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