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console.c 3.79 KiB
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//
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// Console input and output, to the uart.
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// Reads are line at a time.
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// Implements special input characters:
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//   newline -- end of line
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//   control-h -- backspace
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//   control-u -- kill line
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//   control-d -- end of file
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//   control-p -- print process list
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//
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#include <stdarg.h>
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#include "include/types.h"
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#include "include/param.h"
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#include "include/spinlock.h"
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#include "include/sleeplock.h"
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#include "include/fs.h"
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#include "include/file.h"
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#include "include/memlayout.h"
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#include "include/riscv.h"
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#include "include/defs.h"
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#include "include/proc.h"
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#define BACKSPACE 0x100
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#define C(x)  ((x)-'@')  // Control-x
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//
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// send one character to the uart.
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// called by printf(), and to echo input characters,
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// but not from write().
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//
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void
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consputc(int c)
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{
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  if(c == BACKSPACE){
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    // if the user typed backspace, overwrite with a space.
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    uartputc_sync('\b'); uartputc_sync(' '); uartputc_sync('\b');
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  } else {
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    uartputc_sync(c);
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  }
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}
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struct {
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  struct spinlock lock;
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  // input
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#define INPUT_BUF_SIZE 128
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  char buf[INPUT_BUF_SIZE];
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  uint r;  // Read index
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  uint w;  // Write index
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  uint e;  // Edit index
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} cons;
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//
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// user write()s to the console go here.
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//
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int
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consolewrite(int user_src, uint64 src, int n)
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{
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  int i;
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  for(i = 0; i < n; i++){
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    char c;
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    if(either_copyin(&c, user_src, src+i, 1) == -1)
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      break;
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    uartputc(c);
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  }
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  return i;
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} // // user read()s from the console go here. // copy (up to) a whole input line to dst. // user_dist indicates whether dst is a user // or kernel address. // int consoleread(int user_dst, uint64 dst, int n) { uint target; int c; char cbuf; target = n; acquire(&cons.lock); while(n > 0){ // wait until interrupt handler has put some // input into cons.buffer. while(cons.r == cons.w){ if(killed(myproc())){ release(&cons.lock); return -1; } sleep(&cons.r, &cons.lock); } c = cons.buf[cons.r++ % INPUT_BUF_SIZE]; if(c == C('D')){ // end-of-file if(n < target){ // Save ^D for next time, to make sure // caller gets a 0-byte result. cons.r--; } break; } // copy the input byte to the user-space buffer. cbuf = c; if(either_copyout(user_dst, dst, &cbuf, 1) == -1) break; dst++; --n; if(c == '\n'){ // a whole line has arrived, return to // the user-level read(). break; } } release(&cons.lock); return target - n; } // // the console input interrupt handler. // uartintr() calls this for input character. // do erase/kill processing, append to cons.buf, // wake up consoleread() if a whole line has arrived. // void consoleintr(int c) { acquire(&cons.lock); switch(c){
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case C('P'): // Print process list. procdump(); break; case C('U'): // Kill line. while(cons.e != cons.w && cons.buf[(cons.e-1) % INPUT_BUF_SIZE] != '\n'){ cons.e--; consputc(BACKSPACE); } break; case C('H'): // Backspace case '\x7f': // Delete key if(cons.e != cons.w){ cons.e--; consputc(BACKSPACE); } break; default: if(c != 0 && cons.e-cons.r < INPUT_BUF_SIZE){ c = (c == '\r') ? '\n' : c; // echo back to the user. consputc(c); // store for consumption by consoleread(). cons.buf[cons.e++ % INPUT_BUF_SIZE] = c; if(c == '\n' || c == C('D') || cons.e-cons.r == INPUT_BUF_SIZE){ // wake up consoleread() if a whole line (or end-of-file) // has arrived. cons.w = cons.e; wakeup(&cons.r); } } break; } release(&cons.lock); } void consoleinit(void) { initlock(&cons.lock, "cons"); uartinit(); // connect read and write system calls // to consoleread and consolewrite. devsw[CONSOLE].read = consoleread; devsw[CONSOLE].write = consolewrite; }