proc: test subset=pid
diff mbox series

Message ID YFYZZ7WGaZlsnChS@localhost.localdomain
State Accepted
Commit 268af17ada5855a9b703995125a9920ac117b56b
Headers show
Series
  • proc: test subset=pid
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Commit Message

Alexey Dobriyan March 20, 2021, 3:48 p.m. UTC
Test that /proc instance mounted with

	mount -t proc -o subset=pid

contains only ".", "..", "self", "thread-self" and pid directories.

Note:
Currently "subset=pid" doesn't return "." and ".." via readdir.
This must be a bug.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---

 tools/testing/selftests/proc/Makefile          |    1 
 tools/testing/selftests/proc/proc-subset-pid.c |  121 +++++++++++++++++++++++++
 2 files changed, 122 insertions(+)

Comments

Alexey Gladkov March 20, 2021, 5:54 p.m. UTC | #1
On Sat, Mar 20, 2021 at 06:48:55PM +0300, Alexey Dobriyan wrote:
> Test that /proc instance mounted with
> 
> 	mount -t proc -o subset=pid
> 
> contains only ".", "..", "self", "thread-self" and pid directories.
> 
> Note:
> Currently "subset=pid" doesn't return "." and ".." via readdir.
> This must be a bug.

Ops. Good catch! Looks good to me.

Acked-by: Alexey Gladkov <gladkov.alexey@gmail.com>

> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
> ---
> 
>  tools/testing/selftests/proc/Makefile          |    1 
>  tools/testing/selftests/proc/proc-subset-pid.c |  121 +++++++++++++++++++++++++
>  2 files changed, 122 insertions(+)
> 
> --- a/tools/testing/selftests/proc/Makefile
> +++ b/tools/testing/selftests/proc/Makefile
> @@ -12,6 +12,7 @@ TEST_GEN_PROGS += proc-self-map-files-001
>  TEST_GEN_PROGS += proc-self-map-files-002
>  TEST_GEN_PROGS += proc-self-syscall
>  TEST_GEN_PROGS += proc-self-wchan
> +TEST_GEN_PROGS += proc-subset-pid
>  TEST_GEN_PROGS += proc-uptime-001
>  TEST_GEN_PROGS += proc-uptime-002
>  TEST_GEN_PROGS += read
> new file mode 100644
> --- /dev/null
> +++ b/tools/testing/selftests/proc/proc-subset-pid.c
> @@ -0,0 +1,121 @@
> +/*
> + * Copyright (c) 2021 Alexey Dobriyan <adobriyan@gmail.com>
> + *
> + * Permission to use, copy, modify, and distribute this software for any
> + * purpose with or without fee is hereby granted, provided that the above
> + * copyright notice and this permission notice appear in all copies.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
> + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
> + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
> + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
> + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
> + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
> + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
> + */
> +/*
> + * Test that "mount -t proc -o subset=pid" hides everything but pids,
> + * /proc/self and /proc/thread-self.
> + */
> +#undef NDEBUG
> +#include <assert.h>
> +#include <errno.h>
> +#include <sched.h>
> +#include <stdbool.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <sys/mount.h>
> +#include <sys/types.h>
> +#include <sys/stat.h>
> +#include <fcntl.h>
> +#include <dirent.h>
> +#include <unistd.h>
> +#include <stdio.h>
> +
> +static inline bool streq(const char *a, const char *b)
> +{
> +	return strcmp(a, b) == 0;
> +}
> +
> +static void make_private_proc(void)
> +{
> +	if (unshare(CLONE_NEWNS) == -1) {
> +		if (errno == ENOSYS || errno == EPERM) {
> +			exit(4);
> +		}
> +		exit(1);
> +	}
> +	if (mount(NULL, "/", NULL, MS_PRIVATE|MS_REC, NULL) == -1) {
> +		exit(1);
> +	}
> +	if (mount(NULL, "/proc", "proc", 0, "subset=pid") == -1) {
> +		exit(1);
> +	}
> +}
> +
> +static bool string_is_pid(const char *s)
> +{
> +	while (1) {
> +		switch (*s++) {
> +		case '0':case '1':case '2':case '3':case '4':
> +		case '5':case '6':case '7':case '8':case '9':
> +			continue;
> +
> +		case '\0':
> +			return true;
> +
> +		default:
> +			return false;
> +		}
> +	}
> +}
> +
> +int main(void)
> +{
> +	make_private_proc();
> +
> +	DIR *d = opendir("/proc");
> +	assert(d);
> +
> +	struct dirent *de;
> +
> +	bool dot = false;
> +	bool dot_dot = false;
> +	bool self = false;
> +	bool thread_self = false;
> +
> +	while ((de = readdir(d))) {
> +		if (streq(de->d_name, ".")) {
> +			assert(!dot);
> +			dot = true;
> +			assert(de->d_type == DT_DIR);
> +		} else if (streq(de->d_name, "..")) {
> +			assert(!dot_dot);
> +			dot_dot = true;
> +			assert(de->d_type == DT_DIR);
> +		} else if (streq(de->d_name, "self")) {
> +			assert(!self);
> +			self = true;
> +			assert(de->d_type == DT_LNK);
> +		} else if (streq(de->d_name, "thread-self")) {
> +			assert(!thread_self);
> +			thread_self = true;
> +			assert(de->d_type == DT_LNK);
> +		} else {
> +			if (!string_is_pid(de->d_name)) {
> +				fprintf(stderr, "d_name '%s'\n", de->d_name);
> +				assert(0);
> +			}
> +			assert(de->d_type == DT_DIR);
> +		}
> +	}
> +
> +	char c;
> +	int rv = readlink("/proc/cpuinfo", &c, 1);
> +	assert(rv == -1 && errno == ENOENT);
> +
> +	int fd = open("/proc/cpuinfo", O_RDONLY);
> +	assert(fd == -1 && errno == ENOENT);
> +
> +	return 0;
> +}
>

Patch
diff mbox series

--- a/tools/testing/selftests/proc/Makefile
+++ b/tools/testing/selftests/proc/Makefile
@@ -12,6 +12,7 @@  TEST_GEN_PROGS += proc-self-map-files-001
 TEST_GEN_PROGS += proc-self-map-files-002
 TEST_GEN_PROGS += proc-self-syscall
 TEST_GEN_PROGS += proc-self-wchan
+TEST_GEN_PROGS += proc-subset-pid
 TEST_GEN_PROGS += proc-uptime-001
 TEST_GEN_PROGS += proc-uptime-002
 TEST_GEN_PROGS += read
new file mode 100644
--- /dev/null
+++ b/tools/testing/selftests/proc/proc-subset-pid.c
@@ -0,0 +1,121 @@ 
+/*
+ * Copyright (c) 2021 Alexey Dobriyan <adobriyan@gmail.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+/*
+ * Test that "mount -t proc -o subset=pid" hides everything but pids,
+ * /proc/self and /proc/thread-self.
+ */
+#undef NDEBUG
+#include <assert.h>
+#include <errno.h>
+#include <sched.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mount.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <dirent.h>
+#include <unistd.h>
+#include <stdio.h>
+
+static inline bool streq(const char *a, const char *b)
+{
+	return strcmp(a, b) == 0;
+}
+
+static void make_private_proc(void)
+{
+	if (unshare(CLONE_NEWNS) == -1) {
+		if (errno == ENOSYS || errno == EPERM) {
+			exit(4);
+		}
+		exit(1);
+	}
+	if (mount(NULL, "/", NULL, MS_PRIVATE|MS_REC, NULL) == -1) {
+		exit(1);
+	}
+	if (mount(NULL, "/proc", "proc", 0, "subset=pid") == -1) {
+		exit(1);
+	}
+}
+
+static bool string_is_pid(const char *s)
+{
+	while (1) {
+		switch (*s++) {
+		case '0':case '1':case '2':case '3':case '4':
+		case '5':case '6':case '7':case '8':case '9':
+			continue;
+
+		case '\0':
+			return true;
+
+		default:
+			return false;
+		}
+	}
+}
+
+int main(void)
+{
+	make_private_proc();
+
+	DIR *d = opendir("/proc");
+	assert(d);
+
+	struct dirent *de;
+
+	bool dot = false;
+	bool dot_dot = false;
+	bool self = false;
+	bool thread_self = false;
+
+	while ((de = readdir(d))) {
+		if (streq(de->d_name, ".")) {
+			assert(!dot);
+			dot = true;
+			assert(de->d_type == DT_DIR);
+		} else if (streq(de->d_name, "..")) {
+			assert(!dot_dot);
+			dot_dot = true;
+			assert(de->d_type == DT_DIR);
+		} else if (streq(de->d_name, "self")) {
+			assert(!self);
+			self = true;
+			assert(de->d_type == DT_LNK);
+		} else if (streq(de->d_name, "thread-self")) {
+			assert(!thread_self);
+			thread_self = true;
+			assert(de->d_type == DT_LNK);
+		} else {
+			if (!string_is_pid(de->d_name)) {
+				fprintf(stderr, "d_name '%s'\n", de->d_name);
+				assert(0);
+			}
+			assert(de->d_type == DT_DIR);
+		}
+	}
+
+	char c;
+	int rv = readlink("/proc/cpuinfo", &c, 1);
+	assert(rv == -1 && errno == ENOENT);
+
+	int fd = open("/proc/cpuinfo", O_RDONLY);
+	assert(fd == -1 && errno == ENOENT);
+
+	return 0;
+}