tests: add pidfd_open() tests
authorChristian Brauner <christian@brauner.io>
Sat, 23 Mar 2019 11:24:21 +0000 (12:24 +0100)
committerChristian Brauner <christian@brauner.io>
Fri, 28 Jun 2019 10:17:55 +0000 (12:17 +0200)
This adds testing for the new pidfd_open() syscalls. Specifically, we test:
- that no invalid flags can be passed to pidfd_open()
- that no invalid pid can be passed to pidfd_open()
- that a pidfd can be retrieved with pidfd_open()
- that the retrieved pidfd references the correct pid

Signed-off-by: Christian Brauner <christian@brauner.io>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jann Horn <jannh@google.com>
Cc: David Howells <dhowells@redhat.com>
Cc: "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>
Cc: Andy Lutomirsky <luto@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-api@vger.kernel.org
tools/testing/selftests/pidfd/.gitignore
tools/testing/selftests/pidfd/Makefile
tools/testing/selftests/pidfd/pidfd.h [new file with mode: 0644]
tools/testing/selftests/pidfd/pidfd_open_test.c [new file with mode: 0644]
tools/testing/selftests/pidfd/pidfd_test.c

index 4b31c14..720b2d8 100644 (file)
@@ -1,6 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0-only
 CFLAGS += -g -I../../../../usr/include/ -lpthread
 
-TEST_GEN_PROGS := pidfd_test
+TEST_GEN_PROGS := pidfd_test pidfd_open_test
 
 include ../lib.mk
 
diff --git a/tools/testing/selftests/pidfd/pidfd.h b/tools/testing/selftests/pidfd/pidfd.h
new file mode 100644 (file)
index 0000000..8452e91
--- /dev/null
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __PIDFD_H
+#define __PIDFD_H
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <fcntl.h>
+#include <sched.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <syscall.h>
+#include <sys/mount.h>
+
+#include "../kselftest.h"
+
+/*
+ * The kernel reserves 300 pids via RESERVED_PIDS in kernel/pid.c
+ * That means, when it wraps around any pid < 300 will be skipped.
+ * So we need to use a pid > 300 in order to test recycling.
+ */
+#define PID_RECYCLE 1000
+
+/*
+ * Define a few custom error codes for the child process to clearly indicate
+ * what is happening. This way we can tell the difference between a system
+ * error, a test error, etc.
+ */
+#define PIDFD_PASS 0
+#define PIDFD_FAIL 1
+#define PIDFD_ERROR 2
+#define PIDFD_SKIP 3
+#define PIDFD_XFAIL 4
+
+int wait_for_pid(pid_t pid)
+{
+       int status, ret;
+
+again:
+       ret = waitpid(pid, &status, 0);
+       if (ret == -1) {
+               if (errno == EINTR)
+                       goto again;
+
+               return -1;
+       }
+
+       if (!WIFEXITED(status))
+               return -1;
+
+       return WEXITSTATUS(status);
+}
+
+
+#endif /* __PIDFD_H */
diff --git a/tools/testing/selftests/pidfd/pidfd_open_test.c b/tools/testing/selftests/pidfd/pidfd_open_test.c
new file mode 100644 (file)
index 0000000..0377133
--- /dev/null
@@ -0,0 +1,169 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <limits.h>
+#include <linux/types.h>
+#include <linux/wait.h>
+#include <sched.h>
+#include <signal.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <syscall.h>
+#include <sys/mount.h>
+#include <sys/prctl.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include "pidfd.h"
+#include "../kselftest.h"
+
+static inline int sys_pidfd_open(pid_t pid, unsigned int flags)
+{
+       return syscall(__NR_pidfd_open, pid, flags);
+}
+
+static int safe_int(const char *numstr, int *converted)
+{
+       char *err = NULL;
+       long sli;
+
+       errno = 0;
+       sli = strtol(numstr, &err, 0);
+       if (errno == ERANGE && (sli == LONG_MAX || sli == LONG_MIN))
+               return -ERANGE;
+
+       if (errno != 0 && sli == 0)
+               return -EINVAL;
+
+       if (err == numstr || *err != '\0')
+               return -EINVAL;
+
+       if (sli > INT_MAX || sli < INT_MIN)
+               return -ERANGE;
+
+       *converted = (int)sli;
+       return 0;
+}
+
+static int char_left_gc(const char *buffer, size_t len)
+{
+       size_t i;
+
+       for (i = 0; i < len; i++) {
+               if (buffer[i] == ' ' ||
+                   buffer[i] == '\t')
+                       continue;
+
+               return i;
+       }
+
+       return 0;
+}
+
+static int char_right_gc(const char *buffer, size_t len)
+{
+       int i;
+
+       for (i = len - 1; i >= 0; i--) {
+               if (buffer[i] == ' '  ||
+                   buffer[i] == '\t' ||
+                   buffer[i] == '\n' ||
+                   buffer[i] == '\0')
+                       continue;
+
+               return i + 1;
+       }
+
+       return 0;
+}
+
+static char *trim_whitespace_in_place(char *buffer)
+{
+       buffer += char_left_gc(buffer, strlen(buffer));
+       buffer[char_right_gc(buffer, strlen(buffer))] = '\0';
+       return buffer;
+}
+
+static pid_t get_pid_from_fdinfo_file(int pidfd, const char *key, size_t keylen)
+{
+       int ret;
+       char path[512];
+       FILE *f;
+       size_t n = 0;
+       pid_t result = -1;
+       char *line = NULL;
+
+       snprintf(path, sizeof(path), "/proc/self/fdinfo/%d", pidfd);
+
+       f = fopen(path, "re");
+       if (!f)
+               return -1;
+
+       while (getline(&line, &n, f) != -1) {
+               char *numstr;
+
+               if (strncmp(line, key, keylen))
+                       continue;
+
+               numstr = trim_whitespace_in_place(line + 4);
+               ret = safe_int(numstr, &result);
+               if (ret < 0)
+                       goto out;
+
+               break;
+       }
+
+out:
+       free(line);
+       fclose(f);
+       return result;
+}
+
+int main(int argc, char **argv)
+{
+       int pidfd = -1, ret = 1;
+       pid_t pid;
+
+       ksft_set_plan(3);
+
+       pidfd = sys_pidfd_open(-1, 0);
+       if (pidfd >= 0) {
+               ksft_print_msg(
+                       "%s - succeeded to open pidfd for invalid pid -1\n",
+                       strerror(errno));
+               goto on_error;
+       }
+       ksft_test_result_pass("do not allow invalid pid test: passed\n");
+
+       pidfd = sys_pidfd_open(getpid(), 1);
+       if (pidfd >= 0) {
+               ksft_print_msg(
+                       "%s - succeeded to open pidfd with invalid flag value specified\n",
+                       strerror(errno));
+               goto on_error;
+       }
+       ksft_test_result_pass("do not allow invalid flag test: passed\n");
+
+       pidfd = sys_pidfd_open(getpid(), 0);
+       if (pidfd < 0) {
+               ksft_print_msg("%s - failed to open pidfd\n", strerror(errno));
+               goto on_error;
+       }
+       ksft_test_result_pass("open a new pidfd test: passed\n");
+
+       pid = get_pid_from_fdinfo_file(pidfd, "Pid:", sizeof("Pid:") - 1);
+       ksft_print_msg("pidfd %d refers to process with pid %d\n", pidfd, pid);
+
+       ret = 0;
+
+on_error:
+       if (pidfd >= 0)
+               close(pidfd);
+
+       return !ret ? ksft_exit_pass() : ksft_exit_fail();
+}
index 9929dc6..7eaa8a3 100644 (file)
 #include <time.h>
 #include <unistd.h>
 
+#include "pidfd.h"
 #include "../kselftest.h"
 
+#ifndef __NR_pidfd_send_signal
+#define __NR_pidfd_send_signal -1
+#endif
+
 #define str(s) _str(s)
 #define _str(s) #s
 #define CHILD_THREAD_MIN_WAIT 3 /* seconds */
 
 #define MAX_EVENTS 5
-#ifndef __NR_pidfd_send_signal
-#define __NR_pidfd_send_signal 424
-#endif
 
 #ifndef CLONE_PIDFD
 #define CLONE_PIDFD 0x00001000
@@ -91,28 +93,6 @@ static int test_pidfd_send_signal_simple_success(void)
        return 0;
 }
 
-static int wait_for_pid(pid_t pid)
-{
-       int status, ret;
-
-again:
-       ret = waitpid(pid, &status, 0);
-       if (ret == -1) {
-               if (errno == EINTR)
-                       goto again;
-
-               return -1;
-       }
-
-       if (ret != pid)
-               goto again;
-
-       if (!WIFEXITED(status))
-               return -1;
-
-       return WEXITSTATUS(status);
-}
-
 static int test_pidfd_send_signal_exited_fail(void)
 {
        int pidfd, ret, saved_errno;
@@ -157,13 +137,6 @@ static int test_pidfd_send_signal_exited_fail(void)
        return 0;
 }
 
-/*
- * The kernel reserves 300 pids via RESERVED_PIDS in kernel/pid.c
- * That means, when it wraps around any pid < 300 will be skipped.
- * So we need to use a pid > 300 in order to test recycling.
- */
-#define PID_RECYCLE 1000
-
 /*
  * Maximum number of cycles we allow. This is equivalent to PID_MAX_DEFAULT.
  * If users set a higher limit or we have cycled PIDFD_MAX_DEFAULT number of
@@ -172,17 +145,6 @@ static int test_pidfd_send_signal_exited_fail(void)
  */
 #define PIDFD_MAX_DEFAULT 0x8000
 
-/*
- * Define a few custom error codes for the child process to clearly indicate
- * what is happening. This way we can tell the difference between a system
- * error, a test error, etc.
- */
-#define PIDFD_PASS 0
-#define PIDFD_FAIL 1
-#define PIDFD_ERROR 2
-#define PIDFD_SKIP 3
-#define PIDFD_XFAIL 4
-
 static int test_pidfd_send_signal_recycled_pid_fail(void)
 {
        int i, ret;