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#include <kernel/arch/generic.h>
#include <kernel/mem.h>
#include <kernel/panic.h>
#include <kernel/proc.h>
#include <kernel/syscalls.h>
#include <stdint.h>
_Noreturn static void await_finish(struct process *dead, struct process *listener) {
size_t len;
bool res;
assert(dead->state == PS_DEAD);
assert(listener->state == PS_WAITS4CHILDDEATH);
dead->state = PS_DEADER;
listener->state = PS_RUNNING;
len = listener->saved_len < dead->saved_len
? listener->saved_len : dead->saved_len;
res = virt_user_cpy(
listener->pages, listener->saved_addr,
dead->pages, dead->saved_addr, len);
regs_savereturn(&listener->regs, res ? len : -1);
process_switch(listener);
}
_Noreturn void _syscall_exit(const char *msg, size_t len) {
process_current->state = PS_DEAD;
process_current->saved_addr = (void*)msg; // discard const
process_current->saved_len = len;
if (process_current->parent->state == PS_WAITS4CHILDDEATH)
await_finish(process_current, process_current->parent);
process_current = process_find(PS_RUNNING);
if (process_current)
process_switch(process_current);
process_switch_any();
}
int _syscall_await(char *buf, int len) {
process_current->state = PS_WAITS4CHILDDEATH;
process_current->saved_addr = buf;
process_current->saved_len = len;
// find any already dead children
for (struct process *iter = process_current->child;
iter; iter = iter->sibling)
{
if (iter->state == PS_DEAD)
await_finish(iter, process_current); // doesn't return
}
// no dead children yet
// TODO check if the process even has children
process_switch_any();
}
int _syscall_fork() {
struct process *child = process_fork(process_current);
regs_savereturn(&child->regs, 0);
return 1;
}
int _syscall_debuglog(const char *msg, size_t len) {
struct virt_iter iter;
size_t written = 0;
virt_iter_new(&iter, (void*)msg, len, process_current->pages, true, false);
while (virt_iter_next(&iter)) {
tty_write(iter.frag, iter.frag_len);
written += iter.frag_len;
}
return written;
}
int syscall_handler(int num, int a, int b, int c) {
switch (num) {
case _SYSCALL_EXIT:
_syscall_exit((void*)a, b);
case _SYSCALL_AWAIT:
return _syscall_await((void*)a, b);
case _SYSCALL_FORK:
return _syscall_fork();
case _SYSCALL_DEBUGLOG:
return _syscall_debuglog((void*)a, b);
default:
tty_const("unknown syscall ");
panic();
}
}
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