Collin Funk wrote:
> + putenv tests: Silence -Wanalyzer-putenv-of-auto-var.
> + * tests/test-putenv.c (main): Declare static variables to pass to
> + putenv.
While fixing one problem, this patch reintroduced another one.
Namely, the argument to putenv needs to be
- of unlimited lifetime (to cover the case of a getenv() call
after the function terminates), and
- in writable memory (since it becomes part of a 'char ** environ').
When you write
static char *var = "TEST_VAR=abc";
the string is in read-only memory. See:
=========== foo.c ============
static char *var = "TEST_VAR";
int main () {}
==============================
$ gcc foo.c
$ hd < a.out
...
002000 01 00 02 00 54 45 53 54 5F 56 41 52 00 00 00 00 ....TEST_VAR....
...
$ objdump -x a.out
...
15 .rodata 0000000d 0000000000002000 0000000000002000 00002000 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
...
Whereas with this change the string is in writable memory:
=========== foo.c ============
static char var[] = "TEST_VAR";
int main () {}
==============================
$ gcc foo.c
$ hd < a.out
...
003010 54 45 53 54 5F 56 41 52 00 47 43 43 3A 20 28 55 TEST_VAR.GCC: (U
...
$ objdump -x a.out
...
22 .data 00000019 0000000000004000 0000000000004000 00003000 2**3
CONTENTS, ALLOC, LOAD, DATA
...
I'm therefore applying this:
2024-05-24 Bruno Haible <[email protected]>
putenv tests: Put the putenv() argument strings into writable memory.
* tests/test-putenv.c (main): Declare static variables of type 'char[]',
not 'char *'.
diff --git a/tests/test-putenv.c b/tests/test-putenv.c
index b772082d20..535fbbbb3a 100644
--- a/tests/test-putenv.c
+++ b/tests/test-putenv.c
@@ -42,7 +42,7 @@ main (void)
/* Verify adding an environment variable. */
{
- static char *var = "TEST_VAR=abc";
+ static char var[] = "TEST_VAR=abc";
ASSERT (putenv (var) == 0);
ptr = getenv ("TEST_VAR");
ASSERT (ptr != NULL);
@@ -51,14 +51,14 @@ main (void)
/* Verify removing an environment variable. */
{
- static char *var = "TEST_VAR";
+ static char var[] = "TEST_VAR";
ASSERT (putenv (var) == 0);
ASSERT (getenv ("TEST_VAR") == NULL);
}
/* Verify the behavior when removing a variable not in the environment. */
{
- static char *var = "TEST_VAR";
+ static char var[] = "TEST_VAR";
ASSERT (putenv (var) == 0);
ASSERT (getenv ("TEST_VAR") == NULL);
}
