proc: test /proc/self/syscall

Read from /proc/self/syscall should yield read system call and correct
args in the output as current is reading /proc/self/syscall.

Link: http://lkml.kernel.org/r/20180226212145.GB742@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/tools/testing/selftests/proc/.gitignore b/tools/testing/selftests/proc/.gitignore
index 4c851db..c648b27 100644 (file)
--- a/tools/testing/selftests/proc/.gitignore
+++ b/tools/testing/selftests/proc/.gitignore
@@ -1 +1,2 @@
-/proc-self-wchan
+/proc-self-mem
+/proc-self-syscall

diff --git a/tools/testing/selftests/proc/Makefile b/tools/testing/selftests/proc/Makefile
index 592603a..ad20520 100644 (file)
--- a/tools/testing/selftests/proc/Makefile
+++ b/tools/testing/selftests/proc/Makefile
@@ -1,6 +1,7 @@
 CFLAGS += -Wall -O2
 
 TEST_GEN_PROGS :=
+TEST_GEN_PROGS += proc-self-syscall
 TEST_GEN_PROGS += proc-self-wchan
 
 include ../lib.mk

diff --git a/tools/testing/selftests/proc/proc-self-syscall.c b/tools/testing/selftests/proc/proc-self-syscall.c
new file mode 100644 (file)
index 0000000..05eb6f9
--- /dev/null
+++ b/tools/testing/selftests/proc/proc-self-syscall.c
@@ -0,0 +1,45 @@
+#define _GNU_SOURCE
+#include <unistd.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdio.h>
+
+static inline ssize_t sys_read(int fd, void *buf, size_t len)
+{
+       return syscall(SYS_read, fd, buf, len);
+}
+
+int main(void)
+{
+       char buf1[64];
+       char buf2[64];
+       int fd;
+       ssize_t rv;
+
+       fd = open("/proc/self/syscall", O_RDONLY);
+       if (fd == -1) {
+               if (errno == ENOENT)
+                       return 2;
+               return 1;
+       }
+
+       /* Do direct system call as libc can wrap anything. */
+       snprintf(buf1, sizeof(buf1), "%ld 0x%lx 0x%lx 0x%lx",
+                (long)SYS_read, (long)fd, (long)buf2, (long)sizeof(buf2));
+
+       memset(buf2, 0, sizeof(buf2));
+       rv = sys_read(fd, buf2, sizeof(buf2));
+       if (rv < 0)
+               return 1;
+       if (rv < strlen(buf1))
+               return 1;
+       if (strncmp(buf1, buf2, strlen(buf1)) != 0)
+               return 1;
+
+       return 0;
+}