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 int nsinfo__init(struct nsinfo *nsi) 64 { 65 char oldns[PATH_MAX]; 66 char spath[PATH_MAX]; 67 char *newns = NULL; 68 char *statln = NULL; 69 char *nspid; 70 struct stat old_stat; 71 struct stat new_stat; 72 FILE *f = NULL; 73 size_t linesz = 0; 74 int rv = -1; 75 76 if (snprintf(oldns, PATH_MAX, "/proc/self/ns/mnt") >= PATH_MAX) 77 return rv; 78 79 if (asprintf(&newns, "/proc/%d/ns/mnt", nsi->pid) == -1) 80 return rv; 81 82 if (stat(oldns, &old_stat) < 0) 83 goto out; 84 85 if (stat(newns, &new_stat) < 0) 86 goto out; 87 88 /* Check if the mount namespaces differ, if so then indicate that we 89 * want to switch as part of looking up dso/map data. 90 */ 91 if (old_stat.st_ino != new_stat.st_ino) { 92 nsi->need_setns = true; 93 nsi->mntns_path = newns; 94 newns = NULL; 95 } 96 97 /* If we're dealing with a process that is in a different PID namespace, 98 * attempt to work out the innermost tgid for the process. 99 */ 100 if (snprintf(spath, PATH_MAX, "/proc/%d/status", nsi->pid) >= PATH_MAX) 101 goto out; 102 103 f = fopen(spath, "r"); 104 if (f == NULL) 105 goto out; 106 107 while (getline(&statln, &linesz, f) != -1) { 108 /* Use tgid if CONFIG_PID_NS is not defined. */ 109 if (strstr(statln, "Tgid:") != NULL) { 110 nsi->tgid = (pid_t)strtol(strrchr(statln, '\t'), 111 NULL, 10); 112 nsi->nstgid = nsi->tgid; 113 } 114 115 if (strstr(statln, "NStgid:") != NULL) { 116 nspid = strrchr(statln, '\t'); 117 nsi->nstgid = (pid_t)strtol(nspid, NULL, 10); 118 /* If innermost tgid is not the first, process is in a different 119 * PID namespace. 120 */ 121 nsi->in_pidns = (statln + sizeof("NStgid:") - 1) != nspid; 122 break; 123 } 124 } 125 rv = 0; 126 127 out: 128 if (f != NULL) 129 (void) fclose(f); 130 free(statln); 131 free(newns); 132 return rv; 133 } 134 135 struct nsinfo *nsinfo__new(pid_t pid) 136 { 137 struct nsinfo *nsi; 138 139 if (pid == 0) 140 return NULL; 141 142 nsi = calloc(1, sizeof(*nsi)); 143 if (nsi != NULL) { 144 nsi->pid = pid; 145 nsi->tgid = pid; 146 nsi->nstgid = pid; 147 nsi->need_setns = false; 148 nsi->in_pidns = false; 149 /* Init may fail if the process exits while we're trying to look 150 * at its proc information. In that case, save the pid but 151 * don't try to enter the namespace. 152 */ 153 if (nsinfo__init(nsi) == -1) 154 nsi->need_setns = false; 155 156 refcount_set(&nsi->refcnt, 1); 157 } 158 159 return nsi; 160 } 161 162 struct nsinfo *nsinfo__copy(struct nsinfo *nsi) 163 { 164 struct nsinfo *nnsi; 165 166 if (nsi == NULL) 167 return NULL; 168 169 nnsi = calloc(1, sizeof(*nnsi)); 170 if (nnsi != NULL) { 171 nnsi->pid = nsi->pid; 172 nnsi->tgid = nsi->tgid; 173 nnsi->nstgid = nsi->nstgid; 174 nnsi->need_setns = nsi->need_setns; 175 nnsi->in_pidns = nsi->in_pidns; 176 if (nsi->mntns_path) { 177 nnsi->mntns_path = strdup(nsi->mntns_path); 178 if (!nnsi->mntns_path) { 179 free(nnsi); 180 return NULL; 181 } 182 } 183 refcount_set(&nnsi->refcnt, 1); 184 } 185 186 return nnsi; 187 } 188 189 void nsinfo__delete(struct nsinfo *nsi) 190 { 191 zfree(&nsi->mntns_path); 192 free(nsi); 193 } 194 195 struct nsinfo *nsinfo__get(struct nsinfo *nsi) 196 { 197 if (nsi) 198 refcount_inc(&nsi->refcnt); 199 return nsi; 200 } 201 202 void nsinfo__put(struct nsinfo *nsi) 203 { 204 if (nsi && refcount_dec_and_test(&nsi->refcnt)) 205 nsinfo__delete(nsi); 206 } 207 208 void nsinfo__mountns_enter(struct nsinfo *nsi, 209 struct nscookie *nc) 210 { 211 char curpath[PATH_MAX]; 212 int oldns = -1; 213 int newns = -1; 214 char *oldcwd = NULL; 215 216 if (nc == NULL) 217 return; 218 219 nc->oldns = -1; 220 nc->newns = -1; 221 222 if (!nsi || !nsi->need_setns) 223 return; 224 225 if (snprintf(curpath, PATH_MAX, "/proc/self/ns/mnt") >= PATH_MAX) 226 return; 227 228 oldcwd = get_current_dir_name(); 229 if (!oldcwd) 230 return; 231 232 oldns = open(curpath, O_RDONLY); 233 if (oldns < 0) 234 goto errout; 235 236 newns = open(nsi->mntns_path, O_RDONLY); 237 if (newns < 0) 238 goto errout; 239 240 if (setns(newns, CLONE_NEWNS) < 0) 241 goto errout; 242 243 nc->oldcwd = oldcwd; 244 nc->oldns = oldns; 245 nc->newns = newns; 246 return; 247 248 errout: 249 free(oldcwd); 250 if (oldns > -1) 251 close(oldns); 252 if (newns > -1) 253 close(newns); 254 } 255 256 void nsinfo__mountns_exit(struct nscookie *nc) 257 { 258 if (nc == NULL || nc->oldns == -1 || nc->newns == -1 || !nc->oldcwd) 259 return; 260 261 setns(nc->oldns, CLONE_NEWNS); 262 263 if (nc->oldcwd) { 264 WARN_ON_ONCE(chdir(nc->oldcwd)); 265 zfree(&nc->oldcwd); 266 } 267 268 if (nc->oldns > -1) { 269 close(nc->oldns); 270 nc->oldns = -1; 271 } 272 273 if (nc->newns > -1) { 274 close(nc->newns); 275 nc->newns = -1; 276 } 277 } 278 279 char *nsinfo__realpath(const char *path, struct nsinfo *nsi) 280 { 281 char *rpath; 282 struct nscookie nsc; 283 284 nsinfo__mountns_enter(nsi, &nsc); 285 rpath = realpath(path, NULL); 286 nsinfo__mountns_exit(&nsc); 287 288 return rpath; 289 } 290 291 int nsinfo__stat(const char *filename, struct stat *st, struct nsinfo *nsi) 292 { 293 int ret; 294 struct nscookie nsc; 295 296 nsinfo__mountns_enter(nsi, &nsc); 297 ret = stat(filename, st); 298 nsinfo__mountns_exit(&nsc); 299 300 return ret; 301 } 302