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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// Test /proc/*/fd lookup.17 18#undef NDEBUG19#include <assert.h>20#include <dirent.h>21#include <errno.h>22#include <limits.h>23#include <sched.h>24#include <stdio.h>25#include <unistd.h>26#include <sys/types.h>27#include <sys/stat.h>28#include <fcntl.h>29 30#include "proc.h"31 32/* lstat(2) has more "coverage" in case non-symlink pops up somehow. */33static void test_lookup_pass(const char *pathname)34{35 struct stat st;36 ssize_t rv;37 38 memset(&st, 0, sizeof(struct stat));39 rv = lstat(pathname, &st);40 assert(rv == 0);41 assert(S_ISLNK(st.st_mode));42}43 44static void test_lookup_fail(const char *pathname)45{46 struct stat st;47 ssize_t rv;48 49 rv = lstat(pathname, &st);50 assert(rv == -1 && errno == ENOENT);51}52 53static void test_lookup(unsigned int fd)54{55 char buf[64];56 unsigned int c;57 unsigned int u;58 int i;59 60 snprintf(buf, sizeof(buf), "/proc/self/fd/%u", fd);61 test_lookup_pass(buf);62 63 /* leading junk */64 for (c = 1; c <= 255; c++) {65 if (c == '/')66 continue;67 snprintf(buf, sizeof(buf), "/proc/self/fd/%c%u", c, fd);68 test_lookup_fail(buf);69 }70 71 /* trailing junk */72 for (c = 1; c <= 255; c++) {73 if (c == '/')74 continue;75 snprintf(buf, sizeof(buf), "/proc/self/fd/%u%c", fd, c);76 test_lookup_fail(buf);77 }78 79 for (i = INT_MIN; i < INT_MIN + 1024; i++) {80 snprintf(buf, sizeof(buf), "/proc/self/fd/%d", i);81 test_lookup_fail(buf);82 }83 for (i = -1024; i < 0; i++) {84 snprintf(buf, sizeof(buf), "/proc/self/fd/%d", i);85 test_lookup_fail(buf);86 }87 for (u = INT_MAX - 1024; u <= (unsigned int)INT_MAX + 1024; u++) {88 snprintf(buf, sizeof(buf), "/proc/self/fd/%u", u);89 test_lookup_fail(buf);90 }91 for (u = UINT_MAX - 1024; u != 0; u++) {92 snprintf(buf, sizeof(buf), "/proc/self/fd/%u", u);93 test_lookup_fail(buf);94 }95 96 97}98 99int main(void)100{101 struct dirent *de;102 unsigned int fd, target_fd;103 104 if (unshare(CLONE_FILES) == -1)105 return 1;106 107 /* Wipe fdtable. */108 do {109 DIR *d;110 111 d = opendir("/proc/self/fd");112 if (!d)113 return 1;114 115 de = xreaddir(d);116 assert(de->d_type == DT_DIR);117 assert(streq(de->d_name, "."));118 119 de = xreaddir(d);120 assert(de->d_type == DT_DIR);121 assert(streq(de->d_name, ".."));122next:123 de = xreaddir(d);124 if (de) {125 unsigned long long fd_ull;126 unsigned int fd;127 char *end;128 129 assert(de->d_type == DT_LNK);130 131 fd_ull = xstrtoull(de->d_name, &end);132 assert(*end == '\0');133 assert(fd_ull == (unsigned int)fd_ull);134 135 fd = fd_ull;136 if (fd == dirfd(d))137 goto next;138 close(fd);139 }140 141 closedir(d);142 } while (de);143 144 /* Now fdtable is clean. */145 146 fd = open("/", O_PATH|O_DIRECTORY);147 assert(fd == 0);148 test_lookup(fd);149 close(fd);150 151 /* Clean again! */152 153 fd = open("/", O_PATH|O_DIRECTORY);154 assert(fd == 0);155 /* Default RLIMIT_NOFILE-1 */156 target_fd = 1023;157 while (target_fd > 0) {158 if (dup2(fd, target_fd) == target_fd)159 break;160 target_fd /= 2;161 }162 assert(target_fd > 0);163 close(fd);164 test_lookup(target_fd);165 close(target_fd);166 167 return 0;168}169