src/lxc/tools/lxc_device.c

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