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Add an initial fork() implementation

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apio 2022-10-15 18:01:35 +02:00
parent 1624f0360d
commit 20cffdb66c
3 changed files with 38 additions and 4 deletions
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4
kernel/include/sys/Syscall.h
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@ -18,6 +18,7 @@
#define SYS_fcntl 13
#define SYS_mprotect 14
#define SYS_clock 15
#define SYS_fork 16
namespace Syscall
{
@ -41,4 +42,5 @@ void sys_seek(Context* context, int fd, long offset, int whence);
void sys_exec(Context* context, const char* pathname);
void sys_fcntl(Context* context, int fd, int command, uintptr_t arg);
void sys_mprotect(Context* context, void* address, size_t size, int prot);
void sys_clock(Context* context);
void sys_clock(Context* context);
void sys_fork(Context* context);

1
kernel/src/sys/Syscall.cpp
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@ -27,6 +27,7 @@ void Syscall::entry(Context* context)
case SYS_fcntl: sys_fcntl(context, (int)context->rdi, (int)context->rsi, context->rdx); break;
case SYS_mprotect: sys_mprotect(context, (void*)context->rdi, context->rsi, (int)context->rdx); break;
case SYS_clock: sys_clock(context); break;
case SYS_fork: sys_fork(context); break;
default: context->rax = -ENOSYS; break;
}
VMM::exit_syscall_context();

37
kernel/src/sys/exec.cpp
View File

@ -11,12 +11,43 @@
#include "sys/Syscall.h"
#include "sys/elf/ELFLoader.h"
#include "thread/Scheduler.h"
#include "utils/Addresses.h"
void sys_fork(Context* context) // FIXME: Even though both processes's address spaces are the same in content, writing
// to one should not affect the other.
{
kinfoln("fork(): attempting fork");
Task* parent = Scheduler::current_task();
Task* child = Scheduler::create_user_task();
memcpy(&child->regs, &parent->regs, sizeof(Context));
if (parent->floating_saved)
{
memcpy(child->floating_region, parent->floating_region, sizeof(parent->floating_region));
child->floating_saved = true;
}
for (int i = 0; i < TASK_MAX_FDS; i++) { child->files[i] = parent->files[i]; }
size_t stack_bytes = get_top_of_stack(parent->allocated_stack, TASK_PAGES_IN_STACK) - parent->regs.rsp;
child->regs.rsp -= stack_bytes;
memcpy((void*)child->regs.rsp, (void*)parent->regs.rsp, stack_bytes);
child->address_space = parent->address_space.clone();
child->regs.rax = 0;
context->rax = child->id;
kinfoln("fork(): forked parent %d into child %d", parent->id, child->id);
return;
}
void sys_exec(Context* context, const char* pathname)
{
/*context->rax = -ENOSYS; // FIXME: Make exec() work under separate address spaces.
return;*/
char* kpathname = Syscall::strdup_from_user(pathname);
if (!kpathname)
{