basekernel/user/test/write.c

52 lines
1.1 KiB
C

/*
Copyright (C) 2016-2019 The University of Notre Dame
This software is distributed under the GNU General Public License.
See the file LICENSE for details.
*/
/*
A trivial user level program to try out basic system calls.
*/
#include "library/syscalls.h"
#include "library/string.h"
#include "library/user-io.h"
int main(int argc, char *argv[])
{
uint32_t j = 0;
syscall_chdir("/");
printf("got root\n");
int fd = syscall_open_file("kevin", 2, 0);
printf("got fd %d\n", fd);
printf("writing to file...\n");
for(;;) {
j++;
char buffer[100] = "Hello, world! I can write to ";
char num[5];
char newline[2] = "\n";
int n;
uint_to_string(j, num);
strcat(buffer, num);
strcat(buffer, newline);
n = syscall_object_write(fd, buffer, strlen(buffer));
if(n < 0)
break;
printf("wrote %d chars: %s\n", n, buffer);
}
syscall_object_close(fd);
fd = syscall_open_file("kevin", 1, 0);
char buffer[1000];
int n;
printf("reading file...\n");
while((n = syscall_object_read(fd, buffer, 999)) > 0) {
buffer[n] = 0;
printf("%s");
flush();
}
syscall_object_close(fd);
syscall_process_exit(0);
return 0;
}