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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/zalloc.h>
struct namespaces *namespaces__new(struct namespaces_event *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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