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// SPDX-License-Identifier: GPL-2.0
#include <fcntl.h>
#include <libgen.h>
#include <linux/limits.h>
#include <pthread.h>
#include <string.h>
#include <sys/resource.h>
#include <unistd.h>
#include "../kselftest_harness.h"
#define STACKDUMP_FILE "stack_values"
#define STACKDUMP_SCRIPT "stackdump"
#define NUM_THREAD_SPAWN 128
static void *do_nothing(void *)
{
while (1)
pause();
}
static void crashing_child(void)
{
pthread_t thread;
int i;
for (i = 0; i < NUM_THREAD_SPAWN; ++i)
pthread_create(&thread, NULL, do_nothing, NULL);
/* crash on purpose */
i = *(int *)NULL;
}
FIXTURE(coredump)
{
char original_core_pattern[256];
};
FIXTURE_SETUP(coredump)
{
char buf[PATH_MAX];
FILE *file;
char *dir;
int ret;
file = fopen("/proc/sys/kernel/core_pattern", "r");
ASSERT_NE(NULL, file);
ret = fread(self->original_core_pattern, 1, sizeof(self->original_core_pattern), file);
ASSERT_TRUE(ret || feof(file));
ASSERT_LT(ret, sizeof(self->original_core_pattern));
self->original_core_pattern[ret] = '\0';
ret = fclose(file);
ASSERT_EQ(0, ret);
}
FIXTURE_TEARDOWN(coredump)
{
const char *reason;
FILE *file;
int ret;
unlink(STACKDUMP_FILE);
file = fopen("/proc/sys/kernel/core_pattern", "w");
if (!file) {
reason = "Unable to open core_pattern";
goto fail;
}
ret = fprintf(file, "%s", self->original_core_pattern);
if (ret < 0) {
reason = "Unable to write to core_pattern";
goto fail;
}
ret = fclose(file);
if (ret) {
reason = "Unable to close core_pattern";
goto fail;
}
return;
fail:
/* This should never happen */
fprintf(stderr, "Failed to cleanup stackdump test: %s\n", reason);
}
TEST_F(coredump, stackdump)
{
struct sigaction action = {};
unsigned long long stack;
char *test_dir, *line;
size_t line_length;
char buf[PATH_MAX];
int ret, i;
FILE *file;
pid_t pid;
/*
* Step 1: Setup core_pattern so that the stackdump script is executed when the child
* process crashes
*/
ret = readlink("/proc/self/exe", buf, sizeof(buf));
ASSERT_NE(-1, ret);
ASSERT_LT(ret, sizeof(buf));
buf[ret] = '\0';
test_dir = dirname(buf);
file = fopen("/proc/sys/kernel/core_pattern", "w");
ASSERT_NE(NULL, file);
ret = fprintf(file, "|%1$s/%2$s %%P %1$s/%3$s", test_dir, STACKDUMP_SCRIPT, STACKDUMP_FILE);
ASSERT_LT(0, ret);
ret = fclose(file);
ASSERT_EQ(0, ret);
/* Step 2: Create a process who spawns some threads then crashes */
pid = fork();
ASSERT_TRUE(pid >= 0);
if (pid == 0)
crashing_child();
/*
* Step 3: Wait for the stackdump script to write the stack pointers to the stackdump file
*/
for (i = 0; i < 10; ++i) {
file = fopen(STACKDUMP_FILE, "r");
if (file)
break;
sleep(1);
}
ASSERT_NE(file, NULL);
/* Step 4: Make sure all stack pointer values are non-zero */
for (i = 0; -1 != getline(&line, &line_length, file); ++i) {
stack = strtoull(line, NULL, 10);
ASSERT_NE(stack, 0);
}
ASSERT_EQ(i, 1 + NUM_THREAD_SPAWN);
fclose(file);
}
TEST_HARNESS_MAIN
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