Michael Ellerman <m...@ellerman.id.au> writes:
> +static int search_proc_maps(char *needle, unsigned long *low, unsigned long
> *high)
^^ const?
> +{
> + unsigned long start, end;
> + static char buf[4096];
> + char name[128];
> + FILE *f;
> + int rc = -1;
> +
> + f = fopen("/proc/self/maps", "r");
> + if (!f) {
> + perror("fopen");
> + return -1;
> + }
> +
> + while (fgets(buf, sizeof(buf), f)) {
> + rc = sscanf(buf, "%lx-%lx %*c%*c%*c%*c %*x %*d:%*d %*d %127s\n",
> + &start, &end, name);
I suspect it doesn't matter in practice for this particular test, but
since this looks like a generally useful function that could gain users
in the future: does this spuriously fail if the matching line straddles
a 4096-byte boundary? Maybe fscanf(3) should be used instead?
> + if (rc == 2)
> + continue;
> +
> + if (rc != 3) {
> + printf("sscanf errored\n");
> + rc = -1;
> + break;
> + }
> +
> + if (strstr(name, needle)) {
> + *low = start;
> + *high = end - 1;
> + rc = 0;
> + break;
> + }
> + }
> +
> + fclose(f);
> +
> + return rc;
> +}
> +
> +static volatile sig_atomic_t took_signal = 0;
> +
> +static void sigusr1_handler(int sig)
> +{
> + took_signal++;
> +}
> +
> +int test_sigreturn_vdso(void)
> +{
> + unsigned long low, high, size;
> + struct sigaction act;
> + char *p;
> +
> + act.sa_handler = sigusr1_handler;
> + act.sa_flags = 0;
> + sigemptyset(&act.sa_mask);
> +
> + assert(sigaction(SIGUSR1, &act, NULL) == 0);
> +
> + // Confirm the VDSO is mapped, and work out where it is
> + assert(search_proc_maps("[vdso]", &low, &high) == 0);
> + size = high - low + 1;
> + printf("VDSO is at 0x%lx-0x%lx (%lu bytes)\n", low, high, size);
> +
> + kill(getpid(), SIGUSR1);
> + assert(took_signal == 1);
> + printf("Signal delivered OK with VDSO mapped\n");
I haven't looked at the test harness in detail but this should be
reliable if the program is a single thread - lgtm.
