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iproute2/ip/ipnetns.c
Nicolas Dichtel 3c61c01a66 ipnetns: fix ip batch mode when using 'netns exec' 
Since commit a05f6511f5, ip batch mode is broken when using 'netns exec' cmd.

When WIFEXITED() returns true, it means that the child exited normally, hence
we must not call exit() but just returns the status. If we call exit, the next
commands in the file file are not executed.
If WIFEXITED() returns false, we can call exit() because it means that the
child failed.

This patch partially reverts commit a05f6511f5.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
2013-09-03 08:20:16 -07:00

530 lines
12 KiB
C
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#define _ATFILE_SOURCE
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <sys/inotify.h>
#include <sys/mount.h>
#include <sys/param.h>
#include <sys/syscall.h>
#include <stdio.h>
#include <string.h>
#include <sched.h>
#include <fcntl.h>
#include <dirent.h>
#include <errno.h>
#include <unistd.h>
#include <ctype.h>
#include "utils.h"
#include "ip_common.h"
#define NETNS_RUN_DIR "/var/run/netns"
#define NETNS_ETC_DIR "/etc/netns"
#ifndef CLONE_NEWNET
#define CLONE_NEWNET 0x40000000 /* New network namespace (lo, device, names sockets, etc) */
#endif
#ifndef MNT_DETACH
#define MNT_DETACH 0x00000002 /* Just detach from the tree */
#endif /* MNT_DETACH */
/* sys/mount.h may be out too old to have these */
#ifndef MS_REC
#define MS_REC 16384
#endif
#ifndef MS_SLAVE
#define MS_SLAVE (1 << 19)
#endif
#ifndef MS_SHARED
#define MS_SHARED (1 << 20)
#endif
#ifndef HAVE_SETNS
static int setns(int fd, int nstype)
{
#ifdef __NR_setns
return syscall(__NR_setns, fd, nstype);
#else
errno = ENOSYS;
return -1;
#endif
}
#endif /* HAVE_SETNS */
static int usage(void)
{
fprintf(stderr, "Usage: ip netns list\n");
fprintf(stderr, " ip netns add NAME\n");
fprintf(stderr, " ip netns delete NAME\n");
fprintf(stderr, " ip netns identify PID\n");
fprintf(stderr, " ip netns pids NAME\n");
fprintf(stderr, " ip netns exec NAME cmd ...\n");
fprintf(stderr, " ip netns monitor\n");
exit(-1);
}
int get_netns_fd(const char *name)
{
char pathbuf[MAXPATHLEN];
const char *path, *ptr;
path = name;
ptr = strchr(name, '/');
if (!ptr) {
snprintf(pathbuf, sizeof(pathbuf), "%s/%s",
NETNS_RUN_DIR, name );
path = pathbuf;
}
return open(path, O_RDONLY);
}
static int netns_list(int argc, char **argv)
{
struct dirent *entry;
DIR *dir;
dir = opendir(NETNS_RUN_DIR);
if (!dir)
return 0;
while ((entry = readdir(dir)) != NULL) {
if (strcmp(entry->d_name, ".") == 0)
continue;
if (strcmp(entry->d_name, "..") == 0)
continue;
printf("%s\n", entry->d_name);
}
closedir(dir);
return 0;
}
static void bind_etc(const char *name)
{
char etc_netns_path[MAXPATHLEN];
char netns_name[MAXPATHLEN];
char etc_name[MAXPATHLEN];
struct dirent *entry;
DIR *dir;
snprintf(etc_netns_path, sizeof(etc_netns_path), "%s/%s", NETNS_ETC_DIR, name);
dir = opendir(etc_netns_path);
if (!dir)
return;
while ((entry = readdir(dir)) != NULL) {
if (strcmp(entry->d_name, ".") == 0)
continue;
if (strcmp(entry->d_name, "..") == 0)
continue;
snprintf(netns_name, sizeof(netns_name), "%s/%s", etc_netns_path, entry->d_name);
snprintf(etc_name, sizeof(etc_name), "/etc/%s", entry->d_name);
if (mount(netns_name, etc_name, "none", MS_BIND, NULL) < 0) {
fprintf(stderr, "Bind %s -> %s failed: %s\n",
netns_name, etc_name, strerror(errno));
}
}
closedir(dir);
}
static int netns_exec(int argc, char **argv)
{
/* Setup the proper environment for apps that are not netns
* aware, and execute a program in that environment.
*/
const char *name, *cmd;
char net_path[MAXPATHLEN];
int netns;
if (argc < 1) {
fprintf(stderr, "No netns name specified\n");
return -1;
}
if (argc < 2) {
fprintf(stderr, "No command specified\n");
return -1;
}
name = argv[0];
cmd = argv[1];
snprintf(net_path, sizeof(net_path), "%s/%s", NETNS_RUN_DIR, name);
netns = open(net_path, O_RDONLY | O_CLOEXEC);
if (netns < 0) {
fprintf(stderr, "Cannot open network namespace \"%s\": %s\n",
name, strerror(errno));
return -1;
}
if (setns(netns, CLONE_NEWNET) < 0) {
fprintf(stderr, "seting the network namespace \"%s\" failed: %s\n",
name, strerror(errno));
return -1;
}
if (unshare(CLONE_NEWNS) < 0) {
fprintf(stderr, "unshare failed: %s\n", strerror(errno));
return -1;
}
/* Don't let any mounts propagate back to the parent */
if (mount("", "/", "none", MS_SLAVE | MS_REC, NULL)) {
fprintf(stderr, "\"mount --make-rslave /\" failed: %s\n",
strerror(errno));
return -1;
}
/* Mount a version of /sys that describes the network namespace */
if (umount2("/sys", MNT_DETACH) < 0) {
fprintf(stderr, "umount of /sys failed: %s\n", strerror(errno));
return -1;
}
if (mount(name, "/sys", "sysfs", 0, NULL) < 0) {
fprintf(stderr, "mount of /sys failed: %s\n",strerror(errno));
return -1;
}
/* Setup bind mounts for config files in /etc */
bind_etc(name);
fflush(stdout);
if (batch_mode) {
int status;
pid_t pid;
pid = fork();
if (pid < 0) {
perror("fork");
exit(1);
}
if (pid != 0) {
/* Parent */
if (waitpid(pid, &status, 0) < 0) {
perror("waitpid");
exit(1);
}
if (WIFEXITED(status)) {
/* ip must return the status of the child,
* but do_cmd() will add a minus to this,
* so let's add another one here to cancel it.
*/
return -WEXITSTATUS(status);
}
exit(1);
}
}
if (execvp(cmd, argv + 1) < 0)
fprintf(stderr, "exec of \"%s\" failed: %s\n",
cmd, strerror(errno));
_exit(1);
}
static int is_pid(const char *str)
{
int ch;
for (; (ch = *str); str++) {
if (!isdigit(ch))
return 0;
}
return 1;
}
static int netns_pids(int argc, char **argv)
{
const char *name;
char net_path[MAXPATHLEN];
int netns;
struct stat netst;
DIR *dir;
struct dirent *entry;
if (argc < 1) {
fprintf(stderr, "No netns name specified\n");
return -1;
}
if (argc > 1) {
fprintf(stderr, "extra arguments specified\n");
return -1;
}
name = argv[0];
snprintf(net_path, sizeof(net_path), "%s/%s", NETNS_RUN_DIR, name);
netns = open(net_path, O_RDONLY);
if (netns < 0) {
fprintf(stderr, "Cannot open network namespace: %s\n",
strerror(errno));
return -1;
}
if (fstat(netns, &netst) < 0) {
fprintf(stderr, "Stat of netns failed: %s\n",
strerror(errno));
return -1;
}
dir = opendir("/proc/");
if (!dir) {
fprintf(stderr, "Open of /proc failed: %s\n",
strerror(errno));
return -1;
}
while((entry = readdir(dir))) {
char pid_net_path[MAXPATHLEN];
struct stat st;
if (!is_pid(entry->d_name))
continue;
snprintf(pid_net_path, sizeof(pid_net_path), "/proc/%s/ns/net",
entry->d_name);
if (stat(pid_net_path, &st) != 0)
continue;
if ((st.st_dev == netst.st_dev) &&
(st.st_ino == netst.st_ino)) {
printf("%s\n", entry->d_name);
}
}
closedir(dir);
return 0;
}
static int netns_identify(int argc, char **argv)
{
const char *pidstr;
char net_path[MAXPATHLEN];
int netns;
struct stat netst;
DIR *dir;
struct dirent *entry;
if (argc < 1) {
fprintf(stderr, "No pid specified\n");
return -1;
}
if (argc > 1) {
fprintf(stderr, "extra arguments specified\n");
return -1;
}
pidstr = argv[0];
if (!is_pid(pidstr)) {
fprintf(stderr, "Specified string '%s' is not a pid\n",
pidstr);
return -1;
}
snprintf(net_path, sizeof(net_path), "/proc/%s/ns/net", pidstr);
netns = open(net_path, O_RDONLY);
if (netns < 0) {
fprintf(stderr, "Cannot open network namespace: %s\n",
strerror(errno));
return -1;
}
if (fstat(netns, &netst) < 0) {
fprintf(stderr, "Stat of netns failed: %s\n",
strerror(errno));
return -1;
}
dir = opendir(NETNS_RUN_DIR);
if (!dir) {
/* Succeed treat a missing directory as an empty directory */
if (errno == ENOENT)
return 0;
fprintf(stderr, "Failed to open directory %s:%s\n",
NETNS_RUN_DIR, strerror(errno));
return -1;
}
while((entry = readdir(dir))) {
char name_path[MAXPATHLEN];
struct stat st;
if (strcmp(entry->d_name, ".") == 0)
continue;
if (strcmp(entry->d_name, "..") == 0)
continue;
snprintf(name_path, sizeof(name_path), "%s/%s", NETNS_RUN_DIR,
entry->d_name);
if (stat(name_path, &st) != 0)
continue;
if ((st.st_dev == netst.st_dev) &&
(st.st_ino == netst.st_ino)) {
printf("%s\n", entry->d_name);
}
}
closedir(dir);
return 0;
}
static int netns_delete(int argc, char **argv)
{
const char *name;
char netns_path[MAXPATHLEN];
if (argc < 1) {
fprintf(stderr, "No netns name specified\n");
return -1;
}
name = argv[0];
snprintf(netns_path, sizeof(netns_path), "%s/%s", NETNS_RUN_DIR, name);
umount2(netns_path, MNT_DETACH);
if (unlink(netns_path) < 0) {
fprintf(stderr, "Cannot remove namespace file \"%s\": %s\n",
netns_path, strerror(errno));
return -1;
}
return 0;
}
static int netns_add(int argc, char **argv)
{
/* This function creates a new network namespace and
* a new mount namespace and bind them into a well known
* location in the filesystem based on the name provided.
*
* The mount namespace is created so that any necessary
* userspace tweaks like remounting /sys, or bind mounting
* a new /etc/resolv.conf can be shared between uers.
*/
char netns_path[MAXPATHLEN];
const char *name;
int fd;
int made_netns_run_dir_mount = 0;
if (argc < 1) {
fprintf(stderr, "No netns name specified\n");
return -1;
}
name = argv[0];
snprintf(netns_path, sizeof(netns_path), "%s/%s", NETNS_RUN_DIR, name);
/* Create the base netns directory if it doesn't exist */
mkdir(NETNS_RUN_DIR, S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH);
/* Make it possible for network namespace mounts to propagate between
* mount namespaces. This makes it likely that a unmounting a network
* namespace file in one namespace will unmount the network namespace
* file in all namespaces allowing the network namespace to be freed
* sooner.
*/
while (mount("", NETNS_RUN_DIR, "none", MS_SHARED | MS_REC, NULL)) {
/* Fail unless we need to make the mount point */
if (errno != EINVAL || made_netns_run_dir_mount) {
fprintf(stderr, "mount --make-shared %s failed: %s\n",
NETNS_RUN_DIR, strerror(errno));
return -1;
}
/* Upgrade NETNS_RUN_DIR to a mount point */
if (mount(NETNS_RUN_DIR, NETNS_RUN_DIR, "none", MS_BIND, NULL)) {
fprintf(stderr, "mount --bind %s %s failed: %s\n",
NETNS_RUN_DIR, NETNS_RUN_DIR, strerror(errno));
return -1;
}
made_netns_run_dir_mount = 1;
}
/* Create the filesystem state */
fd = open(netns_path, O_RDONLY|O_CREAT|O_EXCL, 0);
if (fd < 0) {
fprintf(stderr, "Cannot not create namespace file \"%s\": %s\n",
netns_path, strerror(errno));
return -1;
}
close(fd);
if (unshare(CLONE_NEWNET) < 0) {
fprintf(stderr, "Failed to create a new network namespace \"%s\": %s\n",
name, strerror(errno));
goto out_delete;
}
/* Bind the netns last so I can watch for it */
if (mount("/proc/self/ns/net", netns_path, "none", MS_BIND, NULL) < 0) {
fprintf(stderr, "Bind /proc/self/ns/net -> %s failed: %s\n",
netns_path, strerror(errno));
goto out_delete;
}
return 0;
out_delete:
netns_delete(argc, argv);
return -1;
}
static int netns_monitor(int argc, char **argv)
{
char buf[4096];
struct inotify_event *event;
int fd;
fd = inotify_init();
if (fd < 0) {
fprintf(stderr, "inotify_init failed: %s\n",
strerror(errno));
return -1;
}
if (inotify_add_watch(fd, NETNS_RUN_DIR, IN_CREATE | IN_DELETE) < 0) {
fprintf(stderr, "inotify_add_watch failed: %s\n",
strerror(errno));
return -1;
}
for(;;) {
ssize_t len = read(fd, buf, sizeof(buf));
if (len < 0) {
fprintf(stderr, "read failed: %s\n",
strerror(errno));
return -1;
}
for (event = (struct inotify_event *)buf;
(char *)event < &buf[len];
event = (struct inotify_event *)((char *)event + sizeof(*event) + event->len)) {
if (event->mask & IN_CREATE)
printf("add %s\n", event->name);
if (event->mask & IN_DELETE)
printf("delete %s\n", event->name);
}
}
return 0;
}
int do_netns(int argc, char **argv)
{
if (argc < 1)
return netns_list(0, NULL);
if ((matches(*argv, "list") == 0) || (matches(*argv, "show") == 0) ||
(matches(*argv, "lst") == 0))
return netns_list(argc-1, argv+1);
if (matches(*argv, "help") == 0)
return usage();
if (matches(*argv, "add") == 0)
return netns_add(argc-1, argv+1);
if (matches(*argv, "delete") == 0)
return netns_delete(argc-1, argv+1);
if (matches(*argv, "identify") == 0)
return netns_identify(argc-1, argv+1);
if (matches(*argv, "pids") == 0)
return netns_pids(argc-1, argv+1);
if (matches(*argv, "exec") == 0)
return netns_exec(argc-1, argv+1);
if (matches(*argv, "monitor") == 0)
return netns_monitor(argc-1, argv+1);
fprintf(stderr, "Command \"%s\" is unknown, try \"ip netns help\".\n", *argv);
exit(-1);
}
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