btrfs.c

   1 /*
   2  * This program is free software; you can redistribute it and/or
   3  * modify it under the terms of the GNU General Public
   4  * License v2 as published by the Free Software Foundation.
   5  *
   6  * This program is distributed in the hope that it will be useful,
   7  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   8  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   9  * General Public License for more details.
  10  *
  11  * You should have received a copy of the GNU General Public
  12  * License along with this program; if not, write to the
  13  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  14  * Boston, MA 021110-1307, USA.
  15  */
  16
  17
  18 #include <stdio.h>
  19 #include <stdlib.h>
  20 #include <string.h>
  21
  22 #include "btrfs_cmds.h"
  23 #include "version.h"
  24
  25 typedef int (*CommandFunction)(int argc, char **argv);
  26
  27 struct Command {
  28         CommandFunction func;   /* function which implements the command */
  29         int     nargs;          /* if == 999, any number of arguments
  30                                    if >= 0, number of arguments,
  31                                    if < 0, _minimum_ number of arguments */
  32         char    *verb;          /* verb */
  33         char    *help;          /* help lines; form the 2nd onward they are
  34                                    indented */
  35
  36         /* the following fields are run-time filled by the program */
  37         char    **cmds;         /* array of subcommands */
  38         int     ncmds;          /* number of subcommand */
  39 };
  40
  41 static struct Command commands[] = {
  42
  43         /*
  44                 avoid short commands different for the case only
  45         */
  46         { do_clone, 2,
  47           "subvolume snapshot", "<source> [<dest>/]<name>\n"
  48                 "Create a writable snapshot of the subvolume <source> with\n"
  49                 "the name <name> in the <dest> directory."
  50         },
  51         { do_delete_subvolume, 1,
  52           "subvolume delete", "<subvolume>\n"
  53                 "Delete the subvolume <subvolume>."
  54         },
  55         { do_create_subvol, 1,
  56           "subvolume create", "[<dest>/]<name>\n"
  57                 "Create a subvolume in <dest> (or the current directory if\n"
  58                 "not passed)."
  59         },
  60         { do_subvol_list, 1, "subvolume list", "<path>\n"
  61                 "List the snapshot/subvolume of a filesystem."
  62         },
  63         { do_defrag, -1,
  64           "filesystem defragment", "[-vcf] [-s start] [-l len] [-t size] <file>|<dir> [<file>|<dir>...]\n"
  65                 "Defragment a file or a directory."
  66         },
  67         { do_set_default_subvol, 2,
  68           "subvolume set-default", "<id> <path>\n"
  69                 "Set the subvolume of the filesystem <path> which will be mounted\n"
  70                 "as default."
  71         },
  72         { do_fssync, 1,
  73           "filesystem sync", "<path>\n"
  74                 "Force a sync on the filesystem <path>."
  75         },
  76         { do_resize, 2,
  77           "filesystem resize", "[+/-]<newsize>[gkm]|max <filesystem>\n"
  78                 "Resize the file system. If 'max' is passed, the filesystem\n"
  79                 "will occupe all available space on the device."
  80         },
  81         { do_show_filesystem, 999,
  82           "filesystem show", "[<uuid>|<label>]\n"
  83                 "Show the info of a btrfs filesystem. If no <uuid> or <label>\n"
  84                 "is passed, info of all the btrfs filesystem are shown."
  85         },
  86         { do_balance, 1,
  87           "filesystem balance", "<path>\n"
  88                 "Balance the chunks across the device."
  89         },
  90         { do_scan,
  91           999, "device scan", "[<device> [<device>..]\n"
  92                 "Scan all device for or the passed device for a btrfs\n"
  93                 "filesystem."
  94         },
  95         { do_add_volume, -2,
  96           "device add", "<dev> [<dev>..] <path>\n"
  97                 "Add a device to a filesystem."
  98         },
  99         { do_remove_volume, -2,
 100           "device delete", "<dev> [<dev>..] <path>\n"
 101                 "Remove a device from a filesystem."
 102         },
 103         /* coming soon
 104         { 2, "filesystem label", "<label> <path>\n"
 105                 "Set the label of a filesystem"
 106         }
 107         */
 108         { 0, 0 , 0 }
 109 };
 110
 111 static char *get_prgname(char *programname)
 112 {
 113         char    *np;
 114         np = strrchr(programname,'/');
 115         if(!np)
 116                 np = programname;
 117         else
 118                 np++;
 119
 120         return np;
 121 }
 122
 123 static void print_help(char *programname, struct Command *cmd)
 124 {
 125         char    *pc;
 126
 127         printf("\t%s %s ", programname, cmd->verb );
 128
 129         for(pc = cmd->help; *pc; pc++){
 130                 putchar(*pc);
 131                 if(*pc == '\n')
 132                         printf("\t\t");
 133         }
 134         putchar('\n');
 135 }
 136
 137 static void help(char *np)
 138 {
 139         struct Command *cp;
 140
 141         printf("Usage:\n");
 142         for( cp = commands; cp->verb; cp++ )
 143                 print_help(np, cp);
 144
 145         printf("\n\t%s help|--help|-h\n\t\tShow the help.\n",np);
 146         printf("\n%s\n", BTRFS_BUILD_VERSION);
 147 }
 148
 149 static int split_command(char *cmd, char ***commands)
 150 {
 151         int     c, l;
 152         char    *p, *s;
 153
 154         for( *commands = 0, l = c = 0, p = s = cmd ; ; p++, l++ ){
 155                 if ( *p && *p != ' ' )
 156                         continue;
 157
 158                 /* c + 2 so that we have room for the null */
 159                 (*commands) = realloc( (*commands), sizeof(char *)*(c + 2));
 160                 (*commands)[c] = strndup(s, l);
 161                 c++;
 162                 l = 0;
 163                 s = p+1;
 164                 if( !*p ) break;
 165         }
 166
 167         (*commands)[c] = 0;
 168         return c;
 169 }
 170
 171 /*
 172         This function checks if the passed command is ambiguous
 173 */
 174 static int check_ambiguity(struct Command *cmd, char **argv){
 175         int             i;
 176         struct Command  *cp;
 177         /* check for ambiguity */
 178         for( i = 0 ; i < cmd->ncmds ; i++ ){
 179                 int match;
 180                 for( match = 0, cp = commands; cp->verb; cp++ ){
 181                         int     j, skip;
 182                         char    *s1, *s2;
 183
 184                         if( cp->ncmds < i )
 185                                 continue;
 186
 187                         for( skip = 0, j = 0 ; j < i ; j++ )
 188                                 if( strcmp(cmd->cmds[j], cp->cmds[j])){
 189                                         skip=1;
 190                                         break;
 191                                 }
 192                         if(skip)
 193                                 continue;
 194
 195                         if( !strcmp(cmd->cmds[i], cp->cmds[i]))
 196                                 continue;
 197                         for(s2 = cp->cmds[i], s1 = argv[i+1];
 198                                 *s1 == *s2 && *s1; s1++, s2++ ) ;
 199                         if( !*s1 )
 200                                 match++;
 201                 }
 202                 if(match){
 203                         int j;
 204                         fprintf(stderr, "ERROR: in command '");
 205                         for( j = 0 ; j <= i ; j++ )
 206                                 fprintf(stderr, "%s%s",j?" ":"", argv[j+1]);
 207                         fprintf(stderr, "', '%s' is ambiguous\n",argv[j]);
 208                         return -2;
 209                 }
 210         }
 211         return 0;
 212 }
 213
 214 /*
 215  * This function, compacts the program name and the command in the first
 216  * element of the '*av' array
 217  */
 218 static int prepare_args(int *ac, char ***av, char *prgname, struct Command *cmd ){
 219
 220         char    **ret;
 221         int     i;
 222         char    *newname;
 223
 224         ret = (char **)malloc(sizeof(char*)*(*ac+1));
 225         newname = (char*)malloc(strlen(prgname)+strlen(cmd->verb)+2);
 226         if( !ret || !newname ){
 227                 free(ret);
 228                 free(newname);
 229                 return -1;
 230         }
 231
 232         ret[0] = newname;
 233         for(i=0; i < *ac ; i++ )
 234                 ret[i+1] = (*av)[i];
 235
 236         strcpy(newname, prgname);
 237         strcat(newname, " ");
 238         strcat(newname, cmd->verb);
 239
 240         (*ac)++;
 241         *av = ret;
 242
 243         return 0;
 244
 245 }
 246
 247
 248
 249 /*
 250
 251         This function perform the following jobs:
 252         - show the help if '--help' or 'help' or '-h' are passed
 253         - verify that a command is not ambiguous, otherwise show which
 254           part of the command is ambiguous
 255         - if after a (even partial) command there is '--help' show the help
 256           for all the matching commands
 257         - if the command doesn't' match show an error
 258         - finally, if a command match, they return which command is matched and
 259           the arguments
 260
 261         The function return 0 in case of help is requested; <0 in case
 262         of uncorrect command; >0 in case of matching commands
 263         argc, argv are the arg-counter and arg-vector (input)
 264         *nargs_ is the number of the arguments after the command (output)
 265         **cmd_  is the invoked command (output)
 266         ***args_ are the arguments after the command
 267
 268 */
 269 static int parse_args(int argc, char **argv,
 270                       CommandFunction *func_,
 271                       int *nargs_, char **cmd_, char ***args_ )
 272 {
 273         struct Command  *cp;
 274         struct Command  *matchcmd=0;
 275         char            *prgname = get_prgname(argv[0]);
 276         int             i=0, helprequested=0;
 277
 278         if( argc < 2 || !strcmp(argv[1], "help") ||
 279                 !strcmp(argv[1], "-h") || !strcmp(argv[1], "--help")){
 280                 help(prgname);
 281                 return 0;
 282         }
 283
 284         for( cp = commands; cp->verb; cp++ )
 285                 if( !cp->ncmds)
 286                         cp->ncmds = split_command(cp->verb, &(cp->cmds));
 287
 288         for( cp = commands; cp->verb; cp++ ){
 289                 int     match;
 290
 291                 if( argc-1 < cp->ncmds )
 292                         continue;
 293                 for( match = 1, i = 0 ; i < cp->ncmds ; i++ ){
 294                         char    *s1, *s2;
 295                         s1 = cp->cmds[i];
 296                         s2 = argv[i+1];
 297
 298                         for(s2 = cp->cmds[i], s1 = argv[i+1];
 299                                 *s1 == *s2 && *s1;
 300                                 s1++, s2++ ) ;
 301                         if( *s1 ){
 302                                 match=0;
 303                                 break;
 304                         }
 305                 }
 306
 307                 /* If you understand why this code works ...
 308                         you are a genious !! */
 309                 if(argc>i+1 && !strcmp(argv[i+1],"--help")){
 310                         if(!helprequested)
 311                                 printf("Usage:\n");
 312                         print_help(prgname, cp);
 313                         helprequested=1;
 314                         continue;
 315                 }
 316
 317                 if(!match)
 318                         continue;
 319
 320                 matchcmd = cp;
 321                 *nargs_  = argc-matchcmd->ncmds-1;
 322                 *cmd_ = matchcmd->verb;
 323                 *args_ = argv+matchcmd->ncmds+1;
 324                 *func_ = cp->func;
 325
 326                 break;
 327         }
 328
 329         if(helprequested){
 330                 printf("\n%s\n", BTRFS_BUILD_VERSION);
 331                 return 0;
 332         }
 333
 334         if(!matchcmd){
 335                 fprintf( stderr, "ERROR: unknown command '%s'\n",argv[1]);
 336                 help(prgname);
 337                 return -1;
 338         }
 339
 340         if(check_ambiguity(matchcmd, argv))
 341                 return -2;
 342
 343         /* check the number of argument */
 344         if (matchcmd->nargs < 0 && matchcmd->nargs < -*nargs_ ){
 345                 fprintf(stderr, "ERROR: '%s' requires minimum %d arg(s)\n",
 346                         matchcmd->verb, -matchcmd->nargs);
 347                         return -2;
 348         }
 349         if(matchcmd->nargs >= 0 && matchcmd->nargs != *nargs_ && matchcmd->nargs != 999){
 350                 fprintf(stderr, "ERROR: '%s' requires %d arg(s)\n",
 351                         matchcmd->verb, matchcmd->nargs);
 352                         return -2;
 353         }
 354
 355         if (prepare_args( nargs_, args_, prgname, matchcmd )){
 356                 fprintf(stderr, "ERROR: not enough memory\\n");
 357                 return -20;
 358         }
 359
 360
 361         return 1;
 362 }
 363 int main(int ac, char **av )
 364 {
 365
 366         char            *cmd=0, **args=0;
 367         int             nargs=0, r;
 368         CommandFunction func=0;
 369
 370         r = parse_args(ac, av, &func, &nargs, &cmd, &args);
 371         if( r <= 0 ){
 372                 /* error or no command to parse*/
 373                 exit(-r);
 374         }
 375
 376         exit(func(nargs, args));
 377
 378 }
 379