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// SPDX-License-Identifier: GPL-2.0
/*
* Test that signal delivery is able to expand the stack segment without
* triggering a SEGV.
*
* Based on test code by Tom Lane.
*/
#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <sys/types.h>
#include <unistd.h>
#include "../pmu/lib.h"
#include "utils.h"
#define _KB (1024)
#define _MB (1024 * 1024)
static char *stack_base_ptr;
static char *stack_top_ptr;
static volatile sig_atomic_t sig_occurred = 0;
static void sigusr1_handler(int signal_arg)
{
sig_occurred = 1;
}
static int consume_stack(unsigned int stack_size, union pipe write_pipe)
{
char stack_cur;
if ((stack_base_ptr - &stack_cur) < stack_size)
return consume_stack(stack_size, write_pipe);
else {
stack_top_ptr = &stack_cur;
FAIL_IF(notify_parent(write_pipe));
while (!sig_occurred)
barrier();
}
return 0;
}
static int child(unsigned int stack_size, union pipe write_pipe)
{
struct sigaction act;
char stack_base;
act.sa_handler = sigusr1_handler;
sigemptyset(&act.sa_mask);
act.sa_flags = 0;
if (sigaction(SIGUSR1, &act, NULL) < 0)
err(1, "sigaction");
stack_base_ptr = (char *) (((size_t) &stack_base + 65535) & ~65535UL);
FAIL_IF(consume_stack(stack_size, write_pipe));
printf("size 0x%06x: OK, stack base %p top %p (%zx used)\n",
stack_size, stack_base_ptr, stack_top_ptr,
stack_base_ptr - stack_top_ptr);
return 0;
}
static int test_one_size(unsigned int stack_size)
{
union pipe read_pipe, write_pipe;
pid_t pid;
FAIL_IF(pipe(read_pipe.fds) == -1);
FAIL_IF(pipe(write_pipe.fds) == -1);
pid = fork();
if (pid == 0) {
close(read_pipe.read_fd);
close(write_pipe.write_fd);
exit(child(stack_size, read_pipe));
}
close(read_pipe.write_fd);
close(write_pipe.read_fd);
FAIL_IF(sync_with_child(read_pipe, write_pipe));
kill(pid, SIGUSR1);
FAIL_IF(wait_for_child(pid));
close(read_pipe.read_fd);
close(write_pipe.write_fd);
return 0;
}
int test(void)
{
unsigned int i, size;
// Test with used stack from 1MB - 64K to 1MB + 64K
// Increment by 64 to get more coverage of odd sizes
for (i = 0; i < (128 * _KB); i += 64) {
size = i + (1 * _MB) - (64 * _KB);
FAIL_IF(test_one_size(size));
}
return 0;
}
int main(void)
{
return test_harness(test, "stack_expansion_signal");
}
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