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 {
 136         return sq_lookup[(unsigned char)c] + quote_path_fully > 0;
 137 }
 138
 139 /* returns the longest prefix not needing a quote up to maxlen if positive.
 140    This stops at the first \0 because it's marked as a character needing an
 141    escape */
 142 static size_t next_quote_pos(const char *s, ssize_t maxlen)
 143 {
 144         size_t len;
 145         if (maxlen < 0) {
 146                 for (len = 0; !sq_must_quote(s[len]); len++);
 147         } else {
 148                 for (len = 0; len < maxlen && !sq_must_quote(s[len]); len++);
 149         }
 150         return len;
 151 }
 152
 153 /*
 154  * C-style name quoting.
 155  *
 156  * (1) if sb and fp are both NULL, inspect the input name and counts the
 157  *     number of bytes that are needed to hold c_style quoted version of name,
 158  *     counting the double quotes around it but not terminating NUL, and
 159  *     returns it.
 160  *     However, if name does not need c_style quoting, it returns 0.
 161  *
 162  * (2) if sb or fp are not NULL, it emits the c_style quoted version
 163  *     of name, enclosed with double quotes if asked and needed only.
 164  *     Return value is the same as in (1).
 165  */
 166 static size_t quote_c_style_counted(const char *name, ssize_t maxlen,
 167                                     struct strbuf *sb, FILE *fp, int no_dq)
 168 {
 169 #undef EMIT
 170 #define EMIT(c)                                 \
 171         do {                                        \
 172                 if (sb) strbuf_addch(sb, (c));          \
 173                 if (fp) fputc((c), fp);                 \
 174                 count++;                                \
 175         } while (0)
 176 #define EMITBUF(s, l)                           \
 177         do {                                        \
 178                 if (sb) strbuf_add(sb, (s), (l));       \
 179                 if (fp) fwrite((s), (l), 1, fp);        \
 180                 count += (l);                           \
 181         } while (0)
 182
 183         size_t len, count = 0;
 184         const char *p = name;
 185
 186         for (;;) {
 187                 int ch;
 188
 189                 len = next_quote_pos(p, maxlen);
 190                 if (len == maxlen || !p[len])
 191                         break;
 192
 193                 if (!no_dq && p == name)
 194                         EMIT('"');
 195
 196                 EMITBUF(p, len);
 197                 EMIT('\\');
 198                 p += len;
 199                 ch = (unsigned char)*p++;
 200                 if (sq_lookup[ch] >= ' ') {
 201                         EMIT(sq_lookup[ch]);
 202                 } else {
 203                         EMIT(((ch >> 6) & 03) + '0');
 204                         EMIT(((ch >> 3) & 07) + '0');
 205                         EMIT(((ch >> 0) & 07) + '0');
 206                 }
 207         }
 208
 209         EMITBUF(p, len);
 210         if (p == name)   /* no ending quote needed */
 211                 return 0;
 212
 213         if (!no_dq)
 214                 EMIT('"');
 215         return count;
 216 }
 217
 218 size_t quote_c_style(const char *name, struct strbuf *sb, FILE *fp, int nodq)
 219 {
 220         return quote_c_style_counted(name, -1, sb, fp, nodq);
 221 }
 222
 223 void write_name_quoted(const char *name, FILE *fp, int terminator)
 224 {
 225         if (terminator) {
 226                 quote_c_style(name, NULL, fp, 0);
 227         } else {
 228                 fputs(name, fp);
 229         }
 230         fputc(terminator, fp);
 231 }
 232
 233 extern void write_name_quotedpfx(const char *pfx, size_t pfxlen,
 234                                  const char *name, FILE *fp, int terminator)
 235 {
 236         int needquote = 0;
 237
 238         if (terminator) {
 239                 needquote = next_quote_pos(pfx, pfxlen) < pfxlen
 240                         || name[next_quote_pos(name, -1)];
 241         }
 242         if (needquote) {
 243                 fputc('"', fp);
 244                 quote_c_style_counted(pfx, pfxlen, NULL, fp, 1);
 245                 quote_c_style(name, NULL, fp, 1);
 246                 fputc('"', fp);
 247         } else {
 248                 fwrite(pfx, pfxlen, 1, fp);
 249                 fputs(name, fp);
 250         }
 251         fputc(terminator, fp);
 252 }
 253
 254 /*
 255  * C-style name unquoting.
 256  *
 257  * Quoted should point at the opening double quote.
 258  * + Returns 0 if it was able to unquote the string properly, and appends the
 259  *   result in the strbuf `sb'.
 260  * + Returns -1 in case of error, and doesn't touch the strbuf. Though note
 261  *   that this function will allocate memory in the strbuf, so calling
 262  *   strbuf_release is mandatory whichever result unquote_c_style returns.
 263  *
 264  * Updates endp pointer to point at one past the ending double quote if given.
 265  */
 266 int unquote_c_style(struct strbuf *sb, const char *quoted, const char **endp)
 267 {
 268         size_t oldlen = sb->len, len;
 269         int ch, ac;
 270
 271         if (*quoted++ != '"')
 272                 return -1;
 273
 274         for (;;) {
 275                 len = strcspn(quoted, "\"\\");
 276                 strbuf_add(sb, quoted, len);
 277                 quoted += len;
 278
 279                 switch (*quoted++) {
 280                   case '"':
 281                         if (endp)
 282                                 *endp = quoted + 1;
 283                         return 0;
 284                   case '\\':
 285                         break;
 286                   default:
 287                         goto error;
 288                 }
 289
 290                 switch ((ch = *quoted++)) {
 291                 case 'a': ch = '\a'; break;
 292                 case 'b': ch = '\b'; break;
 293                 case 'f': ch = '\f'; break;
 294                 case 'n': ch = '\n'; break;
 295                 case 'r': ch = '\r'; break;
 296                 case 't': ch = '\t'; break;
 297                 case 'v': ch = '\v'; break;
 298
 299                 case '\\': case '"':
 300                         break; /* verbatim */
 301
 302                 /* octal values with first digit over 4 overflow */
 303                 case '0': case '1': case '2': case '3':
 304                                         ac = ((ch - '0') << 6);
 305                         if ((ch = *quoted++) < '0' || '7' < ch)
 306                                 goto error;
 307                                         ac |= ((ch - '0') << 3);
 308                         if ((ch = *quoted++) < '0' || '7' < ch)
 309                                 goto error;
 310                                         ac |= (ch - '0');
 311                                         ch = ac;
 312                                         break;
 313                                 default:
 314                         goto error;
 315                         }
 316                 strbuf_addch(sb, ch);
 317                 }
 318
 319   error:
 320         strbuf_setlen(sb, oldlen);
 321         return -1;
 322 }
 323
 324 /* quoting as a string literal for other languages */
 325
 326 void perl_quote_print(FILE *stream, const char *src)
 327 {
 328         const char sq = '\'';
 329         const char bq = '\\';
 330         char c;
 331
 332         fputc(sq, stream);
 333         while ((c = *src++)) {
 334                 if (c == sq || c == bq)
 335                         fputc(bq, stream);
 336                 fputc(c, stream);
 337         }
 338         fputc(sq, stream);
 339 }
 340
 341 void python_quote_print(FILE *stream, const char *src)
 342 {
 343         const char sq = '\'';
 344         const char bq = '\\';
 345         const char nl = '\n';
 346         char c;
 347
 348         fputc(sq, stream);
 349         while ((c = *src++)) {
 350                 if (c == nl) {
 351                         fputc(bq, stream);
 352                         fputc('n', stream);
 353                         continue;
 354                 }
 355                 if (c == sq || c == bq)
 356                         fputc(bq, stream);
 357                 fputc(c, stream);
 358         }
 359         fputc(sq, stream);
 360 }
 361
 362 void tcl_quote_print(FILE *stream, const char *src)
 363 {
 364         char c;
 365
 366         fputc('"', stream);
 367         while ((c = *src++)) {
 368                 switch (c) {
 369                 case '[': case ']':
 370                 case '{': case '}':
 371                 case '$': case '\\': case '"':
 372                         fputc('\\', stream);
 373                 default:
 374                         fputc(c, stream);
 375                         break;
 376                 case '\f':
 377                         fputs("\\f", stream);
 378                         break;
 379                 case '\r':
 380                         fputs("\\r", stream);
 381                         break;
 382                 case '\n':
 383                         fputs("\\n", stream);
 384                         break;
 385                 case '\t':
 386                         fputs("\\t", stream);
 387                         break;
 388                 case '\v':
 389                         fputs("\\v", stream);
 390                         break;
 391                 }
 392         }
 393         fputc('"', stream);
 394 }