blob: 285d6f30d9129095e4d9fa40ebc508650ccd5516 [file] [log] [blame]
Thomas Gleixnerd2912cb2019-06-04 10:11:33 +02001// SPDX-License-Identifier: GPL-2.0-only
Hari Bathinif3b36142017-03-08 02:11:43 +05302/*
Hari Bathinif3b36142017-03-08 02:11:43 +05303 *
4 * Copyright (C) 2017 Hari Bathini, IBM Corporation
5 */
6
7#include "namespaces.h"
Hari Bathinif3b36142017-03-08 02:11:43 +05308#include "event.h"
Arnaldo Carvalho de Meloe5653eb2019-07-05 14:16:15 -03009#include "get_current_dir_name.h"
Krister Johansen843ff372017-07-05 18:48:08 -070010#include <sys/types.h>
11#include <sys/stat.h>
Arnaldo Carvalho de Meloc23c2a02017-09-11 10:50:26 -030012#include <fcntl.h>
Krister Johansen544abd42017-07-05 18:48:10 -070013#include <limits.h>
Krister Johansen843ff372017-07-05 18:48:08 -070014#include <sched.h>
Hari Bathinif3b36142017-03-08 02:11:43 +053015#include <stdlib.h>
16#include <stdio.h>
Arnaldo Carvalho de Melo72f7c4d2017-04-19 19:06:30 -030017#include <string.h>
Krister Johansen843ff372017-07-05 18:48:08 -070018#include <unistd.h>
Jiri Olsab01c1f692018-11-01 18:00:01 +010019#include <asm/bug.h>
Arnaldo Carvalho de Melo055c67e2019-09-18 16:08:52 -030020#include <linux/kernel.h>
Arnaldo Carvalho de Melo7f7c5362019-07-04 11:32:27 -030021#include <linux/zalloc.h>
Hari Bathinif3b36142017-03-08 02:11:43 +053022
Arnaldo Carvalho de Melo055c67e2019-09-18 16:08:52 -030023static 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
33const 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
Arnaldo Carvalho de Melo69d81f02019-08-26 19:02:31 -030040struct namespaces *namespaces__new(struct perf_record_namespaces *event)
Hari Bathinif3b36142017-03-08 02:11:43 +053041{
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
58void namespaces__free(struct namespaces *namespaces)
59{
60 free(namespaces);
61}
Krister Johansen843ff372017-07-05 18:48:08 -070062
Krister Johansenbf2e7102017-07-05 18:48:09 -070063int nsinfo__init(struct nsinfo *nsi)
Krister Johansen843ff372017-07-05 18:48:08 -070064{
65 char oldns[PATH_MAX];
Krister Johansenbf2e7102017-07-05 18:48:09 -070066 char spath[PATH_MAX];
Krister Johansen843ff372017-07-05 18:48:08 -070067 char *newns = NULL;
Krister Johansenbf2e7102017-07-05 18:48:09 -070068 char *statln = NULL;
Krister Johansen843ff372017-07-05 18:48:08 -070069 struct stat old_stat;
70 struct stat new_stat;
Krister Johansenbf2e7102017-07-05 18:48:09 -070071 FILE *f = NULL;
72 size_t linesz = 0;
73 int rv = -1;
Krister Johansen843ff372017-07-05 18:48:08 -070074
75 if (snprintf(oldns, PATH_MAX, "/proc/self/ns/mnt") >= PATH_MAX)
Krister Johansenbf2e7102017-07-05 18:48:09 -070076 return rv;
Krister Johansen843ff372017-07-05 18:48:08 -070077
78 if (asprintf(&newns, "/proc/%d/ns/mnt", nsi->pid) == -1)
Krister Johansenbf2e7102017-07-05 18:48:09 -070079 return rv;
Krister Johansen843ff372017-07-05 18:48:08 -070080
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
Krister Johansenbf2e7102017-07-05 18:48:09 -070096 /* 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
Krister Johansen843ff372017-07-05 18:48:08 -0700122out:
Krister Johansenbf2e7102017-07-05 18:48:09 -0700123 if (f != NULL)
124 (void) fclose(f);
125 free(statln);
Krister Johansen843ff372017-07-05 18:48:08 -0700126 free(newns);
Krister Johansenbf2e7102017-07-05 18:48:09 -0700127 return rv;
Krister Johansen843ff372017-07-05 18:48:08 -0700128}
129
130struct nsinfo *nsinfo__new(pid_t pid)
131{
Krister Johansenbf2e7102017-07-05 18:48:09 -0700132 struct nsinfo *nsi;
Krister Johansen843ff372017-07-05 18:48:08 -0700133
Krister Johansenbf2e7102017-07-05 18:48:09 -0700134 if (pid == 0)
135 return NULL;
136
137 nsi = calloc(1, sizeof(*nsi));
Krister Johansen843ff372017-07-05 18:48:08 -0700138 if (nsi != NULL) {
139 nsi->pid = pid;
Krister Johansenbf2e7102017-07-05 18:48:09 -0700140 nsi->tgid = pid;
141 nsi->nstgid = pid;
Krister Johansen843ff372017-07-05 18:48:08 -0700142 nsi->need_setns = false;
Krister Johansenbf2e7102017-07-05 18:48:09 -0700143 /* 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
Krister Johansen843ff372017-07-05 18:48:08 -0700150 refcount_set(&nsi->refcnt, 1);
151 }
152
153 return nsi;
154}
155
Krister Johansenbf2e7102017-07-05 18:48:09 -0700156struct nsinfo *nsinfo__copy(struct nsinfo *nsi)
157{
158 struct nsinfo *nnsi;
159
Benno Evers3f4417d2018-08-10 15:36:13 +0200160 if (nsi == NULL)
161 return NULL;
162
Krister Johansenbf2e7102017-07-05 18:48:09 -0700163 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
Krister Johansen843ff372017-07-05 18:48:08 -0700182void nsinfo__delete(struct nsinfo *nsi)
183{
184 zfree(&nsi->mntns_path);
185 free(nsi);
186}
187
188struct nsinfo *nsinfo__get(struct nsinfo *nsi)
189{
190 if (nsi)
191 refcount_inc(&nsi->refcnt);
192 return nsi;
193}
194
195void nsinfo__put(struct nsinfo *nsi)
196{
197 if (nsi && refcount_dec_and_test(&nsi->refcnt))
198 nsinfo__delete(nsi);
199}
200
Krister Johansenbf2e7102017-07-05 18:48:09 -0700201void nsinfo__mountns_enter(struct nsinfo *nsi,
202 struct nscookie *nc)
Krister Johansen843ff372017-07-05 18:48:08 -0700203{
204 char curpath[PATH_MAX];
205 int oldns = -1;
206 int newns = -1;
Jiri Olsab01c1f692018-11-01 18:00:01 +0100207 char *oldcwd = NULL;
Krister Johansen843ff372017-07-05 18:48:08 -0700208
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
Jiri Olsab01c1f692018-11-01 18:00:01 +0100221 oldcwd = get_current_dir_name();
222 if (!oldcwd)
223 return;
224
Krister Johansen843ff372017-07-05 18:48:08 -0700225 oldns = open(curpath, O_RDONLY);
226 if (oldns < 0)
Jiri Olsab01c1f692018-11-01 18:00:01 +0100227 goto errout;
Krister Johansen843ff372017-07-05 18:48:08 -0700228
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
Jiri Olsab01c1f692018-11-01 18:00:01 +0100236 nc->oldcwd = oldcwd;
Krister Johansen843ff372017-07-05 18:48:08 -0700237 nc->oldns = oldns;
238 nc->newns = newns;
239 return;
240
241errout:
Jiri Olsab01c1f692018-11-01 18:00:01 +0100242 free(oldcwd);
Krister Johansen843ff372017-07-05 18:48:08 -0700243 if (oldns > -1)
244 close(oldns);
245 if (newns > -1)
246 close(newns);
247}
248
249void nsinfo__mountns_exit(struct nscookie *nc)
250{
Jiri Olsab01c1f692018-11-01 18:00:01 +0100251 if (nc == NULL || nc->oldns == -1 || nc->newns == -1 || !nc->oldcwd)
Krister Johansen843ff372017-07-05 18:48:08 -0700252 return;
253
254 setns(nc->oldns, CLONE_NEWNS);
255
Jiri Olsab01c1f692018-11-01 18:00:01 +0100256 if (nc->oldcwd) {
257 WARN_ON_ONCE(chdir(nc->oldcwd));
258 zfree(&nc->oldcwd);
259 }
260
Krister Johansen843ff372017-07-05 18:48:08 -0700261 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}
Krister Johansen544abd42017-07-05 18:48:10 -0700271
272char *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}