sys/src/libauthsrv/readcons.c

   1 #include <u.h>
   2 #include <libc.h>
   3
   4 /*
   5  *  prompt for a string with a possible default response
   6  */
   7 char*
   8 readcons(char *prompt, char *def, int raw)
   9 {
  10         int fdin, fdout, ctl, n;
  11         char *s, *p;
  12
  13         s = p = nil;
  14         fdout = ctl = -1;
  15
  16         if((fdin = open("/dev/cons", OREAD)) < 0)
  17                 goto Out;
  18         if((fdout = open("/dev/cons", OWRITE)) < 0)
  19                 goto Out;
  20
  21         if(raw){
  22                 if((ctl = open("/dev/consctl", OWRITE)) < 0)
  23                         goto Out;
  24                 write(ctl, "rawon", 5);
  25         }
  26
  27         if(def != nil)
  28                 fprint(fdout, "%s[%s]: ", prompt, def);
  29         else
  30                 fprint(fdout, "%s: ", prompt);
  31
  32         for(;;){
  33                 n = p - s;
  34                 if((n % 32) == 0){
  35                         if((p = realloc(s, n+32)) == nil)
  36                                 break;
  37                         s = p, p += n;
  38                 }
  39
  40                 n = read(fdin, p, 1);
  41                 if(n < 0)
  42                         break;
  43                 if(n == 0 || *p == 0x7f){
  44                         werrstr("input aborted");
  45                         break;
  46                 }
  47
  48                 if(*p == '\n' || *p == '\r'){
  49                         if(p == s && def != nil){
  50                                 free(s);
  51                                 s = strdup(def);
  52                         } else
  53                                 *p = 0;
  54                         if(raw)
  55                                 write(fdout, "\n", 1);
  56                         goto Out;
  57                 } else if(*p == '\b') {
  58                         while(p > s && (p[-1] & 0xc0) == 0x80)
  59                                 *p-- = 0;
  60                         if(p > s)
  61                                 *p-- = 0;
  62                 } else if(*p == 0x15) { /* ^U: line kill */
  63                         if(def != nil)
  64                                 fprint(fdout, "\n%s[%s]: ", prompt, def);
  65                         else
  66                                 fprint(fdout, "\n%s: ", prompt);
  67                         while(p > s)
  68                                 *p-- = 0;
  69                 } else if(*p >= ' ')
  70                         p++;
  71         }
  72         free(s);
  73         s = nil;
  74         if(raw)
  75                 write(fdout, "\n", 1);
  76 Out:
  77         if(ctl >= 0){
  78                 write(ctl, "rawoff", 6);
  79                 close(ctl);
  80         }
  81         if(fdin >= 0)
  82                 close(fdin);
  83         if(fdout >= 0)
  84                 close(fdout);
  85
  86         return s;
  87 }