new file mode 100644
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __CG_MAP_H__
+#define __CG_MAP_H__ 1
+
+const char *cg_id_to_path(__u64 id);
+
+#endif /* __CG_MAP_H__ */
@@ -302,7 +302,9 @@ int get_real_family(int rtm_type, int rtm_family);
int cmd_exec(const char *cmd, char **argv, bool do_fork,
int (*setup)(void *), void *arg);
int make_path(const char *path, mode_t mode);
-char *find_cgroup2_mount(void);
+char *find_cgroup2_mount(bool do_mount);
+__u64 get_cgroup2_id(const char *path);
+char *get_cgroup2_path(__u64 id, bool full);
int get_command_name(const char *pid, char *comm, size_t len);
int get_rtnl_link_stats_rta(struct rtnl_link_stats64 *stats64,
@@ -225,7 +225,7 @@ static int ipvrf_pids(int argc, char **argv)
return -1;
}
- mnt = find_cgroup2_mount();
+ mnt = find_cgroup2_mount(true);
if (!mnt)
return -1;
@@ -366,7 +366,7 @@ static int vrf_switch(const char *name)
}
}
- mnt = find_cgroup2_mount();
+ mnt = find_cgroup2_mount(true);
if (!mnt)
return -1;
@@ -5,7 +5,7 @@ CFLAGS += -fPIC
UTILOBJ = utils.o rt_names.o ll_map.o ll_types.o ll_proto.o ll_addr.o \
inet_proto.o namespace.o json_writer.o json_print.o \
- names.o color.o bpf.o exec.o fs.o
+ names.o color.o bpf.o exec.o fs.o cg_map.o
NLOBJ=libgenl.o libnetlink.o
new file mode 100644
@@ -0,0 +1,133 @@
+/*
+ * cg_map.c cgroup v2 cache
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ * Authors: Dmitry Yakunin <zeil@yandex-team.ru>
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <linux/types.h>
+#include <linux/limits.h>
+#include <ftw.h>
+
+#include "cg_map.h"
+#include "list.h"
+#include "utils.h"
+
+struct cg_cache {
+ struct hlist_node id_hash;
+ __u64 id;
+ char path[];
+};
+
+#define IDMAP_SIZE 1024
+static struct hlist_head id_head[IDMAP_SIZE];
+
+static struct cg_cache *cg_get_by_id(__u64 id)
+{
+ struct hlist_node *n;
+ unsigned int h = id & (IDMAP_SIZE - 1);
+
+ hlist_for_each(n, &id_head[h]) {
+ struct cg_cache *cg
+ = container_of(n, struct cg_cache, id_hash);
+ if (cg->id == id)
+ return cg;
+ }
+
+ return NULL;
+}
+
+static struct cg_cache *cg_entry_create(__u64 id, const char *path)
+{
+ struct cg_cache *cg;
+ unsigned int h = id & (IDMAP_SIZE - 1);
+
+ cg = malloc(sizeof(*cg) + strlen(path) + 1);
+ if (!cg) {
+ fprintf(stderr,
+ "Failed to allocate memory for cgroup2 cache entry");
+ return NULL;
+ }
+ cg->id = id;
+ strcpy(cg->path, path);
+
+ hlist_add_head(&cg->id_hash, &id_head[h]);
+
+ return cg;
+}
+
+static int mntlen;
+
+static int nftw_fn(const char *fpath, const struct stat *sb,
+ int typeflag, struct FTW *ftw)
+{
+ const char *path;
+ __u64 id;
+
+ if (typeflag != FTW_D)
+ return 0;
+
+ id = get_cgroup2_id(fpath);
+ if (!id)
+ return -1;
+
+ path = fpath + mntlen;
+ if (*path == '\0')
+ /* root cgroup */
+ path = "/";
+ if (!cg_entry_create(id, path))
+ return -1;
+
+ return 0;
+}
+
+static void cg_init_map(void)
+{
+ char *mnt;
+
+ mnt = find_cgroup2_mount(false);
+ if (!mnt)
+ exit(1);
+
+ mntlen = strlen(mnt);
+ if (nftw(mnt, nftw_fn, 1024, FTW_MOUNT) < 0)
+ exit(1);
+
+ free(mnt);
+}
+
+const char *cg_id_to_path(__u64 id)
+{
+ static int initialized;
+ static char buf[64];
+ const struct cg_cache *cg;
+ char *path;
+
+ if (!initialized) {
+ cg_init_map();
+ initialized = 1;
+ }
+
+ cg = cg_get_by_id(id);
+ if (cg)
+ return cg->path;
+
+ path = get_cgroup2_path(id, false);
+ if (path) {
+ cg = cg_entry_create(id, path);
+ free(path);
+ if (cg)
+ return cg->path;
+ }
+
+ snprintf(buf, sizeof(buf), "unreachable:%llx", id);
+ return buf;
+}
@@ -59,13 +59,18 @@ static char *find_fs_mount(const char *fs_to_find)
}
/* caller needs to free string returned */
-char *find_cgroup2_mount(void)
+char *find_cgroup2_mount(bool do_mount)
{
char *mnt = find_fs_mount(CGROUP2_FS_NAME);
if (mnt)
return mnt;
+ if (!do_mount) {
+ fprintf(stderr, "Failed to find cgroup2 mount\n");
+ return NULL;
+ }
+
mnt = strdup(MNT_CGRP2_PATH);
if (!mnt) {
fprintf(stderr, "Failed to allocate memory for cgroup2 path\n");
@@ -74,7 +79,7 @@ char *find_cgroup2_mount(void)
}
if (make_path(mnt, 0755)) {
- fprintf(stderr, "Failed to setup vrf cgroup2 directory\n");
+ fprintf(stderr, "Failed to setup cgroup2 directory\n");
free(mnt);
return NULL;
}
@@ -99,6 +104,132 @@ out:
return mnt;
}
+__u64 get_cgroup2_id(const char *path)
+{
+ union {
+ __u64 id;
+ unsigned char bytes[sizeof(__u64)];
+ } cg_id = { .id = 0 };
+ char fh_buf[sizeof(struct file_handle) + sizeof(__u64)] = { 0 };
+ struct file_handle *fhp = (struct file_handle *)fh_buf;
+ int mnt_id, mnt_fd = -1;
+ char *mnt = NULL;
+
+ if (!path) {
+ fprintf(stderr, "Invalid cgroup2 path\n");
+ return 0;
+ }
+
+ fhp->handle_bytes = sizeof(__u64);
+ if (name_to_handle_at(AT_FDCWD, path, fhp, &mnt_id, 0) < 0) {
+ /* try at cgroup2 mount */
+
+ while (*path == '/')
+ path++;
+ if (*path == '\0') {
+ fprintf(stderr, "Invalid cgroup2 path\n");
+ goto out;
+ }
+
+ mnt = find_cgroup2_mount(false);
+ if (!mnt)
+ goto out;
+
+ mnt_fd = open(mnt, O_RDONLY);
+ if (mnt_fd < 0) {
+ fprintf(stderr, "Failed to open cgroup2 mount\n");
+ goto out;
+ }
+
+ fhp->handle_bytes = sizeof(__u64);
+ if (name_to_handle_at(mnt_fd, path, fhp, &mnt_id, 0) < 0) {
+ fprintf(stderr, "Failed to get cgroup2 ID: %s\n",
+ strerror(errno));
+ goto out;
+ }
+ if (fhp->handle_bytes != sizeof(__u64)) {
+ fprintf(stderr, "Invalid size of cgroup2 ID\n");
+ goto out;
+ }
+ }
+
+ memcpy(cg_id.bytes, fhp->f_handle, sizeof(__u64));
+
+out:
+ close(mnt_fd);
+ free(mnt);
+
+ return cg_id.id;
+}
+
+#define FILEID_INO32_GEN 1
+
+/* caller needs to free string returned */
+char *get_cgroup2_path(__u64 id, bool full)
+{
+ union {
+ __u64 id;
+ unsigned char bytes[sizeof(__u64)];
+ } cg_id = { .id = id };
+ char fh_buf[sizeof(struct file_handle) + sizeof(__u64)] = { 0 };
+ struct file_handle *fhp = (struct file_handle *)fh_buf;
+ char fd_path[64];
+ char link_buf[PATH_MAX];
+ int link_len;
+ int mnt_fd = -1, fd = -1;
+ char *mnt, *path = NULL;
+
+ if (!id) {
+ fprintf(stderr, "Invalid cgroup2 ID\n");
+ return NULL;
+ }
+
+ mnt = find_cgroup2_mount(false);
+ if (!mnt)
+ return NULL;
+
+ mnt_fd = open(mnt, O_RDONLY);
+ if (mnt_fd < 0) {
+ fprintf(stderr, "Failed to open cgroup2 mount\n");
+ goto out;
+ }
+
+ fhp->handle_bytes = sizeof(__u64);
+ fhp->handle_type = FILEID_INO32_GEN;
+ memcpy(fhp->f_handle, cg_id.bytes, sizeof(__u64));
+
+ fd = open_by_handle_at(mnt_fd, fhp, 0);
+ if (fd < 0) {
+ fprintf(stderr, "Failed to open cgroup2 by ID\n");
+ goto out;
+ }
+
+ snprintf(fd_path, sizeof(fd_path), "/proc/self/fd/%d", fd);
+ link_len = readlink(fd_path, link_buf, sizeof(link_buf) - 1);
+ if (link_len < 0) {
+ fprintf(stderr,
+ "Failed to read value of symbolic link %s\n",
+ fd_path);
+ goto out;
+ }
+ link_buf[link_len] = '\0';
+
+ if (full)
+ path = strdup(link_buf);
+ else
+ path = strdup(link_buf + strlen(mnt));
+ if (!path)
+ fprintf(stderr,
+ "Failed to allocate memory for cgroup2 path\n");
+
+out:
+ close(fd);
+ close(mnt_fd);
+ free(mnt);
+
+ return path;
+}
+
int make_path(const char *path, mode_t mode)
{
char *dir, *delim;