1 files changed, 94 insertions, 0 deletions

diff --git a/tools/testing/selftests/kcmp/kcmp_test.c b/tools/testing/selftests/kcmp/kcmp_test.c
new file mode 100644
index 000000000000..358cc6bfa35d
--- /dev/null
+++ b/tools/testing/selftests/kcmp/kcmp_test.c
@@ -0,0 +1,94 @@
+#define _GNU_SOURCE
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <limits.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include <fcntl.h>
+
+#include <linux/unistd.h>
+#include <linux/kcmp.h>
+
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+
+static long sys_kcmp(int pid1, int pid2, int type, int fd1, int fd2)
+{
+        return syscall(__NR_kcmp, pid1, pid2, type, fd1, fd2);
+}
+
+int main(int argc, char **argv)
+{
+        const char kpath[] = "kcmp-test-file";
+        int pid1, pid2;
+        int fd1, fd2;
+        int status;
+
+        fd1 = open(kpath, O_RDWR | O_CREAT | O_TRUNC, 0644);
+        pid1 = getpid();
+
+        if (fd1 < 0) {
+                perror("Can't create file");
+                exit(1);
+        }
+
+        pid2 = fork();
+        if (pid2 < 0) {
+                perror("fork failed");
+                exit(1);
+        }
+
+        if (!pid2) {
+                int pid2 = getpid();
+                int ret;
+
+                fd2 = open(kpath, O_RDWR, 0644);
+                if (fd2 < 0) {
+                        perror("Can't open file");
+                        exit(1);
+                }
+
+                /* An example of output and arguments */
+                printf("pid1: %6d pid2: %6d FD: %2ld FILES: %2ld VM: %2ld "
+                       "FS: %2ld SIGHAND: %2ld IO: %2ld SYSVSEM: %2ld "
+                       "INV: %2ld\n",
+                       pid1, pid2,
+                       sys_kcmp(pid1, pid2, KCMP_FILE,          fd1, fd2),
+                       sys_kcmp(pid1, pid2, KCMP_FILES,         0, 0),
+                       sys_kcmp(pid1, pid2, KCMP_VM,            0, 0),
+                       sys_kcmp(pid1, pid2, KCMP_FS,            0, 0),
+                       sys_kcmp(pid1, pid2, KCMP_SIGHAND,       0, 0),
+                       sys_kcmp(pid1, pid2, KCMP_IO,            0, 0),
+                       sys_kcmp(pid1, pid2, KCMP_SYSVSEM,       0, 0),
+
+                        /* This one should fail */
+                       sys_kcmp(pid1, pid2, KCMP_TYPES + 1,     0, 0));
+
+                /* This one should return same fd */
+                ret = sys_kcmp(pid1, pid2, KCMP_FILE, fd1, fd1);
+                if (ret) {
+                        printf("FAIL: 0 expected but %d returned\n", ret);
+                        ret = -1;
+                } else
+                        printf("PASS: 0 returned as expected\n");
+
+                /* Compare with self */
+                ret = sys_kcmp(pid1, pid1, KCMP_VM, 0, 0);
+                if (ret) {
+                        printf("FAIL: 0 expected but %li returned\n", ret);
+                        ret = -1;
+                } else
+                        printf("PASS: 0 returned as expected\n");
+
+                exit(ret);
+        }
+
+        waitpid(pid2, &status, P_ALL);
+
+        return 0;
+}