src/lxc/tools/lxc_device.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #ifndef _GNU_SOURCE
   4 #define _GNU_SOURCE 1
   5 #endif
   6 #include <libgen.h>
   7 #include <limits.h>
   8 #include <stdio.h>
   9 #include <string.h>
  10 #include <sys/types.h>
  11 #include <unistd.h>
  12
  13 #include "lxc.h"
  14
  15 #include "netns_ifaddrs.h"
  16 #include "arguments.h"
  17 #include "config.h"
  18 #include "log.h"
  19 #include "utils.h"
  20
  21 lxc_log_define(lxc_device, lxc);
  22
  23 static bool is_interface(const char *dev_name, pid_t pid);
  24
  25 static const struct option my_longopts[] = {
  26         LXC_COMMON_OPTIONS
  27 };
  28
  29 static struct lxc_arguments my_args = {
  30         .progname     = "lxc-device",
  31         .help         = "\
  32 --name=NAME -- add|del DEV\n\
  33 \n\
  34 lxc-device attach or detach DEV to or from container.\n\
  35 \n\
  36 Options :\n\
  37   -n, --name=NAME      NAME of the container\n\
  38   --rcfile=FILE        Load configuration file FILE\n",
  39         .options      = my_longopts,
  40         .parser       = NULL,
  41         .checker      = NULL,
  42         .log_priority = "ERROR",
  43         .log_file     = "none",
  44 };
  45
  46 static bool is_interface(const char *dev_name, pid_t pid)
  47 {
  48         pid_t p = fork();
  49         if (p < 0) {
  50                 ERROR("Failed to fork task");
  51                 exit(EXIT_FAILURE);
  52         }
  53
  54         if (p == 0) {
  55                 struct netns_ifaddrs *interfaceArray = NULL, *tempIfAddr = NULL;
  56
  57                 if (!switch_to_ns(pid, "net")) {
  58                         ERROR("Failed to enter netns of container");
  59                         _exit(-1);
  60                 }
  61
  62                 /* Grab the list of interfaces */
  63                 if (netns_getifaddrs(&interfaceArray, -1, &(bool){false})) {
  64                         ERROR("Failed to get interfaces list");
  65                         _exit(-1);
  66                 }
  67
  68                 /* Iterate through the interfaces */
  69                 for (tempIfAddr = interfaceArray; tempIfAddr != NULL; tempIfAddr = tempIfAddr->ifa_next) {
  70                         if (strncmp(tempIfAddr->ifa_name, dev_name, strlen(tempIfAddr->ifa_name)) == 0)
  71                                 _exit(EXIT_SUCCESS);
  72                 }
  73
  74                 _exit(EXIT_FAILURE);
  75         }
  76
  77         if (wait_for_pid(p) == 0)
  78                 return true;
  79
  80         return false;
  81 }
  82
  83 int main(int argc, char *argv[])
  84 {
  85         struct lxc_container *c;
  86         struct lxc_log log;
  87         char *cmd, *dev_name, *dst_name;
  88         bool ret = false;
  89
  90         if (geteuid() != 0) {
  91                 ERROR("%s must be run as root", argv[0]);
  92                 exit(EXIT_FAILURE);
  93         }
  94
  95         if (lxc_arguments_parse(&my_args, argc, argv))
  96                 exit(EXIT_FAILURE);
  97
  98         log.name = my_args.name;
  99         log.file = my_args.log_file;
 100         log.level = my_args.log_priority;
 101         log.prefix = my_args.progname;
 102         log.quiet = my_args.quiet;
 103         log.lxcpath = my_args.lxcpath[0];
 104
 105         if (lxc_log_init(&log))
 106                 exit(EXIT_FAILURE);
 107
 108         c = lxc_container_new(my_args.name, my_args.lxcpath[0]);
 109         if (!c) {
 110                 ERROR("%s doesn't exist", my_args.name);
 111                 exit(EXIT_FAILURE);
 112         }
 113
 114         if (my_args.rcfile) {
 115                 c->clear_config(c);
 116
 117                 if (!c->load_config(c, my_args.rcfile)) {
 118                         ERROR("Failed to load rcfile");
 119                         goto err;
 120                 }
 121
 122                 c->configfile = strdup(my_args.rcfile);
 123                 if (!c->configfile) {
 124                         ERROR("Out of memory setting new config filename");
 125                         goto err;
 126                 }
 127         }
 128
 129         if (!c->is_running(c)) {
 130                 ERROR("Container %s is not running", c->name);
 131                 goto err;
 132         }
 133
 134         if (my_args.argc < 2) {
 135                 ERROR("Error: no command given (Please see --help output)");
 136                 goto err;
 137         }
 138
 139         cmd = my_args.argv[0];
 140         dev_name = my_args.argv[1];
 141
 142         if (my_args.argc < 3)
 143                 dst_name = dev_name;
 144         else
 145                 dst_name = my_args.argv[2];
 146
 147         if (strncmp(cmd, "add", strlen(cmd)) == 0) {
 148                 if (is_interface(dev_name, 1))
 149                         ret = c->attach_interface(c, dev_name, dst_name);
 150                 else
 151                         ret = c->add_device_node(c, dev_name, dst_name);
 152                 if (ret != true) {
 153                         ERROR("Failed to add %s to %s", dev_name, c->name);
 154                         goto err;
 155                 }
 156         } else if (strncmp(cmd, "del", strlen(cmd)) == 0) {
 157                 if (is_interface(dev_name, c->init_pid(c)))
 158                         ret = c->detach_interface(c, dev_name, dst_name);
 159                 else
 160                         ret = c->remove_device_node(c, dev_name, dst_name);
 161                 if (ret != true) {
 162                         ERROR("Failed to del %s from %s", dev_name, c->name);
 163                         goto err;
 164                 }
 165         } else {
 166                 ERROR("Error: Please use add or del (Please see --help output)");
 167                 goto err;
 168         }
 169
 170         exit(EXIT_SUCCESS);
 171
 172 err:
 173         lxc_container_put(c);
 174         exit(EXIT_FAILURE);
 175 }