Attachment 1478271 Details for Bug 1621434 – tst-minsigstksz.c (compile with -std=gnu99)

tst-minsigstksz.c (compile with -std=gnu99)

tst-minsigstksz.c (text/plain), 1.53 KB, created by Florian Weimer on 2018-08-23 15:50:57 UTC

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Creator: Florian Weimer

Created: 2018-08-23 15:50:57 UTC

Size: 1.53 KB

patch

obsolete

>#include <err.h>
>#include <signal.h>
>#include <stdlib.h>
>#include <string.h>
>#include <unistd.h>
>
>static volatile sig_atomic_t handler_run;
>
>static void
>handler (int signo)
>{
>  /* Clear a bit of on-stack memory.  */
>  volatile char buffer[256];
>  for (size_t i = 0; i < sizeof (buffer); ++i)
>    buffer[i] = 0;
>  handler_run = 1;
>}
>
>int
>main (void)
>{
>  size_t stack_buffer_size = 64 * 1024 * 1024;
>  void *stack_buffer = malloc (stack_buffer_size);
>  if (stack_buffer == NULL)
>    err (1, "malloc");
>  void *stack_end = stack_buffer + stack_buffer_size;
>  memset (stack_buffer, 0xCC, stack_buffer_size);
>
>  void *stack_bottom = stack_buffer + (stack_buffer_size + MINSIGSTKSZ) / 2;
>  void *stack_top = stack_bottom + MINSIGSTKSZ;
>  stack_t stack =
>    {
>      .ss_sp = stack_bottom,
>      .ss_size = MINSIGSTKSZ,
>    };
>  if (sigaltstack (&stack, NULL) < 0)
>    err (1, "sigaltstack");
>
>  struct sigaction act =
>    {
>      .sa_handler = handler,
>      .sa_flags = SA_ONSTACK,
>    };
>  if (sigaction (SIGUSR1, &act, NULL) < 0)
>    err (1, "sigaction");
>
>  if (kill (getpid (), SIGUSR1) < 0)
>    err (1, "kill");
>
>  if (handler_run != 1)
>    errx (1, "handler did not run");
>
>  for (void *p = stack_buffer; p < stack_bottom; ++p)
>    if (*(unsigned char *) p != 0xCC)
>      errx (1, "changed byte %zd bytes below configured stack\n",
>            stack_bottom - p);
>  for (void *p = stack_top; p < stack_end; ++p)
>    if (*(unsigned char *) p != 0xCC)
>      errx (1, "changed byte %zd bytes above configured stack\n",
>            p - stack_top);
>
>  free (stack_buffer);
>}

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Attachments on bug 1621434: 1478271