+ return ptd_pp;
+}
+
+void
+__del_pagetable(pid_t pid, uintptr_t mount_point)
+{
+ x86_page_table* pptd = (x86_page_table*)(mount_point | (0x3FF << 12));
+
+ // only remove user address space
+ for (size_t i = 0; i < L1_INDEX(KERNEL_MM_BASE); i++) {
+ x86_pte_t ptde = pptd->entry[i];
+ if (!ptde || !(ptde & PG_PRESENT)) {
+ continue;
+ }
+
+ x86_page_table* ppt = (x86_page_table*)(mount_point | (i << 12));
+
+ for (size_t j = 0; j < PG_MAX_ENTRIES; j++) {
+ x86_pte_t pte = ppt->entry[j];
+ // free the 4KB data page
+ if ((pte & PG_PRESENT)) {
+ pmm_free_page(pid, PG_ENTRY_ADDR(pte));
+ }
+ }
+ // free the L2 page table
+ pmm_free_page(pid, PG_ENTRY_ADDR(ptde));
+ }
+ // free the L1 directory
+ pmm_free_page(pid, PG_ENTRY_ADDR(pptd->entry[PG_MAX_ENTRIES - 1]));
+}
+
+void*
+vmm_dup_vmspace(pid_t pid)
+{
+ return __dup_pagetable(pid, PD_REFERENCED);
+}
+
+__DEFINE_LXSYSCALL(pid_t, fork)
+{
+ return dup_proc();
+}
+
+__DEFINE_LXSYSCALL(pid_t, getpid)
+{
+ return __current->pid;
+}
+
+__DEFINE_LXSYSCALL(pid_t, getppid)
+{
+ return __current->parent->pid;
+}
+
+__DEFINE_LXSYSCALL(pid_t, getpgid)
+{
+ return __current->pgid;
+}
+
+__DEFINE_LXSYSCALL2(int, setpgid, pid_t, pid, pid_t, pgid)
+{
+ struct proc_info* proc = pid ? get_process(pid) : __current;
+
+ if (!proc) {
+ __current->k_status = LXINVL;
+ return -1;
+ }
+
+ pgid = pgid ? pgid : proc->pid;
+
+ struct proc_info* gruppenfuhrer = get_process(pgid);
+
+ if (!gruppenfuhrer || proc->pgid == proc->pid) {
+ __current->k_status = LXINVL;
+ return -1;
+ }
+
+ llist_delete(&proc->grp_member);
+ llist_append(&gruppenfuhrer->grp_member, &proc->grp_member);
+
+ proc->pgid = pgid;
+ return 0;
+}
+
+void
+init_proc(struct proc_info* pcb)
+{
+ memset(pcb, 0, sizeof(*pcb));
+
+ pcb->pid = alloc_pid();
+ pcb->created = clock_systime();
+ pcb->state = PROC_CREATED;
+ pcb->pgid = pcb->pid;
+}
+
+void
+__mark_region(uintptr_t start_vpn, uintptr_t end_vpn, int attr)
+{
+ for (size_t i = start_vpn; i < end_vpn; i++) {
+ x86_pte_t* curproc = &PTE_MOUNTED(PD_REFERENCED, i);
+ x86_pte_t* newproc = &PTE_MOUNTED(PD_MOUNT_1, i);
+ cpu_invplg(newproc);
+
+ if (attr == REGION_RSHARED) {
+ // 如果读共享，则将两者的都标注为只读，那么任何写入都将会应用COW策略。
+ cpu_invplg(curproc);
+ *curproc = *curproc & ~PG_WRITE;
+ *newproc = *newproc & ~PG_WRITE;
+ } else {
+ // 如果是私有页，则将该页从新进程中移除。
+ *newproc = 0;
+ }
+ }
+}
+
+pid_t
+dup_proc()
+{
+ struct proc_info pcb;
+ init_proc(&pcb);
+ pcb.mm = __current->mm;
+ pcb.intr_ctx = __current->intr_ctx;
+ pcb.parent = __current;
+
+ region_copy(&__current->mm.regions, &pcb.mm.regions);
+
+ setup_proc_mem(&pcb, PD_REFERENCED);
+
+ // 根据 mm_region 进一步配置页表
+ if (!__current->mm.regions) {
+ goto not_copy;
+ }
+
+ struct mm_region *pos, *n;
+ llist_for_each(pos, n, &pcb.mm.regions->head, head)
+ {
+ // 如果写共享，则不作处理。
+ if ((pos->attr & REGION_WSHARED)) {
+ continue;
+ }
+
+ uintptr_t start_vpn = PG_ALIGN(pos->start) >> 12;
+ uintptr_t end_vpn = PG_ALIGN(pos->end) >> 12;
+ __mark_region(start_vpn, end_vpn, pos->attr);
+ }
git://scm.lunaixsky.com / lunaix-os.git / blobdiff