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) ( (++len < n) && (*bp++ = (x)) )
  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 char *sq_quote(const char *src)
  49 {
  50         char *buf;
  51         size_t cnt;
  52
  53         cnt = sq_quote_buf(NULL, 0, src) + 1;
  54         buf = xmalloc(cnt);
  55         sq_quote_buf(buf, cnt, src);
  56
  57         return buf;
  58 }
  59
  60 char *sq_dequote(char *arg)
  61 {
  62         char *dst = arg;
  63         char *src = arg;
  64         char c;
  65
  66         if (*src != '\'')
  67                 return NULL;
  68         for (;;) {
  69                 c = *++src;
  70                 if (!c)
  71                         return NULL;
  72                 if (c != '\'') {
  73                         *dst++ = c;
  74                         continue;
  75                 }
  76                 /* We stepped out of sq */
  77                 switch (*++src) {
  78                 case '\0':
  79                         *dst = 0;
  80                         return arg;
  81                 case '\\':
  82                         c = *++src;
  83                         if (need_bs_quote(c) && *++src == '\'') {
  84                                 *dst++ = c;
  85                                 continue;
  86                         }
  87                 /* Fallthrough */
  88                 default:
  89                         return NULL;
  90                 }
  91         }
  92 }
  93
  94 /*
  95  * C-style name quoting.
  96  *
  97  * Does one of three things:
  98  *
  99  * (1) if outbuf and outfp are both NULL, inspect the input name and
 100  *     counts the number of bytes that are needed to hold c_style
 101  *     quoted version of name, counting the double quotes around
 102  *     it but not terminating NUL, and returns it.  However, if name
 103  *     does not need c_style quoting, it returns 0.
 104  *
 105  * (2) if outbuf is not NULL, it must point at a buffer large enough
 106  *     to hold the c_style quoted version of name, enclosing double
 107  *     quotes, and terminating NUL.  Fills outbuf with c_style quoted
 108  *     version of name enclosed in double-quote pair.  Return value
 109  *     is undefined.
 110  *
 111  * (3) if outfp is not NULL, outputs c_style quoted version of name,
 112  *     but not enclosed in double-quote pair.  Return value is undefined.
 113  */
 114
 115 static int quote_c_style_counted(const char *name, int namelen,
 116                                  char *outbuf, FILE *outfp, int no_dq)
 117 {
 118 #undef EMIT
 119 #define EMIT(c) \
 120         (outbuf ? (*outbuf++ = (c)) : outfp ? fputc(c, outfp) : (count++))
 121
 122 #define EMITQ() EMIT('\\')
 123
 124         const char *sp;
 125         int ch, count = 0, needquote = 0;
 126
 127         if (!no_dq)
 128                 EMIT('"');
 129         for (sp = name; sp < name + namelen; sp++) {
 130                 ch = *sp;
 131                 if (!ch)
 132                         break;
 133                 if ((ch < ' ') || (ch == '"') || (ch == '\\') ||
 134                     (ch == 0177)) {
 135                         needquote = 1;
 136                         switch (ch) {
 137                         case '\a': EMITQ(); ch = 'a'; break;
 138                         case '\b': EMITQ(); ch = 'b'; break;
 139                         case '\f': EMITQ(); ch = 'f'; break;
 140                         case '\n': EMITQ(); ch = 'n'; break;
 141                         case '\r': EMITQ(); ch = 'r'; break;
 142                         case '\t': EMITQ(); ch = 't'; break;
 143                         case '\v': EMITQ(); ch = 'v'; break;
 144
 145                         case '\\': /* fallthru */
 146                         case '"': EMITQ(); break;
 147                         default:
 148                                 /* octal */
 149                                 EMITQ();
 150                                 EMIT(((ch >> 6) & 03) + '0');
 151                                 EMIT(((ch >> 3) & 07) + '0');
 152                                 ch = (ch & 07) + '0';
 153                                 break;
 154                         }
 155                 }
 156                 EMIT(ch);
 157         }
 158         if (!no_dq)
 159                 EMIT('"');
 160         if (outbuf)
 161                 *outbuf = 0;
 162
 163         return needquote ? count : 0;
 164 }
 165
 166 int quote_c_style(const char *name, char *outbuf, FILE *outfp, int no_dq)
 167 {
 168         int cnt = strlen(name);
 169         return quote_c_style_counted(name, cnt, outbuf, outfp, no_dq);
 170 }
 171
 172 /*
 173  * C-style name unquoting.
 174  *
 175  * Quoted should point at the opening double quote.  Returns
 176  * an allocated memory that holds unquoted name, which the caller
 177  * should free when done.  Updates endp pointer to point at
 178  * one past the ending double quote if given.
 179  */
 180
 181 char *unquote_c_style(const char *quoted, const char **endp)
 182 {
 183         const char *sp;
 184         char *name = NULL, *outp = NULL;
 185         int count = 0, ch, ac;
 186
 187 #undef EMIT
 188 #define EMIT(c) (outp ? (*outp++ = (c)) : (count++))
 189
 190         if (*quoted++ != '"')
 191                 return NULL;
 192
 193         while (1) {
 194                 /* first pass counts and allocates, second pass fills */
 195                 for (sp = quoted; (ch = *sp++) != '"'; ) {
 196                         if (ch == '\\') {
 197                                 switch (ch = *sp++) {
 198                                 case 'a': ch = '\a'; break;
 199                                 case 'b': ch = '\b'; break;
 200                                 case 'f': ch = '\f'; break;
 201                                 case 'n': ch = '\n'; break;
 202                                 case 'r': ch = '\r'; break;
 203                                 case 't': ch = '\t'; break;
 204                                 case 'v': ch = '\v'; break;
 205
 206                                 case '\\': case '"':
 207                                         break; /* verbatim */
 208
 209                                 case '0'...'7':
 210                                         /* octal */
 211                                         ac = ((ch - '0') << 6);
 212                                         if ((ch = *sp++) < '0' || '7' < ch)
 213                                                 return NULL;
 214                                         ac |= ((ch - '0') << 3);
 215                                         if ((ch = *sp++) < '0' || '7' < ch)
 216                                                 return NULL;
 217                                         ac |= (ch - '0');
 218                                         ch = ac;
 219                                         break;
 220                                 default:
 221                                         return NULL; /* malformed */
 222                                 }
 223                         }
 224                         EMIT(ch);
 225                 }
 226
 227                 if (name) {
 228                         *outp = 0;
 229                         if (endp)
 230                                 *endp = sp;
 231                         return name;
 232                 }
 233                 outp = name = xmalloc(count + 1);
 234         }
 235 }
 236
 237 void write_name_quoted(const char *prefix, int prefix_len,
 238                        const char *name, int quote, FILE *out)
 239 {
 240         int needquote;
 241
 242         if (!quote) {
 243         no_quote:
 244                 if (prefix_len)
 245                         fprintf(out, "%.*s", prefix_len, prefix);
 246                 fputs(name, out);
 247                 return;
 248         }
 249
 250         needquote = 0;
 251         if (prefix_len)
 252                 needquote = quote_c_style_counted(prefix, prefix_len,
 253                                                   NULL, NULL, 0);
 254         if (!needquote)
 255                 needquote = quote_c_style(name, NULL, NULL, 0);
 256         if (needquote) {
 257                 fputc('"', out);
 258                 if (prefix_len)
 259                         quote_c_style_counted(prefix, prefix_len,
 260                                               NULL, out, 1);
 261                 quote_c_style(name, NULL, out, 1);
 262                 fputc('"', out);
 263         }
 264         else
 265                 goto no_quote;
 266 }