| 1 | /* |
| 2 | * Copyright (C) 2019 Michael Jeanson <mjeanson@efficios.com> |
| 3 | * |
| 4 | * This library is free software; you can redistribute it and/or modify it |
| 5 | * under the terms of the GNU Lesser General Public License as published by the |
| 6 | * Free Software Foundation; version 2.1 of the License. |
| 7 | * |
| 8 | * This library is distributed in the hope that it will be useful, but WITHOUT |
| 9 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 10 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License |
| 11 | * for more details. |
| 12 | * |
| 13 | * You should have received a copy of the GNU Lesser General Public License |
| 14 | * along with this library; if not, write to the Free Software Foundation, |
| 15 | * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 16 | */ |
| 17 | |
| 18 | #ifndef _GNU_SOURCE |
| 19 | #define _GNU_SOURCE |
| 20 | #endif |
| 21 | |
| 22 | #include <popt.h> |
| 23 | #include <sched.h> |
| 24 | #include <stdarg.h> |
| 25 | #include <stdio.h> |
| 26 | #include <stdlib.h> |
| 27 | #include <string.h> |
| 28 | #include <sys/stat.h> |
| 29 | #include <sys/types.h> |
| 30 | #include <unistd.h> |
| 31 | |
| 32 | #include <common/compat/tid.h> |
| 33 | |
| 34 | #include "signal-helper.h" |
| 35 | #include "utils.h" |
| 36 | |
| 37 | #define LTTNG_PROC_NS_PATH_MAX 40 |
| 38 | |
| 39 | static int debug = 0; |
| 40 | static char *ns_opt = NULL; |
| 41 | static char *before_unshare_wait_file_path = NULL; |
| 42 | static char *after_unshare_wait_file_path = NULL; |
| 43 | static char *after_unshare_signal_file_path = NULL; |
| 44 | |
| 45 | static struct poptOption opts[] = { |
| 46 | /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */ |
| 47 | { "debug", 'd', POPT_ARG_NONE, &debug, 0, "Enable debug output", NULL }, |
| 48 | { "ns", 'n', POPT_ARG_STRING, &ns_opt, 0, "Namespace short identifier", NULL }, |
| 49 | { "before", 'b', POPT_ARG_STRING, &before_unshare_wait_file_path, 0, "Wait for file before unshare", NULL }, |
| 50 | { "after", 'a', POPT_ARG_STRING, &after_unshare_wait_file_path, 0, "Wait for file after unshare", NULL }, |
| 51 | { "signal", 's', POPT_ARG_STRING, &after_unshare_signal_file_path, 0, "Create signal file after unshare", NULL }, |
| 52 | POPT_AUTOHELP |
| 53 | { NULL, 0, 0, NULL, 0 } |
| 54 | }; |
| 55 | |
| 56 | static void debug_printf(const char *format, ...) |
| 57 | { |
| 58 | va_list args; |
| 59 | va_start(args, format); |
| 60 | |
| 61 | if (debug) { |
| 62 | vfprintf(stderr, format, args); |
| 63 | } |
| 64 | |
| 65 | va_end(args); |
| 66 | } |
| 67 | |
| 68 | static int get_ns_inum(const char *ns, ino_t *ns_inum) |
| 69 | { |
| 70 | int ret = 0; |
| 71 | struct stat sb; |
| 72 | char proc_ns_path[LTTNG_PROC_NS_PATH_MAX]; |
| 73 | |
| 74 | /* |
| 75 | * /proc/thread-self was introduced in kernel v3.17 |
| 76 | */ |
| 77 | if (snprintf(proc_ns_path, LTTNG_PROC_NS_PATH_MAX, |
| 78 | "/proc/thread-self/ns/%s", ns) >= 0) { |
| 79 | if (stat(proc_ns_path, &sb) == 0) { |
| 80 | *ns_inum = sb.st_ino; |
| 81 | } else { |
| 82 | ret = -1; |
| 83 | } |
| 84 | goto end; |
| 85 | } |
| 86 | |
| 87 | if (snprintf(proc_ns_path, LTTNG_PROC_NS_PATH_MAX, |
| 88 | "/proc/self/task/%d/%s/net", lttng_gettid(), ns) >= 0) { |
| 89 | if (stat(proc_ns_path, &sb) == 0) { |
| 90 | *ns_inum = sb.st_ino; |
| 91 | } else { |
| 92 | ret = -1; |
| 93 | } |
| 94 | goto end; |
| 95 | } |
| 96 | end: |
| 97 | return ret; |
| 98 | } |
| 99 | |
| 100 | static int do_the_needful(int ns_flag, const char *ns_str) |
| 101 | { |
| 102 | int ret = 0; |
| 103 | ino_t ns1, ns2; |
| 104 | |
| 105 | ret = get_ns_inum(ns_str, &ns1); |
| 106 | if (ret) { |
| 107 | debug_printf("Failed to get ns inode number for namespace %s", |
| 108 | ns_str); |
| 109 | ret = -1; |
| 110 | goto end; |
| 111 | } |
| 112 | debug_printf("Initial %s ns inode number: %lu\n", ns_str, ns1); |
| 113 | |
| 114 | /* Wait on synchronization before unshare. */ |
| 115 | if (before_unshare_wait_file_path) { |
| 116 | ret = wait_on_file(before_unshare_wait_file_path); |
| 117 | if (ret != 0) { |
| 118 | goto end; |
| 119 | } |
| 120 | } |
| 121 | |
| 122 | ret = unshare(ns_flag); |
| 123 | if (ret == -1) { |
| 124 | perror("Failed to unshare namespace"); |
| 125 | goto end; |
| 126 | } |
| 127 | |
| 128 | ret = get_ns_inum(ns_str, &ns2); |
| 129 | if (ret) { |
| 130 | debug_printf("Failed to get ns inode number for namespace %s", |
| 131 | ns_str); |
| 132 | ret = -1; |
| 133 | goto end; |
| 134 | } |
| 135 | debug_printf("Post unshare %s ns inode number: %lu\n", ns_str, ns2); |
| 136 | |
| 137 | /* Signal that the unshare call is completed. */ |
| 138 | if (after_unshare_signal_file_path) { |
| 139 | ret = create_file(after_unshare_signal_file_path); |
| 140 | if (ret != 0) { |
| 141 | goto end; |
| 142 | } |
| 143 | } |
| 144 | |
| 145 | /* Wait on synchronization after unshare. */ |
| 146 | if (after_unshare_wait_file_path) { |
| 147 | ret = wait_on_file(after_unshare_wait_file_path); |
| 148 | if (ret != 0) { |
| 149 | goto end; |
| 150 | } |
| 151 | } |
| 152 | |
| 153 | end: |
| 154 | return ret; |
| 155 | } |
| 156 | |
| 157 | int main(int argc, const char **argv) |
| 158 | { |
| 159 | int opt; |
| 160 | int ret = EXIT_SUCCESS; |
| 161 | poptContext pc; |
| 162 | |
| 163 | pc = poptGetContext(NULL, argc, argv, opts, 0); |
| 164 | poptReadDefaultConfig(pc, 0); |
| 165 | |
| 166 | if (argc < 2) { |
| 167 | poptPrintHelp(pc, stderr, 0); |
| 168 | ret = EXIT_FAILURE; |
| 169 | goto end; |
| 170 | } |
| 171 | |
| 172 | while ((opt = poptGetNextOpt(pc)) >= 0) { |
| 173 | switch (opt) { |
| 174 | default: |
| 175 | poptPrintUsage(pc, stderr, 0); |
| 176 | ret = EXIT_FAILURE; |
| 177 | goto end; |
| 178 | } |
| 179 | } |
| 180 | |
| 181 | if (opt < -1) { |
| 182 | /* an error occurred during option processing */ |
| 183 | poptPrintUsage(pc, stderr, 0); |
| 184 | fprintf(stderr, "%s: %s\n", |
| 185 | poptBadOption(pc, POPT_BADOPTION_NOALIAS), |
| 186 | poptStrerror(opt)); |
| 187 | ret = EXIT_FAILURE; |
| 188 | goto end; |
| 189 | } |
| 190 | |
| 191 | if (ns_opt == NULL) { |
| 192 | poptPrintUsage(pc, stderr, 0); |
| 193 | ret = EXIT_FAILURE; |
| 194 | goto end; |
| 195 | } |
| 196 | |
| 197 | if (set_signal_handler()) { |
| 198 | ret = EXIT_FAILURE; |
| 199 | goto end; |
| 200 | } |
| 201 | |
| 202 | if (strncmp(ns_opt, "cgroup", 3) == 0) { |
| 203 | ret = do_the_needful(CLONE_NEWCGROUP, "cgroup"); |
| 204 | } else if (strncmp(ns_opt, "ipc", 3) == 0) { |
| 205 | ret = do_the_needful(CLONE_NEWIPC, "ipc"); |
| 206 | } else if (strncmp(ns_opt, "mnt", 3) == 0) { |
| 207 | ret = do_the_needful(CLONE_NEWNS, "mnt"); |
| 208 | } else if (strncmp(ns_opt, "net", 3) == 0) { |
| 209 | ret = do_the_needful(CLONE_NEWNET, "net"); |
| 210 | } else if (strncmp(ns_opt, "pid", 3) == 0) { |
| 211 | ret = do_the_needful(CLONE_NEWPID, "pid"); |
| 212 | } else if (strncmp(ns_opt, "user", 3) == 0) { |
| 213 | /* |
| 214 | * Will always fail, requires a single threaded application, |
| 215 | * which can't happen with UST. |
| 216 | */ |
| 217 | ret = do_the_needful(CLONE_NEWUSER, "user"); |
| 218 | } else if (strncmp(ns_opt, "uts", 3) == 0) { |
| 219 | ret = do_the_needful(CLONE_NEWUTS, "uts"); |
| 220 | } else { |
| 221 | printf("invalid ns id\n"); |
| 222 | ret = EXIT_FAILURE; |
| 223 | goto end; |
| 224 | } |
| 225 | ret = ret ? EXIT_FAILURE : EXIT_SUCCESS; |
| 226 | end: |
| 227 | poptFreeContext(pc); |
| 228 | return ret; |
| 229 | } |