quote.c

   1 #include "cache.h"
   2 #include "quote.h"
   3
   4 /* Help to copy the thing properly quoted for the shell safety.
   5  * any single quote is replaced with '\'', and the caller is
   6  * expected to enclose the result within a single quote pair.
   7  *
   8  * E.g.
   9  *  original     sq_quote     result
  10  *  name     ==> name      ==> 'name'
  11  *  a b      ==> a b       ==> 'a b'
  12  *  a'b      ==> a'\''b    ==> 'a'\''b'
  13  */
  14 char *sq_quote(const char *src)
  15 {
  16         static char *buf = NULL;
  17         int cnt, c;
  18         const char *cp;
  19         char *bp;
  20
  21         /* count bytes needed to store the quoted string. */
  22         for (cnt = 3, cp = src; *cp; cnt++, cp++)
  23                 if (*cp == '\'')
  24                         cnt += 3;
  25
  26         buf = xmalloc(cnt);
  27         bp = buf;
  28         *bp++ = '\'';
  29         while ((c = *src++)) {
  30                 if (c != '\'')
  31                         *bp++ = c;
  32                 else {
  33                         bp = strcpy(bp, "'\\''");
  34                         bp += 4;
  35                 }
  36         }
  37         *bp++ = '\'';
  38         *bp = 0;
  39         return buf;
  40 }
  41
  42 /*
  43  * C-style name quoting.
  44  *
  45  * Does one of three things:
  46  *
  47  * (1) if outbuf and outfp are both NULL, inspect the input name and
  48  *     counts the number of bytes that are needed to hold c_style
  49  *     quoted version of name, counting the double quotes around
  50  *     it but not terminating NUL, and returns it.  However, if name
  51  *     does not need c_style quoting, it returns 0.
  52  *
  53  * (2) if outbuf is not NULL, it must point at a buffer large enough
  54  *     to hold the c_style quoted version of name, enclosing double
  55  *     quotes, and terminating NUL.  Fills outbuf with c_style quoted
  56  *     version of name enclosed in double-quote pair.  Return value
  57  *     is undefined.
  58  *
  59  * (3) if outfp is not NULL, outputs c_style quoted version of name,
  60  *     but not enclosed in double-quote pair.  Return value is undefined.
  61  */
  62
  63 int quote_c_style(const char *name, char *outbuf, FILE *outfp, int no_dq)
  64 {
  65 #undef EMIT
  66 #define EMIT(c) \
  67         (outbuf ? (*outbuf++ = (c)) : outfp ? fputc(c, outfp) : (count++))
  68
  69 #define EMITQ() EMIT('\\')
  70
  71         const char *sp;
  72         int ch, count = 0, needquote = 0;
  73
  74         if (!no_dq)
  75                 EMIT('"');
  76         for (sp = name; (ch = *sp++); ) {
  77
  78                 if ((ch < ' ') || (ch == '"') || (ch == '\\') ||
  79                     (ch == 0177)) {
  80                         needquote = 1;
  81                         switch (ch) {
  82                         case '\a': EMITQ(); ch = 'a'; break;
  83                         case '\b': EMITQ(); ch = 'b'; break;
  84                         case '\f': EMITQ(); ch = 'f'; break;
  85                         case '\n': EMITQ(); ch = 'n'; break;
  86                         case '\r': EMITQ(); ch = 'r'; break;
  87                         case '\t': EMITQ(); ch = 't'; break;
  88                         case '\v': EMITQ(); ch = 'v'; break;
  89
  90                         case '\\': /* fallthru */
  91                         case '"': EMITQ(); break;
  92                         case ' ':
  93                                 break;
  94                         default:
  95                                 /* octal */
  96                                 EMITQ();
  97                                 EMIT(((ch >> 6) & 03) + '0');
  98                                 EMIT(((ch >> 3) & 07) + '0');
  99                                 ch = (ch & 07) + '0';
 100                                 break;
 101                         }
 102                 }
 103                 EMIT(ch);
 104         }
 105         if (!no_dq)
 106                 EMIT('"');
 107         if (outbuf)
 108                 *outbuf = 0;
 109
 110         return needquote ? count : 0;
 111 }
 112
 113 /*
 114  * C-style name unquoting.
 115  *
 116  * Quoted should point at the opening double quote.  Returns
 117  * an allocated memory that holds unquoted name, which the caller
 118  * should free when done.  Updates endp pointer to point at
 119  * one past the ending double quote if given.
 120  */
 121
 122 char *unquote_c_style(const char *quoted, const char **endp)
 123 {
 124         const char *sp;
 125         char *name = NULL, *outp = NULL;
 126         int count = 0, ch, ac;
 127
 128 #undef EMIT
 129 #define EMIT(c) (outp ? (*outp++ = (c)) : (count++))
 130
 131         if (*quoted++ != '"')
 132                 return NULL;
 133
 134         while (1) {
 135                 /* first pass counts and allocates, second pass fills */
 136                 for (sp = quoted; (ch = *sp++) != '"'; ) {
 137                         if (ch == '\\') {
 138                                 switch (ch = *sp++) {
 139                                 case 'a': ch = '\a'; break;
 140                                 case 'b': ch = '\b'; break;
 141                                 case 'f': ch = '\f'; break;
 142                                 case 'n': ch = '\n'; break;
 143                                 case 'r': ch = '\r'; break;
 144                                 case 't': ch = '\t'; break;
 145                                 case 'v': ch = '\v'; break;
 146
 147                                 case '\\': case '"':
 148                                         break; /* verbatim */
 149
 150                                 case '0'...'7':
 151                                         /* octal */
 152                                         ac = ((ch - '0') << 6);
 153                                         if ((ch = *sp++) < '0' || '7' < ch)
 154                                                 return NULL;
 155                                         ac |= ((ch - '0') << 3);
 156                                         if ((ch = *sp++) < '0' || '7' < ch)
 157                                                 return NULL;
 158                                         ac |= (ch - '0');
 159                                         ch = ac;
 160                                         break;
 161                                 default:
 162                                         return NULL; /* malformed */
 163                                 }
 164                         }
 165                         EMIT(ch);
 166                 }
 167
 168                 if (name) {
 169                         *outp = 0;
 170                         if (endp)
 171                                 *endp = sp;
 172                         return name;
 173                 }
 174                 outp = name = xmalloc(count + 1);
 175         }
 176 }
 177
 178 void write_name_quoted(const char *prefix, const char *name,
 179                        int quote, FILE *out)
 180 {
 181         int needquote;
 182
 183         if (!quote) {
 184         no_quote:
 185                 if (prefix && prefix[0])
 186                         fputs(prefix, out);
 187                 fputs(name, out);
 188                 return;
 189         }
 190
 191         needquote = 0;
 192         if (prefix && prefix[0])
 193                 needquote = quote_c_style(prefix, NULL, NULL, 0);
 194         if (!needquote)
 195                 needquote = quote_c_style(name, NULL, NULL, 0);
 196         if (needquote) {
 197                 fputc('"', out);
 198                 if (prefix && prefix[0])
 199                         quote_c_style(prefix, NULL, out, 1);
 200                 quote_c_style(name, NULL, out, 1);
 201                 fputc('"', out);
 202         }
 203         else
 204                 goto no_quote;
 205 }