1 /* 2 * Copyright 2018 Alexey Dobriyan <adobriyan (at) 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 34 #include "proc.h" 35 36 static void f_reg(DIR *d, const char *filename) 37 { 38 char buf[4096]; 39 int fd; 40 ssize_t rv; 41 42 /* read from /proc/kmsg can block */ 43 fd = openat(dirfd(d), filename, O_RDONLY|O_NONBLOCK); 44 if (fd == -1) 45 return; 46 rv = read(fd, buf, sizeof(buf)); 47 assert((0 <= rv && rv <= sizeof(buf)) || rv == -1); 48 close(fd); 49 } 50 51 static void f_reg_write(DIR *d, const char *filename, const char *buf, size_t len) 52 { 53 int fd; 54 ssize_t rv; 55 56 fd = openat(dirfd(d), filename, O_WRONLY); 57 if (fd == -1) 58 return; 59 rv = write(fd, buf, len); 60 assert((0 <= rv && rv <= len) || rv == -1); 61 close(fd); 62 } 63 64 static void f_lnk(DIR *d, const char *filename) 65 { 66 char buf[4096]; 67 ssize_t rv; 68 69 rv = readlinkat(dirfd(d), filename, buf, sizeof(buf)); 70 assert((0 <= rv && rv <= sizeof(buf)) || rv == -1); 71 } 72 73 static void f(DIR *d, unsigned int level) 74 { 75 struct dirent *de; 76 77 de = xreaddir(d); 78 assert(de->d_type == DT_DIR); 79 assert(streq(de->d_name, ".")); 80 81 de = xreaddir(d); 82 assert(de->d_type == DT_DIR); 83 assert(streq(de->d_name, "..")); 84 85 while ((de = xreaddir(d))) { 86 assert(!streq(de->d_name, ".")); 87 assert(!streq(de->d_name, "..")); 88 89 switch (de->d_type) { 90 DIR *dd; 91 int fd; 92 93 case DT_REG: 94 if (level == 0 && streq(de->d_name, "sysrq-trigger")) { 95 f_reg_write(d, de->d_name, "h", 1); 96 } else if (level == 1 && streq(de->d_name, "clear_refs")) { 97 f_reg_write(d, de->d_name, "1", 1); 98 } else if (level == 3 && streq(de->d_name, "clear_refs")) { 99 f_reg_write(d, de->d_name, "1", 1); 100 } else { 101 f_reg(d, de->d_name); 102 } 103 break; 104 case DT_DIR: 105 fd = openat(dirfd(d), de->d_name, O_DIRECTORY|O_RDONLY); 106 if (fd == -1) 107 continue; 108 dd = fdopendir(fd); 109 if (!dd) 110 continue; 111 f(dd, level + 1); 112 closedir(dd); 113 break; 114 case DT_LNK: 115 f_lnk(d, de->d_name); 116 break; 117 default: 118 assert(0); 119 } 120 } 121 } 122 123 int main(void) 124 { 125 DIR *d; 126 127 d = opendir("/proc"); 128 if (!d) 129 return 2; 130 f(d, 0); 131 return 0; 132 } 133
