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 int quote_c_style(const char *name, char *outbuf, FILE *outfp, int no_dq)
 116 {
 117 #undef EMIT
 118 #define EMIT(c) \
 119         (outbuf ? (*outbuf++ = (c)) : outfp ? fputc(c, outfp) : (count++))
 120
 121 #define EMITQ() EMIT('\\')
 122
 123         const char *sp;
 124         int ch, count = 0, needquote = 0;
 125
 126         if (!no_dq)
 127                 EMIT('"');
 128         for (sp = name; (ch = *sp++); ) {
 129
 130                 if ((ch < ' ') || (ch == '"') || (ch == '\\') ||
 131                     (ch == 0177)) {
 132                         needquote = 1;
 133                         switch (ch) {
 134                         case '\a': EMITQ(); ch = 'a'; break;
 135                         case '\b': EMITQ(); ch = 'b'; break;
 136                         case '\f': EMITQ(); ch = 'f'; break;
 137                         case '\n': EMITQ(); ch = 'n'; break;
 138                         case '\r': EMITQ(); ch = 'r'; break;
 139                         case '\t': EMITQ(); ch = 't'; break;
 140                         case '\v': EMITQ(); ch = 'v'; break;
 141
 142                         case '\\': /* fallthru */
 143                         case '"': EMITQ(); break;
 144                         case ' ':
 145                                 break;
 146                         default:
 147                                 /* octal */
 148                                 EMITQ();
 149                                 EMIT(((ch >> 6) & 03) + '0');
 150                                 EMIT(((ch >> 3) & 07) + '0');
 151                                 ch = (ch & 07) + '0';
 152                                 break;
 153                         }
 154                 }
 155                 EMIT(ch);
 156         }
 157         if (!no_dq)
 158                 EMIT('"');
 159         if (outbuf)
 160                 *outbuf = 0;
 161
 162         return needquote ? count : 0;
 163 }
 164
 165 /*
 166  * C-style name unquoting.
 167  *
 168  * Quoted should point at the opening double quote.  Returns
 169  * an allocated memory that holds unquoted name, which the caller
 170  * should free when done.  Updates endp pointer to point at
 171  * one past the ending double quote if given.
 172  */
 173
 174 char *unquote_c_style(const char *quoted, const char **endp)
 175 {
 176         const char *sp;
 177         char *name = NULL, *outp = NULL;
 178         int count = 0, ch, ac;
 179
 180 #undef EMIT
 181 #define EMIT(c) (outp ? (*outp++ = (c)) : (count++))
 182
 183         if (*quoted++ != '"')
 184                 return NULL;
 185
 186         while (1) {
 187                 /* first pass counts and allocates, second pass fills */
 188                 for (sp = quoted; (ch = *sp++) != '"'; ) {
 189                         if (ch == '\\') {
 190                                 switch (ch = *sp++) {
 191                                 case 'a': ch = '\a'; break;
 192                                 case 'b': ch = '\b'; break;
 193                                 case 'f': ch = '\f'; break;
 194                                 case 'n': ch = '\n'; break;
 195                                 case 'r': ch = '\r'; break;
 196                                 case 't': ch = '\t'; break;
 197                                 case 'v': ch = '\v'; break;
 198
 199                                 case '\\': case '"':
 200                                         break; /* verbatim */
 201
 202                                 case '0'...'7':
 203                                         /* octal */
 204                                         ac = ((ch - '0') << 6);
 205                                         if ((ch = *sp++) < '0' || '7' < ch)
 206                                                 return NULL;
 207                                         ac |= ((ch - '0') << 3);
 208                                         if ((ch = *sp++) < '0' || '7' < ch)
 209                                                 return NULL;
 210                                         ac |= (ch - '0');
 211                                         ch = ac;
 212                                         break;
 213                                 default:
 214                                         return NULL; /* malformed */
 215                                 }
 216                         }
 217                         EMIT(ch);
 218                 }
 219
 220                 if (name) {
 221                         *outp = 0;
 222                         if (endp)
 223                                 *endp = sp;
 224                         return name;
 225                 }
 226                 outp = name = xmalloc(count + 1);
 227         }
 228 }
 229
 230 void write_name_quoted(const char *prefix, const char *name,
 231                        int quote, FILE *out)
 232 {
 233         int needquote;
 234
 235         if (!quote) {
 236         no_quote:
 237                 if (prefix && prefix[0])
 238                         fputs(prefix, out);
 239                 fputs(name, out);
 240                 return;
 241         }
 242
 243         needquote = 0;
 244         if (prefix && prefix[0])
 245                 needquote = quote_c_style(prefix, NULL, NULL, 0);
 246         if (!needquote)
 247                 needquote = quote_c_style(name, NULL, NULL, 0);
 248         if (needquote) {
 249                 fputc('"', out);
 250                 if (prefix && prefix[0])
 251                         quote_c_style(prefix, NULL, out, 1);
 252                 quote_c_style(name, NULL, out, 1);
 253                 fputc('"', out);
 254         }
 255         else
 256                 goto no_quote;
 257 }