/*
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* namespace.c
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <fcntl.h>
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#include <dirent.h>
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#include <limits.h>
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#include "utils.h"
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#include "namespace.h"
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static void bind_etc(const char *name)
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{
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char etc_netns_path[PATH_MAX];
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char netns_name[PATH_MAX];
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char etc_name[PATH_MAX];
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struct dirent *entry;
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DIR *dir;
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snprintf(etc_netns_path, sizeof(etc_netns_path), "%s/%s", NETNS_ETC_DIR, name);
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dir = opendir(etc_netns_path);
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if (!dir)
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return;
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while ((entry = readdir(dir)) != NULL) {
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if (strcmp(entry->d_name, ".") == 0)
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continue;
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if (strcmp(entry->d_name, "..") == 0)
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continue;
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snprintf(netns_name, sizeof(netns_name), "%s/%s", etc_netns_path, entry->d_name);
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snprintf(etc_name, sizeof(etc_name), "/etc/%s", entry->d_name);
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if (mount(netns_name, etc_name, "none", MS_BIND, NULL) < 0) {
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fprintf(stderr, "Bind %s -> %s failed: %s\n",
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netns_name, etc_name, strerror(errno));
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}
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}
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closedir(dir);
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}
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int netns_switch(char *name)
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{
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char net_path[PATH_MAX];
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int netns;
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snprintf(net_path, sizeof(net_path), "%s/%s", NETNS_RUN_DIR, name);
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netns = open(net_path, O_RDONLY | O_CLOEXEC);
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if (netns < 0) {
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fprintf(stderr, "Cannot open network namespace \"%s\": %s\n",
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name, strerror(errno));
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return -1;
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}
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if (setns(netns, CLONE_NEWNET) < 0) {
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fprintf(stderr, "setting the network namespace \"%s\" failed: %s\n",
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name, strerror(errno));
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close(netns);
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return -1;
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}
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close(netns);
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if (unshare(CLONE_NEWNS) < 0) {
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fprintf(stderr, "unshare failed: %s\n", strerror(errno));
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return -1;
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}
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/* Don't let any mounts propagate back to the parent */
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if (mount("", "/", "none", MS_SLAVE | MS_REC, NULL)) {
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fprintf(stderr, "\"mount --make-rslave /\" failed: %s\n",
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strerror(errno));
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return -1;
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}
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/* Mount a version of /sys that describes the network namespace */
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if (umount2("/sys", MNT_DETACH) < 0) {
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fprintf(stderr, "umount of /sys failed: %s\n", strerror(errno));
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return -1;
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}
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if (mount(name, "/sys", "sysfs", 0, NULL) < 0) {
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fprintf(stderr, "mount of /sys failed: %s\n",strerror(errno));
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return -1;
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}
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/* Setup bind mounts for config files in /etc */
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bind_etc(name);
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return 0;
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}
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int netns_get_fd(const char *name)
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{
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char pathbuf[PATH_MAX];
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const char *path, *ptr;
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path = name;
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ptr = strchr(name, '/');
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if (!ptr) {
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snprintf(pathbuf, sizeof(pathbuf), "%s/%s",
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NETNS_RUN_DIR, name );
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path = pathbuf;
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}
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return open(path, O_RDONLY);
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}
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int netns_foreach(int (*func)(char *nsname, void *arg), void *arg)
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{
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DIR *dir;
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struct dirent *entry;
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dir = opendir(NETNS_RUN_DIR);
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if (!dir)
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return -1;
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while ((entry = readdir(dir)) != NULL) {
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if (strcmp(entry->d_name, ".") == 0)
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continue;
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if (strcmp(entry->d_name, "..") == 0)
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continue;
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if (func(entry->d_name, arg))
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break;
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}
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closedir(dir);
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return 0;
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}
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