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 /*
 110  * Append a string to a string buffer, with or without shell quoting.
 111  * Return true if the buffer overflowed.
 112  */
 113 int add_to_string(char **ptrp, int *sizep, const char *str, int quote)
 114 {
 115         char *p = *ptrp;
 116         int size = *sizep;
 117         int oc;
 118         int err = 0;
 119
 120         if (quote)
 121                 oc = sq_quote_buf(p, size, str);
 122         else {
 123                 oc = strlen(str);
 124                 memcpy(p, str, (size <= oc) ? size - 1 : oc);
 125         }
 126
 127         if (size <= oc) {
 128                 err = 1;
 129                 oc = size - 1;
 130         }
 131
 132         *ptrp += oc;
 133         **ptrp = '\0';
 134         *sizep -= oc;
 135         return err;
 136 }
 137
 138 char *sq_dequote(char *arg)
 139 {
 140         char *dst = arg;
 141         char *src = arg;
 142         char c;
 143
 144         if (*src != '\'')
 145                 return NULL;
 146         for (;;) {
 147                 c = *++src;
 148                 if (!c)
 149                         return NULL;
 150                 if (c != '\'') {
 151                         *dst++ = c;
 152                         continue;
 153                 }
 154                 /* We stepped out of sq */
 155                 switch (*++src) {
 156                 case '\0':
 157                         *dst = 0;
 158                         return arg;
 159                 case '\\':
 160                         c = *++src;
 161                         if (need_bs_quote(c) && *++src == '\'') {
 162                                 *dst++ = c;
 163                                 continue;
 164                         }
 165                 /* Fallthrough */
 166                 default:
 167                         return NULL;
 168                 }
 169         }
 170 }
 171
 172 /*
 173  * C-style name quoting.
 174  *
 175  * Does one of three things:
 176  *
 177  * (1) if outbuf and outfp are both NULL, inspect the input name and
 178  *     counts the number of bytes that are needed to hold c_style
 179  *     quoted version of name, counting the double quotes around
 180  *     it but not terminating NUL, and returns it.  However, if name
 181  *     does not need c_style quoting, it returns 0.
 182  *
 183  * (2) if outbuf is not NULL, it must point at a buffer large enough
 184  *     to hold the c_style quoted version of name, enclosing double
 185  *     quotes, and terminating NUL.  Fills outbuf with c_style quoted
 186  *     version of name enclosed in double-quote pair.  Return value
 187  *     is undefined.
 188  *
 189  * (3) if outfp is not NULL, outputs c_style quoted version of name,
 190  *     but not enclosed in double-quote pair.  Return value is undefined.
 191  */
 192
 193 static int quote_c_style_counted(const char *name, int namelen,
 194                                  char *outbuf, FILE *outfp, int no_dq)
 195 {
 196 #undef EMIT
 197 #define EMIT(c) \
 198         (outbuf ? (*outbuf++ = (c)) : outfp ? fputc(c, outfp) : (count++))
 199
 200 #define EMITQ() EMIT('\\')
 201
 202         const char *sp;
 203         int ch, count = 0, needquote = 0;
 204
 205         if (!no_dq)
 206                 EMIT('"');
 207         for (sp = name; sp < name + namelen; sp++) {
 208                 ch = *sp;
 209                 if (!ch)
 210                         break;
 211                 if ((ch < ' ') || (ch == '"') || (ch == '\\') ||
 212                     (ch == 0177)) {
 213                         needquote = 1;
 214                         switch (ch) {
 215                         case '\a': EMITQ(); ch = 'a'; break;
 216                         case '\b': EMITQ(); ch = 'b'; break;
 217                         case '\f': EMITQ(); ch = 'f'; break;
 218                         case '\n': EMITQ(); ch = 'n'; break;
 219                         case '\r': EMITQ(); ch = 'r'; break;
 220                         case '\t': EMITQ(); ch = 't'; break;
 221                         case '\v': EMITQ(); ch = 'v'; break;
 222
 223                         case '\\': /* fallthru */
 224                         case '"': EMITQ(); break;
 225                         default:
 226                                 /* octal */
 227                                 EMITQ();
 228                                 EMIT(((ch >> 6) & 03) + '0');
 229                                 EMIT(((ch >> 3) & 07) + '0');
 230                                 ch = (ch & 07) + '0';
 231                                 break;
 232                         }
 233                 }
 234                 EMIT(ch);
 235         }
 236         if (!no_dq)
 237                 EMIT('"');
 238         if (outbuf)
 239                 *outbuf = 0;
 240
 241         return needquote ? count : 0;
 242 }
 243
 244 int quote_c_style(const char *name, char *outbuf, FILE *outfp, int no_dq)
 245 {
 246         int cnt = strlen(name);
 247         return quote_c_style_counted(name, cnt, outbuf, outfp, no_dq);
 248 }
 249
 250 /*
 251  * C-style name unquoting.
 252  *
 253  * Quoted should point at the opening double quote.  Returns
 254  * an allocated memory that holds unquoted name, which the caller
 255  * should free when done.  Updates endp pointer to point at
 256  * one past the ending double quote if given.
 257  */
 258
 259 char *unquote_c_style(const char *quoted, const char **endp)
 260 {
 261         const char *sp;
 262         char *name = NULL, *outp = NULL;
 263         int count = 0, ch, ac;
 264
 265 #undef EMIT
 266 #define EMIT(c) (outp ? (*outp++ = (c)) : (count++))
 267
 268         if (*quoted++ != '"')
 269                 return NULL;
 270
 271         while (1) {
 272                 /* first pass counts and allocates, second pass fills */
 273                 for (sp = quoted; (ch = *sp++) != '"'; ) {
 274                         if (ch == '\\') {
 275                                 switch (ch = *sp++) {
 276                                 case 'a': ch = '\a'; break;
 277                                 case 'b': ch = '\b'; break;
 278                                 case 'f': ch = '\f'; break;
 279                                 case 'n': ch = '\n'; break;
 280                                 case 'r': ch = '\r'; break;
 281                                 case 't': ch = '\t'; break;
 282                                 case 'v': ch = '\v'; break;
 283
 284                                 case '\\': case '"':
 285                                         break; /* verbatim */
 286
 287                                 case '0':
 288                                 case '1':
 289                                 case '2':
 290                                 case '3':
 291                                 case '4':
 292                                 case '5':
 293                                 case '6':
 294                                 case '7':
 295                                         /* octal */
 296                                         ac = ((ch - '0') << 6);
 297                                         if ((ch = *sp++) < '0' || '7' < ch)
 298                                                 return NULL;
 299                                         ac |= ((ch - '0') << 3);
 300                                         if ((ch = *sp++) < '0' || '7' < ch)
 301                                                 return NULL;
 302                                         ac |= (ch - '0');
 303                                         ch = ac;
 304                                         break;
 305                                 default:
 306                                         return NULL; /* malformed */
 307                                 }
 308                         }
 309                         EMIT(ch);
 310                 }
 311
 312                 if (name) {
 313                         *outp = 0;
 314                         if (endp)
 315                                 *endp = sp;
 316                         return name;
 317                 }
 318                 outp = name = xmalloc(count + 1);
 319         }
 320 }
 321
 322 void write_name_quoted(const char *prefix, int prefix_len,
 323                        const char *name, int quote, FILE *out)
 324 {
 325         int needquote;
 326
 327         if (!quote) {
 328         no_quote:
 329                 if (prefix_len)
 330                         fprintf(out, "%.*s", prefix_len, prefix);
 331                 fputs(name, out);
 332                 return;
 333         }
 334
 335         needquote = 0;
 336         if (prefix_len)
 337                 needquote = quote_c_style_counted(prefix, prefix_len,
 338                                                   NULL, NULL, 0);
 339         if (!needquote)
 340                 needquote = quote_c_style(name, NULL, NULL, 0);
 341         if (needquote) {
 342                 fputc('"', out);
 343                 if (prefix_len)
 344                         quote_c_style_counted(prefix, prefix_len,
 345                                               NULL, out, 1);
 346                 quote_c_style(name, NULL, out, 1);
 347                 fputc('"', out);
 348         }
 349         else
 350                 goto no_quote;
 351 }