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 static inline int need_bs_quote(char c)
  16 {
  17         return (c == '\'' || c == '!');
  18 }
  19
  20 void sq_quote_buf(struct strbuf *dst, const char *src)
  21 {
  22         char *to_free = NULL;
  23
  24         if (dst->buf == src)
  25                 to_free = strbuf_detach(dst, NULL);
  26
  27         strbuf_addch(dst, '\'');
  28         while (*src) {
  29                 size_t len = strcspn(src, "'!");
  30                 strbuf_add(dst, src, len);
  31                 src += len;
  32                 while (need_bs_quote(*src)) {
  33                         strbuf_addstr(dst, "'\\");
  34                         strbuf_addch(dst, *src++);
  35                         strbuf_addch(dst, '\'');
  36                 }
  37         }
  38         strbuf_addch(dst, '\'');
  39         free(to_free);
  40 }
  41
  42 void sq_quote_print(FILE *stream, const char *src)
  43 {
  44         char c;
  45
  46         fputc('\'', stream);
  47         while ((c = *src++)) {
  48                 if (need_bs_quote(c)) {
  49                         fputs("'\\", stream);
  50                         fputc(c, stream);
  51                         fputc('\'', stream);
  52                 } else {
  53                         fputc(c, stream);
  54                 }
  55         }
  56         fputc('\'', stream);
  57 }
  58
  59 void sq_quote_argv(struct strbuf *dst, const char** argv, size_t maxlen)
  60 {
  61         int i;
  62
  63         /* Copy into destination buffer. */
  64         strbuf_grow(dst, 255);
  65         for (i = 0; argv[i]; ++i) {
  66                 strbuf_addch(dst, ' ');
  67                 sq_quote_buf(dst, argv[i]);
  68                 if (maxlen && dst->len > maxlen)
  69                         die("Too many or long arguments");
  70         }
  71 }
  72
  73 char *sq_dequote(char *arg)
  74 {
  75         char *dst = arg;
  76         char *src = arg;
  77         char c;
  78
  79         if (*src != '\'')
  80                 return NULL;
  81         for (;;) {
  82                 c = *++src;
  83                 if (!c)
  84                         return NULL;
  85                 if (c != '\'') {
  86                         *dst++ = c;
  87                         continue;
  88                 }
  89                 /* We stepped out of sq */
  90                 switch (*++src) {
  91                 case '\0':
  92                         *dst = 0;
  93                         return arg;
  94                 case '\\':
  95                         c = *++src;
  96                         if (need_bs_quote(c) && *++src == '\'') {
  97                                 *dst++ = c;
  98                                 continue;
  99                         }
 100                 /* Fallthrough */
 101                 default:
 102                         return NULL;
 103                 }
 104         }
 105 }
 106
 107 /* 1 means: quote as octal
 108  * 0 means: quote as octal if (quote_path_fully)
 109  * -1 means: never quote
 110  * c: quote as "\\c"
 111  */
 112 #define X8(x)   x, x, x, x, x, x, x, x
 113 #define X16(x)  X8(x), X8(x)
 114 static signed char const sq_lookup[256] = {
 115         /*           0    1    2    3    4    5    6    7 */
 116         /* 0x00 */   1,   1,   1,   1,   1,   1,   1, 'a',
 117         /* 0x08 */ 'b', 't', 'n', 'v', 'f', 'r',   1,   1,
 118         /* 0x10 */ X16(1),
 119         /* 0x20 */  -1,  -1, '"',  -1,  -1,  -1,  -1,  -1,
 120         /* 0x28 */ X16(-1), X16(-1), X16(-1),
 121         /* 0x58 */  -1,  -1,  -1,  -1,'\\',  -1,  -1,  -1,
 122         /* 0x60 */ X16(-1), X8(-1),
 123         /* 0x78 */  -1,  -1,  -1,  -1,  -1,  -1,  -1,   1,
 124         /* 0x80 */ /* set to 0 */
 125 };
 126
 127 static inline int sq_must_quote(char c)
 128 {
 129         return sq_lookup[(unsigned char)c] + quote_path_fully > 0;
 130 }
 131
 132 /* returns the longest prefix not needing a quote up to maxlen if positive.
 133    This stops at the first \0 because it's marked as a character needing an
 134    escape */
 135 static size_t next_quote_pos(const char *s, ssize_t maxlen)
 136 {
 137         size_t len;
 138         if (maxlen < 0) {
 139                 for (len = 0; !sq_must_quote(s[len]); len++);
 140         } else {
 141                 for (len = 0; len < maxlen && !sq_must_quote(s[len]); len++);
 142         }
 143         return len;
 144 }
 145
 146 /*
 147  * C-style name quoting.
 148  *
 149  * (1) if sb and fp are both NULL, inspect the input name and counts the
 150  *     number of bytes that are needed to hold c_style quoted version of name,
 151  *     counting the double quotes around it but not terminating NUL, and
 152  *     returns it.
 153  *     However, if name does not need c_style quoting, it returns 0.
 154  *
 155  * (2) if sb or fp are not NULL, it emits the c_style quoted version
 156  *     of name, enclosed with double quotes if asked and needed only.
 157  *     Return value is the same as in (1).
 158  */
 159 static size_t quote_c_style_counted(const char *name, ssize_t maxlen,
 160                                     struct strbuf *sb, FILE *fp, int no_dq)
 161 {
 162 #undef EMIT
 163 #define EMIT(c)                                 \
 164         do {                                        \
 165                 if (sb) strbuf_addch(sb, (c));          \
 166                 if (fp) fputc((c), fp);                 \
 167                 count++;                                \
 168         } while (0)
 169 #define EMITBUF(s, l)                           \
 170         do {                                        \
 171                 if (sb) strbuf_add(sb, (s), (l));       \
 172                 if (fp) fwrite((s), (l), 1, fp);        \
 173                 count += (l);                           \
 174         } while (0)
 175
 176         size_t len, count = 0;
 177         const char *p = name;
 178
 179         for (;;) {
 180                 int ch;
 181
 182                 len = next_quote_pos(p, maxlen);
 183                 if (len == maxlen || !p[len])
 184                         break;
 185
 186                 if (!no_dq && p == name)
 187                         EMIT('"');
 188
 189                 EMITBUF(p, len);
 190                 EMIT('\\');
 191                 p += len;
 192                 ch = (unsigned char)*p++;
 193                 if (sq_lookup[ch] >= ' ') {
 194                         EMIT(sq_lookup[ch]);
 195                 } else {
 196                         EMIT(((ch >> 6) & 03) + '0');
 197                         EMIT(((ch >> 3) & 07) + '0');
 198                         EMIT(((ch >> 0) & 07) + '0');
 199                 }
 200         }
 201
 202         EMITBUF(p, len);
 203         if (p == name)   /* no ending quote needed */
 204                 return 0;
 205
 206         if (!no_dq)
 207                 EMIT('"');
 208         return count;
 209 }
 210
 211 size_t quote_c_style(const char *name, struct strbuf *sb, FILE *fp, int nodq)
 212 {
 213         return quote_c_style_counted(name, -1, sb, fp, nodq);
 214 }
 215
 216 void quote_two_c_style(struct strbuf *sb, const char *prefix, const char *path, int nodq)
 217 {
 218         if (quote_c_style(prefix, NULL, NULL, 0) ||
 219             quote_c_style(path, NULL, NULL, 0)) {
 220                 if (!nodq)
 221                         strbuf_addch(sb, '"');
 222                 quote_c_style(prefix, sb, NULL, 1);
 223                 quote_c_style(path, sb, NULL, 1);
 224                 if (!nodq)
 225                         strbuf_addch(sb, '"');
 226         } else {
 227                 strbuf_addstr(sb, prefix);
 228                 strbuf_addstr(sb, path);
 229         }
 230 }
 231
 232 void write_name_quoted(const char *name, FILE *fp, int terminator)
 233 {
 234         if (terminator) {
 235                 quote_c_style(name, NULL, fp, 0);
 236         } else {
 237                 fputs(name, fp);
 238         }
 239         fputc(terminator, fp);
 240 }
 241
 242 extern void write_name_quotedpfx(const char *pfx, size_t pfxlen,
 243                                  const char *name, FILE *fp, int terminator)
 244 {
 245         int needquote = 0;
 246
 247         if (terminator) {
 248                 needquote = next_quote_pos(pfx, pfxlen) < pfxlen
 249                         || name[next_quote_pos(name, -1)];
 250         }
 251         if (needquote) {
 252                 fputc('"', fp);
 253                 quote_c_style_counted(pfx, pfxlen, NULL, fp, 1);
 254                 quote_c_style(name, NULL, fp, 1);
 255                 fputc('"', fp);
 256         } else {
 257                 fwrite(pfx, pfxlen, 1, fp);
 258                 fputs(name, fp);
 259         }
 260         fputc(terminator, fp);
 261 }
 262
 263 /*
 264  * C-style name unquoting.
 265  *
 266  * Quoted should point at the opening double quote.
 267  * + Returns 0 if it was able to unquote the string properly, and appends the
 268  *   result in the strbuf `sb'.
 269  * + Returns -1 in case of error, and doesn't touch the strbuf. Though note
 270  *   that this function will allocate memory in the strbuf, so calling
 271  *   strbuf_release is mandatory whichever result unquote_c_style returns.
 272  *
 273  * Updates endp pointer to point at one past the ending double quote if given.
 274  */
 275 int unquote_c_style(struct strbuf *sb, const char *quoted, const char **endp)
 276 {
 277         size_t oldlen = sb->len, len;
 278         int ch, ac;
 279
 280         if (*quoted++ != '"')
 281                 return -1;
 282
 283         for (;;) {
 284                 len = strcspn(quoted, "\"\\");
 285                 strbuf_add(sb, quoted, len);
 286                 quoted += len;
 287
 288                 switch (*quoted++) {
 289                   case '"':
 290                         if (endp)
 291                                 *endp = quoted + 1;
 292                         return 0;
 293                   case '\\':
 294                         break;
 295                   default:
 296                         goto error;
 297                 }
 298
 299                 switch ((ch = *quoted++)) {
 300                 case 'a': ch = '\a'; break;
 301                 case 'b': ch = '\b'; break;
 302                 case 'f': ch = '\f'; break;
 303                 case 'n': ch = '\n'; break;
 304                 case 'r': ch = '\r'; break;
 305                 case 't': ch = '\t'; break;
 306                 case 'v': ch = '\v'; break;
 307
 308                 case '\\': case '"':
 309                         break; /* verbatim */
 310
 311                 /* octal values with first digit over 4 overflow */
 312                 case '0': case '1': case '2': case '3':
 313                                         ac = ((ch - '0') << 6);
 314                         if ((ch = *quoted++) < '0' || '7' < ch)
 315                                 goto error;
 316                                         ac |= ((ch - '0') << 3);
 317                         if ((ch = *quoted++) < '0' || '7' < ch)
 318                                 goto error;
 319                                         ac |= (ch - '0');
 320                                         ch = ac;
 321                                         break;
 322                                 default:
 323                         goto error;
 324                         }
 325                 strbuf_addch(sb, ch);
 326                 }
 327
 328   error:
 329         strbuf_setlen(sb, oldlen);
 330         return -1;
 331 }
 332
 333 /* quoting as a string literal for other languages */
 334
 335 void perl_quote_print(FILE *stream, const char *src)
 336 {
 337         const char sq = '\'';
 338         const char bq = '\\';
 339         char c;
 340
 341         fputc(sq, stream);
 342         while ((c = *src++)) {
 343                 if (c == sq || c == bq)
 344                         fputc(bq, stream);
 345                 fputc(c, stream);
 346         }
 347         fputc(sq, stream);
 348 }
 349
 350 void python_quote_print(FILE *stream, const char *src)
 351 {
 352         const char sq = '\'';
 353         const char bq = '\\';
 354         const char nl = '\n';
 355         char c;
 356
 357         fputc(sq, stream);
 358         while ((c = *src++)) {
 359                 if (c == nl) {
 360                         fputc(bq, stream);
 361                         fputc('n', stream);
 362                         continue;
 363                 }
 364                 if (c == sq || c == bq)
 365                         fputc(bq, stream);
 366                 fputc(c, stream);
 367         }
 368         fputc(sq, stream);
 369 }
 370
 371 void tcl_quote_print(FILE *stream, const char *src)
 372 {
 373         char c;
 374
 375         fputc('"', stream);
 376         while ((c = *src++)) {
 377                 switch (c) {
 378                 case '[': case ']':
 379                 case '{': case '}':
 380                 case '$': case '\\': case '"':
 381                         fputc('\\', stream);
 382                 default:
 383                         fputc(c, stream);
 384                         break;
 385                 case '\f':
 386                         fputs("\\f", stream);
 387                         break;
 388                 case '\r':
 389                         fputs("\\r", stream);
 390                         break;
 391                 case '\n':
 392                         fputs("\\n", stream);
 393                         break;
 394                 case '\t':
 395                         fputs("\\t", stream);
 396                         break;
 397                 case '\v':
 398                         fputs("\\v", stream);
 399                         break;
 400                 }
 401         }
 402         fputc('"', stream);
 403 }