v4.19.13 snapshot.
diff --git a/tools/perf/util/namespaces.c b/tools/perf/util/namespaces.c
new file mode 100644
index 0000000..aed170b
--- /dev/null
+++ b/tools/perf/util/namespaces.c
@@ -0,0 +1,265 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2, as
+ * published by the Free Software Foundation.
+ *
+ * Copyright (C) 2017 Hari Bathini, IBM Corporation
+ */
+
+#include "namespaces.h"
+#include "util.h"
+#include "event.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>
+
+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;
+}