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#include <comus/cpu.h>
#include <comus/syscalls.h>
#include <comus/drivers/uart.h>
#include <comus/memory.h>
#include <comus/procs.h>
#define ARG1(type, name) type name = (type)(current_pcb->regs->rdi)
#define ARG2(type, name) type name = (type)(current_pcb->regs->rsi)
#define ARG3(type, name) type name = (type)(current_pcb->regs->rdx)
#define ARG4(type, name) type name = (type)(current_pcb->regs->rcx)
static int sys_exit(void)
{
ARG1(int, status);
(void)status;
// FIXME: schedule somthing else
while (1)
;
return 1;
}
static int sys_write(void)
{
ARG1(int, fd);
ARG2(const void *, buffer);
ARG3(size_t, nbytes);
const char *map_buf = kmapuseraddr(current_pcb->memctx, buffer, nbytes);
if (map_buf == NULL)
return 0;
// cannot write to stdin
if (fd == 0)
nbytes = 0;
// write to stdout
else if (fd == 1) {
for (size_t i = 0; i < nbytes; i++)
kputc(map_buf[i]);
}
// files
else {
// TODO: write to files
nbytes = 0;
}
kunmapaddr(map_buf);
return nbytes;
}
static int (*syscall_tbl[N_SYSCALLS])(void) = {
[SYS_exit] = sys_exit, [SYS_waitpid] = NULL, [SYS_fork] = NULL,
[SYS_exec] = NULL, [SYS_open] = NULL, [SYS_close] = NULL,
[SYS_read] = NULL, [SYS_write] = sys_write, [SYS_getpid] = NULL,
[SYS_getppid] = NULL, [SYS_gettime] = NULL, [SYS_getprio] = NULL,
[SYS_setprio] = NULL, [SYS_kill] = NULL, [SYS_sleep] = NULL,
[SYS_brk] = NULL, [SYS_sbrk] = NULL,
};
void syscall_handler(struct cpu_regs *regs)
{
uint64_t num;
int (*handler)(void);
int ret = 1;
// make sure were in the kernel memory context
mem_ctx_switch(kernel_mem_ctx);
// update data
current_pcb->regs = regs;
num = current_pcb->regs->rax;
// syscall number
// check for invalid syscall
if (num >= N_SYSCALLS) {
// invalid syscall
// FIXME: kill user process
while (1)
;
}
// run syscall handler (if exists)
handler = syscall_tbl[num];
if (handler != NULL)
handler();
// save return value
current_pcb->regs->rax = ret;
// switch back to process ctx
mem_ctx_switch(current_pcb->memctx);
}
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