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1/*2 * Copyright © 2018 Alexey Dobriyan <adobriyan@gmail.com>3 *4 * Permission to use, copy, modify, and distribute this software for any5 * purpose with or without fee is hereby granted, provided that the above6 * copyright notice and this permission notice appear in all copies.7 *8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.15 */16// Test17// 1) read and lseek on every file in /proc18// 2) readlink of every symlink in /proc19// 3) recursively (1) + (2) for every directory in /proc20// 4) write to /proc/*/clear_refs and /proc/*/task/*/clear_refs21// 5) write to /proc/sysrq-trigger22#undef NDEBUG23#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 <stdio.h>30#include <string.h>31#include <sys/stat.h>32#include <sys/vfs.h>33#include <fcntl.h>34#include <unistd.h>35 36#include "proc.h"37 38static void f_reg(DIR *d, const char *filename)39{40 char buf[4096];41 int fd;42 ssize_t rv;43 44 /* read from /proc/kmsg can block */45 fd = openat(dirfd(d), filename, O_RDONLY|O_NONBLOCK);46 if (fd == -1)47 return;48 /* struct proc_ops::proc_lseek is mandatory if file is seekable. */49 (void)lseek(fd, 0, SEEK_SET);50 rv = read(fd, buf, sizeof(buf));51 assert((0 <= rv && rv <= sizeof(buf)) || rv == -1);52 close(fd);53}54 55static void f_reg_write(DIR *d, const char *filename, const char *buf, size_t len)56{57 int fd;58 ssize_t rv;59 60 fd = openat(dirfd(d), filename, O_WRONLY);61 if (fd == -1)62 return;63 rv = write(fd, buf, len);64 assert((0 <= rv && rv <= len) || rv == -1);65 close(fd);66}67 68static void f_lnk(DIR *d, const char *filename)69{70 char buf[4096];71 ssize_t rv;72 73 rv = readlinkat(dirfd(d), filename, buf, sizeof(buf));74 assert((0 <= rv && rv <= sizeof(buf)) || rv == -1);75}76 77static void f(DIR *d, unsigned int level)78{79 struct dirent *de;80 81 de = xreaddir(d);82 assert(de->d_type == DT_DIR);83 assert(streq(de->d_name, "."));84 85 de = xreaddir(d);86 assert(de->d_type == DT_DIR);87 assert(streq(de->d_name, ".."));88 89 while ((de = xreaddir(d))) {90 assert(!streq(de->d_name, "."));91 assert(!streq(de->d_name, ".."));92 93 switch (de->d_type) {94 DIR *dd;95 int fd;96 97 case DT_REG:98 if (level == 0 && streq(de->d_name, "sysrq-trigger")) {99 f_reg_write(d, de->d_name, "h", 1);100 } else if (level == 1 && streq(de->d_name, "clear_refs")) {101 f_reg_write(d, de->d_name, "1", 1);102 } else if (level == 3 && streq(de->d_name, "clear_refs")) {103 f_reg_write(d, de->d_name, "1", 1);104 } else {105 f_reg(d, de->d_name);106 }107 break;108 case DT_DIR:109 fd = openat(dirfd(d), de->d_name, O_DIRECTORY|O_RDONLY);110 if (fd == -1)111 continue;112 dd = fdopendir(fd);113 if (!dd)114 continue;115 f(dd, level + 1);116 closedir(dd);117 break;118 case DT_LNK:119 f_lnk(d, de->d_name);120 break;121 default:122 assert(0);123 }124 }125}126 127int main(void)128{129 DIR *d;130 struct statfs sfs;131 132 d = opendir("/proc");133 if (!d)134 return 4;135 136 /* Ensure /proc is proc. */137 if (fstatfs(dirfd(d), &sfs) == -1) {138 return 1;139 }140 if (sfs.f_type != 0x9fa0) {141 fprintf(stderr, "error: unexpected f_type %lx\n", (long)sfs.f_type);142 return 2;143 }144 145 f(d, 0);146 147 return 0;148}149