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Date: Tue, 26 Jan 2016 21:26:33 +0100
From: Hauke Mehrtens <hauke@...ke-m.de>
To: musl@...ts.openwall.com
Cc: Hauke Mehrtens <hauke@...ke-m.de>
Subject: [PATCH v3 1/2] vdso: clock_gettime: call normal syscall in case of an error
When the vdso call returns an error just call the normal syscall and
return its result. clock_gettime() only fails with EFAULT if tp points
to an inaccessible address space or with EINVAL if the clk_id is
unknown. EFAULT is an implementation problem and performance for this
case is not important. When it returns EINVAL a normal syscall could
still work, so try it.
This fixes a bug when an error occurred errno was not set and it was a
value different than -1 returned.
In addition on MIPS the Linux kernel 4.4 only supports some clk_ids and
assumes the libc will call the original function if it gets a -ENOSYS,
so do this for all error codes.
Signed-off-by: Hauke Mehrtens <hauke@...ke-m.de>
---
src/time/clock_gettime.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/src/time/clock_gettime.c b/src/time/clock_gettime.c
index 1572de0..9d3ff7e 100644
--- a/src/time/clock_gettime.c
+++ b/src/time/clock_gettime.c
@@ -26,16 +26,18 @@ void *__vdsosym(const char *, const char *);
int __clock_gettime(clockid_t clk, struct timespec *ts)
{
#ifdef VDSO_CGT_SYM
+ int r;
static int (*volatile cgt)(clockid_t, struct timespec *);
if (!cgt) {
void *f = __vdsosym(VDSO_CGT_VER, VDSO_CGT_SYM);
if (!f) f = (void *)sc_clock_gettime;
a_cas_p(&cgt, 0, f);
}
- return cgt(clk, ts);
-#else
- return sc_clock_gettime(clk, ts);
+ r = cgt(clk, ts);
+ /* In case an error occurred try the normal syscall */
+ if (!r) return r;
#endif
+ return sc_clock_gettime(clk, ts);
}
weak_alias(__clock_gettime, clock_gettime);
--
2.7.0.rc3
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