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TOMOYO Linux Cross Reference
Linux/tools/perf/util/namespaces.c

Version: ~ [ linux-5.1-rc1 ] ~ [ linux-5.0.2 ] ~ [ linux-4.20.16 ] ~ [ linux-4.19.29 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.106 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.163 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.176 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.136 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.63 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.39.4 ] ~ [ linux-2.6.38.8 ] ~ [ linux-2.6.37.6 ] ~ [ linux-2.6.36.4 ] ~ [ linux-2.6.35.14 ] ~ [ linux-2.6.34.15 ] ~ [ linux-2.6.33.20 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
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  1 /*
  2  * This program is free software; you can redistribute it and/or modify
  3  * it under the terms of the GNU General Public License, version 2, as
  4  * published by the Free Software Foundation.
  5  *
  6  * Copyright (C) 2017 Hari Bathini, IBM Corporation
  7  */
  8 
  9 #include "namespaces.h"
 10 #include "util.h"
 11 #include "event.h"
 12 #include <sys/types.h>
 13 #include <sys/stat.h>
 14 #include <fcntl.h>
 15 #include <limits.h>
 16 #include <sched.h>
 17 #include <stdlib.h>
 18 #include <stdio.h>
 19 #include <string.h>
 20 #include <unistd.h>
 21 #include <asm/bug.h>
 22 
 23 struct namespaces *namespaces__new(struct namespaces_event *event)
 24 {
 25         struct namespaces *namespaces;
 26         u64 link_info_size = ((event ? event->nr_namespaces : NR_NAMESPACES) *
 27                               sizeof(struct perf_ns_link_info));
 28 
 29         namespaces = zalloc(sizeof(struct namespaces) + link_info_size);
 30         if (!namespaces)
 31                 return NULL;
 32 
 33         namespaces->end_time = -1;
 34 
 35         if (event)
 36                 memcpy(namespaces->link_info, event->link_info, link_info_size);
 37 
 38         return namespaces;
 39 }
 40 
 41 void namespaces__free(struct namespaces *namespaces)
 42 {
 43         free(namespaces);
 44 }
 45 
 46 int nsinfo__init(struct nsinfo *nsi)
 47 {
 48         char oldns[PATH_MAX];
 49         char spath[PATH_MAX];
 50         char *newns = NULL;
 51         char *statln = NULL;
 52         struct stat old_stat;
 53         struct stat new_stat;
 54         FILE *f = NULL;
 55         size_t linesz = 0;
 56         int rv = -1;
 57 
 58         if (snprintf(oldns, PATH_MAX, "/proc/self/ns/mnt") >= PATH_MAX)
 59                 return rv;
 60 
 61         if (asprintf(&newns, "/proc/%d/ns/mnt", nsi->pid) == -1)
 62                 return rv;
 63 
 64         if (stat(oldns, &old_stat) < 0)
 65                 goto out;
 66 
 67         if (stat(newns, &new_stat) < 0)
 68                 goto out;
 69 
 70         /* Check if the mount namespaces differ, if so then indicate that we
 71          * want to switch as part of looking up dso/map data.
 72          */
 73         if (old_stat.st_ino != new_stat.st_ino) {
 74                 nsi->need_setns = true;
 75                 nsi->mntns_path = newns;
 76                 newns = NULL;
 77         }
 78 
 79         /* If we're dealing with a process that is in a different PID namespace,
 80          * attempt to work out the innermost tgid for the process.
 81          */
 82         if (snprintf(spath, PATH_MAX, "/proc/%d/status", nsi->pid) >= PATH_MAX)
 83                 goto out;
 84 
 85         f = fopen(spath, "r");
 86         if (f == NULL)
 87                 goto out;
 88 
 89         while (getline(&statln, &linesz, f) != -1) {
 90                 /* Use tgid if CONFIG_PID_NS is not defined. */
 91                 if (strstr(statln, "Tgid:") != NULL) {
 92                         nsi->tgid = (pid_t)strtol(strrchr(statln, '\t'),
 93                                                      NULL, 10);
 94                         nsi->nstgid = nsi->tgid;
 95                 }
 96 
 97                 if (strstr(statln, "NStgid:") != NULL) {
 98                         nsi->nstgid = (pid_t)strtol(strrchr(statln, '\t'),
 99                                                      NULL, 10);
100                         break;
101                 }
102         }
103         rv = 0;
104 
105 out:
106         if (f != NULL)
107                 (void) fclose(f);
108         free(statln);
109         free(newns);
110         return rv;
111 }
112 
113 struct nsinfo *nsinfo__new(pid_t pid)
114 {
115         struct nsinfo *nsi;
116 
117         if (pid == 0)
118                 return NULL;
119 
120         nsi = calloc(1, sizeof(*nsi));
121         if (nsi != NULL) {
122                 nsi->pid = pid;
123                 nsi->tgid = pid;
124                 nsi->nstgid = pid;
125                 nsi->need_setns = false;
126                 /* Init may fail if the process exits while we're trying to look
127                  * at its proc information.  In that case, save the pid but
128                  * don't try to enter the namespace.
129                  */
130                 if (nsinfo__init(nsi) == -1)
131                         nsi->need_setns = false;
132 
133                 refcount_set(&nsi->refcnt, 1);
134         }
135 
136         return nsi;
137 }
138 
139 struct nsinfo *nsinfo__copy(struct nsinfo *nsi)
140 {
141         struct nsinfo *nnsi;
142 
143         if (nsi == NULL)
144                 return NULL;
145 
146         nnsi = calloc(1, sizeof(*nnsi));
147         if (nnsi != NULL) {
148                 nnsi->pid = nsi->pid;
149                 nnsi->tgid = nsi->tgid;
150                 nnsi->nstgid = nsi->nstgid;
151                 nnsi->need_setns = nsi->need_setns;
152                 if (nsi->mntns_path) {
153                         nnsi->mntns_path = strdup(nsi->mntns_path);
154                         if (!nnsi->mntns_path) {
155                                 free(nnsi);
156                                 return NULL;
157                         }
158                 }
159                 refcount_set(&nnsi->refcnt, 1);
160         }
161 
162         return nnsi;
163 }
164 
165 void nsinfo__delete(struct nsinfo *nsi)
166 {
167         zfree(&nsi->mntns_path);
168         free(nsi);
169 }
170 
171 struct nsinfo *nsinfo__get(struct nsinfo *nsi)
172 {
173         if (nsi)
174                 refcount_inc(&nsi->refcnt);
175         return nsi;
176 }
177 
178 void nsinfo__put(struct nsinfo *nsi)
179 {
180         if (nsi && refcount_dec_and_test(&nsi->refcnt))
181                 nsinfo__delete(nsi);
182 }
183 
184 void nsinfo__mountns_enter(struct nsinfo *nsi,
185                                   struct nscookie *nc)
186 {
187         char curpath[PATH_MAX];
188         int oldns = -1;
189         int newns = -1;
190         char *oldcwd = NULL;
191 
192         if (nc == NULL)
193                 return;
194 
195         nc->oldns = -1;
196         nc->newns = -1;
197 
198         if (!nsi || !nsi->need_setns)
199                 return;
200 
201         if (snprintf(curpath, PATH_MAX, "/proc/self/ns/mnt") >= PATH_MAX)
202                 return;
203 
204         oldcwd = get_current_dir_name();
205         if (!oldcwd)
206                 return;
207 
208         oldns = open(curpath, O_RDONLY);
209         if (oldns < 0)
210                 goto errout;
211 
212         newns = open(nsi->mntns_path, O_RDONLY);
213         if (newns < 0)
214                 goto errout;
215 
216         if (setns(newns, CLONE_NEWNS) < 0)
217                 goto errout;
218 
219         nc->oldcwd = oldcwd;
220         nc->oldns = oldns;
221         nc->newns = newns;
222         return;
223 
224 errout:
225         free(oldcwd);
226         if (oldns > -1)
227                 close(oldns);
228         if (newns > -1)
229                 close(newns);
230 }
231 
232 void nsinfo__mountns_exit(struct nscookie *nc)
233 {
234         if (nc == NULL || nc->oldns == -1 || nc->newns == -1 || !nc->oldcwd)
235                 return;
236 
237         setns(nc->oldns, CLONE_NEWNS);
238 
239         if (nc->oldcwd) {
240                 WARN_ON_ONCE(chdir(nc->oldcwd));
241                 zfree(&nc->oldcwd);
242         }
243 
244         if (nc->oldns > -1) {
245                 close(nc->oldns);
246                 nc->oldns = -1;
247         }
248 
249         if (nc->newns > -1) {
250                 close(nc->newns);
251                 nc->newns = -1;
252         }
253 }
254 
255 char *nsinfo__realpath(const char *path, struct nsinfo *nsi)
256 {
257         char *rpath;
258         struct nscookie nsc;
259 
260         nsinfo__mountns_enter(nsi, &nsc);
261         rpath = realpath(path, NULL);
262         nsinfo__mountns_exit(&nsc);
263 
264         return rpath;
265 }
266 

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