1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * 4 * Copyright (C) 2017 Hari Bathini, IBM Corporation 5 */ 6 7 #include "namespaces.h" 8 #include "event.h" 9 #include "get_current_dir_name.h" 10 #include <sys/types.h> 11 #include <sys/stat.h> 12 #include <fcntl.h> 13 #include <limits.h> 14 #include <sched.h> 15 #include <stdlib.h> 16 #include <stdio.h> 17 #include <string.h> 18 #include <unistd.h> 19 #include <asm/bug.h> 20 #include <linux/kernel.h> 21 #include <linux/zalloc.h> 22 23 static const char *perf_ns__names[] = { 24 [NET_NS_INDEX] = "net", 25 [UTS_NS_INDEX] = "uts", 26 [IPC_NS_INDEX] = "ipc", 27 [PID_NS_INDEX] = "pid", 28 [USER_NS_INDEX] = "user", 29 [MNT_NS_INDEX] = "mnt", 30 [CGROUP_NS_INDEX] = "cgroup", 31 }; 32 33 const char *perf_ns__name(unsigned int id) 34 { 35 if (id >= ARRAY_SIZE(perf_ns__names)) 36 return "UNKNOWN"; 37 return perf_ns__names[id]; 38 } 39 40 struct namespaces *namespaces__new(struct perf_record_namespaces *event) 41 { 42 struct namespaces *namespaces; 43 u64 link_info_size = ((event ? event->nr_namespaces : NR_NAMESPACES) * 44 sizeof(struct perf_ns_link_info)); 45 46 namespaces = zalloc(sizeof(struct namespaces) + link_info_size); 47 if (!namespaces) 48 return NULL; 49 50 namespaces->end_time = -1; 51 52 if (event) 53 memcpy(namespaces->link_info, event->link_info, link_info_size); 54 55 return namespaces; 56 } 57 58 void namespaces__free(struct namespaces *namespaces) 59 { 60 free(namespaces); 61 } 62 63 static int nsinfo__get_nspid(struct nsinfo *nsi, const char *path) 64 { 65 FILE *f = NULL; 66 char *statln = NULL; 67 size_t linesz = 0; 68 char *nspid; 69 70 f = fopen(path, "r"); 71 if (f == NULL) 72 return -1; 73 74 while (getline(&statln, &linesz, f) != -1) { 75 /* Use tgid if CONFIG_PID_NS is not defined. */ 76 if (strstr(statln, "Tgid:") != NULL) { 77 nsi->tgid = (pid_t)strtol(strrchr(statln, '\t'), 78 NULL, 10); 79 nsi->nstgid = nsi->tgid; 80 } 81 82 if (strstr(statln, "NStgid:") != NULL) { 83 nspid = strrchr(statln, '\t'); 84 nsi->nstgid = (pid_t)strtol(nspid, NULL, 10); 85 /* 86 * If innermost tgid is not the first, process is in a different 87 * PID namespace. 88 */ 89 nsi->in_pidns = (statln + sizeof("NStgid:") - 1) != nspid; 90 break; 91 } 92 } 93 94 fclose(f); 95 free(statln); 96 return 0; 97 } 98 99 int nsinfo__init(struct nsinfo *nsi) 100 { 101 char oldns[PATH_MAX]; 102 char spath[PATH_MAX]; 103 char *newns = NULL; 104 struct stat old_stat; 105 struct stat new_stat; 106 int rv = -1; 107 108 if (snprintf(oldns, PATH_MAX, "/proc/self/ns/mnt") >= PATH_MAX) 109 return rv; 110 111 if (asprintf(&newns, "/proc/%d/ns/mnt", nsi->pid) == -1) 112 return rv; 113 114 if (stat(oldns, &old_stat) < 0) 115 goto out; 116 117 if (stat(newns, &new_stat) < 0) 118 goto out; 119 120 /* Check if the mount namespaces differ, if so then indicate that we 121 * want to switch as part of looking up dso/map data. 122 */ 123 if (old_stat.st_ino != new_stat.st_ino) { 124 nsi->need_setns = true; 125 nsi->mntns_path = newns; 126 newns = NULL; 127 } 128 129 /* If we're dealing with a process that is in a different PID namespace, 130 * attempt to work out the innermost tgid for the process. 131 */ 132 if (snprintf(spath, PATH_MAX, "/proc/%d/status", nsi->pid) >= PATH_MAX) 133 goto out; 134 135 rv = nsinfo__get_nspid(nsi, spath); 136 137 out: 138 free(newns); 139 return rv; 140 } 141 142 struct nsinfo *nsinfo__new(pid_t pid) 143 { 144 struct nsinfo *nsi; 145 146 if (pid == 0) 147 return NULL; 148 149 nsi = calloc(1, sizeof(*nsi)); 150 if (nsi != NULL) { 151 nsi->pid = pid; 152 nsi->tgid = pid; 153 nsi->nstgid = pid; 154 nsi->need_setns = false; 155 nsi->in_pidns = false; 156 /* Init may fail if the process exits while we're trying to look 157 * at its proc information. In that case, save the pid but 158 * don't try to enter the namespace. 159 */ 160 if (nsinfo__init(nsi) == -1) 161 nsi->need_setns = false; 162 163 refcount_set(&nsi->refcnt, 1); 164 } 165 166 return nsi; 167 } 168 169 struct nsinfo *nsinfo__copy(struct nsinfo *nsi) 170 { 171 struct nsinfo *nnsi; 172 173 if (nsi == NULL) 174 return NULL; 175 176 nnsi = calloc(1, sizeof(*nnsi)); 177 if (nnsi != NULL) { 178 nnsi->pid = nsi->pid; 179 nnsi->tgid = nsi->tgid; 180 nnsi->nstgid = nsi->nstgid; 181 nnsi->need_setns = nsi->need_setns; 182 nnsi->in_pidns = nsi->in_pidns; 183 if (nsi->mntns_path) { 184 nnsi->mntns_path = strdup(nsi->mntns_path); 185 if (!nnsi->mntns_path) { 186 free(nnsi); 187 return NULL; 188 } 189 } 190 refcount_set(&nnsi->refcnt, 1); 191 } 192 193 return nnsi; 194 } 195 196 void nsinfo__delete(struct nsinfo *nsi) 197 { 198 zfree(&nsi->mntns_path); 199 free(nsi); 200 } 201 202 struct nsinfo *nsinfo__get(struct nsinfo *nsi) 203 { 204 if (nsi) 205 refcount_inc(&nsi->refcnt); 206 return nsi; 207 } 208 209 void nsinfo__put(struct nsinfo *nsi) 210 { 211 if (nsi && refcount_dec_and_test(&nsi->refcnt)) 212 nsinfo__delete(nsi); 213 } 214 215 void nsinfo__mountns_enter(struct nsinfo *nsi, 216 struct nscookie *nc) 217 { 218 char curpath[PATH_MAX]; 219 int oldns = -1; 220 int newns = -1; 221 char *oldcwd = NULL; 222 223 if (nc == NULL) 224 return; 225 226 nc->oldns = -1; 227 nc->newns = -1; 228 229 if (!nsi || !nsi->need_setns) 230 return; 231 232 if (snprintf(curpath, PATH_MAX, "/proc/self/ns/mnt") >= PATH_MAX) 233 return; 234 235 oldcwd = get_current_dir_name(); 236 if (!oldcwd) 237 return; 238 239 oldns = open(curpath, O_RDONLY); 240 if (oldns < 0) 241 goto errout; 242 243 newns = open(nsi->mntns_path, O_RDONLY); 244 if (newns < 0) 245 goto errout; 246 247 if (setns(newns, CLONE_NEWNS) < 0) 248 goto errout; 249 250 nc->oldcwd = oldcwd; 251 nc->oldns = oldns; 252 nc->newns = newns; 253 return; 254 255 errout: 256 free(oldcwd); 257 if (oldns > -1) 258 close(oldns); 259 if (newns > -1) 260 close(newns); 261 } 262 263 void nsinfo__mountns_exit(struct nscookie *nc) 264 { 265 if (nc == NULL || nc->oldns == -1 || nc->newns == -1 || !nc->oldcwd) 266 return; 267 268 setns(nc->oldns, CLONE_NEWNS); 269 270 if (nc->oldcwd) { 271 WARN_ON_ONCE(chdir(nc->oldcwd)); 272 zfree(&nc->oldcwd); 273 } 274 275 if (nc->oldns > -1) { 276 close(nc->oldns); 277 nc->oldns = -1; 278 } 279 280 if (nc->newns > -1) { 281 close(nc->newns); 282 nc->newns = -1; 283 } 284 } 285 286 char *nsinfo__realpath(const char *path, struct nsinfo *nsi) 287 { 288 char *rpath; 289 struct nscookie nsc; 290 291 nsinfo__mountns_enter(nsi, &nsc); 292 rpath = realpath(path, NULL); 293 nsinfo__mountns_exit(&nsc); 294 295 return rpath; 296 } 297 298 int nsinfo__stat(const char *filename, struct stat *st, struct nsinfo *nsi) 299 { 300 int ret; 301 struct nscookie nsc; 302 303 nsinfo__mountns_enter(nsi, &nsc); 304 ret = stat(filename, st); 305 nsinfo__mountns_exit(&nsc); 306 307 return ret; 308 } 309 310 bool nsinfo__is_in_root_namespace(void) 311 { 312 struct nsinfo nsi; 313 314 memset(&nsi, 0x0, sizeof(nsi)); 315 nsinfo__get_nspid(&nsi, "/proc/self/status"); 316 return !nsi.in_pidns; 317 } 318