mdw@git.distorted.org.uk Git - disorder/blob - lib/macros-builtin.c

   1 /*
   2  * This file is part of DisOrder
   3  * Copyright (C) 2008 Richard Kettlewell
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  18  * USA
  19  */
  20
  21 /** @file lib/macros-builtin.c
  22  * @brief Built-in expansions
  23  *
  24  * This is a grab-bag of non-domain-specific expansions.  Documentation will be
  25  * generated from the comments at the head of each function.
  26  */
  27
  28 #include "common.h"
  29
  30 #include <errno.h>
  31 #include <unistd.h>
  32 #include <fcntl.h>
  33 #include <sys/stat.h>
  34 #include <sys/wait.h>
  35
  36 #include "hash.h"
  37 #include "mem.h"
  38 #include "macros.h"
  39 #include "sink.h"
  40 #include "syscalls.h"
  41 #include "log.h"
  42 #include "wstat.h"
  43 #include "kvp.h"
  44 #include "split.h"
  45 #include "printf.h"
  46 #include "vector.h"
  47 #include "filepart.h"
  48
  49 static struct vector include_path;
  50
  51 /** @brief Return 1 if @p s is 'true' else 0 */
  52 int mx_str2bool(const char *s) {
  53   return !strcmp(s, "true");
  54 }
  55
  56 /** @brief Return "true" if @p n is nonzero else "false" */
  57 const char *mx_bool2str(int n) {
  58   return n ? "true" : "false";
  59 }
  60
  61 /** @brief Write a boolean result */
  62 int mx_bool_result(struct sink *output, int result) {
  63   if(sink_writes(output, mx_bool2str(result)) < 0)
  64     return -1;
  65   else
  66     return 0;
  67 }
  68
  69 /** @brief Search the include path */
  70 char *mx_find(const char *name, int report) {
  71   char *path;
  72   int n;
  73
  74   if(name[0] == '/') {
  75     if(access(name, O_RDONLY) < 0) {
  76       if(report)
  77         error(errno, "cannot read %s", name);
  78       return 0;
  79     }
  80     path = xstrdup(name);
  81   } else {
  82     /* Search the include path */
  83     for(n = 0; n < include_path.nvec; ++n) {
  84       byte_xasprintf(&path, "%s/%s", include_path.vec[n], name);
  85       if(access(path, O_RDONLY) == 0)
  86         break;
  87     }
  88     if(n >= include_path.nvec) {
  89       if(report)
  90         error(0, "cannot find '%s' in search path", name);
  91       return 0;
  92     }
  93   }
  94   return path;
  95 }
  96
  97 /*! @include{TEMPLATE}@
  98  *
  99  * Includes TEMPLATE.
 100  *
 101  * TEMPLATE can be an absolute filename starting with a '/'; only the file with
 102  * exactly this name will be included.
 103  *
 104  * Alternatively it can be a relative filename, not starting with a '/'.  In
 105  * this case the file will be searched for in the include path.  When searching
 106  * paths, unreadable files are treated as if they do not exist (rather than
 107  * matching then producing an error).
 108  *
 109  * If the name chosen ends ".tmpl" then the file will be expanded as a
 110  * template.  Anything else is included byte-for-byte without further
 111  * modification.
 112  *
 113  * Only regular files are allowed (no devices, sockets or name pipes).
 114  */
 115 static int exp_include(int attribute((unused)) nargs,
 116                        char **args,
 117                        struct sink *output,
 118                        void *u) {
 119   const char *path;
 120   int fd, n;
 121   char buffer[4096];
 122   struct stat sb;
 123
 124   if(!(path = mx_find(args[0], 1/*report*/))) {
 125     if(sink_printf(output, "[[cannot find '%s']]", args[0]) < 0)
 126       return 0;
 127     return 0;
 128   }
 129   /* If it's a template expand it */
 130   if(strlen(path) >= 5 && !strncmp(path + strlen(path) - 5, ".tmpl", 5))
 131     return mx_expand_file(path, output, u);
 132   /* Read the raw file.  As with mx_expand_file() we insist that the file is a
 133    * regular file. */
 134   if((fd = open(path, O_RDONLY)) < 0)
 135     fatal(errno, "error opening %s", path);
 136   if(fstat(fd, &sb) < 0)
 137     fatal(errno, "error statting %s", path);
 138   if(!S_ISREG(sb.st_mode))
 139     fatal(0, "%s: not a regular file", path);
 140   while((n = read(fd, buffer, sizeof buffer)) > 0) {
 141     if(sink_write(output, buffer, n) < 0) {
 142       xclose(fd);
 143       return -1;
 144     }
 145   }
 146   if(n < 0)
 147     fatal(errno, "error reading %s", path);
 148   xclose(fd);
 149   return 0;
 150 }
 151
 152 /*! @include{COMMAND}@
 153  *
 154  * Executes COMMAND via the shell (using "sh -c") and copies its
 155  * standard output to the template output.  The shell command output
 156  * is not expanded or modified in any other way.
 157  *
 158  * The shell command's standard error is copied to the error log.
 159  *
 160  * If the shell exits nonzero then this is reported to the error log
 161  * but otherwise no special action is taken.
 162  */
 163 static int exp_shell(int attribute((unused)) nargs,
 164                      char **args,
 165                      struct sink *output,
 166                      void attribute((unused)) *u) {
 167   int w, p[2], n;
 168   char buffer[4096];
 169   pid_t pid;
 170
 171   xpipe(p);
 172   if(!(pid = xfork())) {
 173     exitfn = _exit;
 174     xclose(p[0]);
 175     xdup2(p[1], 1);
 176     xclose(p[1]);
 177     execlp("sh", "sh", "-c", args[0], (char *)0);
 178     fatal(errno, "error executing sh");
 179   }
 180   xclose(p[1]);
 181   while((n = read(p[0], buffer, sizeof buffer))) {
 182     if(n < 0) {
 183       if(errno == EINTR)
 184         continue;
 185       else
 186         fatal(errno, "error reading from pipe");
 187     }
 188     if(output->write(output, buffer, n) < 0)
 189       return -1;
 190   }
 191   xclose(p[0]);
 192   while((n = waitpid(pid, &w, 0)) < 0 && errno == EINTR)
 193     ;
 194   if(n < 0)
 195     fatal(errno, "error calling waitpid");
 196   if(w)
 197     error(0, "shell command '%s' %s", args[0], wstat(w));
 198   return 0;
 199 }
 200
 201 /*! @if{CONDITION}{IF-TRUE}{IF-FALSE}@
 202  *
 203  * If CONDITION is "true" then evaluates to IF-TRUE.  Otherwise
 204  * evaluates to IF-FALSE.  The IF-FALSE part is optional.
 205  */
 206 static int exp_if(int nargs,
 207                   const struct mx_node **args,
 208                   struct sink *output,
 209                   void *u) {
 210   char *s;
 211   int rc;
 212
 213   if((rc = mx_expandstr(args[0], &s, u, "argument #0 (CONDITION)")))
 214     return rc;
 215   if(mx_str2bool(s))
 216     return mx_expand(args[1], output, u);
 217   else if(nargs > 2)
 218     return mx_expand(args[2], output, u);
 219   else
 220     return 0;
 221 }
 222
 223 /*! @and{BRANCH}{BRANCH}...@
 224  *
 225  * Expands to "true" if all the branches are "true" otherwise to "false".  If
 226  * there are no brances then the result is "true".  Only as many branches as
 227  * necessary to compute the answer are evaluated (starting from the first one),
 228  * so if later branches have side effects they may not take place.
 229  */
 230 static int exp_and(int nargs,
 231                    const struct mx_node **args,
 232                    struct sink *output,
 233                    void *u) {
 234   int n, result = 1, rc;
 235   char *s, *argname;
 236
 237   for(n = 0; n < nargs; ++n) {
 238     byte_xasprintf(&argname, "argument #%d", n);
 239     if((rc = mx_expandstr(args[n], &s, u, argname)))
 240       return rc;
 241     if(!mx_str2bool(s)) {
 242       result = 0;
 243       break;
 244     }
 245   }
 246   return mx_bool_result(output, result);
 247 }
 248
 249 /*! @or{BRANCH}{BRANCH}...@
 250  *
 251  * Expands to "true" if any of the branches are "true" otherwise to "false".
 252  * If there are no brances then the result is "false".  Only as many branches
 253  * as necessary to compute the answer are evaluated (starting from the first
 254  * one), so if later branches have side effects they may not take place.
 255  */
 256 static int exp_or(int nargs,
 257                   const struct mx_node **args,
 258                   struct sink *output,
 259                   void *u) {
 260   int n, result = 0, rc;
 261   char *s, *argname;
 262
 263   for(n = 0; n < nargs; ++n) {
 264     byte_xasprintf(&argname, "argument #%d", n);
 265     if((rc = mx_expandstr(args[n], &s, u, argname)))
 266       return rc;
 267     if(mx_str2bool(s)) {
 268       result = 1;
 269       break;
 270     }
 271   }
 272   return mx_bool_result(output, result);
 273 }
 274
 275 /*! @not{CONDITION}@
 276  *
 277  * Expands to "true" unless CONDITION is "true" in which case "false".
 278  */
 279 static int exp_not(int attribute((unused)) nargs,
 280                    char **args,
 281                    struct sink *output,
 282                    void attribute((unused)) *u) {
 283   return mx_bool_result(output, !mx_str2bool(args[0]));
 284 }
 285
 286 /*! @#{...}@
 287  *
 288  * Expands to nothing.  The argument(s) are not fully evaluated, and no side
 289  * effects occur.
 290  */
 291 static int exp_comment(int attribute((unused)) nargs,
 292                        const struct mx_node attribute((unused)) **args,
 293                        struct sink attribute((unused)) *output,
 294                        void attribute((unused)) *u) {
 295   return 0;
 296 }
 297
 298 /*! @urlquote{STRING}@
 299  *
 300  * URL-quotes a string, i.e. replaces any characters not safe to use unquoted
 301  * in a URL with %-encoded form.
 302  */
 303 static int exp_urlquote(int attribute((unused)) nargs,
 304                         char **args,
 305                         struct sink *output,
 306                         void attribute((unused)) *u) {
 307   if(sink_writes(output, urlencodestring(args[0])) < 0)
 308     return -1;
 309   else
 310     return 0;
 311 }
 312
 313 /*! @eq{S1}{S2}...@
 314  *
 315  * Expands to "true" if all the arguments are identical, otherwise to "false"
 316  * (i.e. if any pair of arguments differs).
 317  *
 318  * If there are no arguments then expands to "true".  Evaluates all arguments
 319  * (with their side effects) even if that's not strictly necessary to discover
 320  * the result.
 321  */
 322 static int exp_eq(int nargs,
 323                   char **args,
 324                   struct sink *output,
 325                   void attribute((unused)) *u) {
 326   int n, result = 1;
 327
 328   for(n = 1; n < nargs; ++n) {
 329     if(strcmp(args[n], args[0])) {
 330       result = 0;
 331       break;
 332     }
 333   }
 334   return mx_bool_result(output, result);
 335 }
 336
 337 /*! @ne{S1}{S2}...@
 338  *
 339  * Expands to "true" if all of the arguments differ from one another, otherwise
 340  * to "false" (i.e. if any value appears more than once).
 341  *
 342  * If there are no arguments then expands to "true".  Evaluates all arguments
 343  * (with their side effects) even if that's not strictly necessary to discover
 344  * the result.
 345  */
 346 static int exp_ne(int nargs,
 347                   char **args,
 348                   struct sink *output,
 349                   void  attribute((unused))*u) {
 350   hash *h = hash_new(sizeof (char *));
 351   int n, result = 1;
 352
 353   for(n = 0; n < nargs; ++n)
 354     if(hash_add(h, args[n], "", HASH_INSERT)) {
 355       result = 0;
 356       break;
 357     }
 358   return mx_bool_result(output, result);
 359 }
 360
 361 /*! @discard{...}@
 362  *
 363  * Expands to nothing.  Unlike the comment expansion @#{...}, side effects of
 364  * arguments are not suppressed.  So this can be used to surround a collection
 365  * of macro definitions with whitespace, free text commentary, etc.
 366  */
 367 static int exp_discard(int attribute((unused)) nargs,
 368                        char attribute((unused)) **args,
 369                        struct sink attribute((unused)) *output,
 370                        void attribute((unused)) *u) {
 371   return 0;
 372 }
 373
 374 /*! @define{NAME}{ARG1 ARG2...}{DEFINITION}@
 375  *
 376  * Define a macro.  The macro will be called NAME and will act like an
 377  * expansion.  When it is expanded, the expansion is replaced by DEFINITION,
 378  * with each occurence of @ARG1@ etc replaced by the parameters to the
 379  * expansion.
 380  */
 381 static int exp_define(int attribute((unused)) nargs,
 382                       const struct mx_node **args,
 383                       struct sink attribute((unused)) *output,
 384                       void attribute((unused)) *u) {
 385   char **as, *name, *argnames;
 386   int rc, nas;
 387
 388   if((rc = mx_expandstr(args[0], &name, u, "argument #0 (NAME)")))
 389     return rc;
 390   if((rc = mx_expandstr(args[1], &argnames, u, "argument #1 (ARGS)")))
 391     return rc;
 392   as = split(argnames, &nas, 0, 0, 0);
 393   mx_register_macro(name, nas, as, args[2]);
 394   return 0;
 395 }
 396
 397 /*! @basename{PATH}
 398  *
 399  * Expands to the UNQUOTED basename of PATH.
 400  */
 401 static int exp_basename(int attribute((unused)) nargs,
 402                         char **args,
 403                         struct sink attribute((unused)) *output,
 404                         void attribute((unused)) *u) {
 405   return sink_writes(output, d_basename(args[0])) < 0 ? -1 : 0;
 406 }
 407
 408 /*! @dirname{PATH}
 409  *
 410  * Expands to the UNQUOTED directory name of PATH.
 411  */
 412 static int exp_dirname(int attribute((unused)) nargs,
 413                        char **args,
 414                        struct sink attribute((unused)) *output,
 415                        void attribute((unused)) *u) {
 416   return sink_writes(output, d_dirname(args[0])) < 0 ? -1 : 0;
 417 }
 418
 419 /*! @q{STRING}
 420  *
 421  * Expands to STRING.
 422  */
 423 static int exp_q(int attribute((unused)) nargs,
 424                  char **args,
 425                  struct sink attribute((unused)) *output,
 426                  void attribute((unused)) *u) {
 427   return sink_writes(output, args[0]) < 0 ? -1 : 0;
 428 }
 429
 430 /** @brief Register built-in expansions */
 431 void mx_register_builtin(void) {
 432   mx_register("basename", 1, 1, exp_basename);
 433   mx_register("dirname", 1, 1, exp_dirname);
 434   mx_register("discard", 0, INT_MAX, exp_discard);
 435   mx_register("eq", 0, INT_MAX, exp_eq);
 436   mx_register("include", 1, 1, exp_include);
 437   mx_register("ne", 0, INT_MAX, exp_ne);
 438   mx_register("not", 1, 1, exp_not);
 439   mx_register("shell", 1, 1, exp_shell);
 440   mx_register("urlquote", 1, 1, exp_urlquote);
 441   mx_register("q", 1, 1, exp_q);
 442   mx_register_magic("#", 0, INT_MAX, exp_comment);
 443   mx_register_magic("and", 0, INT_MAX, exp_and);
 444   mx_register_magic("define", 3, 3, exp_define);
 445   mx_register_magic("if", 2, 3, exp_if);
 446   mx_register_magic("or", 0, INT_MAX, exp_or);
 447 }
 448
 449 /** @brief Add a directory to the search path
 450  * @param s Directory to add
 451  */
 452 void mx_search_path(const char *s) {
 453   vector_append(&include_path, xstrdup(s));
 454 }
 455
 456 /*
 457 Local Variables:
 458 c-basic-offset:2
 459 comment-column:40
 460 fill-column:79
 461 indent-tabs-mode:nil
 462 End:
 463 */