From: Florian Weimer <fweimer@redhat.com>
To: libc-alpha@sourceware.org
Subject: [PATCH] posix: Move environ helper variables next to environ definition (bug 32541)
Date: Fri, 07 Mar 2025 17:32:41 +0100	[thread overview]
Message-ID: <871pv84x92.fsf@oldenburg.str.redhat.com> (raw)

This helps with statically interposing getenv.

Updates commit 7a61e7f557a97ab597d6fca5e2d1f13f65685c61
("stdlib: Make getenv thread-safe in more cases").

---
 posix/environ.c            |  4 ++++
 stdlib/Makefile            |  2 ++
 stdlib/getenv.c            |  3 ---
 stdlib/tst-getenv-static.c | 38 ++++++++++++++++++++++++++++++++++++++
 4 files changed, 44 insertions(+), 3 deletions(-)

diff --git a/posix/environ.c b/posix/environ.c
index a0ed0d80ea..924effe3cd 100644
--- a/posix/environ.c
+++ b/posix/environ.c
@@ -2,6 +2,7 @@
 
 #include <unistd.h>
 #include <stddef.h>
+#include <stdlib/setenv.h>
 
 /* This must be initialized; we cannot have a weak alias into bss.  */
 char **__environ = NULL;
@@ -10,3 +11,6 @@ weak_alias (__environ, environ)
 /* The SVR4 ABI says `_environ' will be the name to use
    in case the user overrides the weak alias `environ'.  */
 weak_alias (__environ, _environ)
+
+struct environ_array *__environ_array_list;
+environ_counter __environ_counter;
diff --git a/stdlib/Makefile b/stdlib/Makefile
index 1c4fa2382f..c9c8f702a2 100644
--- a/stdlib/Makefile
+++ b/stdlib/Makefile
@@ -282,6 +282,7 @@ tests := \
   tst-environ-change-3 \
   tst-environ-change-4 \
   tst-getenv-signal \
+  tst-getenv-static \
   tst-getenv-thread \
   tst-getenv-unsetenv \
   tst-getrandom \
@@ -377,6 +378,7 @@ tests-internal := \
   # tests-internal
 
 tests-static := \
+  tst-getenv-static \
   tst-secure-getenv \
   # tests-static
 
diff --git a/stdlib/getenv.c b/stdlib/getenv.c
index 5e7212cca6..1a7b0bfc06 100644
--- a/stdlib/getenv.c
+++ b/stdlib/getenv.c
@@ -20,9 +20,6 @@
 #include <string.h>
 #include <unistd.h>
 
-struct environ_array *__environ_array_list;
-environ_counter __environ_counter;
-
 char *
 getenv (const char *name)
 {
diff --git a/stdlib/tst-getenv-static.c b/stdlib/tst-getenv-static.c
new file mode 100644
index 0000000000..f5f484c83a
--- /dev/null
+++ b/stdlib/tst-getenv-static.c
@@ -0,0 +1,38 @@
+/* Static interposition of getenv (bug 32541).
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <stdlib.h>
+#include <support/check.h>
+
+/* Some programs try to interpose getenv for their own use (not
+   glibc's internal use).  Make sure that this is possible without
+   introducing linker failures due to duplicate symbols.  */
+
+char *
+getenv (const char *ignored)
+{
+  return NULL;
+}
+
+static int
+do_test (void)
+{
+  TEST_COMPARE_STRING (getenv ("PATH"), NULL);
+  return 0;
+}
+
+#include <support/test-driver.c>

base-commit: 59dc232df277c21239c357e3519682c26e182cd7