signals/sigaltstack: Report current flag bits in sigaltstack()

sigaltstack()'s reported previous state uses a somewhat odd convention, but the concept of flag bits is new, and we can do the flag bits sensibly. Specifically, let's just report them directly. This will allow saving and restoring the sigaltstack state using sigaltstack() to work correctly.

Andy Lutomirski committed 10 years ago

Commit 0318bc81 parent 158b67b2 files · +18 −4Browse files

Unified · Split

2 files

kernel/signal.c +2 −1
tools/testing/selftests/sigaltstack/sas.c +16 −3

kernel/signal.c+2−1

@@ -3099,7 +3099,8 @@ do_sigaltstack (const stack_t __user uss, stack_t __user uoss, unsigned long s · 3098 unmodified lines
3099	3099
3100	3100	oss.ss_sp = (void __user *) current->sas_ss_sp;
3101	3101	oss.ss_size = current->sas_ss_size;
3102		− oss.ss_flags = sas_ss_flags(sp);
	3102	+ oss.ss_flags = sas_ss_flags(sp) \|
	3103	+ (current->sas_ss_flags & SS_FLAG_BITS);
3103	3104
3104	3105	if (uss) {
3105	3106	void __user *ss_sp;

tools/testing/selftests/sigaltstack/sas.c+16−3

@@ -113,6 +113,19 @@ int main(void) · 112 unmodified lines
113	113	perror("mmap()");
114	114	return EXIT_FAILURE;
115	115	}
	116	+
	117	+ err = sigaltstack(NULL, &stk);
	118	+ if (err) {
	119	+ perror("[FAIL]\tsigaltstack()");
	120	+ exit(EXIT_FAILURE);
	121	+ }
	122	+ if (stk.ss_flags == SS_DISABLE) {
	123	+ printf("[OK]\tInitial sigaltstack state was SS_DISABLE\n");
	124	+ } else {
	125	+ printf("[FAIL]\tInitial sigaltstack state was %i; should have been SS_DISABLE\n", stk.ss_flags);
	126	+ return EXIT_FAILURE;
	127	+ }
	128	+
116	129	stk.ss_sp = sstack;
117	130	stk.ss_size = SIGSTKSZ;
118	131	stk.ss_flags = SS_ONSTACK \| SS_AUTODISARM;
@@ -151,12 +164,12 @@ int main(void) · 32 unmodified lines
151	164	perror("[FAIL]\tsigaltstack()");
152	165	exit(EXIT_FAILURE);
153	166	}
154		− if (stk.ss_flags != 0) {
155		− printf("[FAIL]\tss_flags=%i, should be 0\n",
	167	+ if (stk.ss_flags != SS_AUTODISARM) {
	168	+ printf("[FAIL]\tss_flags=%i, should be SS_AUTODISARM\n",
156	169	stk.ss_flags);
157	170	exit(EXIT_FAILURE);
158	171	}
159		− printf("[OK]\tsigaltstack is enabled after signal\n");
	172	+ printf("[OK]\tsigaltstack is still SS_AUTODISARM after signal\n");
160	173
161	174	printf("[OK]\tTest passed\n");
162	175	return 0;

signals/sigaltstack: Report current flag bits in sigaltstack()

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