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Diffstat (limited to 'fuse/include/fuse_opt.h')
-rw-r--r-- | fuse/include/fuse_opt.h | 270 |
1 files changed, 270 insertions, 0 deletions
diff --git a/fuse/include/fuse_opt.h b/fuse/include/fuse_opt.h new file mode 100644 index 000000000..add0a3089 --- /dev/null +++ b/fuse/include/fuse_opt.h @@ -0,0 +1,270 @@ +/* + FUSE: Filesystem in Userspace + Copyright (C) 2001-2007 Miklos Szeredi <miklos@szeredi.hu> + + This program can be distributed under the terms of the GNU LGPLv2. + See the file COPYING.LIB. +*/ + +#ifndef _FUSE_OPT_H_ +#define _FUSE_OPT_H_ + +/** @file + * + * This file defines the option parsing interface of FUSE + */ + +#ifdef __cplusplus +extern "C" { +#endif + +/** + * Option description + * + * This structure describes a single option, and action associated + * with it, in case it matches. + * + * More than one such match may occur, in which case the action for + * each match is executed. + * + * There are three possible actions in case of a match: + * + * i) An integer (int or unsigned) variable determined by 'offset' is + * set to 'value' + * + * ii) The processing function is called, with 'value' as the key + * + * iii) An integer (any) or string (char *) variable determined by + * 'offset' is set to the value of an option parameter + * + * 'offset' should normally be either set to + * + * - 'offsetof(struct foo, member)' actions i) and iii) + * + * - -1 action ii) + * + * The 'offsetof()' macro is defined in the <stddef.h> header. + * + * The template determines which options match, and also have an + * effect on the action. Normally the action is either i) or ii), but + * if a format is present in the template, then action iii) is + * performed. + * + * The types of templates are: + * + * 1) "-x", "-foo", "--foo", "--foo-bar", etc. These match only + * themselves. Invalid values are "--" and anything beginning + * with "-o" + * + * 2) "foo", "foo-bar", etc. These match "-ofoo", "-ofoo-bar" or + * the relevant option in a comma separated option list + * + * 3) "bar=", "--foo=", etc. These are variations of 1) and 2) + * which have a parameter + * + * 4) "bar=%s", "--foo=%lu", etc. Same matching as above but perform + * action iii). + * + * 5) "-x ", etc. Matches either "-xparam" or "-x param" as + * two separate arguments + * + * 6) "-x %s", etc. Combination of 4) and 5) + * + * If the format is "%s", memory is allocated for the string unlike + * with scanf(). + */ +struct fuse_opt { + /** Matching template and optional parameter formatting */ + const char *templ; + + /** + * Offset of variable within 'data' parameter of fuse_opt_parse() + * or -1 + */ + unsigned long offset; + + /** + * Value to set the variable to, or to be passed as 'key' to the + * processing function. Ignored if template has a format + */ + int value; +}; + +/** + * Key option. In case of a match, the processing function will be + * called with the specified key. + */ +#define FUSE_OPT_KEY(templ, key) { templ, -1U, key } + +/** + * Last option. An array of 'struct fuse_opt' must end with a NULL + * template value + */ +#define FUSE_OPT_END { NULL, 0, 0 } + +/** + * Argument list + */ +struct fuse_args { + /** Argument count */ + int argc; + + /** Argument vector. NULL terminated */ + char **argv; + + /** Is 'argv' allocated? */ + int allocated; +}; + +/** + * Initializer for 'struct fuse_args' + */ +#define FUSE_ARGS_INIT(argc, argv) { argc, argv, 0 } + +/** + * Key value passed to the processing function if an option did not + * match any template + */ +#define FUSE_OPT_KEY_OPT -1 + +/** + * Key value passed to the processing function for all non-options + * + * Non-options are the arguments beginning with a character other than + * '-' or all arguments after the special '--' option + */ +#define FUSE_OPT_KEY_NONOPT -2 + +/** + * Special key value for options to keep + * + * Argument is not passed to processing function, but behave as if the + * processing function returned 1 + */ +#define FUSE_OPT_KEY_KEEP -3 + +/** + * Special key value for options to discard + * + * Argument is not passed to processing function, but behave as if the + * processing function returned zero + */ +#define FUSE_OPT_KEY_DISCARD -4 + +/** + * Processing function + * + * This function is called if + * - option did not match any 'struct fuse_opt' + * - argument is a non-option + * - option did match and offset was set to -1 + * + * The 'arg' parameter will always contain the whole argument or + * option including the parameter if exists. A two-argument option + * ("-x foo") is always converted to single argument option of the + * form "-xfoo" before this function is called. + * + * Options of the form '-ofoo' are passed to this function without the + * '-o' prefix. + * + * The return value of this function determines whether this argument + * is to be inserted into the output argument vector, or discarded. + * + * @param data is the user data passed to the fuse_opt_parse() function + * @param arg is the whole argument or option + * @param key determines why the processing function was called + * @param outargs the current output argument list + * @return -1 on error, 0 if arg is to be discarded, 1 if arg should be kept + */ +typedef int (*fuse_opt_proc_t)(void *data, const char *arg, int key, + struct fuse_args *outargs); + +/** + * Option parsing function + * + * If 'args' was returned from a previous call to fuse_opt_parse() or + * it was constructed from + * + * A NULL 'args' is equivalent to an empty argument vector + * + * A NULL 'opts' is equivalent to an 'opts' array containing a single + * end marker + * + * A NULL 'proc' is equivalent to a processing function always + * returning '1' + * + * @param args is the input and output argument list + * @param data is the user data + * @param opts is the option description array + * @param proc is the processing function + * @return -1 on error, 0 on success + */ +int fuse_opt_parse(struct fuse_args *args, void *data, + const struct fuse_opt opts[], fuse_opt_proc_t proc); + +/** + * Add an option to a comma separated option list + * + * @param opts is a pointer to an option list, may point to a NULL value + * @param opt is the option to add + * @return -1 on allocation error, 0 on success + */ +int fuse_opt_add_opt(char **opts, const char *opt); + +/** + * Add an option, escaping commas, to a comma separated option list + * + * @param opts is a pointer to an option list, may point to a NULL value + * @param opt is the option to add + * @return -1 on allocation error, 0 on success + */ +int fuse_opt_add_opt_escaped(char **opts, const char *opt); + +/** + * Add an argument to a NULL terminated argument vector + * + * @param args is the structure containing the current argument list + * @param arg is the new argument to add + * @return -1 on allocation error, 0 on success + */ +int fuse_opt_add_arg(struct fuse_args *args, const char *arg); + +/** + * Add an argument at the specified position in a NULL terminated + * argument vector + * + * Adds the argument to the N-th position. This is useful for adding + * options at the beginning of the array which must not come after the + * special '--' option. + * + * @param args is the structure containing the current argument list + * @param pos is the position at which to add the argument + * @param arg is the new argument to add + * @return -1 on allocation error, 0 on success + */ +int fuse_opt_insert_arg(struct fuse_args *args, int pos, const char *arg); + +/** + * Free the contents of argument list + * + * The structure itself is not freed + * + * @param args is the structure containing the argument list + */ +void fuse_opt_free_args(struct fuse_args *args); + + +/** + * Check if an option matches + * + * @param opts is the option description array + * @param opt is the option to match + * @return 1 if a match is found, 0 if not + */ +int fuse_opt_match(const struct fuse_opt opts[], const char *opt); + +#ifdef __cplusplus +} +#endif + +#endif /* _FUSE_OPT_H_ */ |