Hello,
I am trying to use qemu-system-arm (0.12.3) to execute an ARM bare
machine program (not a Linux kernel), and I have some trouble when the
program in question tries to read from stdin.
The program does use ARM semihosting to communicate with the host.
Here is the sample code:
======================
#include <stdio.h>
int main() {
int i, j;
char tab[81];
printf("enter a number\n");
scanf("%d", &i);
printf("enter a string (max: 80 char)\n");
scanf("%80s", tab);
printf("enter a number\n");
scanf("%d", &j);
printf("You entered:\n%d\n%s\n%d\n", i, tab, j);
return 0;
}
=======================
(compiled with arm-none-eabi-gcc -O0 -mcpu=cortex-a9)
To execute it, I use:
$ qemu-system-arm -semihosting -cpu cortex-a9 -nographic -kernel ./input.exe
In this case, it does not wait for me to type something:
enter a number
enter a string (max: 80 char)
enter a number
You entered:
134217720
1
Now, if
$ cat data
4 hello 5
$ qemu-system-arm -semihosting -cpu cortex-a9 -nographic -kernel
./input.exe < data
enter a number
enter a string (max: 80 char)
enter a number
You entered:
134217720
ello
5
as you can see, the first 3 chars of 'data' have been changed/swallowed.
If I remove
fcntl(0, F_SETFL, O_NONBLOCK);
from term_init() (qemu-char.c), then I get expected behaviour when I
don't redirect stdin, but this has no effect on the latter case.
What should I do/patch to achieve the behaviour I'd like?
Thanks!
Christophe.
