bug#52835: [PATCH v4 2/4] Avoid double closes in piped-process.

[Bug reports for GUILE, GNU's Ubiquitous Extension Language]

* libguile/posix.c (scm_piped_process): Avoid double closes.
---
 libguile/posix.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/libguile/posix.c b/libguile/posix.c
index e9f49fa27..155ad09b7 100644
--- a/libguile/posix.c
+++ b/libguile/posix.c
@@ -1475,12 +1475,18 @@ scm_piped_process (SCM prog, SCM args, SCM from, SCM to)
       if (reading)
         {
           close (c2p[0]);
-          close (c2p[1]);
+          if (c2p[1] != c2p[0])
+            close (c2p[1]);
         }
       if (writing)
         {
-          close (p2c[0]);
-          close (p2c[1]);
+          if (!(reading && (c2p[0] == p2c[0] ||
+                            c2p[1] == p2c[0])))
+            close (p2c[0]);
+          if (p2c[0] != p2c[1] &&
+              !(reading && (c2p[0] == p2c[1] ||
+                            c2p[1] == p2c[1])))
+            close (p2c[1]);
         }
       errno = errno_save;
       SCM_SYSERROR;
@@ -1488,7 +1494,7 @@ scm_piped_process (SCM prog, SCM args, SCM from, SCM to)
 
   if (reading)
     close (c2p[1]);
-  if (writing)
+  if (writing && !(reading && c2p[1] == p2c[0]))
     close (p2c[0]);
 
   return scm_from_int (pid);
-- 
2.36.0