Release 4.7 tools/testing/selftests/sigaltstack/sas.c
/*
* Stas Sergeev <stsp@users.sourceforge.net>
*
* test sigaltstack(SS_ONSTACK | SS_AUTODISARM)
* If that succeeds, then swapcontext() can be used inside sighandler safely.
*
*/
#define _GNU_SOURCE
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <ucontext.h>
#include <alloca.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#ifndef SS_AUTODISARM
#define SS_AUTODISARM (1U << 31)
#endif
static void *sstack, *ustack;
static ucontext_t uc, sc;
static const char *msg = "[OK]\tStack preserved";
static const char *msg2 = "[FAIL]\tStack corrupted";
struct stk_data {
char msg[128];
int flag;
};
void my_usr1(int sig, siginfo_t *si, void *u)
{
char *aa;
int err;
stack_t stk;
struct stk_data *p;
register unsigned long sp asm("sp");
if (sp < (unsigned long)sstack ||
sp >= (unsigned long)sstack + SIGSTKSZ) {
printf("[FAIL]\tSP is not on sigaltstack\n");
exit(EXIT_FAILURE);
}
/* put some data on stack. other sighandler will try to overwrite it */
aa = alloca(1024);
assert(aa);
p = (struct stk_data *)(aa + 512);
strcpy(p->msg, msg);
p->flag = 1;
printf("[RUN]\tsignal USR1\n");
err = sigaltstack(NULL, &stk);
if (err) {
perror("[FAIL]\tsigaltstack()");
exit(EXIT_FAILURE);
}
if (stk.ss_flags != SS_DISABLE)
printf("[FAIL]\tss_flags=%i, should be SS_DISABLE\n",
stk.ss_flags);
else
printf("[OK]\tsigaltstack is disabled in sighandler\n");
swapcontext(&sc, &uc);
printf("%s\n", p->msg);
if (!p->flag) {
printf("[RUN]\tAborting\n");
exit(EXIT_FAILURE);
}
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| stas sergeev | stas sergeev | 204 | 100.00% | 1 | 100.00% |
| Total | 204 | 100.00% | 1 | 100.00% |
void my_usr2(int sig, siginfo_t *si, void *u)
{
char *aa;
struct stk_data *p;
printf("[RUN]\tsignal USR2\n");
aa = alloca(1024);
/* dont run valgrind on this */
/* try to find the data stored by previous sighandler */
p = memmem(aa, 1024, msg, strlen(msg));
if (p) {
printf("[FAIL]\tsigaltstack re-used\n");
/* corrupt the data */
strcpy(p->msg, msg2);
/* tell other sighandler that his data is corrupted */
p->flag = 0;
}
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| stas sergeev | stas sergeev | 83 | 100.00% | 1 | 100.00% |
| Total | 83 | 100.00% | 1 | 100.00% |
static void switch_fn(void)
{
printf("[RUN]\tswitched to user ctx\n");
raise(SIGUSR2);
setcontext(&sc);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| stas sergeev | stas sergeev | 24 | 100.00% | 1 | 100.00% |
| Total | 24 | 100.00% | 1 | 100.00% |
int main(void)
{
struct sigaction act;
stack_t stk;
int err;
sigemptyset(&act.sa_mask);
act.sa_flags = SA_ONSTACK | SA_SIGINFO;
act.sa_sigaction = my_usr1;
sigaction(SIGUSR1, &act, NULL);
act.sa_sigaction = my_usr2;
sigaction(SIGUSR2, &act, NULL);
sstack = mmap(NULL, SIGSTKSZ, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0);
if (sstack == MAP_FAILED) {
perror("mmap()");
return EXIT_FAILURE;
}
err = sigaltstack(NULL, &stk);
if (err) {
perror("[FAIL]\tsigaltstack()");
exit(EXIT_FAILURE);
}
if (stk.ss_flags == SS_DISABLE) {
printf("[OK]\tInitial sigaltstack state was SS_DISABLE\n");
} else {
printf("[FAIL]\tInitial sigaltstack state was %i; should have been SS_DISABLE\n", stk.ss_flags);
return EXIT_FAILURE;
}
stk.ss_sp = sstack;
stk.ss_size = SIGSTKSZ;
stk.ss_flags = SS_ONSTACK | SS_AUTODISARM;
err = sigaltstack(&stk, NULL);
if (err) {
if (errno == EINVAL) {
printf("[NOTE]\tThe running kernel doesn't support SS_AUTODISARM\n");
/*
* If test cases for the !SS_AUTODISARM variant were
* added, we could still run them. We don't have any
* test cases like that yet, so just exit and report
* success.
*/
return 0;
} else {
perror("[FAIL]\tsigaltstack(SS_ONSTACK | SS_AUTODISARM)");
return EXIT_FAILURE;
}
}
ustack = mmap(NULL, SIGSTKSZ, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0);
if (ustack == MAP_FAILED) {
perror("mmap()");
return EXIT_FAILURE;
}
getcontext(&uc);
uc.uc_link = NULL;
uc.uc_stack.ss_sp = ustack;
uc.uc_stack.ss_size = SIGSTKSZ;
makecontext(&uc, switch_fn, 0);
raise(SIGUSR1);
err = sigaltstack(NULL, &stk);
if (err) {
perror("[FAIL]\tsigaltstack()");
exit(EXIT_FAILURE);
}
if (stk.ss_flags != SS_AUTODISARM) {
printf("[FAIL]\tss_flags=%i, should be SS_AUTODISARM\n",
stk.ss_flags);
exit(EXIT_FAILURE);
}
printf("[OK]\tsigaltstack is still SS_AUTODISARM after signal\n");
printf("[OK]\tTest passed\n");
return 0;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| stas sergeev | stas sergeev | 296 | 79.78% | 1 | 33.33% |
| andy lutomirski | andy lutomirski | 75 | 20.22% | 2 | 66.67% |
| Total | 371 | 100.00% | 3 | 100.00% |
Overall Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| stas sergeev | stas sergeev | 687 | 89.69% | 1 | 25.00% |
| andy lutomirski | andy lutomirski | 79 | 10.31% | 3 | 75.00% |
| Total | 766 | 100.00% | 4 | 100.00% |
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