add a test for making sure vfork/signals are handled properly across different setjmp/longjmps

test/setjmp/tst-vfork-longjmp.c

@@ -0,0 +1,106 @@
+/* make sure we can vfork/exec across setjmp/longjmp's
+ * and make sure signal block masks don't get corrupted
+ * in the process.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <unistd.h>
+#include <errno.h>
+#include <setjmp.h>
+#include <signal.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <string.h>
+
+int verbose = 0;
+
+int execute_child(const char *prog)
+{
+	int status;
+	pid_t child;
+	child = vfork();
+	if (child == 0) {
+		execlp(prog, prog, NULL);
+		perror("Could not execute specified prog");
+		_exit(1);
+	} else if (child == 1)
+		return 1;
+	wait(&status);
+	return WEXITSTATUS(status);
+}
+
+sigset_t orig_mask;
+
+int check_sig_mask(void)
+{
+	int status;
+	pid_t child;
+
+	child = vfork();
+	if (child == 0) {
+		int ret;
+		sigset_t child_mask;
+		memset(&child_mask, 0x00, sizeof(child_mask));
+		ret = sigprocmask(SIG_BLOCK, NULL, &child_mask);
+		if (ret != 0) {
+			perror("could not get child sig block mask");
+			_exit(1);
+		}
+		ret = memcmp(&orig_mask, &child_mask, sizeof(orig_mask));
+		if (verbose) {
+			printf("sigmsk: %08lx%08lx ", child_mask.__val[1], child_mask.__val[0]);
+			printf("sigmsk: %08lx%08lx ", orig_mask.__val[1], orig_mask.__val[0]);
+			printf("%i\n", ret);
+		}
+		_exit(ret);
+	} else if (child == 1)
+		return 1;
+	wait(&status);
+	return WEXITSTATUS(status);
+}
+
+int main(int argc, char *argv[])
+{
+	const char *prog;
+	jmp_buf env;
+	sigjmp_buf sigenv;
+	int cnt, max, ret;
+
+	memset(&orig_mask, 0x00, sizeof(orig_mask));
+	ret = sigprocmask(SIG_BLOCK, NULL, &orig_mask);
+	if (ret != 0) {
+		perror("could not get orig sig block mask");
+		return 1;
+	}
+
+	prog = (argc > 1 ? argv[1] : "true");
+	ret = 0;
+	verbose = 0;
+	max = 10;
+
+	/* test vfork() instead of sigsetjmp/siglongjmp */
+	cnt = 0;
+	sigsetjmp(sigenv, 1);
+	++cnt;
+	if (verbose)
+		printf("sigsetjmp loop %i\n", cnt);
+	ret |= check_sig_mask();
+	ret |= execute_child(prog);
+	if (cnt < max)
+		siglongjmp(sigenv, 0);
+
+	/* test vfork() inside of setjmp/longjmp */
+	cnt = 0;
+	setjmp(env);
+	++cnt;
+	if (verbose)
+		printf("setjmp loop %i\n", cnt);
+	ret |= check_sig_mask();
+	ret |= execute_child(prog);
+	if (cnt < max)
+		longjmp(env, 0);
+
+	return ret;
+}