Fix vdso system call fallback failures.
When a vdso call falls back to making a regular system call, the inline
code for the system call doesn't know about errno and just leaves the
usual kernel result to be translated. Add the missing translation.
Also fix the defaults for non-vdso systems so we actually take the
fallback path (and so avoid unintentionally doing the errno translation
twice in those cases).
Bug: http://b/69626243
Test: ran new tests from http://b/63737556
Change-Id: If379632ea2e059e3d3bc3ff41bf3608dc05fb0a3
diff --git a/libc/bionic/vdso.cpp b/libc/bionic/vdso.cpp
index 8cdb504..969c39f 100644
--- a/libc/bionic/vdso.cpp
+++ b/libc/bionic/vdso.cpp
@@ -26,11 +26,18 @@
#include <unistd.h>
#include "private/KernelArgumentBlock.h"
+static inline int vdso_return(int result) {
+ if (__predict_true(result == 0)) return 0;
+
+ errno = -result;
+ return -1;
+}
+
int clock_gettime(int clock_id, timespec* tp) {
auto vdso_clock_gettime = reinterpret_cast<decltype(&clock_gettime)>(
__libc_globals->vdso[VDSO_CLOCK_GETTIME].fn);
if (__predict_true(vdso_clock_gettime)) {
- return vdso_clock_gettime(clock_id, tp);
+ return vdso_return(vdso_clock_gettime(clock_id, tp));
}
return __clock_gettime(clock_id, tp);
}
@@ -39,17 +46,15 @@
auto vdso_gettimeofday = reinterpret_cast<decltype(&gettimeofday)>(
__libc_globals->vdso[VDSO_GETTIMEOFDAY].fn);
if (__predict_true(vdso_gettimeofday)) {
- return vdso_gettimeofday(tv, tz);
+ return vdso_return(vdso_gettimeofday(tv, tz));
}
return __gettimeofday(tv, tz);
}
void __libc_init_vdso(libc_globals* globals, KernelArgumentBlock& args) {
auto&& vdso = globals->vdso;
- vdso[VDSO_CLOCK_GETTIME] = { VDSO_CLOCK_GETTIME_SYMBOL,
- reinterpret_cast<void*>(__clock_gettime) };
- vdso[VDSO_GETTIMEOFDAY] = { VDSO_GETTIMEOFDAY_SYMBOL,
- reinterpret_cast<void*>(__gettimeofday) };
+ vdso[VDSO_CLOCK_GETTIME] = { VDSO_CLOCK_GETTIME_SYMBOL, nullptr };
+ vdso[VDSO_GETTIMEOFDAY] = { VDSO_GETTIMEOFDAY_SYMBOL, nullptr };
// Do we have a vdso?
uintptr_t vdso_ehdr_addr = args.getauxval(AT_SYSINFO_EHDR);