mhl/escape.h

   1 #ifndef MHL_ESCAPE_H
   2 #define MHL_ESCAPE_H
   3
   4 /* Micro helper library: shell escaping functions */
   5
   6 #include <string.h>
   7 #include <stdlib.h>
   8 #include <stdbool.h>
   9
  10 #define mhl_shell_escape_toesc(x)       \
  11     (((x)==' ')||((x)=='!')||((x)=='#')||((x)=='$')||((x)=='%')||       \
  12      ((x)=='(')||((x)==')')||((x)=='\'')||((x)=='&')||((x)=='~')||      \
  13      ((x)=='{')||((x)=='}')||((x)=='[')||((x)==']')||((x)=='`')||       \
  14      ((x)=='?')||((x)=='|')||((x)=='<')||((x)=='>')||((x)==';')||       \
  15      ((x)=='*')||((x)=='\\')||((x)=='"'))
  16
  17 #define mhl_shell_escape_nottoesc(x)    \
  18     (((x)!=0) && (!mhl_shell_escape_toesc((x))))
  19
  20 /** To be compatible with the general posix command lines we have to escape
  21  strings for the command line
  22
  23  /params const char * in
  24  string for escaping
  25  /returns
  26  return escaped string (later need to free)
  27  */
  28 static inline char* mhl_shell_escape_dup(const char* src)
  29 {
  30     if ((src==NULL)||(!(*src)))
  31         return strdup("");
  32
  33     char* buffer = calloc(1, strlen(src)*2+2);
  34     char* ptr = buffer;
  35
  36     /* look for the first char to escape */
  37     while (1)
  38     {
  39         char c;
  40         /* copy over all chars not to escape */
  41         while ((c=(*src)) && mhl_shell_escape_nottoesc(c))
  42         {
  43             *ptr = c;
  44             ptr++;
  45             src++;
  46         }
  47
  48         /* at this point we either have an \0 or an char to escape */
  49         if (!c)
  50             return buffer;
  51
  52         *ptr = '\\';
  53         ptr++;
  54         *ptr = c;
  55         ptr++;
  56         src++;
  57     }
  58 }
  59
  60 /** Unescape paths or other strings for e.g the internal cd
  61     shell-unescape within a given buffer (writing to it!)
  62
  63  /params const char * src
  64  string for unescaping
  65  /returns
  66  return unescaped string
  67 */
  68 static inline char* mhl_shell_unescape_buf(char* text)
  69 {
  70     if (!text)
  71         return NULL;
  72
  73     /* look for the first \ - that's quick skipover if there's nothing to escape */
  74     char* readptr = text;
  75     while ((*readptr) && ((*readptr)!='\\'))    readptr++;
  76     if (!(*readptr)) return text;
  77
  78     /* if we're here, we're standing on the first '\' */
  79     char* writeptr = readptr;
  80     char c;
  81     while ((c = *readptr))
  82     {
  83         if (c=='\\')
  84         {
  85             readptr++;
  86             switch ((c = *readptr))
  87             {
  88                 case 'n':       (*writeptr) = '\n'; writeptr++; break;
  89                 case 'r':       (*writeptr) = '\r'; writeptr++; break;
  90                 case 't':       (*writeptr) = '\t'; writeptr++; break;
  91
  92                 case ' ':
  93                 case '\\':
  94                 case '#':
  95                 case '$':
  96                 case '%':
  97                 case '(':
  98                 case ')':
  99                 case '[':
 100                 case ']':
 101                 case '{':
 102                 case '}':
 103                 case '<':
 104                 case '>':
 105                 case '!':
 106                 case '*':
 107                 case '?':
 108                 case '~':
 109                 case '`':
 110                 case '"':
 111                 case ';':
 112                 case '\0': /* end of string! malformed escape string */
 113                     goto out;
 114                 default:
 115                     (*writeptr) = c; writeptr++; break;
 116             }
 117         }
 118         else    /* got a normal character */
 119         {
 120             (*writeptr) = *readptr;
 121             writeptr++;
 122         }
 123         readptr++;
 124     }
 125 out:
 126     *writeptr = 0;
 127
 128     return text;
 129 }
 130
 131 /** Check if char in pointer contain escape'd chars
 132
 133  /params const char * in
 134  string for checking
 135  /returns
 136  return TRUE if string contain escaped chars
 137  otherwise return FALSE
 138  */
 139 static inline bool
 140 mhl_shell_is_char_escaped ( const char *in )
 141 {
 142     if (in == NULL || !*in || in[0] != '\\')
 143         return false;
 144     if (mhl_shell_escape_toesc(in[1]))
 145         return true;
 146     return false;
 147 }
 148
 149 #endif