add more syscall impls

1 files changed, 163 insertions, 29 deletions

diff --git a/kernel/syscall.c b/kernel/syscall.c
index 11db5e5..b595b6a 100644
--- a/kernel/syscall.c
+++ b/kernel/syscall.c
@@ -5,21 +5,34 @@
 #include <comus/drivers/pit.h>
 #include <comus/memory.h>
 #include <comus/procs.h>
-#include <stdint.h>
+#include <comus/time.h>
+#include <lib.h>
 
-#define RET(type, name) type *name = (type *)(&current_pcb->regs->rax)
-#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 struct pcb *pcb;
+
+#define RET(type, name) type *name = (type *)(&pcb->regs->rax)
+#define ARG1(type, name) type name = (type)(pcb->regs->rdi)
+#define ARG2(type, name) type name = (type)(pcb->regs->rsi)
+#define ARG3(type, name) type name = (type)(pcb->regs->rdx)
+#define ARG4(type, name) type name = (type)(pcb->regs->rcx)
 
 __attribute__((noreturn)) static int sys_exit(void)
 {
 	ARG1(int, status);
 
-	current_pcb->exit_status = status;
-	pcb_zombify(current_pcb);
-	current_pcb = NULL;
+	pcb->exit_status = status;
+	pcb_zombify(pcb);
+
+	// call next process
+	dispatch();
+}
+
+static int sys_waitpid(void)
+{
+	// arguments are read later
+	// by procs.c
+	pcb->state = PROC_STATE_WAITING;
+	pcb_queue_insert(waiting, pcb);
 
 	// call next process
 	dispatch();
@@ -31,7 +44,7 @@ static int sys_write(void)
 	ARG2(const void *, buffer);
 	ARG3(size_t, nbytes);
 
-	const char *map_buf = kmapuseraddr(current_pcb->memctx, buffer, nbytes);
+	const char *map_buf = kmapuseraddr(pcb->memctx, buffer, nbytes);
 	if (map_buf == NULL)
 		return 0;
 
@@ -56,6 +69,125 @@ static int sys_write(void)
 	return nbytes;
 }
 
+static int sys_getpid(void)
+{
+	return pcb->pid;
+}
+
+static int sys_getppid(void)
+{
+	// init's parent is itself
+	if (pcb->parent == NULL)
+		return init_pcb->pid;
+	return pcb->parent->pid;
+}
+
+static int sys_gettime(void)
+{
+	RET(unsigned long, time);
+	*time = unixtime();
+	return 0;
+}
+
+static int sys_getprio(void)
+{
+	RET(unsigned int, prio);
+	*prio = pcb->priority;
+	return 0;
+}
+
+static int sys_setprio(void)
+{
+	RET(unsigned int, old);
+	ARG1(unsigned int, new);
+
+	*old = pcb->priority;
+	pcb->priority = new;
+	return 0;
+}
+
+static int sys_kill(void)
+{
+	ARG1(pid_t, pid);
+	struct pcb *victim, *parent;
+
+	victim = pcb_find_pid(pid);
+
+	// pid does not exist
+	if (victim == NULL)
+		return 1;
+
+	parent = victim;
+	while (parent) {
+		if (parent->pid == pcb->pid)
+			break;
+		parent = parent->parent;
+	}
+
+	// we do not own this pid
+	if (parent == NULL)
+		return 1;
+
+	switch (victim->state) {
+	case PROC_STATE_KILLED:
+	case PROC_STATE_ZOMBIE:
+		// you can't kill it if it's already dead
+		return 0;
+
+	case PROC_STATE_READY:
+	case PROC_STATE_SLEEPING:
+	case PROC_STATE_BLOCKED:
+		// here, the process is on a queue somewhere; mark
+		// it as "killed", and let the scheduler deal with it
+		victim->state = PROC_STATE_KILLED;
+		return 0;
+
+	case PROC_STATE_RUNNING:
+		// we have met the enemy, and it is us!
+		pcb->exit_status = 1;
+		pcb_zombify(pcb);
+		// we need a new current process
+		dispatch();
+		break;
+
+	case PROC_STATE_WAITING:
+		// similar to the 'running' state, but we don't need
+		// to dispatch a new process
+		victim->exit_status = 1;
+		pcb_queue_remove(waiting, pcb);
+		pcb_zombify(victim);
+		break;
+
+	default:
+		// cannot kill a previable process
+		return 1;
+	}
+
+	return 0;
+}
+
+static int sys_sleep(void)
+{
+	RET(int, ret);
+	ARG1(unsigned long, ms);
+
+	if (ms == 0) {
+		*ret = 0;
+		schedule(pcb);
+		dispatch();
+	}
+
+	pcb->wakeup = ticks + ms;
+	if (pcb_queue_insert(sleeping, pcb)) {
+		WARN("sleep pcb insert failed");
+		return 1;
+	}
+
+	// calling pcb is in sleeping queue,
+	// we must call a new one
+	dispatch();
+}
+
 __attribute__((noreturn)) static int sys_poweroff(void)
 {
 	// TODO: we should probably
@@ -84,7 +216,7 @@ static int sys_drm(void)
 	if (pADDR == NULL)
 		return 1;
 
-	vADDR = mem_mapaddr(current_pcb->memctx, pADDR, (void *)0x1000000000, len,
+	vADDR = mem_mapaddr(pcb->memctx, pADDR, (void *)0x1000000000, len,
 						F_PRESENT | F_WRITEABLE | F_UNPRIVILEGED);
 	if (vADDR == NULL)
 		return 1;
@@ -93,7 +225,7 @@ static int sys_drm(void)
 	height = gpu_dev->height;
 	bpp = gpu_dev->bit_depth;
 
-	mem_ctx_switch(current_pcb->memctx);
+	mem_ctx_switch(pcb->memctx);
 	*res_fb = vADDR;
 	*res_width = width;
 	*res_height = height;
@@ -111,16 +243,16 @@ static int sys_ticks(void)
 }
 
 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,	   [SYS_poweroff] = sys_poweroff,
-	[SYS_drm] = sys_drm,   [SYS_ticks] = sys_ticks,
+	[SYS_exit] = sys_exit,		 [SYS_waitpid] = sys_waitpid,
+	[SYS_fork] = NULL,			 [SYS_exec] = NULL,
+	[SYS_open] = NULL,			 [SYS_close] = NULL,
+	[SYS_read] = NULL,			 [SYS_write] = sys_write,
+	[SYS_getpid] = sys_getpid,	 [SYS_getppid] = sys_getppid,
+	[SYS_gettime] = sys_gettime, [SYS_getprio] = sys_getprio,
+	[SYS_setprio] = sys_setprio, [SYS_kill] = sys_kill,
+	[SYS_sleep] = sys_sleep,	 [SYS_brk] = NULL,
+	[SYS_sbrk] = NULL,			 [SYS_poweroff] = sys_poweroff,
+	[SYS_drm] = sys_drm,		 [SYS_ticks] = sys_ticks,
 };
 
 void syscall_handler(struct cpu_regs *regs)
@@ -133,16 +265,17 @@ void syscall_handler(struct cpu_regs *regs)
 	mem_ctx_switch(kernel_mem_ctx);
 
 	// update data
-	current_pcb->regs = regs;
-	num = current_pcb->regs->rax;
-	current_pcb->regs->rax = 0;
+	pcb = current_pcb;
+	pcb->regs = regs;
+	num = pcb->regs->rax;
+	pcb->regs->rax = 0;
+	current_pcb = NULL;
 
 	// check for invalid syscall
 	if (num >= N_SYSCALLS) {
 		// kill process
-		current_pcb->exit_status = 1;
-		pcb_zombify(current_pcb);
-		current_pcb = NULL;
+		pcb->exit_status = 1;
+		pcb_zombify(pcb);
 		// call next process
 		dispatch();
 	}
@@ -154,7 +287,8 @@ void syscall_handler(struct cpu_regs *regs)
 
 	// on failure, set rax
 	if (ret)
-		current_pcb->regs->rax = ret;
+		pcb->regs->rax = ret;
 
 	// return to current pcb
+	current_pcb = pcb;
 }