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 '\'', any exclamation point
   6  * is replaced with '\!', and the whole thing is enclosed in a
   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  *  a!b      ==> a'\!'b    ==> 'a'\!'b'
  14  */
  15 #undef EMIT
  16 #define EMIT(x) do { if (++len < n) *bp++ = (x); } while(0)
  17
  18 static inline int need_bs_quote(char c)
  19 {
  20         return (c == '\'' || c == '!');
  21 }
  22
  23 size_t sq_quote_buf(char *dst, size_t n, const char *src)
  24 {
  25         char c;
  26         char *bp = dst;
  27         size_t len = 0;
  28
  29         EMIT('\'');
  30         while ((c = *src++)) {
  31                 if (need_bs_quote(c)) {
  32                         EMIT('\'');
  33                         EMIT('\\');
  34                         EMIT(c);
  35                         EMIT('\'');
  36                 } else {
  37                         EMIT(c);
  38                 }
  39         }
  40         EMIT('\'');
  41
  42         if ( n )
  43                 *bp = 0;
  44
  45         return len;
  46 }
  47
  48 void sq_quote_print(FILE *stream, const char *src)
  49 {
  50         char c;
  51
  52         fputc('\'', stream);
  53         while ((c = *src++)) {
  54                 if (need_bs_quote(c)) {
  55                         fputs("'\\", stream);
  56                         fputc(c, stream);
  57                         fputc('\'', stream);
  58                 } else {
  59                         fputc(c, stream);
  60                 }
  61         }
  62         fputc('\'', stream);
  63 }
  64
  65 char *sq_quote(const char *src)
  66 {
  67         char *buf;
  68         size_t cnt;
  69
  70         cnt = sq_quote_buf(NULL, 0, src) + 1;
  71         buf = xmalloc(cnt);
  72         sq_quote_buf(buf, cnt, src);
  73
  74         return buf;
  75 }
  76
  77 char *sq_dequote(char *arg)
  78 {
  79         char *dst = arg;
  80         char *src = arg;
  81         char c;
  82
  83         if (*src != '\'')
  84                 return NULL;
  85         for (;;) {
  86                 c = *++src;
  87                 if (!c)
  88                         return NULL;
  89                 if (c != '\'') {
  90                         *dst++ = c;
  91                         continue;
  92                 }
  93                 /* We stepped out of sq */
  94                 switch (*++src) {
  95                 case '\0':
  96                         *dst = 0;
  97                         return arg;
  98                 case '\\':
  99                         c = *++src;
 100                         if (need_bs_quote(c) && *++src == '\'') {
 101                                 *dst++ = c;
 102                                 continue;
 103                         }
 104                 /* Fallthrough */
 105                 default:
 106                         return NULL;
 107                 }
 108         }
 109 }
 110
 111 /*
 112  * C-style name quoting.
 113  *
 114  * Does one of three things:
 115  *
 116  * (1) if outbuf and outfp are both NULL, inspect the input name and
 117  *     counts the number of bytes that are needed to hold c_style
 118  *     quoted version of name, counting the double quotes around
 119  *     it but not terminating NUL, and returns it.  However, if name
 120  *     does not need c_style quoting, it returns 0.
 121  *
 122  * (2) if outbuf is not NULL, it must point at a buffer large enough
 123  *     to hold the c_style quoted version of name, enclosing double
 124  *     quotes, and terminating NUL.  Fills outbuf with c_style quoted
 125  *     version of name enclosed in double-quote pair.  Return value
 126  *     is undefined.
 127  *
 128  * (3) if outfp is not NULL, outputs c_style quoted version of name,
 129  *     but not enclosed in double-quote pair.  Return value is undefined.
 130  */
 131
 132 static int quote_c_style_counted(const char *name, int namelen,
 133                                  char *outbuf, FILE *outfp, int no_dq)
 134 {
 135 #undef EMIT
 136 #define EMIT(c) \
 137         (outbuf ? (*outbuf++ = (c)) : outfp ? fputc(c, outfp) : (count++))
 138
 139 #define EMITQ() EMIT('\\')
 140
 141         const char *sp;
 142         int ch, count = 0, needquote = 0;
 143
 144         if (!no_dq)
 145                 EMIT('"');
 146         for (sp = name; sp < name + namelen; sp++) {
 147                 ch = *sp;
 148                 if (!ch)
 149                         break;
 150                 if ((ch < ' ') || (ch == '"') || (ch == '\\') ||
 151                     (ch == 0177)) {
 152                         needquote = 1;
 153                         switch (ch) {
 154                         case '\a': EMITQ(); ch = 'a'; break;
 155                         case '\b': EMITQ(); ch = 'b'; break;
 156                         case '\f': EMITQ(); ch = 'f'; break;
 157                         case '\n': EMITQ(); ch = 'n'; break;
 158                         case '\r': EMITQ(); ch = 'r'; break;
 159                         case '\t': EMITQ(); ch = 't'; break;
 160                         case '\v': EMITQ(); ch = 'v'; break;
 161
 162                         case '\\': /* fallthru */
 163                         case '"': EMITQ(); break;
 164                         default:
 165                                 /* octal */
 166                                 EMITQ();
 167                                 EMIT(((ch >> 6) & 03) + '0');
 168                                 EMIT(((ch >> 3) & 07) + '0');
 169                                 ch = (ch & 07) + '0';
 170                                 break;
 171                         }
 172                 }
 173                 EMIT(ch);
 174         }
 175         if (!no_dq)
 176                 EMIT('"');
 177         if (outbuf)
 178                 *outbuf = 0;
 179
 180         return needquote ? count : 0;
 181 }
 182
 183 int quote_c_style(const char *name, char *outbuf, FILE *outfp, int no_dq)
 184 {
 185         int cnt = strlen(name);
 186         return quote_c_style_counted(name, cnt, outbuf, outfp, no_dq);
 187 }
 188
 189 /*
 190  * C-style name unquoting.
 191  *
 192  * Quoted should point at the opening double quote.  Returns
 193  * an allocated memory that holds unquoted name, which the caller
 194  * should free when done.  Updates endp pointer to point at
 195  * one past the ending double quote if given.
 196  */
 197
 198 char *unquote_c_style(const char *quoted, const char **endp)
 199 {
 200         const char *sp;
 201         char *name = NULL, *outp = NULL;
 202         int count = 0, ch, ac;
 203
 204 #undef EMIT
 205 #define EMIT(c) (outp ? (*outp++ = (c)) : (count++))
 206
 207         if (*quoted++ != '"')
 208                 return NULL;
 209
 210         while (1) {
 211                 /* first pass counts and allocates, second pass fills */
 212                 for (sp = quoted; (ch = *sp++) != '"'; ) {
 213                         if (ch == '\\') {
 214                                 switch (ch = *sp++) {
 215                                 case 'a': ch = '\a'; break;
 216                                 case 'b': ch = '\b'; break;
 217                                 case 'f': ch = '\f'; break;
 218                                 case 'n': ch = '\n'; break;
 219                                 case 'r': ch = '\r'; break;
 220                                 case 't': ch = '\t'; break;
 221                                 case 'v': ch = '\v'; break;
 222
 223                                 case '\\': case '"':
 224                                         break; /* verbatim */
 225
 226                                 case '0':
 227                                 case '1':
 228                                 case '2':
 229                                 case '3':
 230                                 case '4':
 231                                 case '5':
 232                                 case '6':
 233                                 case '7':
 234                                         /* octal */
 235                                         ac = ((ch - '0') << 6);
 236                                         if ((ch = *sp++) < '0' || '7' < ch)
 237                                                 return NULL;
 238                                         ac |= ((ch - '0') << 3);
 239                                         if ((ch = *sp++) < '0' || '7' < ch)
 240                                                 return NULL;
 241                                         ac |= (ch - '0');
 242                                         ch = ac;
 243                                         break;
 244                                 default:
 245                                         return NULL; /* malformed */
 246                                 }
 247                         }
 248                         EMIT(ch);
 249                 }
 250
 251                 if (name) {
 252                         *outp = 0;
 253                         if (endp)
 254                                 *endp = sp;
 255                         return name;
 256                 }
 257                 outp = name = xmalloc(count + 1);
 258         }
 259 }
 260
 261 void write_name_quoted(const char *prefix, int prefix_len,
 262                        const char *name, int quote, FILE *out)
 263 {
 264         int needquote;
 265
 266         if (!quote) {
 267         no_quote:
 268                 if (prefix_len)
 269                         fprintf(out, "%.*s", prefix_len, prefix);
 270                 fputs(name, out);
 271                 return;
 272         }
 273
 274         needquote = 0;
 275         if (prefix_len)
 276                 needquote = quote_c_style_counted(prefix, prefix_len,
 277                                                   NULL, NULL, 0);
 278         if (!needquote)
 279                 needquote = quote_c_style(name, NULL, NULL, 0);
 280         if (needquote) {
 281                 fputc('"', out);
 282                 if (prefix_len)
 283                         quote_c_style_counted(prefix, prefix_len,
 284                                               NULL, out, 1);
 285                 quote_c_style(name, NULL, out, 1);
 286                 fputc('"', out);
 287         }
 288         else
 289                 goto no_quote;
 290 }