1 // SPDX-License-Identifier: GPL-2.0-only
4 * Copyright (C) 2017 Hari Bathini, IBM Corporation
7 #include "namespaces.h"
9 #include "get_current_dir_name.h"
10 #include <sys/types.h>
20 #include <linux/kernel.h>
21 #include <linux/zalloc.h>
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",
33 const char *perf_ns__name(unsigned int id)
35 if (id >= ARRAY_SIZE(perf_ns__names))
37 return perf_ns__names[id];
40 struct namespaces *namespaces__new(struct perf_record_namespaces *event)
42 struct namespaces *namespaces;
43 u64 link_info_size = ((event ? event->nr_namespaces : NR_NAMESPACES) *
44 sizeof(struct perf_ns_link_info));
46 namespaces = zalloc(sizeof(struct namespaces) + link_info_size);
50 namespaces->end_time = -1;
53 memcpy(namespaces->link_info, event->link_info, link_info_size);
58 void namespaces__free(struct namespaces *namespaces)
63 int nsinfo__init(struct nsinfo *nsi)
76 if (snprintf(oldns, PATH_MAX, "/proc/self/ns/mnt") >= PATH_MAX)
79 if (asprintf(&newns, "/proc/%d/ns/mnt", nsi->pid) == -1)
82 if (stat(oldns, &old_stat) < 0)
85 if (stat(newns, &new_stat) < 0)
88 /* Check if the mount namespaces differ, if so then indicate that we
89 * want to switch as part of looking up dso/map data.
91 if (old_stat.st_ino != new_stat.st_ino) {
92 nsi->need_setns = true;
93 nsi->mntns_path = newns;
97 /* If we're dealing with a process that is in a different PID namespace,
98 * attempt to work out the innermost tgid for the process.
100 if (snprintf(spath, PATH_MAX, "/proc/%d/status", nsi->pid) >= PATH_MAX)
103 f = fopen(spath, "r");
107 while (getline(&statln, &linesz, f) != -1) {
108 /* Use tgid if CONFIG_PID_NS is not defined. */
109 if (strstr(statln, "Tgid:") != NULL) {
110 nsi->tgid = (pid_t)strtol(strrchr(statln, '\t'),
112 nsi->nstgid = nsi->tgid;
115 if (strstr(statln, "NStgid:") != NULL) {
116 nspid = strrchr(statln, '\t');
117 nsi->nstgid = (pid_t)strtol(nspid, NULL, 10);
118 /* If innermost tgid is not the first, process is in a different
121 nsi->in_pidns = (statln + sizeof("NStgid:") - 1) != nspid;
135 struct nsinfo *nsinfo__new(pid_t pid)
142 nsi = calloc(1, sizeof(*nsi));
147 nsi->need_setns = false;
148 nsi->in_pidns = false;
149 /* Init may fail if the process exits while we're trying to look
150 * at its proc information. In that case, save the pid but
151 * don't try to enter the namespace.
153 if (nsinfo__init(nsi) == -1)
154 nsi->need_setns = false;
156 refcount_set(&nsi->refcnt, 1);
162 struct nsinfo *nsinfo__copy(struct nsinfo *nsi)
169 nnsi = calloc(1, sizeof(*nnsi));
171 nnsi->pid = nsi->pid;
172 nnsi->tgid = nsi->tgid;
173 nnsi->nstgid = nsi->nstgid;
174 nnsi->need_setns = nsi->need_setns;
175 nnsi->in_pidns = nsi->in_pidns;
176 if (nsi->mntns_path) {
177 nnsi->mntns_path = strdup(nsi->mntns_path);
178 if (!nnsi->mntns_path) {
183 refcount_set(&nnsi->refcnt, 1);
189 void nsinfo__delete(struct nsinfo *nsi)
191 zfree(&nsi->mntns_path);
195 struct nsinfo *nsinfo__get(struct nsinfo *nsi)
198 refcount_inc(&nsi->refcnt);
202 void nsinfo__put(struct nsinfo *nsi)
204 if (nsi && refcount_dec_and_test(&nsi->refcnt))
208 void nsinfo__mountns_enter(struct nsinfo *nsi,
211 char curpath[PATH_MAX];
222 if (!nsi || !nsi->need_setns)
225 if (snprintf(curpath, PATH_MAX, "/proc/self/ns/mnt") >= PATH_MAX)
228 oldcwd = get_current_dir_name();
232 oldns = open(curpath, O_RDONLY);
236 newns = open(nsi->mntns_path, O_RDONLY);
240 if (setns(newns, CLONE_NEWNS) < 0)
256 void nsinfo__mountns_exit(struct nscookie *nc)
258 if (nc == NULL || nc->oldns == -1 || nc->newns == -1 || !nc->oldcwd)
261 setns(nc->oldns, CLONE_NEWNS);
264 WARN_ON_ONCE(chdir(nc->oldcwd));
268 if (nc->oldns > -1) {
273 if (nc->newns > -1) {
279 char *nsinfo__realpath(const char *path, struct nsinfo *nsi)
284 nsinfo__mountns_enter(nsi, &nsc);
285 rpath = realpath(path, NULL);
286 nsinfo__mountns_exit(&nsc);
291 int nsinfo__stat(const char *filename, struct stat *st, struct nsinfo *nsi)
296 nsinfo__mountns_enter(nsi, &nsc);
297 ret = stat(filename, st);
298 nsinfo__mountns_exit(&nsc);