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