2 * Stas Sergeev <stsp@users.sourceforge.net>
4 * test sigaltstack(SS_ONSTACK | SS_AUTODISARM)
5 * If that succeeds, then swapcontext() can be used inside sighandler safely.
21 #define SS_AUTODISARM (1 << 4)
24 static void *sstack, *ustack;
25 static ucontext_t uc, sc;
26 static const char *msg = "[OK]\tStack preserved";
27 static const char *msg2 = "[FAIL]\tStack corrupted";
33 void my_usr1(int sig, siginfo_t *si, void *u)
40 register unsigned long sp asm("sp");
42 if (sp < (unsigned long)sstack ||
43 sp >= (unsigned long)sstack + SIGSTKSZ) {
44 printf("[FAIL]\tSP is not on sigaltstack\n");
47 /* put some data on stack. other sighandler will try to overwrite it */
50 p = (struct stk_data *)(aa + 512);
53 printf("[RUN]\tsignal USR1\n");
54 err = sigaltstack(NULL, &stk);
56 perror("[FAIL]\tsigaltstack()");
59 if (stk.ss_flags != SS_DISABLE)
60 printf("[FAIL]\tss_flags=%i, should be SS_DISABLE\n",
63 printf("[OK]\tsigaltstack is disabled in sighandler\n");
64 swapcontext(&sc, &uc);
65 printf("%s\n", p->msg);
67 printf("[RUN]\tAborting\n");
72 void my_usr2(int sig, siginfo_t *si, void *u)
77 printf("[RUN]\tsignal USR2\n");
79 /* dont run valgrind on this */
80 /* try to find the data stored by previous sighandler */
81 p = memmem(aa, 1024, msg, strlen(msg));
83 printf("[FAIL]\tsigaltstack re-used\n");
84 /* corrupt the data */
86 /* tell other sighandler that his data is corrupted */
91 static void switch_fn(void)
93 printf("[RUN]\tswitched to user ctx\n");
100 struct sigaction act;
104 sigemptyset(&act.sa_mask);
105 act.sa_flags = SA_ONSTACK | SA_SIGINFO;
106 act.sa_sigaction = my_usr1;
107 sigaction(SIGUSR1, &act, NULL);
108 act.sa_sigaction = my_usr2;
109 sigaction(SIGUSR2, &act, NULL);
110 sstack = mmap(NULL, SIGSTKSZ, PROT_READ | PROT_WRITE,
111 MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0);
112 if (sstack == MAP_FAILED) {
117 stk.ss_size = SIGSTKSZ;
118 stk.ss_flags = SS_ONSTACK | SS_AUTODISARM;
119 err = sigaltstack(&stk, NULL);
121 if (errno == EINVAL) {
122 printf("[NOTE]\tThe running kernel doesn't support SS_AUTODISARM\n");
124 * If test cases for the !SS_AUTODISARM variant were
125 * added, we could still run them. We don't have any
126 * test cases like that yet, so just exit and report
131 perror("[FAIL]\tsigaltstack(SS_ONSTACK | SS_AUTODISARM)");
136 ustack = mmap(NULL, SIGSTKSZ, PROT_READ | PROT_WRITE,
137 MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0);
138 if (ustack == MAP_FAILED) {
144 uc.uc_stack.ss_sp = ustack;
145 uc.uc_stack.ss_size = SIGSTKSZ;
146 makecontext(&uc, switch_fn, 0);
149 err = sigaltstack(NULL, &stk);
151 perror("[FAIL]\tsigaltstack()");
154 if (stk.ss_flags != 0) {
155 printf("[FAIL]\tss_flags=%i, should be 0\n",
159 printf("[OK]\tsigaltstack is enabled after signal\n");
161 printf("[OK]\tTest passed\n");