Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/*
2 * Copyright © 2018 Alexey Dobriyan <adobriyan@gmail.com>
3 *
4 * Permission to use, copy, modify, and distribute this software for any
5 * purpose with or without fee is hereby granted, provided that the above
6 * copyright notice and this permission notice appear in all copies.
7 *
8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15 */
16// Test
17// 1) read of every file in /proc
18// 2) readlink of every symlink in /proc
19// 3) recursively (1) + (2) for every directory in /proc
20// 4) write to /proc/*/clear_refs and /proc/*/task/*/clear_refs
21// 5) write to /proc/sysrq-trigger
22#undef NDEBUG
23#include <assert.h>
24#include <errno.h>
25#include <sys/types.h>
26#include <dirent.h>
27#include <stdbool.h>
28#include <stdlib.h>
29#include <string.h>
30#include <sys/stat.h>
31#include <fcntl.h>
32#include <unistd.h>
33
34static inline bool streq(const char *s1, const char *s2)
35{
36 return strcmp(s1, s2) == 0;
37}
38
39static struct dirent *xreaddir(DIR *d)
40{
41 struct dirent *de;
42
43 errno = 0;
44 de = readdir(d);
45 if (!de && errno != 0) {
46 exit(1);
47 }
48 return de;
49}
50
51static void f_reg(DIR *d, const char *filename)
52{
53 char buf[4096];
54 int fd;
55 ssize_t rv;
56
57 /* read from /proc/kmsg can block */
58 fd = openat(dirfd(d), filename, O_RDONLY|O_NONBLOCK);
59 if (fd == -1)
60 return;
61 rv = read(fd, buf, sizeof(buf));
62 assert((0 <= rv && rv <= sizeof(buf)) || rv == -1);
63 close(fd);
64}
65
66static void f_reg_write(DIR *d, const char *filename, const char *buf, size_t len)
67{
68 int fd;
69 ssize_t rv;
70
71 fd = openat(dirfd(d), filename, O_WRONLY);
72 if (fd == -1)
73 return;
74 rv = write(fd, buf, len);
75 assert((0 <= rv && rv <= len) || rv == -1);
76 close(fd);
77}
78
79static void f_lnk(DIR *d, const char *filename)
80{
81 char buf[4096];
82 ssize_t rv;
83
84 rv = readlinkat(dirfd(d), filename, buf, sizeof(buf));
85 assert((0 <= rv && rv <= sizeof(buf)) || rv == -1);
86}
87
88static void f(DIR *d, unsigned int level)
89{
90 struct dirent *de;
91
92 de = xreaddir(d);
93 assert(de->d_type == DT_DIR);
94 assert(streq(de->d_name, "."));
95
96 de = xreaddir(d);
97 assert(de->d_type == DT_DIR);
98 assert(streq(de->d_name, ".."));
99
100 while ((de = xreaddir(d))) {
101 assert(!streq(de->d_name, "."));
102 assert(!streq(de->d_name, ".."));
103
104 switch (de->d_type) {
105 DIR *dd;
106 int fd;
107
108 case DT_REG:
109 if (level == 0 && streq(de->d_name, "sysrq-trigger")) {
110 f_reg_write(d, de->d_name, "h", 1);
111 } else if (level == 1 && streq(de->d_name, "clear_refs")) {
112 f_reg_write(d, de->d_name, "1", 1);
113 } else if (level == 3 && streq(de->d_name, "clear_refs")) {
114 f_reg_write(d, de->d_name, "1", 1);
115 } else {
116 f_reg(d, de->d_name);
117 }
118 break;
119 case DT_DIR:
120 fd = openat(dirfd(d), de->d_name, O_DIRECTORY|O_RDONLY);
121 if (fd == -1)
122 continue;
123 dd = fdopendir(fd);
124 if (!dd)
125 continue;
126 f(dd, level + 1);
127 closedir(dd);
128 break;
129 case DT_LNK:
130 f_lnk(d, de->d_name);
131 break;
132 default:
133 assert(0);
134 }
135 }
136}
137
138int main(void)
139{
140 DIR *d;
141
142 d = opendir("/proc");
143 if (!d)
144 return 2;
145 f(d, 0);
146 return 0;
147}