mhl/escape.h

   1 #ifndef __MHL_SHELL_ESCAPE_H
   2 #define __MHL_SHELL_ESCAPE_H
   3
   4 /* Micro helper library: shell escaping functions */
   5
   6 #include <string.h>
   7 #include <stdlib.h>
   8
   9 #include <mhl/types.h>
  10
  11 #define mhl_shell_escape_toesc(x)       \
  12     (((x)==' ')||((x)=='!')||((x)=='#')||((x)=='$')||((x)=='%')||       \
  13      ((x)=='(')||((x)==')')||((x)=='\'')||((x)=='&')||((x)=='~')||      \
  14      ((x)=='{')||((x)=='}')||((x)=='[')||((x)==']')||((x)=='`')||       \
  15      ((x)=='?')||((x)=='|')||((x)=='<')||((x)=='>')||((x)==';')||       \
  16      ((x)=='*')||((x)=='\\')||((x)=='"'))
  17
  18 #define mhl_shell_escape_nottoesc(x)    \
  19     (((x)!=0) && (!mhl_shell_escape_toesc((x))))
  20
  21 /* type for escaped string - just for a bit more type safety ;-p */
  22 typedef struct { char* s; } SHELL_ESCAPED_STR;
  23
  24 /** To be compatible with the general posix command lines we have to escape
  25  strings for the command line
  26
  27  /params const char * in
  28  string for escaping
  29  /returns
  30  return escaped string (later need to free)
  31  */
  32 static inline SHELL_ESCAPED_STR mhl_shell_escape_dup(const char* src)
  33 {
  34     if ((src==NULL)||(!(*src)))
  35         return (SHELL_ESCAPED_STR){ .s = strdup("") };
  36
  37     char* buffer = calloc(1, strlen(src)*2+2);
  38     char* ptr = buffer;
  39
  40     /* look for the first char to escape */
  41     while (1)
  42     {
  43         char c;
  44         /* copy over all chars not to escape */
  45         while ((c=(*src)) && mhl_shell_escape_nottoesc(c))
  46         {
  47             *ptr = c;
  48             ptr++;
  49             src++;
  50         }
  51
  52         /* at this point we either have an \0 or an char to escape */
  53         if (!c)
  54             return (SHELL_ESCAPED_STR){ .s = buffer };
  55
  56         *ptr = '\\';
  57         ptr++;
  58         *ptr = c;
  59         ptr++;
  60         src++;
  61     }
  62 }
  63
  64 /** Unescape paths or other strings for e.g the internal cd
  65     shell-unescape within a given buffer (writing to it!)
  66
  67  /params const char * in
  68  string for unescaping
  69  /returns
  70  return unescaped string
  71 */
  72 static inline char* mhl_shell_unescape_buf(char* text)
  73 {
  74     if (!text)
  75         return NULL;
  76
  77     /* look for the first \ - that's quick skipover if there's nothing to escape */
  78     char* readptr = text;
  79     while ((*readptr) && ((*readptr)!='\\'))    readptr++;
  80     if (!(*readptr)) return text;
  81
  82     /* if we're here, we're standing on the first '\' */
  83     char* writeptr = readptr;
  84     char c;
  85     while ((c = *readptr))
  86     {
  87         if (c=='\\')
  88         {
  89             readptr++;
  90             switch ((c = *readptr))
  91             {
  92                 case 'n':       (*writeptr) = '\n'; writeptr++; break;
  93                 case 'r':       (*writeptr) = '\r'; writeptr++; break;
  94                 case 't':       (*writeptr) = '\t'; writeptr++; break;
  95
  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 '~':
 113                 case '`':
 114                 case '"':
 115                 case ';':
 116                 case '\0': /* end of line! malformed escape string */
 117                     goto out;
 118                 default:
 119                     (*writeptr) = c; writeptr++; break;
 120             }
 121         }
 122         else    /* got a normal character */
 123         {
 124             (*writeptr) = *readptr;
 125             writeptr++;
 126         }
 127         readptr++;
 128     }
 129 out:
 130     *writeptr = 0;
 131
 132     return text;
 133 }
 134
 135 /** Check if char in pointer contain escape'd chars
 136
 137  /params const char * in
 138  string for checking
 139  /returns
 140  return TRUE if string contain escaped chars
 141  otherwise return FALSE
 142  */
 143 static inline bool
 144 mhl_shell_is_char_escaped ( const char *in )
 145 {
 146     if (in == NULL || !*in || in[0] != '\\')
 147         return false;
 148     if (mhl_shell_escape_toesc(in[1]))
 149         return true;
 150     return false;
 151 }
 152
 153 #endif