diff options
Diffstat (limited to 'tools/testing/selftests/sigaltstack/sas.c')
| -rw-r--r-- | tools/testing/selftests/sigaltstack/sas.c | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/tools/testing/selftests/sigaltstack/sas.c b/tools/testing/selftests/sigaltstack/sas.c new file mode 100644 index 000000000000..1bb01258e559 --- /dev/null +++ b/tools/testing/selftests/sigaltstack/sas.c @@ -0,0 +1,176 @@ +/* + * Stas Sergeev <[email protected]> + * + * 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); + } +} + +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; + } +} + +static void switch_fn(void) +{ + printf("[RUN]\tswitched to user ctx\n"); + raise(SIGUSR2); + setcontext(&sc); +} + +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; +} |