2011-04-16 20:01:04 -05:00

115 lines
2.1 KiB
C

/*
* vim:tabstop=4
* vim:noexpandtab
*/
#include <system.h>
#include <syscall.h>
/*
* System calls themselves
*/
/*
* print something to the core terminal
*/
static int print(char * s) {
kprintf(s);
return 0;
}
/*
* Exit the current task.
* DOES NOT RETURN!
*/
static int exit(int retval) {
/* Deschedule the current task */
task_exit(retval);
while (1) { };
return retval;
}
static int read(int fd, char * ptr, int len) {
if (fd >= current_task->next_fd) {
return -1;
}
fs_node_t * node = current_task->descriptors[fd];
uint32_t out = read_fs(node, node->offset, len, (uint8_t *)ptr);
node->offset += out;
return out;
}
static int write(int fd, char * ptr, int len) {
if (fd >= current_task->next_fd) {
return -1;
}
fs_node_t * node = current_task->descriptors[fd];
uint32_t out = write_fs(node, node->offset, len, (uint8_t *)ptr);
node->offset += out;
return out;
}
static int open(const char * file, int flags, int mode) {
fs_node_t * node = kopen(file, 0);
if (!node) {
return -1;
}
current_task->descriptors[current_task->next_fd] = node;
node->offset = 0;
return current_task->next_fd++;
}
static int close(int fd) {
if (fd <= current_task->next_fd) {
return -1;
}
close_fs(current_task->descriptors[fd]);
return 0;
}
/*
* System Call Internals
*/
static void syscall_handler(struct regs * r);
static uintptr_t syscalls[] = {
/* System Call Table */
(uintptr_t)&exit,
(uintptr_t)&print,
(uintptr_t)&open,
(uintptr_t)&read,
(uintptr_t)&write,
(uintptr_t)&close
};
uint32_t num_syscalls = 6;
void
syscalls_install() {
isrs_install_handler(0x7F, &syscall_handler);
}
void
syscall_handler(
struct regs * r
) {
if (r->eax >= num_syscalls) {
return;
}
uintptr_t location = syscalls[r->eax];
uint32_t ret;
__asm__ __volatile__ (
"push %1\n"
"push %2\n"
"push %3\n"
"push %4\n"
"push %5\n"
"call *%6\n"
"pop %%ebx\n"
"pop %%ebx\n"
"pop %%ebx\n"
"pop %%ebx\n"
"pop %%ebx\n"
: "=a" (ret) : "r" (r->edi), "r" (r->esi), "r" (r->edx), "r" (r->ecx), "r" (r->ebx), "r" (location));
r->eax = ret;
}