kern/src/readline.c

   1 #ifdef __SHARC__
   2 #pragma nosharc
   3 #endif
   4
   5 #include <error.h>
   6 #include <stdio.h>
   7 #include <assert.h>
   8 #include <atomic.h>
   9
  10 int readline(char *buf, size_t buf_l, const char *prompt, ...)
  11 {
  12         static spinlock_t readline_lock = SPINLOCK_INITIALIZER_IRQSAVE;
  13         int i, c, echoing, retval;
  14         va_list ap;
  15
  16         spin_lock_irqsave(&readline_lock);
  17         va_start(ap, prompt);
  18         if (prompt != NULL)
  19                 vcprintf(prompt, ap);
  20         va_end(ap);
  21
  22         i = 0;
  23         echoing = iscons(0);
  24         while (1) {
  25                 c = getchar();
  26                 if (c < 0) {
  27                         printk("read error: %e\n", c);  /* %e! */
  28                         retval = i;
  29                         break;
  30                 } else if (c == '\b' || c == 0x7f) {
  31                         if (i > 0) {
  32                                 if (echoing)
  33                                         cputchar(c);
  34                                 i--;
  35                         }
  36                         continue;
  37                 } else if (c == '\n' || c == '\r') {
  38                         /* sending a \n regardless, since the serial port gives us a \r for
  39                          * carriage returns. (probably won't get a \r anymore) */
  40                         if (echoing)
  41                                 cputchar('\n');
  42                         assert(i <= buf_l - 1); /* never write to buf_l - 1 til the end */
  43                         buf[i++] = c;
  44                         retval =  i;
  45                         break;
  46                 } else if (c >= ' ' && i < buf_l - 1) {
  47                         if (echoing)
  48                                 cputchar(c);
  49                         buf[i++] = c;
  50                 }
  51         }
  52         spin_unlock_irqsave(&readline_lock);
  53         return retval;
  54 }
  55