summaryrefslogtreecommitdiffstats
path: root/tools/perf/util/namespaces.c
diff options
context:
space:
mode:
Diffstat (limited to 'tools/perf/util/namespaces.c')
-rw-r--r--tools/perf/util/namespaces.c376
1 files changed, 376 insertions, 0 deletions
diff --git a/tools/perf/util/namespaces.c b/tools/perf/util/namespaces.c
new file mode 100644
index 0000000000..cb185c5659
--- /dev/null
+++ b/tools/perf/util/namespaces.c
@@ -0,0 +1,376 @@
+// 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(pid_t *tgid, pid_t *nstgid, bool *in_pidns, 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) {
+ *tgid = (pid_t)strtol(strrchr(statln, '\t'), NULL, 10);
+ *nstgid = *tgid;
+ }
+
+ if (strstr(statln, "NStgid:") != NULL) {
+ nspid = strrchr(statln, '\t');
+ *nstgid = (pid_t)strtol(nspid, NULL, 10);
+ /*
+ * If innermost tgid is not the first, process is in a different
+ * PID namespace.
+ */
+ *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) {
+ RC_CHK_ACCESS(nsi)->need_setns = true;
+ RC_CHK_ACCESS(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(&RC_CHK_ACCESS(nsi)->tgid, &RC_CHK_ACCESS(nsi)->nstgid,
+ &RC_CHK_ACCESS(nsi)->in_pidns, spath);
+
+out:
+ free(newns);
+ return rv;
+}
+
+static struct nsinfo *nsinfo__alloc(void)
+{
+ struct nsinfo *res;
+ RC_STRUCT(nsinfo) *nsi;
+
+ nsi = calloc(1, sizeof(*nsi));
+ if (ADD_RC_CHK(res, nsi))
+ refcount_set(&nsi->refcnt, 1);
+
+ return res;
+}
+
+struct nsinfo *nsinfo__new(pid_t pid)
+{
+ struct nsinfo *nsi;
+
+ if (pid == 0)
+ return NULL;
+
+ nsi = nsinfo__alloc();
+ if (!nsi)
+ return NULL;
+
+ RC_CHK_ACCESS(nsi)->pid = pid;
+ RC_CHK_ACCESS(nsi)->tgid = pid;
+ RC_CHK_ACCESS(nsi)->nstgid = pid;
+ nsinfo__clear_need_setns(nsi);
+ RC_CHK_ACCESS(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)
+ nsinfo__clear_need_setns(nsi);
+
+ return nsi;
+}
+
+static const char *nsinfo__mntns_path(const struct nsinfo *nsi)
+{
+ return RC_CHK_ACCESS(nsi)->mntns_path;
+}
+
+struct nsinfo *nsinfo__copy(const struct nsinfo *nsi)
+{
+ struct nsinfo *nnsi;
+
+ if (nsi == NULL)
+ return NULL;
+
+ nnsi = nsinfo__alloc();
+ if (!nnsi)
+ return NULL;
+
+ RC_CHK_ACCESS(nnsi)->pid = nsinfo__pid(nsi);
+ RC_CHK_ACCESS(nnsi)->tgid = nsinfo__tgid(nsi);
+ RC_CHK_ACCESS(nnsi)->nstgid = nsinfo__nstgid(nsi);
+ RC_CHK_ACCESS(nnsi)->need_setns = nsinfo__need_setns(nsi);
+ RC_CHK_ACCESS(nnsi)->in_pidns = nsinfo__in_pidns(nsi);
+ if (nsinfo__mntns_path(nsi)) {
+ RC_CHK_ACCESS(nnsi)->mntns_path = strdup(nsinfo__mntns_path(nsi));
+ if (!RC_CHK_ACCESS(nnsi)->mntns_path) {
+ nsinfo__put(nnsi);
+ return NULL;
+ }
+ }
+
+ return nnsi;
+}
+
+static refcount_t *nsinfo__refcnt(struct nsinfo *nsi)
+{
+ return &RC_CHK_ACCESS(nsi)->refcnt;
+}
+
+static void nsinfo__delete(struct nsinfo *nsi)
+{
+ if (nsi) {
+ WARN_ONCE(refcount_read(nsinfo__refcnt(nsi)) != 0, "nsinfo refcnt unbalanced\n");
+ zfree(&RC_CHK_ACCESS(nsi)->mntns_path);
+ RC_CHK_FREE(nsi);
+ }
+}
+
+struct nsinfo *nsinfo__get(struct nsinfo *nsi)
+{
+ struct nsinfo *result;
+
+ if (RC_CHK_GET(result, nsi))
+ refcount_inc(nsinfo__refcnt(nsi));
+
+ return result;
+}
+
+void nsinfo__put(struct nsinfo *nsi)
+{
+ if (nsi && refcount_dec_and_test(nsinfo__refcnt(nsi)))
+ nsinfo__delete(nsi);
+ else
+ RC_CHK_PUT(nsi);
+}
+
+bool nsinfo__need_setns(const struct nsinfo *nsi)
+{
+ return RC_CHK_ACCESS(nsi)->need_setns;
+}
+
+void nsinfo__clear_need_setns(struct nsinfo *nsi)
+{
+ RC_CHK_ACCESS(nsi)->need_setns = false;
+}
+
+pid_t nsinfo__tgid(const struct nsinfo *nsi)
+{
+ return RC_CHK_ACCESS(nsi)->tgid;
+}
+
+pid_t nsinfo__nstgid(const struct nsinfo *nsi)
+{
+ return RC_CHK_ACCESS(nsi)->nstgid;
+}
+
+pid_t nsinfo__pid(const struct nsinfo *nsi)
+{
+ return RC_CHK_ACCESS(nsi)->pid;
+}
+
+pid_t nsinfo__in_pidns(const struct nsinfo *nsi)
+{
+ return RC_CHK_ACCESS(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 || !nsinfo__need_setns(nsi))
+ 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(nsinfo__mntns_path(nsi), 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)
+{
+ pid_t tgid = 0, nstgid = 0;
+ bool in_pidns = false;
+
+ nsinfo__get_nspid(&tgid, &nstgid, &in_pidns, "/proc/self/status");
+ return !in_pidns;
+}