1 // SPDX-License-Identifier: GPL-2.0
2
3 #include <fcntl.h>
4 #include <libgen.h>
5 #include <linux/limits.h>
6 #include <pthread.h>
7 #include <string.h>
8 #include <sys/resource.h>
9 #include <unistd.h>
10
11 #include "../kselftest_harness.h"
12
13 #define STACKDUMP_FILE "stack_values"
14 #define STACKDUMP_SCRIPT "stackdump"
15 #define NUM_THREAD_SPAWN 128
16
do_nothing(void *)17 static void *do_nothing(void *)
18 {
19 while (1)
20 pause();
21 }
22
crashing_child(void)23 static void crashing_child(void)
24 {
25 pthread_t thread;
26 int i;
27
28 for (i = 0; i < NUM_THREAD_SPAWN; ++i)
29 pthread_create(&thread, NULL, do_nothing, NULL);
30
31 /* crash on purpose */
32 i = *(int *)NULL;
33 }
34
FIXTURE(coredump)35 FIXTURE(coredump)
36 {
37 char original_core_pattern[256];
38 };
39
FIXTURE_SETUP(coredump)40 FIXTURE_SETUP(coredump)
41 {
42 char buf[PATH_MAX];
43 FILE *file;
44 char *dir;
45 int ret;
46
47 file = fopen("/proc/sys/kernel/core_pattern", "r");
48 ASSERT_NE(NULL, file);
49
50 ret = fread(self->original_core_pattern, 1, sizeof(self->original_core_pattern), file);
51 ASSERT_TRUE(ret || feof(file));
52 ASSERT_LT(ret, sizeof(self->original_core_pattern));
53
54 self->original_core_pattern[ret] = '\0';
55
56 ret = fclose(file);
57 ASSERT_EQ(0, ret);
58 }
59
FIXTURE_TEARDOWN(coredump)60 FIXTURE_TEARDOWN(coredump)
61 {
62 const char *reason;
63 FILE *file;
64 int ret;
65
66 unlink(STACKDUMP_FILE);
67
68 file = fopen("/proc/sys/kernel/core_pattern", "w");
69 if (!file) {
70 reason = "Unable to open core_pattern";
71 goto fail;
72 }
73
74 ret = fprintf(file, "%s", self->original_core_pattern);
75 if (ret < 0) {
76 reason = "Unable to write to core_pattern";
77 goto fail;
78 }
79
80 ret = fclose(file);
81 if (ret) {
82 reason = "Unable to close core_pattern";
83 goto fail;
84 }
85
86 return;
87 fail:
88 /* This should never happen */
89 fprintf(stderr, "Failed to cleanup stackdump test: %s\n", reason);
90 }
91
TEST_F(coredump,stackdump)92 TEST_F(coredump, stackdump)
93 {
94 struct sigaction action = {};
95 unsigned long long stack;
96 char *test_dir, *line;
97 size_t line_length;
98 char buf[PATH_MAX];
99 int ret, i;
100 FILE *file;
101 pid_t pid;
102
103 /*
104 * Step 1: Setup core_pattern so that the stackdump script is executed when the child
105 * process crashes
106 */
107 ret = readlink("/proc/self/exe", buf, sizeof(buf));
108 ASSERT_NE(-1, ret);
109 ASSERT_LT(ret, sizeof(buf));
110 buf[ret] = '\0';
111
112 test_dir = dirname(buf);
113
114 file = fopen("/proc/sys/kernel/core_pattern", "w");
115 ASSERT_NE(NULL, file);
116
117 ret = fprintf(file, "|%1$s/%2$s %%P %1$s/%3$s", test_dir, STACKDUMP_SCRIPT, STACKDUMP_FILE);
118 ASSERT_LT(0, ret);
119
120 ret = fclose(file);
121 ASSERT_EQ(0, ret);
122
123 /* Step 2: Create a process who spawns some threads then crashes */
124 pid = fork();
125 ASSERT_TRUE(pid >= 0);
126 if (pid == 0)
127 crashing_child();
128
129 /*
130 * Step 3: Wait for the stackdump script to write the stack pointers to the stackdump file
131 */
132 for (i = 0; i < 10; ++i) {
133 file = fopen(STACKDUMP_FILE, "r");
134 if (file)
135 break;
136 sleep(1);
137 }
138 ASSERT_NE(file, NULL);
139
140 /* Step 4: Make sure all stack pointer values are non-zero */
141 for (i = 0; -1 != getline(&line, &line_length, file); ++i) {
142 stack = strtoull(line, NULL, 10);
143 ASSERT_NE(stack, 0);
144 }
145
146 ASSERT_EQ(i, 1 + NUM_THREAD_SPAWN);
147
148 fclose(file);
149 }
150
151 TEST_HARNESS_MAIN
152