make btrfs cross compilation friendly

[btrfs-progs-unstable/devel.git] / btrfs.c

/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "kerncompat.h"
#include "btrfs_cmds.h"
#include "version.h"

#define BASIC_HELP 0
#define ADVANCED_HELP 1

typedef int (*CommandFunction)(int argc, char **argv);

struct Command {
        CommandFunction func;   /* function which implements the command */
        int     nargs;          /* if == 999, any number of arguments
                                   if >= 0, number of arguments,
                                   if < 0, _minimum_ number of arguments */
        char    *verb;          /* verb */
        char    *help;          /* help lines; from the 2nd line onward they 
                                   are automatically indented */
        char    *adv_help;      /* advanced help message; from the 2nd line 
                                   onward they are automatically indented */

        /* the following fields are run-time filled by the program */
        char    **cmds;         /* array of subcommands */
        int     ncmds;          /* number of subcommand */
};

static struct Command commands[] = {

        /*
                avoid short commands different for the case only
        */
        { do_clone, -2,
          "subvolume snapshot", "[-r] <source> [<dest>/]<name>\n"
                "Create a writable/readonly snapshot of the subvolume <source> with\n"
                "the name <name> in the <dest> directory.",
          NULL
        },
        { do_delete_subvolume, 1,
          "subvolume delete", "<subvolume>\n"
                "Delete the subvolume <subvolume>.",
          NULL
        },
        { do_create_subvol, 1,
          "subvolume create", "[<dest>/]<name>\n"
                "Create a subvolume in <dest> (or the current directory if\n"
                "not passed).",
          NULL
        },
        { do_subvol_list, 1, "subvolume list", "<path>\n"
                "List the snapshot/subvolume of a filesystem.",
          NULL
        },
        { do_set_default_subvol, 2,
          "subvolume set-default", "<id> <path>\n"
                "Set the subvolume of the filesystem <path> which will be mounted\n"
                "as default.",
          NULL
        },
        { do_find_newer, 2, "subvolume find-new", "<path> <last_gen>\n"
                "List the recently modified files in a filesystem.",
          NULL
        },
        { do_defrag, -1,
          "filesystem defragment", "[-vf] [-c[zlib,lzo]] [-s start] [-l len] [-t size] <file>|<dir> [<file>|<dir>...]\n"
                "Defragment a file or a directory.",
                "[-vcf] [-s start] [-l len] [-t size] <file>|<dir> [<file>|<dir>...]\n"
                "Defragment file data or directory metadata.\n"
                "-v         be verbose\n"
                "-c         compress the file while defragmenting\n"
                "-f         flush data to disk immediately after defragmenting\n"
                "-s start   defragment only from byte onward\n"
                "-l len     defragment only up to len bytes\n"
                "-t size    minimal size of file to be considered for defragmenting\n"
        },
        { do_fssync, 1,
          "filesystem sync", "<path>\n"
                "Force a sync on the filesystem <path>.",
          NULL
        },
        { do_resize, 2,
          "filesystem resize", "[+/-]<newsize>[gkm]|max <filesystem>\n"
                "Resize the file system. If 'max' is passed, the filesystem\n"
                "will occupe all available space on the device.",
          NULL
        },
        { do_show_filesystem, 999,
          "filesystem show", "[<device>|<uuid>|<label>]\n"
                "Show the info of a btrfs filesystem. If no argument\n"
                "is passed, info of all the btrfs filesystem are shown.",
          NULL
        },
        { do_df_filesystem, 1,
          "filesystem df", "<path>\n"
                "Show space usage information for a mount point.",
          NULL
        },
        { do_balance, 1,
          "filesystem balance", "<path>\n"
                "Balance the chunks across the device.",
          NULL
        },
        { do_change_label, -1,
          "filesystem label", "<device> [<newlabel>]\n"
          "With one argument, get the label of filesystem on <device>.\n"
          "If <newlabel> is passed, set the filesystem label to <newlabel>.\n"
          "The filesystem must be unmounted.\n"
        },
        { do_scan, 999, 
          "device scan", "[<device>...]\n"
                "Scan all device for or the passed device for a btrfs\n"
                "filesystem.",
          NULL
        },
        { do_add_volume, -2,
          "device add", "<device> [<device>...] <path>\n"
                "Add a device to a filesystem.",
          NULL
        },
        { do_remove_volume, -2,
          "device delete", "<device> [<device>...] <path>\n"
                "Remove a device from a filesystem.",
          NULL
        },
        { 0, 0, 0, 0 }
};

static char *get_prgname(char *programname)
{
        char    *np;
        np = strrchr(programname,'/');
        if(!np)
                np = programname;
        else
                np++;

        return np;
}

static void print_help(char *programname, struct Command *cmd, int helptype)
{
        char    *pc;

        printf("\t%s %s ", programname, cmd->verb );

        if (helptype == ADVANCED_HELP && cmd->adv_help)
                for(pc = cmd->adv_help; *pc; pc++){
                        putchar(*pc);
                        if(*pc == '\n')
                                printf("\t\t");
                }
        else
                for(pc = cmd->help; *pc; pc++){
                        putchar(*pc);
                        if(*pc == '\n')
                                printf("\t\t");
                }

        putchar('\n');
}

static void help(char *np)
{
        struct Command *cp;

        printf("Usage:\n");
        for( cp = commands; cp->verb; cp++ )
                print_help(np, cp, BASIC_HELP);

        printf("\n\t%s help|--help|-h\n\t\tShow the help.\n",np);
        printf("\n\t%s <cmd> --help\n\t\tShow detailed help for a command or\n\t\t"
               "subset of commands.\n",np);
        printf("\n%s\n", BTRFS_BUILD_VERSION);
}

static int split_command(char *cmd, char ***commands)
{
        int     c, l;
        char    *p, *s;

        for( *commands = 0, l = c = 0, p = s = cmd ; ; p++, l++ ){
                if ( *p && *p != ' ' )
                        continue;

                /* c + 2 so that we have room for the null */
                (*commands) = realloc( (*commands), sizeof(char *)*(c + 2));
                (*commands)[c] = strndup(s, l);
                c++;
                l = 0;
                s = p+1;
                if( !*p ) break;
        }

        (*commands)[c] = 0;
        return c;
}

/*
        This function checks if the passed command is ambiguous
*/
static int check_ambiguity(struct Command *cmd, char **argv){
        int             i;
        struct Command  *cp;
        /* check for ambiguity */
        for( i = 0 ; i < cmd->ncmds ; i++ ){
                int match;
                for( match = 0, cp = commands; cp->verb; cp++ ){
                        int     j, skip;
                        char    *s1, *s2;

                        if( cp->ncmds < i )
                                continue;

                        for( skip = 0, j = 0 ; j < i ; j++ )
                                if( strcmp(cmd->cmds[j], cp->cmds[j])){
                                        skip=1;
                                        break;
                                }
                        if(skip)
                                continue;

                        if( !strcmp(cmd->cmds[i], cp->cmds[i]))
                                continue;
                        for(s2 = cp->cmds[i], s1 = argv[i+1];
                                *s1 == *s2 && *s1; s1++, s2++ ) ;
                        if( !*s1 )
                                match++;
                }
                if(match){
                        int j;
                        fprintf(stderr, "ERROR: in command '");
                        for( j = 0 ; j <= i ; j++ )
                                fprintf(stderr, "%s%s",j?" ":"", argv[j+1]);
                        fprintf(stderr, "', '%s' is ambiguous\n",argv[j]);
                        return -2;
                }
        }
        return 0;
}

/*
 * This function, compacts the program name and the command in the first
 * element of the '*av' array
 */
static int prepare_args(int *ac, char ***av, char *prgname, struct Command *cmd ){

        char    **ret;
        int     i;
        char    *newname;

        ret = (char **)malloc(sizeof(char*)*(*ac+1));
        newname = (char*)malloc(strlen(prgname)+strlen(cmd->verb)+2);
        if( !ret || !newname ){
                free(ret);
                free(newname);
                return -1;
        }

        ret[0] = newname;
        for(i=0; i < *ac ; i++ )
                ret[i+1] = (*av)[i];

        strcpy(newname, prgname);
        strcat(newname, " ");
        strcat(newname, cmd->verb);

        (*ac)++;
        *av = ret;

        return 0;

}



/*
        This function performs the following jobs:
        - show the help if '--help' or 'help' or '-h' are passed
        - verify that a command is not ambiguous, otherwise show which
          part of the command is ambiguous
        - if after a (even partial) command there is '--help' show detailed help
          for all the matching commands
        - if the command doesn't match show an error
        - finally, if a command matches, they return which command matched and
          the arguments

        The function return 0 in case of help is requested; <0 in case
        of uncorrect command; >0 in case of matching commands
        argc, argv are the arg-counter and arg-vector (input)
        *nargs_ is the number of the arguments after the command (output)
        **cmd_  is the invoked command (output)
        ***args_ are the arguments after the command

*/
static int parse_args(int argc, char **argv,
                      CommandFunction *func_,
                      int *nargs_, char **cmd_, char ***args_ )
{
        struct Command  *cp;
        struct Command  *matchcmd=0;
        char            *prgname = get_prgname(argv[0]);
        int             i=0, helprequested=0;

        if( argc < 2 || !strcmp(argv[1], "help") ||
                !strcmp(argv[1], "-h") || !strcmp(argv[1], "--help")){
                help(prgname);
                return 0;
        }

        for( cp = commands; cp->verb; cp++ )
                if( !cp->ncmds)
                        cp->ncmds = split_command(cp->verb, &(cp->cmds));

        for( cp = commands; cp->verb; cp++ ){
                int     match;

                if( argc-1 < cp->ncmds )
                        continue;
                for( match = 1, i = 0 ; i < cp->ncmds ; i++ ){
                        char    *s1, *s2;
                        s1 = cp->cmds[i];
                        s2 = argv[i+1];

                        for(s2 = cp->cmds[i], s1 = argv[i+1];
                                *s1 == *s2 && *s1;
                                s1++, s2++ ) ;
                        if( *s1 ){
                                match=0;
                                break;
                        }
                }

                /* If you understand why this code works ...
                        you are a genious !! */
                if(argc>i+1 && !strcmp(argv[i+1],"--help")){
                        if(!helprequested)
                                printf("Usage:\n");
                        print_help(prgname, cp, ADVANCED_HELP);
                        helprequested=1;
                        continue;
                }

                if(!match)
                        continue;

                matchcmd = cp;
                *nargs_  = argc-matchcmd->ncmds-1;
                *cmd_ = matchcmd->verb;
                *args_ = argv+matchcmd->ncmds+1;
                *func_ = cp->func;

                break;
        }

        if(helprequested){
                printf("\n%s\n", BTRFS_BUILD_VERSION);
                return 0;
        }

        if(!matchcmd){
                fprintf( stderr, "ERROR: unknown command '%s'\n",argv[1]);
                help(prgname);
                return -1;
        }

        if(check_ambiguity(matchcmd, argv))
                return -2;

        /* check the number of argument */
        if (matchcmd->nargs < 0 && matchcmd->nargs < -*nargs_ ){
                fprintf(stderr, "ERROR: '%s' requires minimum %d arg(s)\n",
                        matchcmd->verb, -matchcmd->nargs);
                        return -2;
        }
        if(matchcmd->nargs >= 0 && matchcmd->nargs != *nargs_ && matchcmd->nargs != 999){
                fprintf(stderr, "ERROR: '%s' requires %d arg(s)\n",
                        matchcmd->verb, matchcmd->nargs);
                        return -2;
        }
        
        if (prepare_args( nargs_, args_, prgname, matchcmd )){
                fprintf(stderr, "ERROR: not enough memory\\n");
                return -20;
        }


        return 1;
}
int main(int ac, char **av )
{

        char            *cmd=0, **args=0;
        int             nargs=0, r;
        CommandFunction func=0;

        r = parse_args(ac, av, &func, &nargs, &cmd, &args);
        if( r <= 0 ){
                /* error or no command to parse*/
                exit(-r);
        }

        exit(func(nargs, args));

}