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 size_t sq_quote_buf(char *dst, size_t n, const char *src)
  19 {
  20         char c;
  21         char *bp = dst;
  22         size_t len = 0;
  23
  24         EMIT('\'');
  25         while ((c = *src++)) {
  26                 if (c == '\'' || c == '!') {
  27                         EMIT('\'');
  28                         EMIT('\\');
  29                         EMIT(c);
  30                         EMIT('\'');
  31                 } else {
  32                         EMIT(c);
  33                 }
  34         }
  35         EMIT('\'');
  36
  37         if ( n )
  38                 *bp = 0;
  39
  40         return len;
  41 }
  42
  43 char *sq_quote(const char *src)
  44 {
  45         char *buf;
  46         size_t cnt;
  47
  48         cnt = sq_quote_buf(NULL, 0, src) + 1;
  49         buf = xmalloc(cnt);
  50         sq_quote_buf(buf, cnt, src);
  51
  52         return buf;
  53 }
  54
  55 /*
  56  * C-style name quoting.
  57  *
  58  * Does one of three things:
  59  *
  60  * (1) if outbuf and outfp are both NULL, inspect the input name and
  61  *     counts the number of bytes that are needed to hold c_style
  62  *     quoted version of name, counting the double quotes around
  63  *     it but not terminating NUL, and returns it.  However, if name
  64  *     does not need c_style quoting, it returns 0.
  65  *
  66  * (2) if outbuf is not NULL, it must point at a buffer large enough
  67  *     to hold the c_style quoted version of name, enclosing double
  68  *     quotes, and terminating NUL.  Fills outbuf with c_style quoted
  69  *     version of name enclosed in double-quote pair.  Return value
  70  *     is undefined.
  71  *
  72  * (3) if outfp is not NULL, outputs c_style quoted version of name,
  73  *     but not enclosed in double-quote pair.  Return value is undefined.
  74  */
  75
  76 int quote_c_style(const char *name, char *outbuf, FILE *outfp, int no_dq)
  77 {
  78 #undef EMIT
  79 #define EMIT(c) \
  80         (outbuf ? (*outbuf++ = (c)) : outfp ? fputc(c, outfp) : (count++))
  81
  82 #define EMITQ() EMIT('\\')
  83
  84         const char *sp;
  85         int ch, count = 0, needquote = 0;
  86
  87         if (!no_dq)
  88                 EMIT('"');
  89         for (sp = name; (ch = *sp++); ) {
  90
  91                 if ((ch < ' ') || (ch == '"') || (ch == '\\') ||
  92                     (ch == 0177)) {
  93                         needquote = 1;
  94                         switch (ch) {
  95                         case '\a': EMITQ(); ch = 'a'; break;
  96                         case '\b': EMITQ(); ch = 'b'; break;
  97                         case '\f': EMITQ(); ch = 'f'; break;
  98                         case '\n': EMITQ(); ch = 'n'; break;
  99                         case '\r': EMITQ(); ch = 'r'; break;
 100                         case '\t': EMITQ(); ch = 't'; break;
 101                         case '\v': EMITQ(); ch = 'v'; break;
 102
 103                         case '\\': /* fallthru */
 104                         case '"': EMITQ(); break;
 105                         case ' ':
 106                                 break;
 107                         default:
 108                                 /* octal */
 109                                 EMITQ();
 110                                 EMIT(((ch >> 6) & 03) + '0');
 111                                 EMIT(((ch >> 3) & 07) + '0');
 112                                 ch = (ch & 07) + '0';
 113                                 break;
 114                         }
 115                 }
 116                 EMIT(ch);
 117         }
 118         if (!no_dq)
 119                 EMIT('"');
 120         if (outbuf)
 121                 *outbuf = 0;
 122
 123         return needquote ? count : 0;
 124 }
 125
 126 /*
 127  * C-style name unquoting.
 128  *
 129  * Quoted should point at the opening double quote.  Returns
 130  * an allocated memory that holds unquoted name, which the caller
 131  * should free when done.  Updates endp pointer to point at
 132  * one past the ending double quote if given.
 133  */
 134
 135 char *unquote_c_style(const char *quoted, const char **endp)
 136 {
 137         const char *sp;
 138         char *name = NULL, *outp = NULL;
 139         int count = 0, ch, ac;
 140
 141 #undef EMIT
 142 #define EMIT(c) (outp ? (*outp++ = (c)) : (count++))
 143
 144         if (*quoted++ != '"')
 145                 return NULL;
 146
 147         while (1) {
 148                 /* first pass counts and allocates, second pass fills */
 149                 for (sp = quoted; (ch = *sp++) != '"'; ) {
 150                         if (ch == '\\') {
 151                                 switch (ch = *sp++) {
 152                                 case 'a': ch = '\a'; break;
 153                                 case 'b': ch = '\b'; break;
 154                                 case 'f': ch = '\f'; break;
 155                                 case 'n': ch = '\n'; break;
 156                                 case 'r': ch = '\r'; break;
 157                                 case 't': ch = '\t'; break;
 158                                 case 'v': ch = '\v'; break;
 159
 160                                 case '\\': case '"':
 161                                         break; /* verbatim */
 162
 163                                 case '0'...'7':
 164                                         /* octal */
 165                                         ac = ((ch - '0') << 6);
 166                                         if ((ch = *sp++) < '0' || '7' < ch)
 167                                                 return NULL;
 168                                         ac |= ((ch - '0') << 3);
 169                                         if ((ch = *sp++) < '0' || '7' < ch)
 170                                                 return NULL;
 171                                         ac |= (ch - '0');
 172                                         ch = ac;
 173                                         break;
 174                                 default:
 175                                         return NULL; /* malformed */
 176                                 }
 177                         }
 178                         EMIT(ch);
 179                 }
 180
 181                 if (name) {
 182                         *outp = 0;
 183                         if (endp)
 184                                 *endp = sp;
 185                         return name;
 186                 }
 187                 outp = name = xmalloc(count + 1);
 188         }
 189 }
 190
 191 void write_name_quoted(const char *prefix, const char *name,
 192                        int quote, FILE *out)
 193 {
 194         int needquote;
 195
 196         if (!quote) {
 197         no_quote:
 198                 if (prefix && prefix[0])
 199                         fputs(prefix, out);
 200                 fputs(name, out);
 201                 return;
 202         }
 203
 204         needquote = 0;
 205         if (prefix && prefix[0])
 206                 needquote = quote_c_style(prefix, NULL, NULL, 0);
 207         if (!needquote)
 208                 needquote = quote_c_style(name, NULL, NULL, 0);
 209         if (needquote) {
 210                 fputc('"', out);
 211                 if (prefix && prefix[0])
 212                         quote_c_style(prefix, NULL, out, 1);
 213                 quote_c_style(name, NULL, out, 1);
 214                 fputc('"', out);
 215         }
 216         else
 217                 goto no_quote;
 218 }