tools/env/fw_env_main.c

   1 /*
   2  * (C) Copyright 2000-2008
   3  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   4  *
   5  * SPDX-License-Identifier:     GPL-2.0+
   6  */
   7
   8 /*
   9  * Command line user interface to firmware (=U-Boot) environment.
  10  *
  11  * Implements:
  12  *      fw_printenv [ -a key ] [[ -n name ] | [ name ... ]]
  13  *              - prints the value of a single environment variable
  14  *                "name", the ``name=value'' pairs of one or more
  15  *                environment variables "name", or the whole
  16  *                environment if no names are specified.
  17  *      fw_setenv [ -a key ] name [ value ... ]
  18  *              - If a name without any values is given, the variable
  19  *                with this name is deleted from the environment;
  20  *                otherwise, all "value" arguments are concatenated,
  21  *                separated by single blank characters, and the
  22  *                resulting string is assigned to the environment
  23  *                variable "name"
  24  *
  25  * If '-a key' is specified, the env block is encrypted with AES 128 CBC.
  26  * The 'key' argument is in the format of 32 hexadecimal numbers (16 bytes
  27  * of AES key), eg. '-a aabbccddeeff00112233445566778899'.
  28  */
  29
  30 #include <fcntl.h>
  31 #include <getopt.h>
  32 #include <stdio.h>
  33 #include <string.h>
  34 #include <stdlib.h>
  35 #include <sys/file.h>
  36 #include <unistd.h>
  37 #include "fw_env.h"
  38
  39 #define CMD_PRINTENV    "fw_printenv"
  40 #define CMD_SETENV      "fw_setenv"
  41
  42 static struct option long_options[] = {
  43         {"script", required_argument, NULL, 's'},
  44         {"help", no_argument, NULL, 'h'},
  45         {NULL, 0, NULL, 0}
  46 };
  47
  48 void usage(void)
  49 {
  50
  51         fprintf(stderr, "fw_printenv/fw_setenv, "
  52                 "a command line interface to U-Boot environment\n\n"
  53 #ifndef CONFIG_FILE
  54                 "usage:\tfw_printenv [-a key] [-n] [variable name]\n"
  55                 "\tfw_setenv [-a key] [variable name] [variable value]\n"
  56 #else
  57                 "usage:\tfw_printenv [-c /my/fw_env.config] [-a key] [-n] [variable name]\n"
  58                 "\tfw_setenv [-c /my/fw_env.config] [-a key] [variable name] [variable value]\n"
  59 #endif
  60                 "\tfw_setenv -s [ file ]\n"
  61                 "\tfw_setenv -s - < [ file ]\n\n"
  62                 "The file passed as argument contains only pairs "
  63                 "name / value\n"
  64                 "Example:\n"
  65                 "# Any line starting with # is treated as comment\n"
  66                 "\n"
  67                 "\t      netdev         eth0\n"
  68                 "\t      kernel_addr    400000\n"
  69                 "\t      var1\n"
  70                 "\t      var2          The quick brown fox jumps over the "
  71                 "lazy dog\n"
  72                 "\n"
  73                 "A variable without value will be dropped. It is possible\n"
  74                 "to put any number of spaces between the fields, but any\n"
  75                 "space inside the value is treated as part of the value "
  76                 "itself.\n\n"
  77         );
  78 }
  79
  80 int main(int argc, char *argv[])
  81 {
  82         char *p;
  83         char *cmdname = *argv;
  84         char *script_file = NULL;
  85         int c;
  86         const char *lockname = "/var/lock/" CMD_PRINTENV ".lock";
  87         int lockfd = -1;
  88         int retval = EXIT_SUCCESS;
  89
  90         lockfd = open(lockname, O_WRONLY | O_CREAT | O_TRUNC, 0666);
  91         if (-1 == lockfd) {
  92                 fprintf(stderr, "Error opening lock file %s\n", lockname);
  93                 return EXIT_FAILURE;
  94         }
  95
  96         if (-1 == flock(lockfd, LOCK_EX)) {
  97                 fprintf(stderr, "Error locking file %s\n", lockname);
  98                 close(lockfd);
  99                 return EXIT_FAILURE;
 100         }
 101
 102         if ((p = strrchr (cmdname, '/')) != NULL) {
 103                 cmdname = p + 1;
 104         }
 105
 106         while ((c = getopt_long (argc, argv, "a:c:ns:h",
 107                 long_options, NULL)) != EOF) {
 108                 switch (c) {
 109                 case 'a':
 110                         /* AES key, handled later */
 111                         break;
 112                 case 'c':
 113                         /* handled later */
 114                         break;
 115                 case 'n':
 116                         /* handled in fw_printenv */
 117                         break;
 118                 case 's':
 119                         script_file = optarg;
 120                         break;
 121                 case 'h':
 122                         usage();
 123                         goto exit;
 124                 default: /* '?' */
 125                         fprintf(stderr, "Try `%s --help' for more information."
 126                                 "\n", cmdname);
 127                         retval = EXIT_FAILURE;
 128                         goto exit;
 129                 }
 130         }
 131
 132         if (strcmp(cmdname, CMD_PRINTENV) == 0) {
 133                 if (fw_printenv(argc, argv) != 0)
 134                         retval = EXIT_FAILURE;
 135         } else if (strcmp(cmdname, CMD_SETENV) == 0) {
 136                 if (!script_file) {
 137                         if (fw_setenv(argc, argv) != 0)
 138                                 retval = EXIT_FAILURE;
 139                 } else {
 140                         if (fw_parse_script(script_file) != 0)
 141                                 retval = EXIT_FAILURE;
 142                 }
 143         } else {
 144                 fprintf(stderr,
 145                         "Identity crisis - may be called as `" CMD_PRINTENV
 146                         "' or as `" CMD_SETENV "' but not as `%s'\n",
 147                         cmdname);
 148                 retval = EXIT_FAILURE;
 149         }
 150
 151 exit:
 152         flock(lockfd, LOCK_UN);
 153         close(lockfd);
 154         return retval;
 155 }