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1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
2 | /* | |
3 | * getopt.h - a simple getopt(3) implementation. | |
4 | * | |
5 | * Copyright (C) 2020 Sean Anderson <[email protected]> | |
6 | * Copyright (c) 2007 Sascha Hauer <[email protected]>, Pengutronix | |
7 | */ | |
8 | ||
9 | #ifndef __GETOPT_H | |
10 | #define __GETOPT_H | |
11 | ||
12 | /** | |
13 | * struct getopt_state - Saved state across getopt() calls | |
14 | */ | |
15 | struct getopt_state { | |
16 | /** | |
17 | * @index: Index of the next unparsed argument of @argv. If getopt() has | |
18 | * parsed all of @argv, then @index will equal @argc. | |
19 | */ | |
20 | int index; | |
21 | /* private: */ | |
22 | /** @arg_index: Index within the current argument */ | |
23 | int arg_index; | |
24 | union { | |
25 | /* public: */ | |
26 | /** | |
27 | * @opt: Option being parsed when an error occurs. @opt is only | |
28 | * valid when getopt() returns ``?`` or ``:``. | |
29 | */ | |
30 | int opt; | |
31 | /** | |
32 | * @arg: The argument to an option, NULL if there is none. @arg | |
33 | * is only valid when getopt() returns an option character. | |
34 | */ | |
35 | char *arg; | |
36 | /* private: */ | |
37 | }; | |
38 | }; | |
39 | ||
40 | /** | |
41 | * getopt_init_state() - Initialize a &struct getopt_state | |
42 | * @gs: The state to initialize | |
43 | * | |
44 | * This must be called before using @gs with getopt(). | |
45 | */ | |
46 | void getopt_init_state(struct getopt_state *gs); | |
47 | ||
48 | int __getopt(struct getopt_state *gs, int argc, char *const argv[], | |
49 | const char *optstring, bool silent); | |
50 | ||
51 | /** | |
52 | * getopt() - Parse short command-line options | |
53 | * @gs: Internal state and out-of-band return arguments. This must be | |
54 | * initialized with getopt_init_context() beforehand. | |
55 | * @argc: Number of arguments, not including the %NULL terminator | |
56 | * @argv: Argument list, terminated by %NULL | |
57 | * @optstring: Option specification, as described below | |
58 | * | |
59 | * getopt() parses short options. Short options are single characters. They may | |
60 | * be followed by a required argument or an optional argument. Arguments to | |
61 | * options may occur in the same argument as an option (like ``-larg``), or | |
62 | * in the following argument (like ``-l arg``). An argument containing | |
63 | * options begins with a ``-``. If an option expects no arguments, then it may | |
64 | * be immediately followed by another option (like ``ls -alR``). | |
65 | * | |
66 | * @optstring is a list of accepted options. If an option is followed by ``:`` | |
67 | * in @optstring, then it expects a mandatory argument. If an option is followed | |
68 | * by ``::`` in @optstring, it expects an optional argument. @gs.arg points | |
69 | * to the argument, if one is parsed. | |
70 | * | |
71 | * getopt() stops parsing options when it encounters the first non-option | |
72 | * argument, when it encounters the argument ``--``, or when it runs out of | |
73 | * arguments. For example, in ``ls -l foo -R``, option parsing will stop when | |
74 | * getopt() encounters ``foo``, if ``l`` does not expect an argument. However, | |
75 | * the whole list of arguments would be parsed if ``l`` expects an argument. | |
76 | * | |
77 | * An example invocation of getopt() might look like:: | |
78 | * | |
79 | * char *argv[] = { "program", "-cbx", "-a", "foo", "bar", 0 }; | |
80 | * int opt, argc = ARRAY_SIZE(argv) - 1; | |
81 | * struct getopt_state gs; | |
82 | * | |
83 | * getopt_init_state(&gs); | |
84 | * while ((opt = getopt(&gs, argc, argv, "a::b:c")) != -1) | |
85 | * printf("opt = %c, index = %d, arg = \"%s\"\n", opt, gs.index, gs.arg); | |
86 | * printf("%d argument(s) left\n", argc - gs.index); | |
87 | * | |
88 | * and would produce an output of:: | |
89 | * | |
90 | * opt = c, index = 1, arg = "<NULL>" | |
91 | * opt = b, index = 2, arg = "x" | |
92 | * opt = a, index = 4, arg = "foo" | |
93 | * 1 argument(s) left | |
94 | * | |
95 | * For further information, refer to the getopt(3) man page. | |
96 | * | |
97 | * Return: | |
98 | * * An option character if an option is found. @gs.arg is set to the | |
99 | * argument if there is one, otherwise it is set to ``NULL``. | |
100 | * * ``-1`` if there are no more options, if a non-option argument is | |
101 | * encountered, or if an ``--`` argument is encountered. | |
102 | * * ``'?'`` if we encounter an option not in @optstring. @gs.opt is set to | |
103 | * the unknown option. | |
104 | * * ``':'`` if an argument is required, but no argument follows the | |
105 | * option. @gs.opt is set to the option missing its argument. | |
106 | * | |
107 | * @gs.index is always set to the index of the next unparsed argument in @argv. | |
108 | */ | |
109 | static inline int getopt(struct getopt_state *gs, int argc, | |
110 | char *const argv[], const char *optstring) | |
111 | { | |
112 | return __getopt(gs, argc, argv, optstring, false); | |
113 | } | |
114 | ||
115 | /** | |
116 | * getopt_silent() - Parse short command-line options silently | |
117 | * @gs: State | |
118 | * @argc: Argument count | |
119 | * @argv: Argument list | |
120 | * @optstring: Option specification | |
121 | * | |
122 | * Same as getopt(), except no error messages are printed. | |
123 | */ | |
124 | static inline int getopt_silent(struct getopt_state *gs, int argc, | |
125 | char *const argv[], const char *optstring) | |
126 | { | |
127 | return __getopt(gs, argc, argv, optstring, true); | |
128 | } | |
129 | ||
130 | #endif /* __GETOPT_H */ |