[CRIU] [PATCH 1/2] zdtm: Add binfmt_misc test

[Kirill Tkhai]

On 11.12.2015 09:59, Andrew Vagin wrote:
> On Thu, Dec 10, 2015 at 01:06:10PM +0300, Kirill Tkhai wrote:
>> Generate random binfmt_misc entries of different types
>> and check that they remain registered after the signal.
>>
>> Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
>> ---
>>  test/zdtm/live/static/binfmt_misc.c |  193 +++++++++++++++++++++++++++++++++++
>>  1 file changed, 193 insertions(+)
>>  create mode 100644 test/zdtm/live/static/binfmt_misc.c
> 
> You need to add binfmt_misc.desc, because this test should be executed in a
> new mntns.
> 
> Is binfmt_misc containerized in the upstream kernel? If it isn't, should
> we dump and restore it on the upstream kernel?

No it isn't. How do we handle the same situations in CRIU? Is there a .desc option?

>>
>> diff --git a/test/zdtm/live/static/binfmt_misc.c b/test/zdtm/live/static/binfmt_misc.c
>> new file mode 100644
>> index 0000000..ea12993
>> --- /dev/null
>> +++ b/test/zdtm/live/static/binfmt_misc.c
>> @@ -0,0 +1,193 @@
>> +#include <errno.h>
>> +#include <fcntl.h>
>> +#include <stdlib.h>
>> +#include <string.h>
>> +#include <sys/types.h>
>> +#include <sys/stat.h>
>> +#include <sys/mount.h>
>> +#include <linux/limits.h>
>> +
>> +#include "zdtmtst.h"
>> +
>> +const char *test_doc	= "Check that binfmt_misc entries remain registered";
>> +const char *test_author	= "Kirill Tkhai <ktkhai at odin.com";
>> +
>> +#define MAX_REG_STR 256
>> +#define MAX_MAGIC 16
>> +#define MAX_MAGIC_OFFSET 128 /* Max magic+offset */
>> +#define MAX_EXTENSION 128
>> +
>> +#define MNTDIR "binfmt_misc.dir"
>> +
>> +const char *NAME[2] = { "magic_file", "extension_file" };
>> +
>> +/* :name:type:offset:magic:mask:interpreter:flags */
>> +
>> +void create_magic_pattern(char *buf, const char *name)
>> +{
>> +	int i, magic, mask, offset;
>> +
>> +	magic = rand() % (MAX_MAGIC + 1);
>> +	mask  = (rand() % 2) ? magic : 0;
>> +	offset = MAX_MAGIC_OFFSET - magic;
>> +	offset = rand() % (offset + 1);
>> +
>> +	buf += sprintf(buf, ":%s:M:%d:", name, offset);
>> +
>> +	for (i = 0; i < magic; i++)
>> +		buf += sprintf(buf, "\\x%02x", rand() % 256);
>> +
>> +	buf += sprintf(buf, ":");
>> +
>> +	for (i = 0; i < mask; i++)
>> +		buf += sprintf(buf, "\\x%02x", rand() % 256);
>> +
>> +	sprintf(buf, ":/bin/interpreter:OCP");
>> +}
>> +
>> +void create_extension_pattern(char *buf, const char *name)
>> +{
>> +	int i, extension;
>> +
>> +	extension = rand() % (MAX_EXTENSION + 1);
>> +	buf += sprintf(buf, ":%s:E::", name);
>> +
>> +	for (i = 0; i < extension; i++) {
>> +		int c = rand();
>> +
>> +		if (c == '\0' || c == ':' || c == '\n' || c == '/')
>> +			c = '1';
>> +		buf += sprintf(buf, "%c", c);
>> +	}
>> +
>> +	sprintf(buf, "::/bin/bash:");
>> +}
>> +
>> +int dump_content(const char *path, char **dump)
>> +{
>> +	int fd, len;
>> +	char *p;
>> +
>> +	p = *dump = malloc(PAGE_SIZE);
>> +	if (!p) {
>> +		fail("malloc");
>> +		return -1;
>> +	}
>> +
>> +	fd = open(path, O_RDONLY);
>> +	if (fd < 0) {
>> +		fail("open");
>> +		return -1;
>> +	}
>> +
>> +	len = read(fd, p, PAGE_SIZE-1);
>> +	close(fd);
>> +	if (len <= 0) {
>> +		fail("read");
>> +		return -1;
>> +	}
>> +
>> +	p[len] = '\0';
>> +
>> +	return 0;
>> +}
>> +
>> +int main(int argc, char **argv)
>> +{
>> +	char buf[MAX_REG_STR + 1];
>> +	char path[PATH_MAX];
>> +	char *dump[2];
>> +	int i, fd, len;
>> +
>> +	test_init(argc, argv);
>> +
>> +	if (mkdir(MNTDIR, 0777)) {
>> +		fail("mkdir");
>> +		exit(1);
>> +	}
>> +
>> +	if (mount("none", MNTDIR, "binfmt_misc", 0, NULL)) {
>> +		fail("mount failed");
>> +		exit(1);
>> +	}
>> +
>> +	/* Register binfmt_entries */
>> +	sprintf(path, MNTDIR "/" "register");
>> +	fd = open(path, O_WRONLY);
>> +	if (!fd) {
>> +		fail("open");
>> +		exit(1);
>> +	}
>> +
>> +	for (i = 0; i < 2; i++) {
>> +		if (i % 2 == 0)
>> +			create_magic_pattern(buf, NAME[i]);
>> +		else
>> +			create_extension_pattern(buf, NAME[i]);
>> +
>> +		test_msg("string: %s\n", buf);
>> +		len = strlen(buf);
>> +
>> +		if (len != write(fd, buf, len)) {
>> +			fail("write %s", NAME[i]);
>> +			exit(1);
>> +		}
>> +	}
>> +
>> +	close(fd);
>> +
>> +	/* Disable one of the entries */
>> +	sprintf(path, MNTDIR "/%s", NAME[0]);
>> +	fd = open(path, O_WRONLY);
>> +	if (!fd || write(fd, "0", 1) != 1) {
>> +		fail("Can't disable %s\n", path);
>> +		exit(1);
>> +	}
>> +	close(fd);
>> +
>> +	/* Dump files content */
>> +	for (i = 0; i < 2; i ++) {
>> +		sprintf(path, MNTDIR "/%s", NAME[i]);
>> +		if (dump_content(path, &dump[i]))
>> +			exit(1);
>> +	}
>> +
>> +	test_daemon();
>> +	test_waitsig();
>> +
>> +	/* Check */
>> +	for (i = 0; i < 2; i ++) {
>> +		char *tmp;
>> +
>> +		sprintf(path, MNTDIR "/%s", NAME[i]);
>> +		if (dump_content(path, &tmp))
>> +			exit(1);
>> +
>> +		if (strcmp(tmp, dump[i])) {
>> +			fail("Content differs:\n%s\nand\n%s\n", tmp, dump[i]);
>> +			exit(1);
>> +		}
>> +		free(dump[i]);
>> +		free(tmp);
>> +	}
>> +
>> +	pass();
>> +
>> +	/* Clean up */
>> +	for (i = 0; i < 2; i++) {
>> +		sprintf(path, MNTDIR "/%s", NAME[i]);
>> +		fd = open(path, O_WRONLY);
>> +		if (fd < 0) {
>> +			fail("open %s", path);
>> +			continue;
>> +		}
>> +		if (write(fd, "-1", 2) != 2)
>> +			fail("cleanup %s", path);
> 
> You need to use pr_perror here. fail() is used only when you check
> results.
> 
>> +		close(fd);
>> +	}
>> +
>> +	umount(MNTDIR);
>> +	rmdir(MNTDIR);
>> +
>> +	return 0;
>> +}
>>