[PATCH -mm] proc: shotgun test read/readdir/readlink + a little write

From: Alexey Dobriyan
Date: Thu Mar 15 2018 - 16:13:02 EST


Interact with nearly everything in /proc.

Hopefully memleak checkers and KASAN will find something.

Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxx>
---

tools/testing/selftests/proc/.gitignore | 1
tools/testing/selftests/proc/Makefile | 1
tools/testing/selftests/proc/read.c | 146 ++++++++++++++++++++++++++++++++
3 files changed, 148 insertions(+)

--- a/tools/testing/selftests/proc/.gitignore
+++ b/tools/testing/selftests/proc/.gitignore
@@ -4,3 +4,4 @@
/proc-self-map-files-002
/proc-self-syscall
/proc-self-wchan
+/read
--- a/tools/testing/selftests/proc/Makefile
+++ b/tools/testing/selftests/proc/Makefile
@@ -7,5 +7,6 @@ TEST_GEN_PROGS += proc-self-map-files-001
TEST_GEN_PROGS += proc-self-map-files-002
TEST_GEN_PROGS += proc-self-syscall
TEST_GEN_PROGS += proc-self-wchan
+TEST_GEN_PROGS += read

include ../lib.mk
new file mode 100644
--- /dev/null
+++ b/tools/testing/selftests/proc/read.c
@@ -0,0 +1,146 @@
+/*
+ * Copyright © 2018 Alexey Dobriyan <adobriyan@xxxxxxxxx>
+ *
+ * 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
+// 1) read of every file in /proc
+// 2) readlink of every symlink in /proc
+// 3) recursively (1) + (2) for every directory in /proc
+// 4) write to /proc/*/clear_refs and /proc/*/task/*/clear_refs
+// 5) write to /proc/sysrq-trigger
+#undef NDEBUG
+#include <assert.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <dirent.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+static inline bool streq(const char *s1, const char *s2)
+{
+ return strcmp(s1, s2) == 0;
+}
+
+static struct dirent *xreaddir(DIR *d)
+{
+ struct dirent *de;
+
+ errno = 0;
+ de = readdir(d);
+ if (!de && errno != 0) {
+ exit(1);
+ }
+ return de;
+}
+
+static void f_reg(DIR *d, const char *filename)
+{
+ char buf[4096];
+ int fd;
+ ssize_t rv;
+
+ fd = openat(dirfd(d), filename, O_RDONLY);
+ if (fd == -1)
+ return;
+ rv = read(fd, buf, sizeof(buf));
+ assert((0 <= rv && rv <= sizeof(buf)) || rv == -1);
+ close(fd);
+}
+
+static void f_reg_write(DIR *d, const char *filename, const char *buf, size_t len)
+{
+ int fd;
+ ssize_t rv;
+
+ fd = openat(dirfd(d), filename, O_WRONLY);
+ if (fd == -1)
+ return;
+ rv = write(fd, buf, len);
+ assert((0 <= rv && rv <= len) || rv == -1);
+ close(fd);
+}
+
+static void f_lnk(DIR *d, const char *filename)
+{
+ char buf[4096];
+ ssize_t rv;
+
+ rv = readlinkat(dirfd(d), filename, buf, sizeof(buf));
+ assert((0 <= rv && rv <= sizeof(buf)) || rv == -1);
+}
+
+static void f(DIR *d, unsigned int level)
+{
+ struct dirent *de;
+
+ de = xreaddir(d);
+ assert(de->d_type == DT_DIR);
+ assert(streq(de->d_name, "."));
+
+ de = xreaddir(d);
+ assert(de->d_type == DT_DIR);
+ assert(streq(de->d_name, ".."));
+
+ while ((de = xreaddir(d))) {
+ assert(!streq(de->d_name, "."));
+ assert(!streq(de->d_name, ".."));
+
+ switch (de->d_type) {
+ DIR *dd;
+ int fd;
+
+ case DT_REG:
+ if (level == 1 && streq(de->d_name, "clear_refs")) {
+ f_reg_write(d, de->d_name, "1", 1);
+ } else if (level == 1 && streq(de->d_name, "sysrq-trigger")) {
+ f_reg_write(d, de->d_name, "h", 1);
+ } else if (level == 3 && streq(de->d_name, "clear_refs")) {
+ f_reg_write(d, de->d_name, "1", 1);
+ } else {
+ f_reg(d, de->d_name);
+ }
+ break;
+ case DT_DIR:
+ fd = openat(dirfd(d), de->d_name, O_DIRECTORY|O_RDONLY);
+ if (fd == -1)
+ continue;
+ dd = fdopendir(fd);
+ if (!dd)
+ continue;
+ f(dd, level + 1);
+ closedir(dd);
+ break;
+ case DT_LNK:
+ f_lnk(d, de->d_name);
+ break;
+ default:
+ assert(0);
+ }
+ }
+}
+
+int main(void)
+{
+ DIR *d;
+
+ d = opendir("/proc");
+ if (!d)
+ return 2;
+ f(d, 0);
+ return 0;
+}