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signal: Align the sigset_t size passed to from user space to kernel.

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Pass kernel space sigset_t size to __rt_sigprocmask to workaround
the miss-match of NSIG/sigset_t definition between kernel and bionic.

Note: Patch originally from Google...
Change-Id: I4840fdc56d0b90d7ce2334250f04a84caffcba2a
Signed-off-by: Chenyang Du <chenyang.du@intel.com>
Signed-off-by: Bruce Beare <bruce.j.beare@intel.com>
This commit is contained in:
Bruce Beare 2011-12-05 11:25:37 -08:00 committed by Jean-Baptiste Queru
parent cb1df91616
commit e4a21c89a8
1 changed files with 37 additions and 8 deletions
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45
libc/bionic/pthread.c
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@ -1861,7 +1861,21 @@ int pthread_kill(pthread_t tid, int sig)
return ret;
}
extern int __rt_sigprocmask(int, const sigset_t *, sigset_t *, size_t);
/* Despite the fact that our kernel headers define sigset_t explicitly
* as a 32-bit integer, the kernel system call really expects a 64-bit
* bitmap for the signal set, or more exactly an array of two-32-bit
* values (see $KERNEL/arch/$ARCH/include/asm/signal.h for details).
*
* Unfortunately, we cannot fix the sigset_t definition without breaking
* the C library ABI, so perform a little runtime translation here.
*/
typedef union {
sigset_t bionic;
uint32_t kernel[2];
} kernel_sigset_t;
/* this is a private syscall stub */
extern int __rt_sigprocmask(int, const kernel_sigset_t *, kernel_sigset_t *, size_t);
int pthread_sigmask(int how, const sigset_t *set, sigset_t *oset)
{
@ -1870,16 +1884,31 @@ int pthread_sigmask(int how, const sigset_t *set, sigset_t *oset)
*/
int ret, old_errno = errno;
/* Use NSIG which corresponds to the number of signals in
* our 32-bit sigset_t implementation. As such, this function, or
* anything that deals with sigset_t cannot manage real-time signals
* (signo >= 32). We might want to introduce sigset_rt_t as an
* extension to do so in the future.
*/
ret = __rt_sigprocmask(how, set, oset, NSIG / 8);
/* We must convert *set into a kernel_sigset_t */
kernel_sigset_t in_set, *in_set_ptr;
kernel_sigset_t out_set;
in_set.kernel[0] = in_set.kernel[1] = 0;
out_set.kernel[0] = out_set.kernel[1] = 0;
/* 'in_set_ptr' is the second parameter to __rt_sigprocmask. It must be NULL
* if 'set' is NULL to ensure correct semantics (which in this case would
* be to ignore 'how' and return the current signal set into 'oset'.
*/
if (set == NULL) {
in_set_ptr = NULL;
} else {
in_set.bionic = *set;
in_set_ptr = &in_set;
}
ret = __rt_sigprocmask(how, in_set_ptr, &out_set, sizeof(kernel_sigset_t));
if (ret < 0)
ret = errno;
if (oset)
*oset = out_set.bionic;
errno = old_errno;
return ret;
}