[PATCHv2 2/3] selftests: Add test of O_BENEATH & openat(2)
From: David Drysdale
Date: Tue Nov 04 2014 - 05:02:32 EST
Add simple tests of openat(2) variations, including examples that
check the new O_BENEATH flag.
Signed-off-by: David Drysdale <drysdale@xxxxxxxxxx>
---
tools/testing/selftests/Makefile | 1 +
tools/testing/selftests/openat/.gitignore | 4 +
tools/testing/selftests/openat/Makefile | 28 +++++
tools/testing/selftests/openat/openat.c | 180 ++++++++++++++++++++++++++++++
4 files changed, 213 insertions(+)
create mode 100644 tools/testing/selftests/openat/.gitignore
create mode 100644 tools/testing/selftests/openat/Makefile
create mode 100644 tools/testing/selftests/openat/openat.c
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 36ff2e4c7b6f..812e973233d2 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -14,6 +14,7 @@ TARGETS += powerpc
TARGETS += user
TARGETS += sysctl
TARGETS += firmware
+TARGETS += openat
TARGETS_HOTPLUG = cpu-hotplug
TARGETS_HOTPLUG += memory-hotplug
diff --git a/tools/testing/selftests/openat/.gitignore b/tools/testing/selftests/openat/.gitignore
new file mode 100644
index 000000000000..835b2dcd8678
--- /dev/null
+++ b/tools/testing/selftests/openat/.gitignore
@@ -0,0 +1,4 @@
+openat
+subdir
+topfile
+symlinkdown
\ No newline at end of file
diff --git a/tools/testing/selftests/openat/Makefile b/tools/testing/selftests/openat/Makefile
new file mode 100644
index 000000000000..84cd06e7ee82
--- /dev/null
+++ b/tools/testing/selftests/openat/Makefile
@@ -0,0 +1,28 @@
+CC = $(CROSS_COMPILE)gcc
+CFLAGS = -Wall
+BINARIES = openat
+DEPS = subdir topfile symlinkdown subdir/bottomfile subdir/symlinkup subdir/symlinkout subdir/symlinkin
+all: $(BINARIES) $(DEPS)
+
+subdir:
+ mkdir -p subdir
+topfile:
+ echo 0123456789 > $@
+subdir/bottomfile: | subdir
+ echo 0123456789 > $@
+subdir/symlinkup: | subdir
+ ln -s ../topfile $@
+subdir/symlinkout: | subdir
+ ln -s /etc/passwd $@
+subdir/symlinkin: | subdir
+ ln -s bottomfile $@
+symlinkdown:
+ ln -s subdir/bottomfile $@
+%: %.c
+ $(CC) $(CFLAGS) -o $@ $^
+
+run_tests: all
+ ./openat
+
+clean:
+ rm -rf $(BINARIES) $(DEPS)
diff --git a/tools/testing/selftests/openat/openat.c b/tools/testing/selftests/openat/openat.c
new file mode 100644
index 000000000000..0c030cbd10dc
--- /dev/null
+++ b/tools/testing/selftests/openat/openat.c
@@ -0,0 +1,180 @@
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+
+#include <linux/fcntl.h>
+
+/* Bypass glibc */
+static int openat_(int dirfd, const char *pathname, int flags)
+{
+ return syscall(__NR_openat, dirfd, pathname, flags);
+}
+
+static int openat_or_die(int dfd, const char *path, int flags)
+{
+ int fd = openat_(dfd, path, flags);
+
+ if (fd < 0) {
+ printf("Failed to openat(%d, '%s'); "
+ "check prerequisites are available\n", dfd, path);
+ exit(1);
+ }
+ return fd;
+}
+
+static int check_openat(int dfd, const char *path, int flags)
+{
+ int rc;
+ int fd;
+ char buffer[4];
+
+ errno = 0;
+ printf("Check success of openat(%d, '%s', %x)... ",
+ dfd, path?:"(null)", flags);
+ fd = openat_(dfd, path, flags);
+ if (fd < 0) {
+ printf("[FAIL]: openat() failed, rc=%d errno=%d (%s)\n",
+ fd, errno, strerror(errno));
+ return 1;
+ }
+ errno = 0;
+ rc = read(fd, buffer, sizeof(buffer));
+ if (rc < 0) {
+ printf("[FAIL]: read() failed, rc=%d errno=%d (%s)\n",
+ rc, errno, strerror(errno));
+ return 1;
+ }
+ close(fd);
+ printf("[OK]\n");
+ return 0;
+}
+
+#define check_openat_fail(dfd, path, flags, errno) \
+ _check_openat_fail(dfd, path, flags, errno, #errno)
+static int _check_openat_fail(int dfd, const char *path, int flags,
+ int expected_errno, const char *errno_str)
+{
+ int rc;
+
+ errno = 0;
+ printf("Check failure of openat(%d, '%s', %x) with %s... ",
+ dfd, path?:"(null)", flags, errno_str);
+ rc = openat_(dfd, path, flags);
+ if (rc > 0) {
+ printf("[FAIL] (unexpected success from openat(2))\n");
+ close(rc);
+ return 1;
+ }
+ if (errno != expected_errno) {
+ printf("[FAIL] (expected errno %d (%s) not %d (%s)\n",
+ expected_errno, strerror(expected_errno),
+ errno, strerror(errno));
+ return 1;
+ }
+ printf("[OK]\n");
+ return 0;
+}
+
+int check_proc(void)
+{
+ int proc_dfd = openat_(AT_FDCWD, "/proc/self", O_RDONLY);
+ int fail = 0;
+
+ if (proc_dfd < 0) {
+ printf("'/proc/self' unavailable (errno=%d '%s'), skipping\n",
+ errno, strerror(errno));
+ return 1;
+ }
+ fail |= check_openat(proc_dfd, "root/etc/passwd", O_RDONLY);
+#ifdef O_BENEATH
+ fail |= check_openat_fail(proc_dfd, "root/etc/passwd",
+ O_RDONLY|O_BENEATH, EPERM);
+#endif
+ return fail;
+}
+
+int main(int argc, char *argv[])
+{
+ int fail = 0;
+ int dot_dfd = openat_or_die(AT_FDCWD, ".", O_RDONLY);
+ int subdir_dfd = openat_or_die(AT_FDCWD, "subdir", O_RDONLY);
+ int file_fd = openat_or_die(AT_FDCWD, "topfile", O_RDONLY);
+
+ /* Sanity check normal behavior */
+ fail |= check_openat(AT_FDCWD, "topfile", O_RDONLY);
+ fail |= check_openat(AT_FDCWD, "subdir/bottomfile", O_RDONLY);
+
+ fail |= check_openat(dot_dfd, "topfile", O_RDONLY);
+ fail |= check_openat(dot_dfd, "subdir/bottomfile", O_RDONLY);
+ fail |= check_openat(dot_dfd, "subdir/../topfile", O_RDONLY);
+
+ fail |= check_openat(subdir_dfd, "../topfile", O_RDONLY);
+ fail |= check_openat(subdir_dfd, "bottomfile", O_RDONLY);
+ fail |= check_openat(subdir_dfd, "../subdir/bottomfile", O_RDONLY);
+ fail |= check_openat(subdir_dfd, "symlinkup", O_RDONLY);
+ fail |= check_openat(subdir_dfd, "symlinkout", O_RDONLY);
+
+ fail |= check_openat(AT_FDCWD, "/etc/passwd", O_RDONLY);
+ fail |= check_openat(dot_dfd, "/etc/passwd", O_RDONLY);
+ fail |= check_openat(subdir_dfd, "/etc/passwd", O_RDONLY);
+
+ fail |= check_openat_fail(AT_FDCWD, "bogus", O_RDONLY, ENOENT);
+ fail |= check_openat_fail(dot_dfd, "bogus", O_RDONLY, ENOENT);
+ fail |= check_openat_fail(999, "bogus", O_RDONLY, EBADF);
+ fail |= check_openat_fail(file_fd, "bogus", O_RDONLY, ENOTDIR);
+
+#ifdef O_BENEATH
+ /* Test out O_BENEATH */
+ fail |= check_openat(AT_FDCWD, "topfile", O_RDONLY|O_BENEATH);
+ fail |= check_openat(AT_FDCWD, "subdir/bottomfile",
+ O_RDONLY|O_BENEATH);
+
+ fail |= check_openat(dot_dfd, "topfile", O_RDONLY|O_BENEATH);
+ fail |= check_openat(dot_dfd, "subdir/bottomfile",
+ O_RDONLY|O_BENEATH);
+ fail |= check_openat(subdir_dfd, "bottomfile", O_RDONLY|O_BENEATH);
+
+ /* Symlinks without .. or leading / are OK */
+ fail |= check_openat(dot_dfd, "symlinkdown", O_RDONLY|O_BENEATH);
+ fail |= check_openat(dot_dfd, "subdir/symlinkin", O_RDONLY|O_BENEATH);
+ fail |= check_openat(subdir_dfd, "symlinkin", O_RDONLY|O_BENEATH);
+ /* ... unless of course we specify O_NOFOLLOW */
+ fail |= check_openat_fail(dot_dfd, "symlinkdown",
+ O_RDONLY|O_BENEATH|O_NOFOLLOW, ELOOP);
+ fail |= check_openat_fail(dot_dfd, "subdir/symlinkin",
+ O_RDONLY|O_BENEATH|O_NOFOLLOW, ELOOP);
+ fail |= check_openat_fail(subdir_dfd, "symlinkin",
+ O_RDONLY|O_BENEATH|O_NOFOLLOW, ELOOP);
+
+ /* Can't open paths with ".." in them */
+ fail |= check_openat_fail(dot_dfd, "subdir/../topfile",
+ O_RDONLY|O_BENEATH, EPERM);
+ fail |= check_openat_fail(subdir_dfd, "../topfile",
+ O_RDONLY|O_BENEATH, EPERM);
+ fail |= check_openat_fail(subdir_dfd, "../subdir/bottomfile",
+ O_RDONLY|O_BENEATH, EPERM);
+
+ /* Can't open paths starting with "/" */
+ fail |= check_openat_fail(AT_FDCWD, "/etc/passwd",
+ O_RDONLY|O_BENEATH, EPERM);
+ fail |= check_openat_fail(dot_dfd, "/etc/passwd",
+ O_RDONLY|O_BENEATH, EPERM);
+ fail |= check_openat_fail(subdir_dfd, "/etc/passwd",
+ O_RDONLY|O_BENEATH, EPERM);
+ /* Can't sneak around constraints with symlinks */
+ fail |= check_openat_fail(subdir_dfd, "symlinkup",
+ O_RDONLY|O_BENEATH, EPERM);
+ fail |= check_openat_fail(subdir_dfd, "symlinkout",
+ O_RDONLY|O_BENEATH, EPERM);
+#else
+ printf("Skipping O_BENEATH tests due to missing #define\n");
+#endif
+ fail |= check_proc();
+
+ return fail ? -1 : 0;
+}
--
2.1.0.rc2.206.gedb03e5
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