1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Test that signal delivery is able to expand the stack segment without
4 * triggering a SEGV.
5 *
6 * Based on test code by Tom Lane.
7 */
8
9 #include <err.h>
10 #include <stdio.h>
11 #include <stdlib.h>
12 #include <signal.h>
13 #include <sys/types.h>
14 #include <unistd.h>
15
16 #include "../pmu/lib.h"
17 #include "utils.h"
18
19 #define _KB (1024)
20 #define _MB (1024 * 1024)
21
22 static char *stack_base_ptr;
23 static char *stack_top_ptr;
24
25 static volatile sig_atomic_t sig_occurred = 0;
26
27 static void sigusr1_handler(int signal_arg)
28 {
29 sig_occurred = 1;
30 }
31
32 static int consume_stack(unsigned int stack_size, union pipe write_pipe)
33 {
34 char stack_cur;
35
36 if ((stack_base_ptr - &stack_cur) < stack_size)
37 return consume_stack(stack_size, write_pipe);
38 else {
39 stack_top_ptr = &stack_cur;
40
41 FAIL_IF(notify_parent(write_pipe));
42
43 while (!sig_occurred)
44 barrier();
45 }
46
47 return 0;
48 }
49
50 static int child(unsigned int stack_size, union pipe write_pipe)
51 {
52 struct sigaction act;
53 char stack_base;
54
55 act.sa_handler = sigusr1_handler;
56 sigemptyset(&act.sa_mask);
57 act.sa_flags = 0;
58 if (sigaction(SIGUSR1, &act, NULL) < 0)
59 err(1, "sigaction");
60
61 stack_base_ptr = (char *) (((size_t) &stack_base + 65535) & ~65535UL);
62
63 FAIL_IF(consume_stack(stack_size, write_pipe));
64
65 printf("size 0x%06x: OK, stack base %p top %p (%zx used)\n",
66 stack_size, stack_base_ptr, stack_top_ptr,
67 stack_base_ptr - stack_top_ptr);
68
69 return 0;
70 }
71
72 static int test_one_size(unsigned int stack_size)
73 {
74 union pipe read_pipe, write_pipe;
75 pid_t pid;
76
77 FAIL_IF(pipe(read_pipe.fds) == -1);
78 FAIL_IF(pipe(write_pipe.fds) == -1);
79
80 pid = fork();
81 if (pid == 0) {
82 close(read_pipe.read_fd);
83 close(write_pipe.write_fd);
84 exit(child(stack_size, read_pipe));
85 }
86
87 close(read_pipe.write_fd);
88 close(write_pipe.read_fd);
89 FAIL_IF(sync_with_child(read_pipe, write_pipe));
90
91 kill(pid, SIGUSR1);
92
93 FAIL_IF(wait_for_child(pid));
94
95 close(read_pipe.read_fd);
96 close(write_pipe.write_fd);
97
98 return 0;
99 }
100
101 int test(void)
102 {
103 unsigned int i, size;
104
105 // Test with used stack from 1MB - 64K to 1MB + 64K
106 // Increment by 64 to get more coverage of odd sizes
107 for (i = 0; i < (128 * _KB); i += 64) {
108 size = i + (1 * _MB) - (64 * _KB);
109 FAIL_IF(test_one_size(size));
110 }
111
112 return 0;
113 }
114
115 int main(void)
116 {
117 return test_harness(test, "stack_expansion_signal");
118 }
119
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