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_quote_argv(const char** argv, int count)
  78 {
  79         char *buf, *to;
  80         int i;
  81         size_t len = 0;
  82
  83         /* Count argv if needed. */
  84         if (count < 0) {
  85                 for (count = 0; argv[count]; count++)
  86                         ; /* just counting */
  87         }
  88
  89         /* Special case: no argv. */
  90         if (!count)
  91                 return xcalloc(1,1);
  92
  93         /* Get destination buffer length. */
  94         for (i = 0; i < count; i++)
  95                 len += sq_quote_buf(NULL, 0, argv[i]) + 1;
  96
  97         /* Alloc destination buffer. */
  98         to = buf = xmalloc(len + 1);
  99
 100         /* Copy into destination buffer. */
 101         for (i = 0; i < count; ++i) {
 102                 *to++ = ' ';
 103                 to += sq_quote_buf(to, len, argv[i]);
 104         }
 105
 106         return buf;
 107 }
 108
 109 char *sq_dequote(char *arg)
 110 {
 111         char *dst = arg;
 112         char *src = arg;
 113         char c;
 114
 115         if (*src != '\'')
 116                 return NULL;
 117         for (;;) {
 118                 c = *++src;
 119                 if (!c)
 120                         return NULL;
 121                 if (c != '\'') {
 122                         *dst++ = c;
 123                         continue;
 124                 }
 125                 /* We stepped out of sq */
 126                 switch (*++src) {
 127                 case '\0':
 128                         *dst = 0;
 129                         return arg;
 130                 case '\\':
 131                         c = *++src;
 132                         if (need_bs_quote(c) && *++src == '\'') {
 133                                 *dst++ = c;
 134                                 continue;
 135                         }
 136                 /* Fallthrough */
 137                 default:
 138                         return NULL;
 139                 }
 140         }
 141 }
 142
 143 /*
 144  * C-style name quoting.
 145  *
 146  * Does one of three things:
 147  *
 148  * (1) if outbuf and outfp are both NULL, inspect the input name and
 149  *     counts the number of bytes that are needed to hold c_style
 150  *     quoted version of name, counting the double quotes around
 151  *     it but not terminating NUL, and returns it.  However, if name
 152  *     does not need c_style quoting, it returns 0.
 153  *
 154  * (2) if outbuf is not NULL, it must point at a buffer large enough
 155  *     to hold the c_style quoted version of name, enclosing double
 156  *     quotes, and terminating NUL.  Fills outbuf with c_style quoted
 157  *     version of name enclosed in double-quote pair.  Return value
 158  *     is undefined.
 159  *
 160  * (3) if outfp is not NULL, outputs c_style quoted version of name,
 161  *     but not enclosed in double-quote pair.  Return value is undefined.
 162  */
 163
 164 static int quote_c_style_counted(const char *name, int namelen,
 165                                  char *outbuf, FILE *outfp, int no_dq)
 166 {
 167 #undef EMIT
 168 #define EMIT(c) \
 169         (outbuf ? (*outbuf++ = (c)) : outfp ? fputc(c, outfp) : (count++))
 170
 171 #define EMITQ() EMIT('\\')
 172
 173         const char *sp;
 174         int ch, count = 0, needquote = 0;
 175
 176         if (!no_dq)
 177                 EMIT('"');
 178         for (sp = name; sp < name + namelen; sp++) {
 179                 ch = *sp;
 180                 if (!ch)
 181                         break;
 182                 if ((ch < ' ') || (ch == '"') || (ch == '\\') ||
 183                     (ch == 0177)) {
 184                         needquote = 1;
 185                         switch (ch) {
 186                         case '\a': EMITQ(); ch = 'a'; break;
 187                         case '\b': EMITQ(); ch = 'b'; break;
 188                         case '\f': EMITQ(); ch = 'f'; break;
 189                         case '\n': EMITQ(); ch = 'n'; break;
 190                         case '\r': EMITQ(); ch = 'r'; break;
 191                         case '\t': EMITQ(); ch = 't'; break;
 192                         case '\v': EMITQ(); ch = 'v'; break;
 193
 194                         case '\\': /* fallthru */
 195                         case '"': EMITQ(); break;
 196                         default:
 197                                 /* octal */
 198                                 EMITQ();
 199                                 EMIT(((ch >> 6) & 03) + '0');
 200                                 EMIT(((ch >> 3) & 07) + '0');
 201                                 ch = (ch & 07) + '0';
 202                                 break;
 203                         }
 204                 }
 205                 EMIT(ch);
 206         }
 207         if (!no_dq)
 208                 EMIT('"');
 209         if (outbuf)
 210                 *outbuf = 0;
 211
 212         return needquote ? count : 0;
 213 }
 214
 215 int quote_c_style(const char *name, char *outbuf, FILE *outfp, int no_dq)
 216 {
 217         int cnt = strlen(name);
 218         return quote_c_style_counted(name, cnt, outbuf, outfp, no_dq);
 219 }
 220
 221 /*
 222  * C-style name unquoting.
 223  *
 224  * Quoted should point at the opening double quote.  Returns
 225  * an allocated memory that holds unquoted name, which the caller
 226  * should free when done.  Updates endp pointer to point at
 227  * one past the ending double quote if given.
 228  */
 229
 230 char *unquote_c_style(const char *quoted, const char **endp)
 231 {
 232         const char *sp;
 233         char *name = NULL, *outp = NULL;
 234         int count = 0, ch, ac;
 235
 236 #undef EMIT
 237 #define EMIT(c) (outp ? (*outp++ = (c)) : (count++))
 238
 239         if (*quoted++ != '"')
 240                 return NULL;
 241
 242         while (1) {
 243                 /* first pass counts and allocates, second pass fills */
 244                 for (sp = quoted; (ch = *sp++) != '"'; ) {
 245                         if (ch == '\\') {
 246                                 switch (ch = *sp++) {
 247                                 case 'a': ch = '\a'; break;
 248                                 case 'b': ch = '\b'; break;
 249                                 case 'f': ch = '\f'; break;
 250                                 case 'n': ch = '\n'; break;
 251                                 case 'r': ch = '\r'; break;
 252                                 case 't': ch = '\t'; break;
 253                                 case 'v': ch = '\v'; break;
 254
 255                                 case '\\': case '"':
 256                                         break; /* verbatim */
 257
 258                                 case '0':
 259                                 case '1':
 260                                 case '2':
 261                                 case '3':
 262                                 case '4':
 263                                 case '5':
 264                                 case '6':
 265                                 case '7':
 266                                         /* octal */
 267                                         ac = ((ch - '0') << 6);
 268                                         if ((ch = *sp++) < '0' || '7' < ch)
 269                                                 return NULL;
 270                                         ac |= ((ch - '0') << 3);
 271                                         if ((ch = *sp++) < '0' || '7' < ch)
 272                                                 return NULL;
 273                                         ac |= (ch - '0');
 274                                         ch = ac;
 275                                         break;
 276                                 default:
 277                                         return NULL; /* malformed */
 278                                 }
 279                         }
 280                         EMIT(ch);
 281                 }
 282
 283                 if (name) {
 284                         *outp = 0;
 285                         if (endp)
 286                                 *endp = sp;
 287                         return name;
 288                 }
 289                 outp = name = xmalloc(count + 1);
 290         }
 291 }
 292
 293 void write_name_quoted(const char *prefix, int prefix_len,
 294                        const char *name, int quote, FILE *out)
 295 {
 296         int needquote;
 297
 298         if (!quote) {
 299         no_quote:
 300                 if (prefix_len)
 301                         fprintf(out, "%.*s", prefix_len, prefix);
 302                 fputs(name, out);
 303                 return;
 304         }
 305
 306         needquote = 0;
 307         if (prefix_len)
 308                 needquote = quote_c_style_counted(prefix, prefix_len,
 309                                                   NULL, NULL, 0);
 310         if (!needquote)
 311                 needquote = quote_c_style(name, NULL, NULL, 0);
 312         if (needquote) {
 313                 fputc('"', out);
 314                 if (prefix_len)
 315                         quote_c_style_counted(prefix, prefix_len,
 316                                               NULL, out, 1);
 317                 quote_c_style(name, NULL, out, 1);
 318                 fputc('"', out);
 319         }
 320         else
 321                 goto no_quote;
 322 }