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Message-Id: <1481392069-3138-6-git-send-email-dsa@cumulusnetworks.com>
Date: Sat, 10 Dec 2016 09:47:46 -0800
From: David Ahern <dsa@...ulusnetworks.com>
To: netdev@...r.kernel.org, stephen@...workplumber.org
Cc: David Ahern <dsa@...ulusnetworks.com>
Subject: [iproute2 net-next 5/8] Add filesystem APIs to lib
Add make_path to recursively call mkdir as needed to create a given
path with the given mode.
Add find_cgroup2_mount to lookup path where cgroup2 is mounted. If it
is not already mounted, cgroup2 is mounted under /var/run/cgroup2 for
use by iproute2.
Signed-off-by: David Ahern <dsa@...ulusnetworks.com>
---
include/utils.h | 2 +
lib/Makefile | 2 +-
lib/fs.c | 143 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 146 insertions(+), 1 deletion(-)
create mode 100644 lib/fs.c
diff --git a/include/utils.h b/include/utils.h
index ac4517a3bde1..dc1d6b9607dd 100644
--- a/include/utils.h
+++ b/include/utils.h
@@ -257,5 +257,7 @@ int get_guid(__u64 *guid, const char *arg);
int get_real_family(int rtm_type, int rtm_family);
int cmd_exec(const char *cmd, char **argv, bool do_fork);
+int make_path(const char *path, mode_t mode);
+char *find_cgroup2_mount(void);
#endif /* __UTILS_H__ */
diff --git a/lib/Makefile b/lib/Makefile
index 749073261c49..0c57662b4f8f 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -8,7 +8,7 @@ CFLAGS += -fPIC
UTILOBJ = utils.o rt_names.o ll_types.o ll_proto.o ll_addr.o \
inet_proto.o namespace.o json_writer.o \
- names.o color.o bpf.o exec.o
+ names.o color.o bpf.o exec.o fs.o
NLOBJ=libgenl.o ll_map.o libnetlink.o
diff --git a/lib/fs.c b/lib/fs.c
new file mode 100644
index 000000000000..39cc96dccca9
--- /dev/null
+++ b/lib/fs.c
@@ -0,0 +1,143 @@
+/*
+ * fs.c filesystem APIs
+ *
+ * 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: David Ahern <dsa@...ulusnetworks.com>
+ *
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/socket.h>
+#include <sys/mount.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <limits.h>
+
+#include "utils.h"
+
+#define CGROUP2_FS_NAME "cgroup2"
+
+/* if not already mounted cgroup2 is mounted here for iproute2's use */
+#define MNT_CGRP2_PATH "/var/run/cgroup2"
+
+/* return mount path of first occurrence of given fstype */
+static char *find_fs_mount(const char *fs_to_find)
+{
+ char path[4096];
+ char fstype[128]; /* max length of any filesystem name */
+ char *mnt = NULL;
+ FILE *fp;
+
+ fp = fopen("/proc/mounts", "r");
+ if (!fp) {
+ fprintf(stderr,
+ "Failed to open mounts file: %s\n", strerror(errno));
+ return NULL;
+ }
+
+ while (fscanf(fp, "%*s %4096s %127s %*s %*d %*d\n",
+ path, fstype) == 2) {
+ if (strcmp(fstype, fs_to_find) == 0) {
+ mnt = strdup(path);
+ break;
+ }
+ }
+
+ fclose(fp);
+
+ return mnt;
+}
+
+/* caller needs to free string returned */
+char *find_cgroup2_mount(void)
+{
+ char *mnt = find_fs_mount(CGROUP2_FS_NAME);
+
+ if (mnt)
+ return mnt;
+
+ mnt = strdup(MNT_CGRP2_PATH);
+ if (!mnt) {
+ fprintf(stderr, "Failed to allocate memory for cgroup2 path\n");
+ return NULL;
+
+ }
+
+ if (make_path(mnt, 0755)) {
+ fprintf(stderr, "Failed to setup vrf cgroup2 directory\n");
+ free(mnt);
+ return NULL;
+ }
+
+ if (mount("none", mnt, CGROUP2_FS_NAME, 0, NULL)) {
+ /* EBUSY means already mounted */
+ if (errno != EBUSY) {
+ fprintf(stderr,
+ "Failed to mount cgroup2. Are CGROUPS enabled in your kernel?\n");
+ free(mnt);
+ return NULL;
+ }
+ }
+ return mnt;
+}
+
+int make_path(const char *path, mode_t mode)
+{
+ char *dir, *delim;
+ struct stat sbuf;
+ int rc = -1;
+
+ delim = dir = strdup(path);
+ if (dir == NULL) {
+ fprintf(stderr, "strdup failed copying path");
+ return -1;
+ }
+
+ /* skip '/' -- it had better exist */
+ if (*delim == '/')
+ delim++;
+
+ while (1) {
+ delim = strchr(delim, '/');
+ if (delim)
+ *delim = '\0';
+
+ if (stat(dir, &sbuf) != 0) {
+ if (errno != ENOENT) {
+ fprintf(stderr,
+ "stat failed for %s: %s\n",
+ dir, strerror(errno));
+ goto out;
+ }
+
+ if (mkdir(dir, mode) != 0) {
+ fprintf(stderr,
+ "mkdir failed for %s: %s",
+ dir, strerror(errno));
+ goto out;
+ }
+ }
+
+ if (delim == NULL)
+ break;
+
+ *delim = '/';
+ delim++;
+ if (*delim == '\0')
+ break;
+ }
+ rc = 0;
+out:
+ free(dir);
+
+ return rc;
+}
--
2.1.4
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