compiled-tools/loadenv.c

   1
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <errno.h>
   5 #include <err.h>
   6 #include <string.h>
   7 #include <tool/libarray.h>
   8
   9 static char* helptext =
  10 "Usage: loadenv [-0c] <FILE> <COMMAND> [<ARG> [...]]\n"
  11 "See loadenv(1).\n"
  12 ;
  13
  14
  15 struct dedupdata {
  16         size_t envnamelen;
  17         char * env;
  18         Array** envarray;
  19 };
  20
  21 array_loop_control
  22 remove_duplicate(array_index_t index, char* item, struct dedupdata * dedupdata)
  23 {
  24         if(strchr(item, '=')-item == dedupdata->envnamelen && strncmp(item, dedupdata->env, dedupdata->envnamelen) == 0)
  25         {
  26                 array_delete(dedupdata->envarray, index, 1);
  27                 return ARRAY_LOOP_STOP;
  28         }
  29         return ARRAY_LOOP_CONTINUE;
  30 }
  31
  32 #ifdef DEBUG
  33 array_loop_control
  34 pprint(array_index_t index, char * item, void * x)
  35 {
  36         warnx("index %d item %s", index, item);
  37         return ARRAY_LOOP_CONTINUE;
  38 }
  39 #endif
  40
  41 int main(int argc, char** argv, char** current_env)
  42 {
  43         FILE * envfile;
  44         Array* envarray;
  45         unsigned char argidx;
  46         unsigned char delimiter;
  47         char * env;
  48         size_t envsize;
  49         size_t envnamelen;
  50         ssize_t read_status;
  51         char * envval;
  52         struct dedupdata dedupdata;
  53         unsigned char copy_current_environment;
  54         unsigned int it;
  55
  56         delimiter = '\n';
  57         copy_current_environment = 0;
  58         argidx = 1;
  59
  60         while(argidx < argc)
  61         {
  62                 if(strcmp(argv[argidx], "-0")==0)
  63                 {
  64                         delimiter = '\0';
  65                 }
  66                 else if(strcmp(argv[argidx], "-c")==0)
  67                 {
  68                         copy_current_environment = 1;
  69                 }
  70                 else if(strcmp(argv[argidx], "--help")==0)
  71                 {
  72                         printf("%s", helptext);
  73                         exit(0);
  74                 }
  75                 else if(argv[argidx][0] == '-')
  76                 {
  77                         errx(-2, "unknown option: %s", argv[argidx]);
  78                 }
  79                 else {
  80                         break;
  81                 }
  82                 argidx++;
  83         }
  84
  85         if(argidx+1 < argc)
  86         {
  87                 if(envfile = fopen(argv[argidx], "r"))
  88                 {
  89                         array_init(&envarray, 2);
  90
  91                         /* copy current environment */
  92                         if(copy_current_environment)
  93                         {
  94                                 for(it = 0; current_env[it] != NULL; it++)
  95                                 {
  96                                         array_append(&envarray, current_env[it]);
  97                                 }
  98                         }
  99
 100                         /* read up environments from file */
 101                         while(1)
 102                         {
 103                                 env = NULL;
 104                                 envsize = 0;
 105                                 read_status = getdelim(&env, &envsize, delimiter, envfile);
 106                                 if(read_status == -1) break;
 107                                 if(!env) goto read_next_env;
 108
 109                                 // chomp
 110                                 envsize = strlen(env);
 111                                 if(envsize == 0) goto read_next_env;
 112                                 if(env[envsize-1] == delimiter) env[envsize-1] = '\0';
 113                                 envsize = strlen(env);
 114
 115                                 // ignore empty
 116                                 if(envsize == 0) goto read_next_env;
 117
 118                                 // ignore comments
 119                                 if(delimiter == '\n' && env[0] == '#') goto read_next_env;
 120
 121                                 // locate value
 122                                 envval = strchr(env, '=');
 123
 124                                 if(envval == NULL)
 125                                 {
 126                                         // remove the named environment variable if it's a name only without '=' equal sign in it.
 127                                         dedupdata.envnamelen = envsize;
 128                                         dedupdata.env = env;
 129                                         dedupdata.envarray = &envarray;
 130                                         array_foreach(&envarray, 0, (array_loop_control(*)(array_index_t, char*, void*))remove_duplicate, &dedupdata);
 131                                 }
 132                                 else
 133                                 {
 134                                         envval++;  // envval point past to the '=' equal sign
 135
 136                                         #ifdef DEBUG
 137                                         array_foreach(&envarray, 0, pprint, NULL);
 138                                         #endif
 139
 140                                         // deduplicate
 141                                         dedupdata.envnamelen = envval - env - 1;
 142                                         dedupdata.env = env;
 143                                         dedupdata.envarray = &envarray;
 144                                         array_foreach(&envarray, 0, (array_loop_control(*)(array_index_t, char*, void*))remove_duplicate, &dedupdata);
 145
 146                                         // add to the env list
 147                                         array_append(&envarray, env);
 148                                 }
 149
 150                                 read_next_env:
 151                                 if(env) free(env);
 152                         }
 153
 154                         array_append(&envarray, NULL);
 155                 }
 156                 else
 157                 {
 158                         perror("fopen");
 159                         goto fail;
 160                 }
 161
 162                 #ifdef DEBUG
 163                 array_foreach(&envarray, 0, pprint, NULL);
 164                 #endif
 165
 166                 execvpe(argv[argidx+1], &argv[argidx+1], array_getarray(&envarray));
 167                 goto fail;
 168         }
 169         else
 170         {
 171                 fprintf(stderr, "%s", helptext);
 172                 exit(-2);
 173         }
 174
 175         fail:
 176         return errno == 0 ? -1 : errno;
 177 }