[Valgrind-developers] [valgrind/VALGRIND_3_25_BRANCH] Don't count closed inherited file descriptors

[Mark W. <ma...@so...>]

https://sourceware.org/git/gitweb.cgi?p=valgrind.git;h=46c50747724c70c4200257361b55ebb615a2fb35

commit 46c50747724c70c4200257361b55ebb615a2fb35
Author: Mark Wielaard <ma...@kl...>
Date:   Wed May 14 00:13:06 2025 +0200

    Don't count closed inherited file descriptors
    
    Programs which close some inherited file descriptors and are run under
    valgrind with -q and --track-fds=yes would still show the FILE
    DESCRIPTORS banner even if there were no non-inherited file
    descriptors still open.
    
    Fix this by not counting already closed inherited file descriptors.
    
    Add a simple testcase to show /usr/bin/cat /dev/null doesn't produce
    any output running under valgrind -q --track-fds=yes.
    
    https://bugs.kde.org/show_bug.cgi?id=504177
    (cherry picked from commit 29a5fcb3f6371584f89f9b54c793cc0f29802553)

Diff:
---
 NEWS                                  | 1 +
 coregrind/m_syswrap/syswrap-generic.c | 2 +-
 none/tests/Makefile.am                | 1 +
 none/tests/fdleak_cat.stderr.exp      | 0
 none/tests/fdleak_cat.vgtest          | 3 +++
 5 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/NEWS b/NEWS
index 3f084a52be..533b008166 100644
--- a/NEWS
+++ b/NEWS
@@ -7,6 +7,7 @@ The following bugs have been fixed or resolved on this branch.
 
 503641  close_range syscalls started failing with 3.25.0
 503914  mount syscall param filesystemtype may be NULL
+504177  FILE DESCRIPTORS banner shows when closing some inherited fds
 
 To see details of a given bug, visit
   https://bugs.kde.org/show_bug.cgi?id=XXXXXX
diff --git a/coregrind/m_syswrap/syswrap-generic.c b/coregrind/m_syswrap/syswrap-generic.c
index 82a682a5ce..81c8fc028d 100644
--- a/coregrind/m_syswrap/syswrap-generic.c
+++ b/coregrind/m_syswrap/syswrap-generic.c
@@ -987,7 +987,7 @@ void VG_(show_open_fds) (const HChar* when)
    int inherited = 0;
 
    for (i = allocated_fds; i; i = i->next) {
-      if (i->where == NULL)
+      if (i->where == NULL && !i->fd_closed)
          inherited++;
    }
 
diff --git a/none/tests/Makefile.am b/none/tests/Makefile.am
index 043454828a..bebc2f4dd1 100644
--- a/none/tests/Makefile.am
+++ b/none/tests/Makefile.am
@@ -140,6 +140,7 @@ EXTRA_DIST = \
 	execve.vgtest execve.stdout.exp execve.stderr.exp \
 	faultstatus.vgtest faultstatus.stderr.exp faultstatus.stderr.exp-s390x \
 	fcntl_setown.vgtest fcntl_setown.stdout.exp fcntl_setown.stderr.exp \
+	fdleak_cat.vgtest fdleak_cat.stderr.exp \
 	fdleak_cmsg.stderr.exp fdleak_cmsg.vgtest \
 	fdleak_cmsg_xml.stderr.exp-ppc64le \
 	fdleak_cmsg_xml.stderr.exp fdleak_cmsg_xml.vgtest \
diff --git a/none/tests/fdleak_cat.stderr.exp b/none/tests/fdleak_cat.stderr.exp
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/none/tests/fdleak_cat.vgtest b/none/tests/fdleak_cat.vgtest
new file mode 100644
index 0000000000..11a618d855
--- /dev/null
+++ b/none/tests/fdleak_cat.vgtest
@@ -0,0 +1,3 @@
+prog: /usr/bin/cat
+vgopts: -q --track-fds=yes
+args: /dev/null