1 files changed, 347 insertions, 0 deletions
diff --git a/tools/perf/util/namespaces.c b/tools/perf/util/namespaces.c
new file mode 100644
index 000000000..dd536220c
--- /dev/null
+++ b/tools/perf/util/namespaces.c
@@ -0,0 +1,347 @@
+// 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);
+}
+
+static int nsinfo__get_nspid(struct nsinfo *nsi, const char *path)
+{
+	FILE *f = NULL;
+	char *statln = NULL;
+	size_t linesz = 0;
+	char *nspid;
+
+	f = fopen(path, "r");
+	if (f == NULL)
+		return -1;
+
+	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 = nsinfo__tgid(nsi);
+		}
+
+		if (strstr(statln, "NStgid:") != NULL) {
+			nspid = strrchr(statln, '\t');
+			nsi->nstgid = (pid_t)strtol(nspid, NULL, 10);
+			/*
+			 * If innermost tgid is not the first, process is in a different
+			 * PID namespace.
+			 */
+			nsi->in_pidns = (statln + sizeof("NStgid:") - 1) != nspid;
+			break;
+		}
+	}
+
+	fclose(f);
+	free(statln);
+	return 0;
+}
+
+int nsinfo__init(struct nsinfo *nsi)
+{
+	char oldns[PATH_MAX];
+	char spath[PATH_MAX];
+	char *newns = NULL;
+	struct stat old_stat;
+	struct stat new_stat;
+	int rv = -1;
+
+	if (snprintf(oldns, PATH_MAX, "/proc/self/ns/mnt") >= PATH_MAX)
+		return rv;
+
+	if (asprintf(&newns, "/proc/%d/ns/mnt", nsinfo__pid(nsi)) == -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", nsinfo__pid(nsi)) >= PATH_MAX)
+		goto out;
+
+	rv = nsinfo__get_nspid(nsi, spath);
+
+out:
+	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;
+		nsi->in_pidns = 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(const struct nsinfo *nsi)
+{
+	struct nsinfo *nnsi;
+
+	if (nsi == NULL)
+		return NULL;
+
+	nnsi = calloc(1, sizeof(*nnsi));
+	if (nnsi != NULL) {
+		nnsi->pid = nsinfo__pid(nsi);
+		nnsi->tgid = nsinfo__tgid(nsi);
+		nnsi->nstgid = nsinfo__nstgid(nsi);
+		nnsi->need_setns = nsinfo__need_setns(nsi);
+		nnsi->in_pidns = nsinfo__in_pidns(nsi);
+		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;
+}
+
+static 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);
+}
+
+bool nsinfo__need_setns(const struct nsinfo *nsi)
+{
+        return nsi->need_setns;
+}
+
+void nsinfo__clear_need_setns(struct nsinfo *nsi)
+{
+        nsi->need_setns = false;
+}
+
+pid_t nsinfo__tgid(const struct nsinfo  *nsi)
+{
+        return nsi->tgid;
+}
+
+pid_t nsinfo__nstgid(const struct nsinfo  *nsi)
+{
+        return nsi->nstgid;
+}
+
+pid_t nsinfo__pid(const struct nsinfo  *nsi)
+{
+        return nsi->pid;
+}
+
+pid_t nsinfo__in_pidns(const struct nsinfo  *nsi)
+{
+        return nsi->in_pidns;
+}
+
+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;
+}
+
+int nsinfo__stat(const char *filename, struct stat *st, struct nsinfo *nsi)
+{
+	int ret;
+	struct nscookie nsc;
+
+	nsinfo__mountns_enter(nsi, &nsc);
+	ret = stat(filename, st);
+	nsinfo__mountns_exit(&nsc);
+
+	return ret;
+}
+
+bool nsinfo__is_in_root_namespace(void)
+{
+	struct nsinfo nsi;
+
+	memset(&nsi, 0x0, sizeof(nsi));
+	nsinfo__get_nspid(&nsi, "/proc/self/status");
+	return !nsi.in_pidns;
+}