args.c revision 2a813ffadf19957f1798cfc68a3ea78199ce1f49 
1/* vi: set sw=4 ts=4 :
2 * args.c - Command line argument parsing.
3 *
4 * Copyright 2006 Rob Landley <rob@landley.net>
5 */
6
7#include "toys.h"
8
9// Design goals:
10//   Don't use getopt()
11//   Don't permute original arguments.
12//   handle --long gracefully "(noshort)a(along)b(blong1)(blong2)"
13//   After each argument:
14//       Note that pointer and long are always the same size, even on 64 bit.
15//     : plus a string argument, keep most recent if more than one
16//     * plus a string argument, appended to a list
17//     ? plus a signed long argument (TODO: Bounds checking?)
18//     @ plus an occurrence counter (which is a long)
19//     | this is required.  If more than one marked, only one required.
20//     (longopt)
21//     +X enabling this enables X (switch on)
22//     ~X enabling this disables X (switch off)
23//       x~x means toggle x, I.E. specifying it again switches it off.
24//     !X die with error if X already set (x!x die if x supplied twice)
25//     [yz] needs at least one of y or z.
26//   at the beginning:
27//     + stop at first nonoption argument
28//     ? return array of remaining arguments in first vararg
29//     <0 at least # leftover arguments needed (default 0)
30//     >9 at most # leftover arguments needed (default MAX_INT)
31//     # don't show_usage() on unknown argument.
32//     & first argument has imaginary dash (ala tar/ps)
33//       If given twice, all arguments have imaginary dash
34
35// Notes from getopt man page
36//   - and -- cannot be arguments.
37//     -- force end of arguments
38//     - is a synonym for stdin in file arguments
39//   -abc means -a -b -c
40
41/* This uses a getopt-like option string, but not getopt() itself.
42 *
43 *   Each option in options corresponds to a bit position in the return
44 * value (last argument is (1<<0), the next to last is (1<<1) and so on.
45 * If the option isn't seen in argv its bit is 0.  Options which have an
46 * argument use the next vararg.  (So varargs used by options go from left to
47 * right, but bits set by arguments go from right to left.)
48 *
49 * Example:
50 *   get_optflags("ab:c:d", NULL, &bstring, &cstring);
51 *   argv = ["command", "-b", "fruit", "-d"]
52 *   flags = 5, bstring="fruit", cstring=NULL;
53 */
54
55struct opts {
56	struct opts *next;
57	char c;
58	int type;
59	int shift;
60	void *arg;
61};
62
63struct getoptflagstate
64{
65	int argc;
66	char *arg;
67	struct opts *opts, *this;
68	int noerror, nodash_now;
69};
70
71static struct getoptflagstate gof;
72
73// Returns zero if it didn't consume the rest of the current -abcdef
74static int gotflag(void)
75{
76	char *arg = NULL;
77	int type;
78	int ret = 0;
79
80	// Did we recognize this option?
81	if (!gof.this && !gof.noerror) error_exit("Unknown option %s\n", gof.arg);
82	else toys.optflags |= 1 << gof.this->shift;
83
84	// Does this option take an argument?
85	gof.arg++;
86	if (gof.this->type & 255) {
87		// Make "tar xCjfv blah1 blah2 thingy" work like
88		// "tar -x -C blah1 -j -f blah2 -v thingy"
89		if (!gof.nodash_now && !*gof.arg) {
90			gof.arg = toys.argv[++gof.argc];
91			if (!gof.arg) error_exit("Missing argument");
92		} else {
93			arg = gof.arg;
94			ret++;
95		}
96	} else gof.this = NULL;
97
98	// If the last option had an argument, grab it.
99	if (!gof.this)  return 0;
100	type = gof.this->type & 255;
101	if (!gof.arg && !(gof.arg = toys.argv[++gof.argc]))
102		error_exit("Missing argument");
103	if (type == ':') gof.this->arg = arg;
104	else if (type == '*') {
105		struct arg_list *temp, **list;
106		list = (struct arg_list **)gof.this->arg;
107		temp = xmalloc(sizeof(struct arg_list));
108		temp->arg = arg;
109		temp->next = *list;
110		*list = temp;
111	} else if (type == '?') {
112	} else if (type == '@') {
113	}
114
115	return ret;
116}
117
118// Fill out toys.optflags and toys.optargs.  This isn't reentrant because
119// we don't bzero(&gof, sizeof(gof));
120
121void get_optflags(void)
122{
123	int stopearly = 0, optarg = 0, nodash = 0, minargs = 0, maxargs = INT_MAX;
124	struct longopts {
125		struct longopts *next;
126		struct opts *opt;
127		char *str;
128		int len;
129	} *longopts = NULL;
130	long *nextarg = (long *)&toy;
131	char *options = toys.which->options;
132
133	if (options) {
134		// Parse leading special behavior indicators
135		for (;;) {
136			if (*options == '+') stopearly++;
137			else if (*options == '<') minargs=*(++options)-'0';
138			else if (*options == '>') maxargs=*(++options)-'0';
139			else if (*options == '#') gof.noerror++;
140			else if (*options == '&') nodash++;
141			else break;
142			options++;
143		}
144
145		// Parse rest of opts into array
146		while (*options) {
147
148			// Allocate a new option entry when necessary
149			if (!gof.this) {
150				gof.this = xzalloc(sizeof(struct opts));
151				gof.this->next = gof.opts;
152				gof.opts = gof.this;
153			}
154			// Each option must start with (or an option character.  (Bare
155			// longopts only come at the start of the string.)
156			if (*options == '(') {
157				char *end;
158				struct longopts *lo = xmalloc(sizeof(struct longopts));
159
160				// Find the end of the longopt
161				for (end = ++options; *end && *end != ')'; end++);
162				if (CFG_DEBUG && !*end) error_exit("Unterminated optstring");
163
164				// Allocate and init a new struct longopts
165				lo = xmalloc(sizeof(struct longopts));
166				lo->next = longopts;
167				lo->opt = gof.this;
168				lo->str = options;
169				lo->len = end-options;
170				longopts = lo;
171				options = end;
172
173				// For leading longopts (with no corresponding short opt), note
174				// that this option struct has been used.
175				gof.this->shift++;
176
177			// If this is the start of a new option that wasn't a longopt,
178
179			} else if (index(":*?@", *options)) {
180				gof.this->type |= *options;
181				// Pointer and long guaranteed to be the same size by LP64.
182				*(++nextarg) = 0;
183				gof.this->arg = (void *)nextarg;
184			} else if (*options == '|') {
185			} else if (*options == '+') {
186			} else if (*options == '~') {
187			} else if (*options == '!') {
188			} else if (*options == '[') {
189
190			// At this point, we've hit the end of the previous option.  The
191			// current character is the start of a new option.  If we've already
192			// assigned an option to this struct, loop to allocate a new one.
193			// (It'll get back here afterwards.)
194			} else if(gof.this->shift || gof.this->c) {
195				gof.this = NULL;
196				continue;
197
198			// Claim this option, loop to see what's after it.
199			} else gof.this->c = *options;
200
201			options++;
202		}
203	}
204
205	// Initialize shift bits (have to calculate this ahead of time because
206	// longopts jump into the middle of the list), and allocate space to
207	// store optargs.
208	gof.argc = 0;
209	for (gof.this = gof.opts; gof.this; gof.this = gof.this->next)
210		gof.this->shift = gof.argc++;
211	toys.optargs = xzalloc(sizeof(char *)*(++gof.argc));
212
213	// Iterate through command line arguments, skipping argv[0]
214	for (gof.argc=1; toys.argv[gof.argc]; gof.argc++) {
215		char *arg = toys.argv[gof.argc];
216
217		// Parse this argument
218		if (stopearly>1) goto notflag;
219
220		gof.nodash_now = 0;
221
222		// Various things with dashes
223		if (*arg == '-') {
224
225			// Handle -
226			if (!arg[1]) goto notflag;
227			arg++;
228			if (*arg=='-') {
229				struct longopts *lo;
230
231				arg++;
232				// Handle --
233				if (!*arg) {
234					stopearly += 2;
235					goto notflag;
236				}
237				// Handle --longopt
238
239				for (lo = longopts; lo; lo = lo->next) {
240					if (!strncmp(arg, lo->str, lo->len)) {
241						if (arg[lo->len]) {
242							if (arg[lo->len]=='='
243								&& (lo->opt->type & 255))
244							{
245								arg += lo->len;
246							} else continue;
247
248						// *options should be nul, this makes sure
249						// that the while (*arg) loop terminates;
250						} arg = options-1;
251						gof.this = lo->opt;
252						break;
253					}
254				}
255				// Long option parsed, jump to option handling.
256				gotflag();
257				continue;
258			}
259
260		// Handle things that don't start with a dash.
261		} else {
262			if (nodash && (nodash>1 || gof.argc == 1)) gof.nodash_now = 1;
263			else goto notflag;
264		}
265
266		// At this point, we have the args part of -args.  Loop through
267		// each entry (could be -abc meaning -a -b -c)
268		while (*arg) {
269			// Identify next option char.
270			for (gof.this = gof.opts; gof.this && *arg != gof.this->c;
271					gof.this = gof.this->next);
272			if (gotflag()) break;
273			arg++;
274		}
275		continue;
276
277		// Not a flag, save value in toys.optargs[]
278notflag:
279		if (stopearly) stopearly++;
280		toys.optargs[optarg++] = toys.argv[gof.argc];
281	}
282
283	// Sanity check
284	if (optarg<minargs) error_exit("Need %d arguments", minargs);
285	if (optarg>maxargs) error_exit("Max %d arguments", maxargs);
286}
287