[v4,1/2] linux: wait4: Fix incorrect return value comparison
Commit Message
Patch 600f00b "linux: Use long time_t for wait4/getrusage" introduced
two bugs:
- The usage32 struct was set if the wait4 syscall had an error.
- For 32-bit systems the usage struct was set even if it was specified
as NULL.
This patch fixes the two issues.
---
sysdeps/unix/sysv/linux/wait4.c | 19 +++++++++----------
1 file changed, 9 insertions(+), 10 deletions(-)
Comments
On Apr 10 2020, Alistair Francis via Libc-alpha wrote:
> Patch 600f00b "linux: Use long time_t for wait4/getrusage" introduced
> two bugs:
> - The usage32 struct was set if the wait4 syscall had an error.
> - For 32-bit systems the usage struct was set even if it was specified
> as NULL.
>
> This patch fixes the two issues.
Ok.
Andreas.
@@ -29,13 +29,13 @@ __wait4_time64 (pid_t pid, int *stat_loc, int options, struct __rusage64 *usage)
# if __KERNEL_OLD_TIMEVAL_MATCHES_TIMEVAL64
return SYSCALL_CANCEL (wait4, pid, stat_loc, options, usage);
# else
+ pid_t ret;
struct __rusage32 usage32;
- pid_t ret = SYSCALL_CANCEL (wait4, pid, stat_loc, options, &usage32);
- if (ret != 0)
- return ret;
+ ret = SYSCALL_CANCEL (wait4, pid, stat_loc, options,
+ usage != NULL ? &usage32 : NULL);
- if (usage != NULL)
+ if (ret > 0 && usage != NULL)
rusage32_to_rusage64 (&usage32, usage);
return ret;
@@ -114,15 +114,14 @@ libc_hidden_def (__wait4_time64)
pid_t
__wait4 (pid_t pid, int *stat_loc, int options, struct rusage *usage)
{
- pid_t ret ;
+ pid_t ret;
struct __rusage64 usage64;
- ret = __wait4_time64 (pid, stat_loc, options, &usage64);
+ ret = __wait4_time64 (pid, stat_loc, options,
+ usage != NULL ? &usage64 : NULL);
- if (ret != 0)
- return ret;
-
- rusage64_to_rusage (&usage64, usage);
+ if (ret > 0 && usage != 0)
+ rusage64_to_rusage (&usage64, usage);
return ret;
}