tauxx.c - plan9port - [fork] Plan 9 from user space
  HTML git clone git://src.adamsgaard.dk/plan9port
   DIR Log
   DIR Files
   DIR Refs
   DIR README
   DIR LICENSE
       ---
       tauxx.c (2303B)
       ---
            1 #include "common.h"
            2 
            3 /* expand a path relative to some `.' */
            4 extern String *
            5 abspath(char *path, char *dot, String *to)
            6 {
            7         if (*path == '/') {
            8                 to = s_append(to, path);
            9         } else {
           10                 to = s_append(to, dot);
           11                 to = s_append(to, "/");
           12                 to = s_append(to, path);
           13         }
           14         return to;
           15 }
           16 
           17 /* return a pointer to the base component of a pathname */
           18 extern char *
           19 basename(char *path)
           20 {
           21         char *cp;
           22 
           23         cp = strrchr(path, '/');
           24         return cp==0 ? path : cp+1;
           25 }
           26 
           27 /* append a sub-expression match onto a String */
           28 extern void
           29 append_match(Resub *subexp, String *sp, int se)
           30 {
           31         char *cp, *ep;
           32 
           33         cp = subexp[se].s.sp;
           34         ep = subexp[se].e.ep;
           35         for (; cp < ep; cp++)
           36                 s_putc(sp, *cp);
           37         s_terminate(sp);
           38 }
           39 
           40 /*
           41  *  check for shell characters in a String
           42  */
           43 static char *illegalchars = "\r\n";
           44 
           45 extern int
           46 shellchars(char *cp)
           47 {
           48         char *sp;
           49 
           50         for(sp=illegalchars; *sp; sp++)
           51                 if(strchr(cp, *sp))
           52                         return 1;
           53         return 0;
           54 }
           55 
           56 static char *specialchars = " ()<>{};=\\'`^&|";
           57 static char *escape = "%%";
           58 
           59 int
           60 hexchar(int x)
           61 {
           62         x &= 0xf;
           63         if(x < 10)
           64                 return '0' + x;
           65         else
           66                 return 'A' + x - 10;
           67 }
           68 
           69 /*
           70  *  rewrite a string to escape shell characters
           71  */
           72 extern String*
           73 escapespecial(String *s)
           74 {
           75         String *ns;
           76         char *sp;
           77 
           78         for(sp = specialchars; *sp; sp++)
           79                 if(strchr(s_to_c(s), *sp))
           80                         break;
           81         if(*sp == 0)
           82                 return s;
           83 
           84         ns = s_new();
           85         for(sp = s_to_c(s); *sp; sp++){
           86                 if(strchr(specialchars, *sp)){
           87                         s_append(ns, escape);
           88                         s_putc(ns, hexchar(*sp>>4));
           89                         s_putc(ns, hexchar(*sp));
           90                 } else
           91                         s_putc(ns, *sp);
           92         }
           93         s_terminate(ns);
           94         s_free(s);
           95         return ns;
           96 }
           97 
           98 uint
           99 hex2uint(char x)
          100 {
          101         if(x >= '0' && x <= '9')
          102                 return x - '0';
          103         if(x >= 'A' && x <= 'F')
          104                 return (x - 'A') + 10;
          105         if(x >= 'a' && x <= 'f')
          106                 return (x - 'a') + 10;
          107         return -512;
          108 }
          109 
          110 /*
          111  *  rewrite a string to remove shell characters escapes
          112  */
          113 extern String*
          114 unescapespecial(String *s)
          115 {
          116         String *ns;
          117         char *sp;
          118         uint c, n;
          119 
          120         if(strstr(s_to_c(s), escape) == 0)
          121                 return s;
          122         n = strlen(escape);
          123 
          124         ns = s_new();
          125         for(sp = s_to_c(s); *sp; sp++){
          126                 if(strncmp(sp, escape, n) == 0){
          127                         c = (hex2uint(sp[n])<<4) + hex2uint(sp[n+1]);
          128                         if(c < 0)
          129                                 s_putc(ns, *sp);
          130                         else {
          131                                 s_putc(ns, c);
          132                                 sp += n+2-1;
          133                         }
          134                 } else
          135                         s_putc(ns, *sp);
          136         }
          137         s_terminate(ns);
          138         s_free(s);
          139         return ns;
          140 
          141 }
          142 
          143 int
          144 returnable(char *path)
          145 {
          146 
          147         return strcmp(path, "/dev/null") != 0;
          148 }