[LTP] [PATCH v3] syscall01: use 32bit syscalls if available

[LTP] [PATCH v3] syscall01: use 32bit syscalls if available

[Edward Liaw via ltp]

For 32-bit applications, the getuid/getgid syscalls return 16-bit ids,
and the getuid32 and getgid32 syscalls return 32-bit ids.  When
CONFIG_UID16 is disabled in the kernel, getuid/getgid (16-bit UIDs) are
no longer available.  Thus this test will fail when compiled as 32-bit
and with CONFIG_UID16 disabled.  For 64-bit applications, this is not an
issue because getuid/getgid return 32-bit ids and getuid32/getgid32 are
not defined.

The fix for this is to use getuid32/getgid32 if they are available to
match the behavior of glibc.

Signed-off-by: Edward Liaw <edliaw@google.com>
---
 testcases/kernel/syscalls/syscall/syscall01.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/testcases/kernel/syscalls/syscall/syscall01.c b/testcases/kernel/syscalls/syscall/syscall01.c
index 167e6ee86..76e793221 100644
--- a/testcases/kernel/syscalls/syscall/syscall01.c
+++ b/testcases/kernel/syscalls/syscall/syscall01.c
@@ -37,7 +37,11 @@ static void verify_getuid(void)
 	uid_t u1, u2;
 
 	u1 = getuid();
+#ifdef SYS_getuid32
+	u2 = syscall(SYS_getuid32);
+#else
 	u2 = syscall(SYS_getuid);
+#endif
 
 	if (u1 == u2) {
 		tst_res(TPASS, "getuid() == syscall(SYS_getuid)");
@@ -52,7 +56,11 @@ static void verify_getgid(void)
 	gid_t g1, g2;
 
 	g1 = getgid();
+#ifdef SYS_getgid32
+	g2 = syscall(SYS_getgid32);
+#else
 	g2 = syscall(SYS_getgid);
+#endif
 
 	if (g1 == g2) {
 		tst_res(TPASS, "getgid() == syscall(SYS_getgid)");
-- 
2.39.2.637.g21b0678d19-goog


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Re: [LTP] [PATCH v3] syscall01: use 32bit syscalls if available

[Cyril Hrubis]

Hi!
> For 32-bit applications, the getuid/getgid syscalls return 16-bit ids,
> and the getuid32 and getgid32 syscalls return 32-bit ids.  When
> CONFIG_UID16 is disabled in the kernel, getuid/getgid (16-bit UIDs) are
> no longer available.  Thus this test will fail when compiled as 32-bit
> and with CONFIG_UID16 disabled.  For 64-bit applications, this is not an
> issue because getuid/getgid return 32-bit ids and getuid32/getgid32 are
> not defined.
> 
> The fix for this is to use getuid32/getgid32 if they are available to
> match the behavior of glibc.

Sounds reasonable, since we are attempting to test syscall() and not the
getuid implementation. Also this probably fixes the case where the test
would be executed with UID that does not fit into 16 bits as well.

Pushed, thanks.

-- 
Cyril Hrubis
chrubis@suse.cz

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