From 61d47c4e71c1f080e7412315c8685bc682a8e53a Mon Sep 17 00:00:00 2001
From: Alexey Dobriyan <adobriyan@gmail.com>
Date: Tue, 21 Aug 2018 21:54:16 -0700
Subject: [PATCH] proc: test /proc/self symlink
There are plans to change how /proc/self result is calculated,
for that a test is necessary.
Use direct system call because of this whole getpid caching story.
Link: http://lkml.kernel.org/r/20180627195103.GB18113@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
tools/testing/selftests/proc/.gitignore | 1 +
tools/testing/selftests/proc/Makefile | 2 ++
tools/testing/selftests/proc/proc.h | 7 +++++
tools/testing/selftests/proc/self.c | 39 +++++++++++++++++++++++++
4 files changed, 49 insertions(+)
create mode 100644 tools/testing/selftests/proc/self.c
diff --git a/tools/testing/selftests/proc/.gitignore b/tools/testing/selftests/proc/.gitignore
index 74e5912e9f2e..ee33d6c3137f 100644
--- a/tools/testing/selftests/proc/.gitignore
+++ b/tools/testing/selftests/proc/.gitignore
@@ -9,3 +9,4 @@
/proc-uptime-001
/proc-uptime-002
/read
+/self
diff --git a/tools/testing/selftests/proc/Makefile b/tools/testing/selftests/proc/Makefile
index db310eedc268..344bca8e4b28 100644
--- a/tools/testing/selftests/proc/Makefile
+++ b/tools/testing/selftests/proc/Makefile
@@ -1,4 +1,5 @@
CFLAGS += -Wall -O2 -Wno-unused-function
+CFLAGS += -D_GNU_SOURCE
TEST_GEN_PROGS :=
TEST_GEN_PROGS += fd-001-lookup
@@ -12,5 +13,6 @@ TEST_GEN_PROGS += proc-self-wchan
TEST_GEN_PROGS += proc-uptime-001
TEST_GEN_PROGS += proc-uptime-002
TEST_GEN_PROGS += read
+TEST_GEN_PROGS += self
include ../lib.mk
diff --git a/tools/testing/selftests/proc/proc.h b/tools/testing/selftests/proc/proc.h
index 4e178166fd84..31ca4b0c007f 100644
--- a/tools/testing/selftests/proc/proc.h
+++ b/tools/testing/selftests/proc/proc.h
@@ -6,6 +6,13 @@
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
+#include <unistd.h>
+#include <sys/syscall.h>
+
+static inline pid_t sys_getpid(void)
+{
+ return syscall(SYS_getpid);
+}
static inline bool streq(const char *s1, const char *s2)
{
diff --git a/tools/testing/selftests/proc/self.c b/tools/testing/selftests/proc/self.c
new file mode 100644
index 000000000000..21c15a1ffefb
--- /dev/null
+++ b/tools/testing/selftests/proc/self.c
@@ -0,0 +1,39 @@
+/*
+ * Copyright © 2018 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 /proc/self gives correct TGID.
+#undef NDEBUG
+#include <assert.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#include "proc.h"
+
+int main(void)
+{
+ char buf1[64], buf2[64];
+ pid_t pid;
+ ssize_t rv;
+
+ pid = sys_getpid();
+ snprintf(buf1, sizeof(buf1), "%u", pid);
+
+ rv = readlink("/proc/self", buf2, sizeof(buf2));
+ assert(rv == strlen(buf1));
+ buf2[rv] = '\0';
+ assert(streq(buf1, buf2));
+
+ return 0;
+}