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 [[ -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 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
  26 #include <fcntl.h>
  27 #include <getopt.h>
  28 #include <stdio.h>
  29 #include <string.h>
  30 #include <stdlib.h>
  31 #include <sys/file.h>
  32 #include <unistd.h>
  33 #include "fw_env.h"
  34
  35 #define CMD_PRINTENV    "fw_printenv"
  36 #define CMD_SETENV      "fw_setenv"
  37
  38 static struct option long_options[] = {
  39         {"script", required_argument, NULL, 's'},
  40         {"help", no_argument, NULL, 'h'},
  41         {NULL, 0, NULL, 0}
  42 };
  43
  44 void usage(void)
  45 {
  46
  47         fprintf(stderr, "fw_printenv/fw_setenv, "
  48                 "a command line interface to U-Boot environment\n\n"
  49                 "usage:\tfw_printenv [-n] [variable name]\n"
  50                 "\tfw_setenv [variable name] [variable value]\n"
  51                 "\tfw_setenv -s [ file ]\n"
  52                 "\tfw_setenv -s - < [ file ]\n\n"
  53                 "The file passed as argument contains only pairs "
  54                 "name / value\n"
  55                 "Example:\n"
  56                 "# Any line starting with # is treated as comment\n"
  57                 "\n"
  58                 "\t      netdev         eth0\n"
  59                 "\t      kernel_addr    400000\n"
  60                 "\t      var1\n"
  61                 "\t      var2          The quick brown fox jumps over the "
  62                 "lazy dog\n"
  63                 "\n"
  64                 "A variable without value will be dropped. It is possible\n"
  65                 "to put any number of spaces between the fields, but any\n"
  66                 "space inside the value is treated as part of the value "
  67                 "itself.\n\n"
  68         );
  69 }
  70
  71 int main(int argc, char *argv[])
  72 {
  73         char *p;
  74         char *cmdname = *argv;
  75         char *script_file = NULL;
  76         int c;
  77         const char *lockname = "/var/lock/" CMD_PRINTENV ".lock";
  78         int lockfd = -1;
  79         int retval = EXIT_SUCCESS;
  80
  81         lockfd = open(lockname, O_WRONLY | O_CREAT | O_TRUNC, 0666);
  82         if (-1 == lockfd) {
  83                 fprintf(stderr, "Error opening lock file %s\n", lockname);
  84                 return EXIT_FAILURE;
  85         }
  86
  87         if (-1 == flock(lockfd, LOCK_EX)) {
  88                 fprintf(stderr, "Error locking file %s\n", lockname);
  89                 close(lockfd);
  90                 return EXIT_FAILURE;
  91         }
  92
  93         if ((p = strrchr (cmdname, '/')) != NULL) {
  94                 cmdname = p + 1;
  95         }
  96
  97         while ((c = getopt_long (argc, argv, "ns:h",
  98                 long_options, NULL)) != EOF) {
  99                 switch (c) {
 100                 case 'n':
 101                         /* handled in fw_printenv */
 102                         break;
 103                 case 's':
 104                         script_file = optarg;
 105                         break;
 106                 case 'h':
 107                         usage();
 108                         goto exit;
 109                 default: /* '?' */
 110                         fprintf(stderr, "Try `%s --help' for more information."
 111                                 "\n", cmdname);
 112                         retval = EXIT_FAILURE;
 113                         goto exit;
 114                 }
 115         }
 116
 117         if (strcmp(cmdname, CMD_PRINTENV) == 0) {
 118                 if (fw_printenv(argc, argv) != 0)
 119                         retval = EXIT_FAILURE;
 120         } else if (strcmp(cmdname, CMD_SETENV) == 0) {
 121                 if (!script_file) {
 122                         if (fw_setenv(argc, argv) != 0)
 123                                 retval = EXIT_FAILURE;
 124                 } else {
 125                         if (fw_parse_script(script_file) != 0)
 126                                 retval = EXIT_FAILURE;
 127                 }
 128         } else {
 129                 fprintf(stderr,
 130                         "Identity crisis - may be called as `" CMD_PRINTENV
 131                         "' or as `" CMD_SETENV "' but not as `%s'\n",
 132                         cmdname);
 133                 retval = EXIT_FAILURE;
 134         }
 135
 136 exit:
 137         flock(lockfd, LOCK_UN);
 138         close(lockfd);
 139         return retval;
 140 }