[LTP] [PATCH v4 2/2] syscalls/statfs02, fstatfs02: Accept segfault instead of EFAULT

[Tudor Cretu]

The [f]statfs02 testsuites check that [f]statfs returns EFUALT when the
provided buf parameter is invalid. There are cases in which the supported
libcs don't exhibit this behaviour.

glibc versions newer than 2.34 and on systems that support [f]statfs64,
call the syscall with a local struct statfs and then copy the result
into buf. This throws a segfault for an invalid buf. musl dereferences buf
before the syscall is called and, similarly, throws a segfault.

Allow the tests to pass if segfault is thrown instead of returning EFAULT.

Signed-off-by: Tudor Cretu <tudor.cretu@arm.com>
---
 testcases/kernel/syscalls/fstatfs/fstatfs02.c | 23 ++++++++++++++++++-
 testcases/kernel/syscalls/statfs/statfs02.c   | 23 ++++++++++++++++++-
 2 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/testcases/kernel/syscalls/fstatfs/fstatfs02.c b/testcases/kernel/syscalls/fstatfs/fstatfs02.c
index 4267bd02b..e12ad2b70 100644
--- a/testcases/kernel/syscalls/fstatfs/fstatfs02.c
+++ b/testcases/kernel/syscalls/fstatfs/fstatfs02.c
@@ -9,6 +9,7 @@
  */
 
 #include <errno.h>
+#include <stdlib.h>
 #include <sys/types.h>
 #include <sys/statfs.h>
 #include <sys/wait.h>
@@ -33,7 +34,26 @@ static struct test_case_t {
 
 static void fstatfs_verify(unsigned int n)
 {
-	TST_EXP_FAIL(fstatfs(tests[n].fd, tests[n].sbuf), tests[n].error, "fstatfs()");
+	int pid, status;
+
+	pid = SAFE_FORK();
+	if (!pid) {
+		TST_EXP_FAIL(fstatfs(tests[n].fd, tests[n].sbuf), tests[n].error, "fstatfs()");
+		exit(0);
+	}
+
+	SAFE_WAITPID(pid, &status, 0);
+
+	if (WIFEXITED(status))
+		return;
+
+	if (tests[n].error == EFAULT &&
+	    WIFSIGNALED(status) && WTERMSIG(status) == SIGSEGV) {
+		tst_res(TPASS, "Got SIGSEGV instead of EFAULT");
+		return;
+	}
+
+	tst_res(TFAIL, "Child %s", tst_strstatus(status));
 }
 
 static void setup(void)
@@ -57,4 +77,5 @@ static struct tst_test test = {
 	.setup = setup,
 	.cleanup = cleanup,
 	.needs_tmpdir = 1,
+	.forks_child = 1,
 };
diff --git a/testcases/kernel/syscalls/statfs/statfs02.c b/testcases/kernel/syscalls/statfs/statfs02.c
index f906c84ff..be5e1ee16 100644
--- a/testcases/kernel/syscalls/statfs/statfs02.c
+++ b/testcases/kernel/syscalls/statfs/statfs02.c
@@ -22,6 +22,7 @@
 
 #include <errno.h>
 #include <fcntl.h>
+#include <stdlib.h>
 #include <sys/statfs.h>
 #include <sys/wait.h>
 #include "tst_test.h"
@@ -56,7 +57,26 @@ static void cleanup(void);
 
 static void statfs_verify(unsigned int n)
 {
-	TST_EXP_FAIL(statfs(tests[n].path, tests[n].buf), tests[n].exp_error, "statfs()");
+	int pid, status;
+
+	pid = SAFE_FORK();
+	if (!pid) {
+		TST_EXP_FAIL(statfs(tests[n].path, tests[n].buf), tests[n].exp_error, "statfs()");
+		exit(0);
+	}
+
+	SAFE_WAITPID(pid, &status, 0);
+
+	if (WIFEXITED(status))
+		return;
+
+	if (tests[n].exp_error == EFAULT &&
+	    WIFSIGNALED(status) && WTERMSIG(status) == SIGSEGV) {
+		tst_res(TPASS, "Got SIGSEGV instead of EFAULT");
+		return;
+	}
+
+	tst_res(TFAIL, "Child %s", tst_strstatus(status));
 }
 
 static void setup(void)
@@ -86,4 +106,5 @@ static struct tst_test test = {
 	.setup = setup,
 	.cleanup = cleanup,
 	.needs_tmpdir = 1,
+	.forks_child = 1,
 };
-- 
2.25.1