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