toybox/lib/args.c
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   1/* args.c - Command line argument parsing.
   2 *
   3 * Copyright 2006 Rob Landley <rob@landley.net>
   4 */
   5
   6// NOTE: If option parsing segfaults, switch on TOYBOX_DEBUG in menuconfig.
   7
   8// Enabling TOYBOX_DEBUG in .config adds syntax checks to option string parsing
   9// which aren't needed in the final code (your option string is hardwired and
  10// should be correct when you ship), but are useful for development.
  11
  12#include "toys.h"
  13
  14// Design goals:
  15//   Don't use getopt() out of libc.
  16//   Don't permute original arguments (screwing up ps/top output).
  17//   Integrated --long options "(noshort)a(along)b(blong1)(blong2)"
  18
  19/* This uses a getopt-like option string, but not getopt() itself. We call
  20 * it the get_opt string.
  21 *
  22 * Each option in the get_opt string corresponds to a bit position in the
  23 * return value. The rightmost argument is (1<<0), the next to last is (1<<1)
  24 * and so on. If the option isn't seen in argv[], its bit remains 0.
  25 *
  26 * Options which have an argument fill in the corresponding slot in the global
  27 * union "this" (see generated/globals.h), which it treats as an array of longs
  28 * (note that sizeof(long)==sizeof(pointer) is guaranteed by LP64).
  29 *
  30 * You don't have to free the option strings, which point into the environment
  31 * space. List objects should be freed by main() when command_main() returns.
  32 *
  33 * Example:
  34 *   Calling get_optflags() when toys.which->options="ab:c:d" and
  35 *   argv = ["command", "-b", "fruit", "-d", "walrus"] results in:
  36 *
  37 *     Changes to struct toys:
  38 *       toys.optflags = 5 (I.E. 0101 so -b = 4 | -d = 1)
  39 *       toys.optargs[0] = "walrus" (leftover argument)
  40 *       toys.optargs[1] = NULL (end of list)
  41 *       toys.optc = 1 (there was 1 leftover argument)
  42 *
  43 *     Changes to union this:
  44 *       this[0]=NULL (because -c didn't get an argument this time)
  45 *       this[1]="fruit" (argument to -b)
  46 */
  47
  48// What you can put in a get_opt string:
  49//   Any otherwise unused character (all letters, unprefixed numbers) specify
  50//   an option that sets a flag. The bit value is the same as the binary digit
  51//   if you string the option characters together in order.
  52//   So in "abcdefgh" a = 128, h = 1
  53//
  54//   Suffixes specify that this option takes an argument (stored in GLOBALS):
  55//       Note that pointer and long are always the same size, even on 64 bit.
  56//     : string argument, keep most recent if more than one
  57//     * string argument, appended to a struct arg_list linked list.
  58//     # signed long argument
  59//       <LOW     - die if less than LOW
  60//       >HIGH    - die if greater than HIGH
  61//       =DEFAULT - value if not specified
  62//     - signed long argument defaulting to negative (say + for positive)
  63//     . double precision floating point argument (with CFG_TOYBOX_FLOAT)
  64//       Chop this option out with USE_TOYBOX_FLOAT() in option string
  65//       Same <LOW>HIGH=DEFAULT as #
  66//     @ occurrence counter (which is a long)
  67//     % time offset in milliseconds with optional s/m/h/d suffix
  68//     (longopt)
  69//     | this is required. If more than one marked, only one required.
  70//     ; long option's argument is optional (can only be supplied with --opt=)
  71//     ^ Stop parsing after encountering this argument
  72//    " " (space char) the "plus an argument" must be separate
  73//        I.E. "-j 3" not "-j3". So "kill -stop" != "kill -s top"
  74//
  75//   At the beginning of the get_opt string (before any options):
  76//     ^ stop at first nonoption argument
  77//     <0 die if less than # leftover arguments (default 0)
  78//     >9 die if > # leftover arguments (default MAX_INT)
  79//     ? Allow unknown arguments (pass them through to command).
  80//     & first arg has imaginary dash (ala tar/ps/ar) which sets FLAGS_NODASH
  81//
  82//   At the end: [groups] of previously seen options
  83//     - Only one in group (switch off)    [-abc] means -ab=-b, -ba=-a, -abc=-c
  84//     + Synonyms (switch on all)          [+abc] means -ab=-abc, -c=-abc
  85//     ! More than one in group is error   [!abc] means -ab calls error_exit()
  86//       primarily useful if you can switch things back off again.
  87
  88// Notes from getopt man page
  89//   - and -- cannot be arguments.
  90//     -- force end of arguments
  91//     - is a synonym for stdin in file arguments
  92//   -abcd means -a -b -c -d (but if -b takes an argument, then it's -a -b cd)
  93
  94// Linked list of all known options (option string parsed into this).
  95// Hangs off getoptflagstate, freed at end of option parsing.
  96struct opts {
  97  struct opts *next;
  98  long *arg;         // Pointer into union "this" to store arguments at.
  99  int c;             // Argument character to match
 100  int flags;         // |=1, ^=2, " "=4, ;=8
 101  unsigned long long dex[3]; // bits to disable/enable/exclude in toys.optflags
 102  char type;         // Type of arguments to store union "this"
 103  union {
 104    long l;
 105    FLOAT f;
 106  } val[3];          // low, high, default - range of allowed values
 107};
 108
 109// linked list of long options. (Hangs off getoptflagstate, free at end of
 110// option parsing, details about flag to set and global slot to fill out
 111// stored in related short option struct, but if opt->c = -1 the long option
 112// is "bare" (has no corresponding short option).
 113struct longopts {
 114  struct longopts *next;
 115  struct opts *opt;
 116  char *str;
 117  int len;
 118};
 119
 120// State during argument parsing.
 121struct getoptflagstate
 122{
 123  int argc, minargs, maxargs;
 124  char *arg;
 125  struct opts *opts;
 126  struct longopts *longopts;
 127  int noerror, nodash_now, stopearly;
 128  unsigned excludes, requires;
 129};
 130
 131// Use getoptflagstate to parse parse one command line option from argv
 132static int gotflag(struct getoptflagstate *gof, struct opts *opt)
 133{
 134  int type;
 135
 136  // Did we recognize this option?
 137  if (!opt) {
 138    if (gof->noerror) return 1;
 139    help_exit("Unknown option %s", gof->arg);
 140  }
 141
 142  // Might enabling this switch off something else?
 143  if (toys.optflags & opt->dex[0]) {
 144    struct opts *clr;
 145    unsigned long long i = 1;
 146
 147    // Forget saved argument for flag we switch back off
 148    for (clr=gof->opts, i=1; clr; clr = clr->next, i<<=1)
 149      if (clr->arg && (i & toys.optflags & opt->dex[0])) *clr->arg = 0;
 150    toys.optflags &= ~opt->dex[0];
 151  }
 152
 153  // Set flags
 154  toys.optflags |= opt->dex[1];
 155  gof->excludes |= opt->dex[2];
 156  if (opt->flags&2) gof->stopearly=2;
 157
 158  if (toys.optflags & gof->excludes) {
 159    struct opts *bad;
 160    unsigned i = 1;
 161
 162    for (bad=gof->opts, i=1; bad ;bad = bad->next, i<<=1) {
 163      if (opt == bad || !(i & toys.optflags)) continue;
 164      if (toys.optflags & bad->dex[2]) break;
 165    }
 166    if (bad) help_exit("No '%c' with '%c'", opt->c, bad->c);
 167  }
 168
 169  // Does this option take an argument?
 170  if (!gof->arg) {
 171    if (opt->flags & 8) return 0;
 172    gof->arg = "";
 173  } else gof->arg++;
 174  type = opt->type;
 175
 176  if (type == '@') ++*(opt->arg);
 177  else if (type) {
 178    char *arg = gof->arg;
 179
 180    // Handle "-xblah" and "-x blah", but also a third case: "abxc blah"
 181    // to make "tar xCjfv blah1 blah2 thingy" work like
 182    // "tar -x -C blah1 -j -f blah2 -v thingy"
 183
 184    if (gof->nodash_now || (!arg[0] && !(opt->flags & 8)))
 185      arg = toys.argv[++gof->argc];
 186    if (!arg) {
 187      char *s = "Missing argument to ";
 188      struct longopts *lo;
 189
 190      if (opt->c != -1) help_exit("%s-%c", s, opt->c);
 191
 192      for (lo = gof->longopts; lo->opt != opt; lo = lo->next);
 193      help_exit("%s--%.*s", s, lo->len, lo->str);
 194    }
 195
 196    if (type == ':') *(opt->arg) = (long)arg;
 197    else if (type == '*') {
 198      struct arg_list **list;
 199
 200      list = (struct arg_list **)opt->arg;
 201      while (*list) list=&((*list)->next);
 202      *list = xzalloc(sizeof(struct arg_list));
 203      (*list)->arg = arg;
 204    } else if (type == '#' || type == '-') {
 205      long l = atolx(arg);
 206      if (type == '-' && !ispunct(*arg)) l*=-1;
 207      if (l < opt->val[0].l) help_exit("-%c < %ld", opt->c, opt->val[0].l);
 208      if (l > opt->val[1].l) help_exit("-%c > %ld", opt->c, opt->val[1].l);
 209
 210      *(opt->arg) = l;
 211    } else if (CFG_TOYBOX_FLOAT && type == '.') {
 212      FLOAT *f = (FLOAT *)(opt->arg);
 213
 214      *f = strtod(arg, &arg);
 215      if (opt->val[0].l != LONG_MIN && *f < opt->val[0].f)
 216        help_exit("-%c < %lf", opt->c, (double)opt->val[0].f);
 217      if (opt->val[1].l != LONG_MAX && *f > opt->val[1].f)
 218        help_exit("-%c > %lf", opt->c, (double)opt->val[1].f);
 219    } else if (type=='%') *(opt->arg) = xparsemillitime(arg);
 220
 221    if (!gof->nodash_now) gof->arg = "";
 222  }
 223
 224  return 0;
 225}
 226
 227// Parse this command's options string into struct getoptflagstate, which
 228// includes a struct opts linked list in reverse order (I.E. right-to-left)
 229void parse_optflaglist(struct getoptflagstate *gof)
 230{
 231  char *options = toys.which->options;
 232  long *nextarg = (long *)&this;
 233  struct opts *new = 0;
 234  int idx;
 235
 236  // Parse option format string
 237  memset(gof, 0, sizeof(struct getoptflagstate));
 238  gof->maxargs = INT_MAX;
 239  if (!options) return;
 240
 241  // Parse leading special behavior indicators
 242  for (;;) {
 243    if (*options == '^') gof->stopearly++;
 244    else if (*options == '<') gof->minargs=*(++options)-'0';
 245    else if (*options == '>') gof->maxargs=*(++options)-'0';
 246    else if (*options == '?') gof->noerror++;
 247    else if (*options == '&') toys.optflags |= FLAGS_NODASH;
 248    else break;
 249    options++;
 250  }
 251
 252  // Parse option string into a linked list of options with attributes.
 253
 254  if (!*options) gof->stopearly++;
 255  while (*options) {
 256    char *temp;
 257
 258    // Option groups come after all options are defined
 259    if (*options == '[') break;
 260
 261    // Allocate a new list entry when necessary
 262    if (!new) {
 263      new = xzalloc(sizeof(struct opts));
 264      new->next = gof->opts;
 265      gof->opts = new;
 266      new->val[0].l = LONG_MIN;
 267      new->val[1].l = LONG_MAX;
 268    }
 269    // Each option must start with "(" or an option character.  (Bare
 270    // longopts only come at the start of the string.)
 271    if (*options == '(' && new->c != -1) {
 272      char *end;
 273      struct longopts *lo;
 274
 275      // Find the end of the longopt
 276      for (end = ++options; *end && *end != ')'; end++);
 277      if (CFG_TOYBOX_DEBUG && !*end) error_exit("(longopt) didn't end");
 278
 279      // init a new struct longopts
 280      lo = xmalloc(sizeof(struct longopts));
 281      lo->next = gof->longopts;
 282      lo->opt = new;
 283      lo->str = options;
 284      lo->len = end-options;
 285      gof->longopts = lo;
 286      options = ++end;
 287
 288      // Mark this struct opt as used, even when no short opt.
 289      if (!new->c) new->c = -1;
 290
 291      continue;
 292
 293    // If this is the start of a new option that wasn't a longopt,
 294
 295    } else if (strchr(":*#@.-%", *options)) {
 296      if (CFG_TOYBOX_DEBUG && new->type)
 297        error_exit("multiple types %c:%c%c", new->c, new->type, *options);
 298      new->type = *options;
 299    } else if (-1 != (idx = stridx("|^ ;", *options))) new->flags |= 1<<idx;
 300    // bounds checking
 301    else if (-1 != (idx = stridx("<>=", *options))) {
 302      if (new->type == '#' || new->type == '%') {
 303        long l = strtol(++options, &temp, 10);
 304        if (temp != options) new->val[idx].l = l;
 305      } else if (CFG_TOYBOX_FLOAT && new->type == '.') {
 306        FLOAT f = strtod(++options, &temp);
 307        if (temp != options) new->val[idx].f = f;
 308      } else error_exit("<>= only after .#%%");
 309      options = --temp;
 310
 311    // At this point, we've hit the end of the previous option.  The
 312    // current character is the start of a new option.  If we've already
 313    // assigned an option to this struct, loop to allocate a new one.
 314    // (It'll get back here afterwards and fall through to next else.)
 315    } else if (new->c) {
 316      new = 0;
 317      continue;
 318
 319    // Claim this option, loop to see what's after it.
 320    } else new->c = *options;
 321
 322    options++;
 323  }
 324
 325  // Initialize enable/disable/exclude masks and pointers to store arguments.
 326  // (This goes right to left so we need the whole list before we can start.)
 327  idx = 0;
 328  for (new = gof->opts; new; new = new->next) {
 329    unsigned long long u = 1L<<idx++;
 330
 331    if (new->c == 1) new->c = 0;
 332    new->dex[1] = u;
 333    if (new->flags & 1) gof->requires |= u;
 334    if (new->type) {
 335      new->arg = (void *)nextarg;
 336      *(nextarg++) = new->val[2].l;
 337    }
 338  }
 339
 340  // Parse trailing group indicators
 341  while (*options) {
 342    unsigned bits = 0;
 343
 344    if (CFG_TOYBOX_DEBUG && *options != '[') error_exit("trailing %s", options);
 345
 346    idx = stridx("-+!", *++options);
 347    if (CFG_TOYBOX_DEBUG && idx == -1) error_exit("[ needs +-!");
 348    if (CFG_TOYBOX_DEBUG && (options[1] == ']' || !options[1]))
 349      error_exit("empty []");
 350
 351    // Don't advance past ] but do process it once in loop.
 352    while (*options++ != ']') {
 353      struct opts *opt;
 354      int i;
 355
 356      if (CFG_TOYBOX_DEBUG && !*options) error_exit("[ without ]");
 357      // Find this option flag (in previously parsed struct opt)
 358      for (i=0, opt = gof->opts; ; i++, opt = opt->next) {
 359        if (*options == ']') {
 360          if (!opt) break;
 361          if (bits&(1<<i)) opt->dex[idx] |= bits&~(1<<i);
 362        } else {
 363          if (*options==1) break;
 364          if (CFG_TOYBOX_DEBUG && !opt)
 365            error_exit("[] unknown target %c", *options);
 366          if (opt->c == *options) {
 367            bits |= 1<<i;
 368            break;
 369          }
 370        }
 371      }
 372    }
 373  }
 374}
 375
 376// Fill out toys.optflags, toys.optargs, and this[] from toys.argv
 377
 378void get_optflags(void)
 379{
 380  struct getoptflagstate gof;
 381  struct opts *catch;
 382  unsigned long long saveflags;
 383  char *letters[]={"s",""};
 384
 385  // Option parsing is a two stage process: parse the option string into
 386  // a struct opts list, then use that list to process argv[];
 387
 388  // Allocate memory for optargs
 389  saveflags = 0;
 390  while (toys.argv[saveflags++]);
 391  toys.optargs = xzalloc(sizeof(char *)*saveflags);
 392
 393  parse_optflaglist(&gof);
 394
 395  // Iterate through command line arguments, skipping argv[0]
 396  for (gof.argc=1; toys.argv[gof.argc]; gof.argc++) {
 397    gof.arg = toys.argv[gof.argc];
 398    catch = NULL;
 399
 400    // Parse this argument
 401    if (gof.stopearly>1) goto notflag;
 402
 403    gof.nodash_now = 0;
 404
 405    // Various things with dashes
 406    if (*gof.arg == '-') {
 407
 408      // Handle -
 409      if (!gof.arg[1]) goto notflag;
 410      gof.arg++;
 411      if (*gof.arg=='-') {
 412        struct longopts *lo;
 413
 414        gof.arg++;
 415        // Handle --
 416        if (!*gof.arg) {
 417          gof.stopearly += 2;
 418          continue;
 419        }
 420
 421        // do we match a known --longopt?
 422        for (lo = gof.longopts; lo; lo = lo->next) {
 423          if (!strncmp(gof.arg, lo->str, lo->len)) {
 424            if (!gof.arg[lo->len]) gof.arg = 0;
 425            else if (gof.arg[lo->len] == '=' && lo->opt->type)
 426              gof.arg += lo->len;
 427            else continue;
 428            // It's a match.
 429            catch = lo->opt;
 430            break;
 431          }
 432        }
 433
 434        // Should we handle this --longopt as a non-option argument?
 435        if (!lo && gof.noerror) {
 436          gof.arg -= 2;
 437          goto notflag;
 438        }
 439
 440        // Long option parsed, handle option.
 441        gotflag(&gof, catch);
 442        continue;
 443      }
 444
 445    // Handle things that don't start with a dash.
 446    } else {
 447      if ((toys.optflags & FLAGS_NODASH) && gof.argc == 1) gof.nodash_now = 1;
 448      else goto notflag;
 449    }
 450
 451    // At this point, we have the args part of -args.  Loop through
 452    // each entry (could be -abc meaning -a -b -c)
 453    saveflags = toys.optflags;
 454    while (*gof.arg) {
 455
 456      // Identify next option char.
 457      for (catch = gof.opts; catch; catch = catch->next)
 458        if (*gof.arg == catch->c)
 459          if (!((catch->flags&4) && gof.arg[1])) break;
 460
 461      // Handle option char (advancing past what was used)
 462      if (gotflag(&gof, catch) ) {
 463        toys.optflags = saveflags;
 464        gof.arg = toys.argv[gof.argc];
 465        goto notflag;
 466      }
 467    }
 468    continue;
 469
 470    // Not a flag, save value in toys.optargs[]
 471notflag:
 472    if (gof.stopearly) gof.stopearly++;
 473    toys.optargs[toys.optc++] = toys.argv[gof.argc];
 474  }
 475
 476  // Sanity check
 477  if (toys.optc<gof.minargs)
 478    help_exit("Need%s %d argument%s", letters[!!(gof.minargs-1)],
 479      gof.minargs, letters[!(gof.minargs-1)]);
 480  if (toys.optc>gof.maxargs)
 481    help_exit("Max %d argument%s", gof.maxargs, letters[!(gof.maxargs-1)]);
 482  if (gof.requires && !(gof.requires & toys.optflags)) {
 483    struct opts *req;
 484    char needs[32], *s = needs;
 485
 486    for (req = gof.opts; req; req = req->next)
 487      if (req->flags & 1) *(s++) = req->c;
 488    *s = 0;
 489
 490    help_exit("Needs %s-%s", s[1] ? "one of " : "", needs);
 491  }
 492
 493  if (CFG_TOYBOX_FREE) {
 494    llist_traverse(gof.opts, free);
 495    llist_traverse(gof.longopts, free);
 496  }
 497}
 498