[PATCH] selftests/nolibc: disable brk()/sbrk() tests on musl

[Thomas Weißschuh]

On musl calls to brk() and sbrk() always fail with ENOMEM.
Detect this and skip the tests on musl.

Tested on glibc 2.39 and musl 1.2.5 in addition to nolibc.

Signed-off-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
---
 tools/testing/selftests/nolibc/nolibc-test.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
index 94bb6e11c16f..89be9ba95179 100644
--- a/tools/testing/selftests/nolibc/nolibc-test.c
+++ b/tools/testing/selftests/nolibc/nolibc-test.c
@@ -942,6 +942,7 @@ int run_syscall(int min, int max)
 	int ret = 0;
 	void *p1, *p2;
 	int has_gettid = 1;
+	int has_brk;
 
 	/* <proc> indicates whether or not /proc is mounted */
 	proc = stat("/proc", &stat_buf) == 0;
@@ -954,6 +955,9 @@ int run_syscall(int min, int max)
 	has_gettid = __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 30);
 #endif
 
+	/* on musl setting brk()/sbrk() always fails */
+	has_brk = brk(0) == 0;
+
 	for (test = min; test >= 0 && test <= max; test++) {
 		int llen = 0; /* line length */
 
@@ -969,9 +973,9 @@ int run_syscall(int min, int max)
 		CASE_TEST(kill_0);            EXPECT_SYSZR(1, kill(getpid(), 0)); break;
 		CASE_TEST(kill_CONT);         EXPECT_SYSZR(1, kill(getpid(), 0)); break;
 		CASE_TEST(kill_BADPID);       EXPECT_SYSER(1, kill(INT_MAX, 0), -1, ESRCH); break;
-		CASE_TEST(sbrk_0);            EXPECT_PTRNE(1, sbrk(0), (void *)-1); break;
-		CASE_TEST(sbrk);              if ((p1 = p2 = sbrk(4096)) != (void *)-1) p2 = sbrk(-4096); EXPECT_SYSZR(1, (p2 == (void *)-1) || p2 == p1); break;
-		CASE_TEST(brk);               EXPECT_SYSZR(1, brk(sbrk(0))); break;
+		CASE_TEST(sbrk_0);            EXPECT_PTRNE(has_brk, sbrk(0), (void *)-1); break;
+		CASE_TEST(sbrk);              if ((p1 = p2 = sbrk(4096)) != (void *)-1) p2 = sbrk(-4096); EXPECT_SYSZR(has_brk, (p2 == (void *)-1) || p2 == p1); break;
+		CASE_TEST(brk);               EXPECT_SYSZR(has_brk, brk(sbrk(0))); break;
 		CASE_TEST(chdir_root);        EXPECT_SYSZR(1, chdir("/")); chdir(getenv("PWD")); break;
 		CASE_TEST(chdir_dot);         EXPECT_SYSZR(1, chdir(".")); break;
 		CASE_TEST(chdir_blah);        EXPECT_SYSER(1, chdir("/blah"), -1, ENOENT); break;

---
base-commit: 0adab2b6b7336fb6ee3c6456a432dad3b1d25647
change-id: 20240423-nolibc-musl-brk-7784add29801

Best regards,
-- 
Thomas Weißschuh <linux@xxxxxxxxxxxxxx>