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Commit 05c3f292 authored by Alexey Dobriyan's avatar Alexey Dobriyan Committed by Linus Torvalds
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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: default avatarAlexey 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: default avatarAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 9cdd83e3

tools/testing/selftests/proc/.gitignore

+1 −0
Original line number Diff line number Diff line
@@ -3,3 +3,4 @@ 
/proc-self-map-files-002

/proc-self-syscall

/proc-self-wchan

/read

tools/testing/selftests/proc/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -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

tools/testing/selftests/proc/read.c

0 → 100644
+147 −0
Original line number Diff line number Diff line 
/*

 * 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;

}