release/src/router/ntfs-3g/include/fuse-lite/fuse_opt.h

   1 /*
   2   FUSE: Filesystem in Userspace
   3   Copyright (C) 2001-2007  Miklos Szeredi <miklos@szeredi.hu>
   4
   5   This program can be distributed under the terms of the GNU LGPLv2.
   6   See the file COPYING.LIB.
   7 */
   8
   9 #ifndef _FUSE_OPT_H_
  10 #define _FUSE_OPT_H_
  11
  12 /** @file
  13  *
  14  * This file defines the option parsing interface of FUSE
  15  */
  16
  17 #ifdef __cplusplus
  18 extern "C" {
  19 #endif
  20
  21 /**
  22  * Option description
  23  *
  24  * This structure describes a single option, and and action associated
  25  * with it, in case it matches.
  26  *
  27  * More than one such match may occur, in which case the action for
  28  * each match is executed.
  29  *
  30  * There are three possible actions in case of a match:
  31  *
  32  * i) An integer (int or unsigned) variable determined by 'offset' is
  33  *    set to 'value'
  34  *
  35  * ii) The processing function is called, with 'value' as the key
  36  *
  37  * iii) An integer (any) or string (char *) variable determined by
  38  *    'offset' is set to the value of an option parameter
  39  *
  40  * 'offset' should normally be either set to
  41  *
  42  *  - 'offsetof(struct foo, member)'  actions i) and iii)
  43  *
  44  *  - -1                              action ii)
  45  *
  46  * The 'offsetof()' macro is defined in the <stddef.h> header.
  47  *
  48  * The template determines which options match, and also have an
  49  * effect on the action.  Normally the action is either i) or ii), but
  50  * if a format is present in the template, then action iii) is
  51  * performed.
  52  *
  53  * The types of templates are:
  54  *
  55  * 1) "-x", "-foo", "--foo", "--foo-bar", etc.  These match only
  56  *   themselves.  Invalid values are "--" and anything beginning
  57  *   with "-o"
  58  *
  59  * 2) "foo", "foo-bar", etc.  These match "-ofoo", "-ofoo-bar" or
  60  *    the relevant option in a comma separated option list
  61  *
  62  * 3) "bar=", "--foo=", etc.  These are variations of 1) and 2)
  63  *    which have a parameter
  64  *
  65  * 4) "bar=%s", "--foo=%lu", etc.  Same matching as above but perform
  66  *    action iii).
  67  *
  68  * 5) "-x ", etc.  Matches either "-xparam" or "-x param" as
  69  *    two separate arguments
  70  *
  71  * 6) "-x %s", etc.  Combination of 4) and 5)
  72  *
  73  * If the format is "%s", memory is allocated for the string unlike
  74  * with scanf().
  75  */
  76 struct fuse_opt {
  77         /** Matching template and optional parameter formatting */
  78         const char *templ;
  79
  80         /**
  81          * Offset of variable within 'data' parameter of fuse_opt_parse()
  82          * or -1
  83          */
  84         unsigned long offset;
  85
  86         /**
  87          * Value to set the variable to, or to be passed as 'key' to the
  88          * processing function.  Ignored if template has a format
  89          */
  90         int value;
  91 };
  92
  93 /**
  94  * Key option.  In case of a match, the processing function will be
  95  * called with the specified key.
  96  */
  97 #define FUSE_OPT_KEY(templ, key) { templ, -1U, key }
  98
  99 /**
 100  * Last option.  An array of 'struct fuse_opt' must end with a NULL
 101  * template value
 102  */
 103 #define FUSE_OPT_END { .templ = NULL }
 104
 105 /**
 106  * Argument list
 107  */
 108 struct fuse_args {
 109         /** Argument count */
 110         int argc;
 111
 112         /** Argument vector.  NULL terminated */
 113         char **argv;
 114
 115         /** Is 'argv' allocated? */
 116         int allocated;
 117 };
 118
 119 /**
 120  * Initializer for 'struct fuse_args'
 121  */
 122 #define FUSE_ARGS_INIT(argc, argv) { argc, argv, 0 }
 123
 124 /**
 125  * Key value passed to the processing function if an option did not
 126  * match any template
 127  */
 128 #define FUSE_OPT_KEY_OPT     -1
 129
 130 /**
 131  * Key value passed to the processing function for all non-options
 132  *
 133  * Non-options are the arguments beginning with a charater other than
 134  * '-' or all arguments after the special '--' option
 135  */
 136 #define FUSE_OPT_KEY_NONOPT  -2
 137
 138 /**
 139  * Special key value for options to keep
 140  *
 141  * Argument is not passed to processing function, but behave as if the
 142  * processing function returned 1
 143  */
 144 #define FUSE_OPT_KEY_KEEP -3
 145
 146 /**
 147  * Special key value for options to discard
 148  *
 149  * Argument is not passed to processing function, but behave as if the
 150  * processing function returned zero
 151  */
 152 #define FUSE_OPT_KEY_DISCARD -4
 153
 154 /**
 155  * Processing function
 156  *
 157  * This function is called if
 158  *    - option did not match any 'struct fuse_opt'
 159  *    - argument is a non-option
 160  *    - option did match and offset was set to -1
 161  *
 162  * The 'arg' parameter will always contain the whole argument or
 163  * option including the parameter if exists.  A two-argument option
 164  * ("-x foo") is always converted to single arguemnt option of the
 165  * form "-xfoo" before this function is called.
 166  *
 167  * Options of the form '-ofoo' are passed to this function without the
 168  * '-o' prefix.
 169  *
 170  * The return value of this function determines whether this argument
 171  * is to be inserted into the output argument vector, or discarded.
 172  *
 173  * @param data is the user data passed to the fuse_opt_parse() function
 174  * @param arg is the whole argument or option
 175  * @param key determines why the processing function was called
 176  * @param outargs the current output argument list
 177  * @return -1 on error, 0 if arg is to be discarded, 1 if arg should be kept
 178  */
 179 typedef int (*fuse_opt_proc_t)(void *data, const char *arg, int key,
 180                                struct fuse_args *outargs);
 181
 182 /**
 183  * Option parsing function
 184  *
 185  * If 'args' was returned from a previous call to fuse_opt_parse() or
 186  * it was constructed from
 187  *
 188  * A NULL 'args' is equivalent to an empty argument vector
 189  *
 190  * A NULL 'opts' is equivalent to an 'opts' array containing a single
 191  * end marker
 192  *
 193  * A NULL 'proc' is equivalent to a processing function always
 194  * returning '1'
 195  *
 196  * @param args is the input and output argument list
 197  * @param data is the user data
 198  * @param opts is the option description array
 199  * @param proc is the processing function
 200  * @return -1 on error, 0 on success
 201  */
 202 int fuse_opt_parse(struct fuse_args *args, void *data,
 203                    const struct fuse_opt opts[], fuse_opt_proc_t proc);
 204
 205 /**
 206  * Add an option to a comma separated option list
 207  *
 208  * @param opts is a pointer to an option list, may point to a NULL value
 209  * @param opt is the option to add
 210  * @return -1 on allocation error, 0 on success
 211  */
 212 int fuse_opt_add_opt(char **opts, const char *opt);
 213
 214 /**
 215  * Add an argument to a NULL terminated argument vector
 216  *
 217  * @param args is the structure containing the current argument list
 218  * @param arg is the new argument to add
 219  * @return -1 on allocation error, 0 on success
 220  */
 221 int fuse_opt_add_arg(struct fuse_args *args, const char *arg);
 222
 223 /**
 224  * Add an argument at the specified position in a NULL terminated
 225  * argument vector
 226  *
 227  * Adds the argument to the N-th position.  This is useful for adding
 228  * options at the beggining of the array which must not come after the
 229  * special '--' option.
 230  *
 231  * @param args is the structure containing the current argument list
 232  * @param pos is the position at which to add the argument
 233  * @param arg is the new argument to add
 234  * @return -1 on allocation error, 0 on success
 235  */
 236 int fuse_opt_insert_arg(struct fuse_args *args, int pos, const char *arg);
 237
 238 /**
 239  * Free the contents of argument list
 240  *
 241  * The structure itself is not freed
 242  *
 243  * @param args is the structure containing the argument list
 244  */
 245 void fuse_opt_free_args(struct fuse_args *args);
 246
 247
 248 /**
 249  * Check if an option matches
 250  *
 251  * @param opts is the option description array
 252  * @param opt is the option to match
 253  * @return 1 if a match is found, 0 if not
 254  */
 255 int fuse_opt_match(const struct fuse_opt opts[], const char *opt);
 256
 257 #ifdef __cplusplus
 258 }
 259 #endif
 260
 261 #endif /* _FUSE_OPT_H_ */