1 files changed, 148 insertions, 0 deletions
diff --git a/tools/testing/selftests/proc/read.c b/tools/testing/selftests/proc/read.c
new file mode 100644
index 0000000000..35ee78dff1
--- /dev/null
+++ b/tools/testing/selftests/proc/read.c
@@ -0,0 +1,148 @@
+/*
+ * 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 and lseek on 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 <stdio.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/vfs.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "proc.h"
+
+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;
+	/* struct proc_ops::proc_lseek is mandatory if file is seekable. */
+	(void)lseek(fd, 0, SEEK_SET);
+	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;
+	struct statfs sfs;
+
+	d = opendir("/proc");
+	if (!d)
+		return 4;
+
+	/* Ensure /proc is proc. */
+	if (fstatfs(dirfd(d), &sfs) == -1) {
+		return 1;
+	}
+	if (sfs.f_type != 0x9fa0) {
+		fprintf(stderr, "error: unexpected f_type %lx\n", (long)sfs.f_type);
+		return 2;
+	}
+
+	f(d, 0);
+
+	return 0;
+}