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//
// run random system calls in parallel forever.
//
#include "kernel/param.h"
#include "kernel/types.h"
#include "kernel/stat.h"
#include "user/user.h"
#include "kernel/fs.h"
#include "kernel/fcntl.h"
#include "kernel/syscall.h"
#include "kernel/memlayout.h"
#include "kernel/riscv.h"
// from FreeBSD.
int
do_rand(unsigned long *ctx)
{
/*
* Compute x = (7^5 * x) mod (2^31 - 1)
* without overflowing 31 bits:
* (2^31 - 1) = 127773 * (7^5) + 2836
* From "Random number generators: good ones are hard to find",
* Park and Miller, Communications of the ACM, vol. 31, no. 10,
* October 1988, p. 1195.
*/
long hi, lo, x;
/* Transform to [1, 0x7ffffffe] range. */
x = (*ctx % 0x7ffffffe) + 1;
hi = x / 127773;
lo = x % 127773;
x = 16807 * lo - 2836 * hi;
if (x < 0)
x += 0x7fffffff;
/* Transform to [0, 0x7ffffffd] range. */
x--;
*ctx = x;
return (x);
}
unsigned long rand_next = 1;
int
rand(void)
{
return (do_rand(&rand_next));
}
void
go(int which_child)
{
int fd = -1;
static char buf[999];
char *break0 = sbrk(0);
uint64 iters = 0;
while(1){
iters++;
if((iters % 500) == 0)
write(1, which_child?"B":"A", 1);
int what = rand() % 20;
if(what == 1){
close(open("a", O_CREATE|O_RDWR));
} else if(what == 2){
close(open("b", O_CREATE|O_RDWR));
} else if(what == 3){
unlink("a");
} else if(what == 4){
unlink("b");
} else if(what == 5){
close(fd);
fd = open("a", O_CREATE|O_RDWR);
} else if(what == 6){
close(fd);
fd = open("b", O_CREATE|O_RDWR);
} else if(what == 7){
write(fd, buf, sizeof(buf));
} else if(what == 8){
read(fd, buf, sizeof(buf));
} else if(what == 9){
mkdir("a");
close(open("a/a", O_CREATE|O_RDWR));
unlink("a/a");
} else if(what == 10){
mkdir("b");
close(open("b/b", O_CREATE|O_RDWR));
unlink("b/b");
} else if(what == 11){
unlink("b");
link("a", "b");
} else if(what == 12){
unlink("a");
link("b", "a");
} else if(what == 13){
int pid = fork();
if(pid == 0){
exit(0);
} else if(pid < 0){
printf("grind: fork failed\n");
exit(1);
}
wait(0);
} else if(what == 14){
int pid = fork();
if(pid == 0){
fork();
fork();
exit(0);
} else if(pid < 0){
printf("grind: fork failed\n");
exit(1);
}
wait(0);
} else if(what == 15){
sbrk(6011);
} else if(what == 16){
if(sbrk(0) > break0)
sbrk(-(sbrk(0) - break0));
} else if(what == 17){
int pid = fork();
if(pid == 0){
close(open("a", O_CREATE|O_RDWR));
exit(0);
} else if(pid < 0){
printf("grind: fork failed\n");
exit(1);
}
kill(pid);
wait(0);
} else if(what == 18){
int pid = fork();
if(pid == 0){
kill(getpid());
exit(0);
} else if(pid < 0){
printf("grind: fork failed\n");
exit(1);
}
wait(0);
} else if(what == 19){
int fds[2];
if(pipe(fds) < 0){
printf("grind: pipe failed\n");
exit(1);
}
int pid = fork();
if(pid == 0){
fork();
fork();
if(write(fds[1], "x", 1) != 1)
printf("grind: pipe write failed\n");
char c;
if(read(fds[0], &c, 1) != 1)
printf("grind: pipe read failed\n");
exit(0);
} else if(pid < 0){
printf("grind: fork failed\n");
exit(1);
}
close(fds[0]);
close(fds[1]);
wait(0);
}
}
}
int
main()
{
unlink("a");
unlink("b");
int pid1 = fork();
if(pid1 < 0){
printf("grind: fork failed\n");
exit(1);
}
if(pid1 == 0){
rand_next = 31;
go(0);
exit(0);
}
int pid2 = fork();
if(pid2 < 0){
printf("grind: fork failed\n");
exit(1);
}
if(pid2 == 0){
rand_next = 7177;
go(1);
exit(0);
}
int st1 = -1;
wait(&st1);
if(st1 != 0){
kill(pid1);
kill(pid2);
}
int st2 = -1;
wait(&st2);
exit(0);
}
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