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- // 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/kernel.h>
- #include <linux/zalloc.h>
- static const char *perf_ns__names[] = {
- [NET_NS_INDEX] = "net",
- [UTS_NS_INDEX] = "uts",
- [IPC_NS_INDEX] = "ipc",
- [PID_NS_INDEX] = "pid",
- [USER_NS_INDEX] = "user",
- [MNT_NS_INDEX] = "mnt",
- [CGROUP_NS_INDEX] = "cgroup",
- };
- const char *perf_ns__name(unsigned int id)
- {
- if (id >= ARRAY_SIZE(perf_ns__names))
- return "UNKNOWN";
- return perf_ns__names[id];
- }
- 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;
- }
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