src/lib-roff/quotearg.c

   1 /*@
   2  * Copyright (c) 2014 - 2015 Steffen (Daode) Nurpmeso <sdaoden@users.sf.net>.
   3  *
   4  * Copyright (C) 2004
   5  *    Free Software Foundation, Inc.
   6  *      Written by:  Jeff Conrad    (jeff_conrad@msn.com)
   7  *        and        Keith Marshall (keith.d.marshall@ntlworld.com)
   8  *
   9  * This is free software; you can redistribute it and/or modify it under
  10  * the terms of the GNU General Public License as published by the Free
  11  * Software Foundation; either version 2, or (at your option) any later
  12  * version.
  13  *
  14  * This is distributed in the hope that it will be useful, but WITHOUT ANY
  15  * WARRANTY; without even the implied warranty of MERCHANTABILITY or
  16  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  17  * for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License along
  20  * with groff; see the file COPYING.  If not, write to the Free Software
  21  * Foundation, 51 Franklin St - Fifth Floor, Boston, MA 02110-1301, USA.
  22  */
  23
  24 #include "config.h"
  25
  26 #include <ctype.h>
  27 #include <limits.h>
  28 #include <stdio.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31
  32 #include "nonposix.h"
  33
  34 /* Define the default mechanism, and messages, for error reporting
  35  * (user may substitute a preferred alternative, by defining his own
  36  *  implementation of the macros REPORT_ERROR, QUOTE_ARG_MALLOC_FAILED
  37  *  and QUOTE_ARG_REALLOC_FAILED, in the header file `nonposix.h').
  38  */
  39
  40 #ifndef  REPORT_ERROR
  41 # define REPORT_ERROR(WHY)  fprintf(stderr, "%s:%s\n", program_name, WHY)
  42 #endif
  43 #ifndef  QUOTE_ARG_MALLOC_ERROR
  44 # define QUOTE_ARG_MALLOC_ERROR   "malloc: Buffer allocation failed"
  45 #endif
  46 #ifndef  QUOTE_ARG_REALLOC_ERROR
  47 # define QUOTE_ARG_REALLOC_ERROR  "realloc: Buffer resize failed"
  48 #endif
  49
  50 extern char *program_name;      /* FIXME main program must define this */
  51
  52 static int
  53 needs_quoting(const char *string)
  54 {
  55   /* Scan `string' to see whether it needs quoting for MSVC `spawn'/`exec'
  56    * (i.e., whether it contains whitespace or embedded quotes).
  57    */
  58
  59   if (string == NULL)           /* ignore NULL strings */
  60     return false;
  61
  62   if (*string == '\0')          /* explicit arguments of zero length      */
  63     return true;                /* need quoting, so they aren't discarded */
  64
  65   while (*string) {
  66     /* Scan non-NULL strings, up to '\0' terminator,
  67      * returning 'true' if quote or white space found.
  68      */
  69
  70     if (*string == '"' || isspace(*string))
  71       return true;
  72
  73     /* otherwise, continue scanning to end of string */
  74
  75     ++string;
  76   }
  77
  78   /* Fall through, if no quotes or white space found,
  79    * in which case, return `false'.
  80    */
  81   return false;
  82 }
  83
  84 char *
  85 quote_arg(char *string)
  86 {
  87   /* Enclose arguments in double quotes so that the parsing done in the
  88    * MSVC runtime startup code doesn't split them at whitespace.  Escape
  89    * embedded double quotes so that they emerge intact from the parsing.
  90    */
  91
  92   int backslashes;
  93   char *quoted, *p, *q;
  94
  95   if (needs_quoting(string)) {
  96     /* Need to create a quoted copy of `string';
  97      * maximum buffer space needed is twice the original length,
  98      * plus two enclosing quotes and one `\0' terminator.
  99      */
 100
 101     if ((quoted = (char *)malloc(2 * strlen(string) + 3)) == NULL) {
 102       /* Couldn't get a buffer for the quoted string,
 103        * so complain, and bail out gracefully.
 104        */
 105
 106       REPORT_ERROR(QUOTE_ARG_MALLOC_ERROR);
 107       exit(1);
 108     }
 109
 110     /* Ok to proceed:
 111      * insert the opening quote, then copy the source string,
 112      * adding escapes as required.
 113      */
 114
 115     *quoted = '"';
 116     for (backslashes = 0, p = string, q = quoted; *p; p++) {
 117       if (*p == '\\') {
 118         /* Just count backslashes when we find them.
 119          * We will copy them out later, when we know if the count
 120          * needs to be adjusted, to escape an embedded quote.
 121          */
 122
 123         ++backslashes;
 124       }
 125       else if (*p == '"') {
 126         /* This embedded quote character must be escaped,
 127          * but first double up any immediately preceding backslashes,
 128          * with one extra, as the escape character.
 129          */
 130
 131         for (backslashes += backslashes + 1; backslashes; backslashes--)
 132           *++q = '\\';
 133
 134         /* and now, add the quote character itself */
 135
 136         *++q = '"';
 137       }
 138       else {
 139         /* Any other character is simply copied,
 140          * but first, if we have any pending backslashes,
 141          * we must now insert them, without any count adjustment.
 142          */
 143
 144         while (backslashes) {
 145           *++q = '\\';
 146           --backslashes;
 147         }
 148
 149         /* and then, copy the current character */
 150
 151         *++q = *p;
 152       }
 153     }
 154
 155     /* At end of argument:
 156      * If any backslashes remain to be copied out, append them now,
 157      * doubling the actual count to protect against reduction by MSVC,
 158      * as a consequence of the immediately following closing quote.
 159      */
 160
 161     for (backslashes += backslashes; backslashes; backslashes--)
 162       *++q = '\\';
 163
 164     /* Finally,
 165      * add the closing quote, terminate the quoted string,
 166      * and adjust its size to what was actually required,
 167      * ready for return.
 168      */
 169
 170     *++q = '"';
 171     *++q = '\0';
 172     if ((string = (char *)realloc(quoted, strlen(quoted) + 1)) == NULL) {
 173       /* but bail out gracefully, on error */
 174
 175       REPORT_ERROR(QUOTE_ARG_REALLOC_ERROR);
 176       exit(1);
 177     }
 178   }
 179
 180   /* `string' now refers to the argument,
 181    * quoted and escaped, as required.
 182    */
 183
 184   return string;
 185 }
 186
 187 void
 188 purge_quoted_args(char **argv)
 189 {
 190   /* To avoid memory leaks,
 191    * free all memory previously allocated by `quoted_arg()',
 192    * within the scope of the referring argument vector, `argv'.
 193    */
 194
 195   if (argv)
 196     while (*argv) {
 197       /* Any argument beginning with a double quote
 198        * SHOULD have been allocated by `quoted_arg()'.
 199        */
 200
 201       if (**argv == '"')
 202         free( *argv );          /* so free its allocation */
 203       ++argv;                   /* and continue to the next argument */
 204     }
 205 }
 206
 207 // s-it2-mode