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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 | /* * 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; } |