proc: selftests: shotgun testing of read/readdir/readlink/write

Perform reads with nearly everything in /proc, and some writing as well.

Hopefully memleak checkers and KASAN will find something.

[adobriyan@gmail.com: /proc/kmsg can and will block if read under root]
Link: http://lkml.kernel.org/r/20180316232147.GA20146@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
[adobriyan@gmail.com: /proc/sysrq-trigger lives on the ground floor]
Link: http://lkml.kernel.org/r/20180317164911.GA3445@avx2
Link: http://lkml.kernel.org/r/20180315201251.GA12396@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
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 78c40f5..5627df8 100644 (file)
--- a/tools/testing/selftests/proc/.gitignore
+++ b/tools/testing/selftests/proc/.gitignore
@@ -3,3 +3,4 @@
 /proc-self-map-files-002
 /proc-self-syscall
 /proc-self-wchan
+/read

diff --git a/tools/testing/selftests/proc/Makefile b/tools/testing/selftests/proc/Makefile
index d7f7058..312a398 100644 (file)
--- a/tools/testing/selftests/proc/Makefile
+++ b/tools/testing/selftests/proc/Makefile
@@ -6,5 +6,6 @@ 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

diff --git a/tools/testing/selftests/proc/read.c b/tools/testing/selftests/proc/read.c
new file mode 100644 (file)
index 0000000..12e397f
--- /dev/null
+++ b/tools/testing/selftests/proc/read.c
@@ -0,0 +1,147 @@
+/*
+ * 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
+// 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;
+
+       /* read from /proc/kmsg can block */
+       fd = openat(dirfd(d), filename, O_RDONLY|O_NONBLOCK);
+       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 == 0 && streq(de->d_name, "sysrq-trigger")) {
+                               f_reg_write(d, de->d_name, "h", 1);
+                       } else if (level == 1 && streq(de->d_name, "clear_refs")) {
+                               f_reg_write(d, de->d_name, "1", 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;
+}