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
perf_ns__name(unsigned int id)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
namespaces__new(struct perf_record_namespaces * event)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
namespaces__free(struct namespaces * namespaces)58 void namespaces__free(struct namespaces *namespaces)
59 {
60 free(namespaces);
61 }
62
nsinfo__get_nspid(struct nsinfo * nsi,const char * path)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 = nsinfo__tgid(nsi);
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
nsinfo__init(struct nsinfo * nsi)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", nsinfo__pid(nsi)) == -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", nsinfo__pid(nsi)) >= PATH_MAX)
133 goto out;
134
135 rv = nsinfo__get_nspid(nsi, spath);
136
137 out:
138 free(newns);
139 return rv;
140 }
141
nsinfo__new(pid_t pid)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
nsinfo__copy(const struct nsinfo * nsi)169 struct nsinfo *nsinfo__copy(const 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 = nsinfo__pid(nsi);
179 nnsi->tgid = nsinfo__tgid(nsi);
180 nnsi->nstgid = nsinfo__nstgid(nsi);
181 nnsi->need_setns = nsinfo__need_setns(nsi);
182 nnsi->in_pidns = nsinfo__in_pidns(nsi);
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
nsinfo__delete(struct nsinfo * nsi)196 static void nsinfo__delete(struct nsinfo *nsi)
197 {
198 zfree(&nsi->mntns_path);
199 free(nsi);
200 }
201
nsinfo__get(struct nsinfo * nsi)202 struct nsinfo *nsinfo__get(struct nsinfo *nsi)
203 {
204 if (nsi)
205 refcount_inc(&nsi->refcnt);
206 return nsi;
207 }
208
nsinfo__put(struct nsinfo * nsi)209 void nsinfo__put(struct nsinfo *nsi)
210 {
211 if (nsi && refcount_dec_and_test(&nsi->refcnt))
212 nsinfo__delete(nsi);
213 }
214
nsinfo__need_setns(const struct nsinfo * nsi)215 bool nsinfo__need_setns(const struct nsinfo *nsi)
216 {
217 return nsi->need_setns;
218 }
219
nsinfo__clear_need_setns(struct nsinfo * nsi)220 void nsinfo__clear_need_setns(struct nsinfo *nsi)
221 {
222 nsi->need_setns = false;
223 }
224
nsinfo__tgid(const struct nsinfo * nsi)225 pid_t nsinfo__tgid(const struct nsinfo *nsi)
226 {
227 return nsi->tgid;
228 }
229
nsinfo__nstgid(const struct nsinfo * nsi)230 pid_t nsinfo__nstgid(const struct nsinfo *nsi)
231 {
232 return nsi->nstgid;
233 }
234
nsinfo__pid(const struct nsinfo * nsi)235 pid_t nsinfo__pid(const struct nsinfo *nsi)
236 {
237 return nsi->pid;
238 }
239
nsinfo__in_pidns(const struct nsinfo * nsi)240 pid_t nsinfo__in_pidns(const struct nsinfo *nsi)
241 {
242 return nsi->in_pidns;
243 }
244
nsinfo__mountns_enter(struct nsinfo * nsi,struct nscookie * nc)245 void nsinfo__mountns_enter(struct nsinfo *nsi,
246 struct nscookie *nc)
247 {
248 char curpath[PATH_MAX];
249 int oldns = -1;
250 int newns = -1;
251 char *oldcwd = NULL;
252
253 if (nc == NULL)
254 return;
255
256 nc->oldns = -1;
257 nc->newns = -1;
258
259 if (!nsi || !nsi->need_setns)
260 return;
261
262 if (snprintf(curpath, PATH_MAX, "/proc/self/ns/mnt") >= PATH_MAX)
263 return;
264
265 oldcwd = get_current_dir_name();
266 if (!oldcwd)
267 return;
268
269 oldns = open(curpath, O_RDONLY);
270 if (oldns < 0)
271 goto errout;
272
273 newns = open(nsi->mntns_path, O_RDONLY);
274 if (newns < 0)
275 goto errout;
276
277 if (setns(newns, CLONE_NEWNS) < 0)
278 goto errout;
279
280 nc->oldcwd = oldcwd;
281 nc->oldns = oldns;
282 nc->newns = newns;
283 return;
284
285 errout:
286 free(oldcwd);
287 if (oldns > -1)
288 close(oldns);
289 if (newns > -1)
290 close(newns);
291 }
292
nsinfo__mountns_exit(struct nscookie * nc)293 void nsinfo__mountns_exit(struct nscookie *nc)
294 {
295 if (nc == NULL || nc->oldns == -1 || nc->newns == -1 || !nc->oldcwd)
296 return;
297
298 setns(nc->oldns, CLONE_NEWNS);
299
300 if (nc->oldcwd) {
301 WARN_ON_ONCE(chdir(nc->oldcwd));
302 zfree(&nc->oldcwd);
303 }
304
305 if (nc->oldns > -1) {
306 close(nc->oldns);
307 nc->oldns = -1;
308 }
309
310 if (nc->newns > -1) {
311 close(nc->newns);
312 nc->newns = -1;
313 }
314 }
315
nsinfo__realpath(const char * path,struct nsinfo * nsi)316 char *nsinfo__realpath(const char *path, struct nsinfo *nsi)
317 {
318 char *rpath;
319 struct nscookie nsc;
320
321 nsinfo__mountns_enter(nsi, &nsc);
322 rpath = realpath(path, NULL);
323 nsinfo__mountns_exit(&nsc);
324
325 return rpath;
326 }
327
nsinfo__stat(const char * filename,struct stat * st,struct nsinfo * nsi)328 int nsinfo__stat(const char *filename, struct stat *st, struct nsinfo *nsi)
329 {
330 int ret;
331 struct nscookie nsc;
332
333 nsinfo__mountns_enter(nsi, &nsc);
334 ret = stat(filename, st);
335 nsinfo__mountns_exit(&nsc);
336
337 return ret;
338 }
339
nsinfo__is_in_root_namespace(void)340 bool nsinfo__is_in_root_namespace(void)
341 {
342 struct nsinfo nsi;
343
344 memset(&nsi, 0x0, sizeof(nsi));
345 nsinfo__get_nspid(&nsi, "/proc/self/status");
346 return !nsi.in_pidns;
347 }
348