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