statmount_test_ns.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2
  3#define _GNU_SOURCE
  4
  5#include <assert.h>
  6#include <fcntl.h>
  7#include <limits.h>
  8#include <sched.h>
  9#include <stdlib.h>
 10#include <sys/mount.h>
 11#include <sys/stat.h>
 12#include <sys/wait.h>
 13#include <linux/nsfs.h>
 14#include <linux/stat.h>
 15
 16#include "statmount.h"
 17#include "../utils.h"
 18#include "kselftest.h"
 19
 20#define NSID_PASS 0
 21#define NSID_FAIL 1
 22#define NSID_SKIP 2
 23#define NSID_ERROR 3
 24
 25static void handle_result(int ret, const char *testname)
 26{
 27	if (ret == NSID_PASS)
 28		ksft_test_result_pass("%s\n", testname);
 29	else if (ret == NSID_FAIL)
 30		ksft_test_result_fail("%s\n", testname);
 31	else if (ret == NSID_ERROR)
 32		ksft_exit_fail_msg("%s\n", testname);
 33	else
 34		ksft_test_result_skip("%s\n", testname);
 35}
 36
 37static inline int wait_for_pid(pid_t pid)
 38{
 39	int status, ret;
 40
 41again:
 42	ret = waitpid(pid, &status, 0);
 43	if (ret == -1) {
 44		if (errno == EINTR)
 45			goto again;
 46
 47		ksft_print_msg("waitpid returned -1, errno=%d\n", errno);
 48		return -1;
 49	}
 50
 51	if (!WIFEXITED(status)) {
 52		ksft_print_msg(
 53		       "waitpid !WIFEXITED, WIFSIGNALED=%d, WTERMSIG=%d\n",
 54		       WIFSIGNALED(status), WTERMSIG(status));
 55		return -1;
 56	}
 57
 58	ret = WEXITSTATUS(status);
 59	return ret;
 60}
 61
 62static int get_mnt_ns_id(const char *mnt_ns, uint64_t *mnt_ns_id)
 63{
 64	int fd = open(mnt_ns, O_RDONLY);
 65
 66	if (fd < 0) {
 67		ksft_print_msg("failed to open for ns %s: %s\n",
 68			       mnt_ns, strerror(errno));
 69		sleep(60);
 70		return NSID_ERROR;
 71	}
 72
 73	if (ioctl(fd, NS_GET_MNTNS_ID, mnt_ns_id) < 0) {
 74		ksft_print_msg("failed to get the nsid for ns %s: %s\n",
 75			       mnt_ns, strerror(errno));
 76		return NSID_ERROR;
 77	}
 78	close(fd);
 79	return NSID_PASS;
 80}
 81
 82static int setup_namespace(void)
 83{
 84	if (setup_userns() != 0)
 85		return NSID_ERROR;
 86
 87	return NSID_PASS;
 88}
 89
 90static int _test_statmount_mnt_ns_id(void)
 91{
 92	struct statmount sm;
 93	uint64_t mnt_ns_id;
 94	uint64_t root_id;
 95	int ret;
 96
 97	ret = get_mnt_ns_id("/proc/self/ns/mnt", &mnt_ns_id);
 98	if (ret != NSID_PASS)
 99		return ret;
100
101	root_id = get_unique_mnt_id("/");
102	if (!root_id)
103		return NSID_ERROR;
104
105	ret = statmount(root_id, 0, STATMOUNT_MNT_NS_ID, &sm, sizeof(sm), 0);
106	if (ret == -1) {
107		ksft_print_msg("statmount mnt ns id: %s\n", strerror(errno));
108		return NSID_ERROR;
109	}
110
111	if (sm.size != sizeof(sm)) {
112		ksft_print_msg("unexpected size: %u != %u\n", sm.size,
113			       (uint32_t)sizeof(sm));
114		return NSID_FAIL;
115	}
116	if (sm.mask != STATMOUNT_MNT_NS_ID) {
117		ksft_print_msg("statmount mnt ns id unavailable\n");
118		return NSID_SKIP;
119	}
120
121	if (sm.mnt_ns_id != mnt_ns_id) {
122		ksft_print_msg("unexpected mnt ns ID: 0x%llx != 0x%llx\n",
123			       (unsigned long long)sm.mnt_ns_id,
124			       (unsigned long long)mnt_ns_id);
125		return NSID_FAIL;
126	}
127
128	return NSID_PASS;
129}
130
131static void test_statmount_mnt_ns_id(void)
132{
133	pid_t pid;
134	int ret;
135
136	pid = fork();
137	if (pid < 0)
138		ksft_exit_fail_msg("failed to fork: %s\n", strerror(errno));
139
140	/* We're the original pid, wait for the result. */
141	if (pid != 0) {
142		ret = wait_for_pid(pid);
143		handle_result(ret, "test statmount ns id");
144		return;
145	}
146
147	ret = setup_namespace();
148	if (ret != NSID_PASS)
149		exit(ret);
150	ret = _test_statmount_mnt_ns_id();
151	exit(ret);
152}
153
154static int validate_external_listmount(pid_t pid, uint64_t child_nr_mounts)
155{
156	uint64_t list[256];
157	uint64_t mnt_ns_id;
158	uint64_t nr_mounts;
159	char buf[256];
160	int ret;
161
162	/* Get the mount ns id for our child. */
163	snprintf(buf, sizeof(buf), "/proc/%lu/ns/mnt", (unsigned long)pid);
164	ret = get_mnt_ns_id(buf, &mnt_ns_id);
165
166	nr_mounts = listmount(LSMT_ROOT, mnt_ns_id, 0, list, 256, 0);
167	if (nr_mounts == (uint64_t)-1) {
168		ksft_print_msg("listmount: %s\n", strerror(errno));
169		return NSID_ERROR;
170	}
171
172	if (nr_mounts != child_nr_mounts) {
173		ksft_print_msg("listmount results is %zi != %zi\n", nr_mounts,
174			       child_nr_mounts);
175		return NSID_FAIL;
176	}
177
178	/* Validate that all of our entries match our mnt_ns_id. */
179	for (int i = 0; i < nr_mounts; i++) {
180		struct statmount sm;
181
182		ret = statmount(list[i], mnt_ns_id, STATMOUNT_MNT_NS_ID, &sm,
183				sizeof(sm), 0);
184		if (ret < 0) {
185			ksft_print_msg("statmount mnt ns id: %s\n", strerror(errno));
186			return NSID_ERROR;
187		}
188
189		if (sm.mask != STATMOUNT_MNT_NS_ID) {
190			ksft_print_msg("statmount mnt ns id unavailable\n");
191			return NSID_SKIP;
192		}
193
194		if (sm.mnt_ns_id != mnt_ns_id) {
195			ksft_print_msg("listmount gave us the wrong ns id: 0x%llx != 0x%llx\n",
196				       (unsigned long long)sm.mnt_ns_id,
197				       (unsigned long long)mnt_ns_id);
198			return NSID_FAIL;
199		}
200	}
201
202	return NSID_PASS;
203}
204
205static void test_listmount_ns(void)
206{
207	uint64_t nr_mounts;
208	char pval;
209	int child_ready_pipe[2];
210	int parent_ready_pipe[2];
211	pid_t pid;
212	int ret, child_ret;
213
214	if (pipe(child_ready_pipe) < 0)
215		ksft_exit_fail_msg("failed to create the child pipe: %s\n",
216				   strerror(errno));
217	if (pipe(parent_ready_pipe) < 0)
218		ksft_exit_fail_msg("failed to create the parent pipe: %s\n",
219				   strerror(errno));
220
221	pid = fork();
222	if (pid < 0)
223		ksft_exit_fail_msg("failed to fork: %s\n", strerror(errno));
224
225	if (pid == 0) {
226		char cval;
227		uint64_t list[256];
228
229		close(child_ready_pipe[0]);
230		close(parent_ready_pipe[1]);
231
232		ret = setup_namespace();
233		if (ret != NSID_PASS)
234			exit(ret);
235
236		nr_mounts = listmount(LSMT_ROOT, 0, 0, list, 256, 0);
237		if (nr_mounts == (uint64_t)-1) {
238			ksft_print_msg("listmount: %s\n", strerror(errno));
239			exit(NSID_FAIL);
240		}
241
242		/*
243		 * Tell our parent how many mounts we have, and then wait for it
244		 * to tell us we're done.
245		 */
246		if (write(child_ready_pipe[1], &nr_mounts, sizeof(nr_mounts)) !=
247					sizeof(nr_mounts))
248			ret = NSID_ERROR;
249		if (read(parent_ready_pipe[0], &cval, sizeof(cval)) != sizeof(cval))
250			ret = NSID_ERROR;
251		exit(NSID_PASS);
252	}
253
254	close(child_ready_pipe[1]);
255	close(parent_ready_pipe[0]);
256
257	/* Wait until the child has created everything. */
258	if (read(child_ready_pipe[0], &nr_mounts, sizeof(nr_mounts)) !=
259	    sizeof(nr_mounts))
260		ret = NSID_ERROR;
261
262	ret = validate_external_listmount(pid, nr_mounts);
263
264	if (write(parent_ready_pipe[1], &pval, sizeof(pval)) != sizeof(pval))
265		ret = NSID_ERROR;
266
267	child_ret = wait_for_pid(pid);
268	if (child_ret != NSID_PASS)
269		ret = child_ret;
270	handle_result(ret, "test listmount ns id");
271}
272
273int main(void)
274{
275	int ret;
276
277	ksft_print_header();
278	ret = statmount(0, 0, 0, NULL, 0, 0);
279	assert(ret == -1);
280	if (errno == ENOSYS)
281		ksft_exit_skip("statmount() syscall not supported\n");
282
283	ksft_set_plan(2);
284	test_statmount_mnt_ns_id();
285	test_listmount_ns();
286
287	if (ksft_get_fail_cnt() + ksft_get_error_cnt() > 0)
288		ksft_exit_fail();
289	else
290		ksft_exit_pass();
291}