err);
- if (err == 0)
- err = renumber_file_descriptor (err, err);
- do dup2 (in, 0); while (errno == EINTR);
- close (in);
- }
- if (out > 1)
- {
- if (err == 1)
- err = renumber_file_descriptor (err, err);
- do dup2 (out, 1); while (errno == EINTR);
- close (out);
- }
- if (err > 2)
- {
- do dup2 (err, 2); while (errno == EINTR);
- close (err);
- }
+ /* Dup each non-yet-dup2'd fd that's in the way to the next available fd,
+ so that we can safely dup2 to 0/1/2 without potentially overwriting
+ in/out/err. Note that dup2 doesn't do anything if its arguments are
+ equal. */
+ if (out == 0)
+ do out = dup (out); while (errno == EINTR);
+ if (err == 0)
+ do err = dup (err); while (errno == EINTR);
+ do dup2 (in, 0); while (errno == EINTR);
+
+ if (err == 1)
+ do err = dup (err); while (errno == EINTR);
+ do dup2 (out, 1); while (errno == EINTR);
+
+ do dup2 (err, 2); while (errno == EINTR);
+
+ if (in > 2) close (in);
+ if (out > 2) close (out);
+ if (err > 2) close (err);
execvp (exec_file, exec_argv);
--
2.34.0
