Files
jsix/src/user/srv.init/loader.cpp
Justin C. Miller 4e73e933db [libj6] Update how init args are passed and used
Now the init args are a linked list - this also means ld.so can use its
own plus those of the program (eg, SLP and VFS handles). __init_libj6
now adds the head of the list to its global init_args structure, and the
j6_find_init_handle function can be used to find a handle in those args
for a given proto.

This fixes situations like the logger using the wrong mailbox for the
service locator and never finding the uart driver.
2024-02-20 20:51:14 -08:00

321 lines
10 KiB
C++

#include <stdio.h>
#include <string.h>
#include <bootproto/init.h>
#include <elf/file.h>
#include <elf/headers.h>
#include <j6/errors.h>
#include <j6/flags.h>
#include <j6/init.h>
#include <j6/protocols.h>
#include <j6/syscalls.h>
#include <j6/syslog.hh>
#include <util/xoroshiro.h>
#include "j6romfs.h"
#include "loader.h"
using bootproto::module;
static constexpr size_t MiB = 0x10'0000ull;
static constexpr size_t stack_size = 16 * MiB;
static constexpr uintptr_t stack_top = 0x7f0'0000'0000;
static util::xoroshiro256pp rng {0x123456};
inline uintptr_t align_up(uintptr_t a) { return ((a-1) & ~(MiB-1)) + MiB; }
class stack_pusher
{
public:
stack_pusher(uint8_t *local_top, uintptr_t child_top) :
m_local_top {local_top}, m_child_top {child_top}, m_used {0}, m_last_arg {0} {
memset(local_top - 4096, 0, 4096); // Zero top page
}
template <typename T, size_t A = 8>
T * push(size_t extra = 0) {
m_used += sizeof(T) + extra;
m_used = (m_used + (A-1ull)) & ~(A-1ull);
return reinterpret_cast<T*>(local_pointer());
}
template <typename T>
T * push_arg(size_t extra = 0) {
T * arg = push<T>(extra);
arg->header.size = sizeof(T) + extra;
arg->header.type = T::type_id;
arg->header.next = reinterpret_cast<j6_arg_header*>(m_last_arg);
m_last_arg = child_pointer();
return arg;
}
void push_current_pointer() {
uintptr_t addr = child_pointer();
uintptr_t *ptr = push<uintptr_t, 16>();
*ptr = addr;
}
uint8_t * local_pointer() { return m_local_top - m_used; }
uintptr_t child_pointer() { return m_child_top - m_used; }
private:
uint8_t *m_local_top;
uintptr_t m_child_top;
size_t m_used;
uintptr_t m_last_arg;
};
j6_handle_t
map_phys(j6_handle_t sys, uintptr_t phys, size_t len, j6_vm_flags flags)
{
j6_handle_t vma = j6_handle_invalid;
j6_status_t res = j6_system_map_phys(sys, &vma, phys, len, flags);
if (res != j6_status_ok)
return j6_handle_invalid;
res = j6_vma_map(vma, 0, &phys, j6_vm_flag_exact);
if (res != j6_status_ok)
return j6_handle_invalid;
return vma;
}
uintptr_t
load_program_into(j6_handle_t proc, elf::file &file, uintptr_t image_base, const char *path)
{
uintptr_t eop = 0; // end of program
for (auto &seg : file.segments()) {
if (seg.type != elf::segment_type::load)
continue;
uintptr_t addr = 0;
// TODO: way to remap VMA as read-only if there's no write flag on
// the segment
unsigned long flags = j6_vm_flag_write;
if (seg.flags && elf::segment_flags::exec)
flags |= j6_vm_flag_exec;
uintptr_t start = file.base() + seg.offset;
size_t prologue = seg.vaddr & 0xfff;
size_t epilogue = seg.mem_size - seg.file_size;
j6_handle_t sub_vma = j6_handle_invalid;
j6_status_t res = j6_vma_create_map(&sub_vma, seg.mem_size+prologue, &addr, flags);
if (res != j6_status_ok) {
j6::syslog(" ** error loading ELF '%s': creating sub vma: %lx", path, res);
return 0;
}
uint8_t *src = reinterpret_cast<uint8_t *>(start);
uint8_t *dest = reinterpret_cast<uint8_t *>(addr);
memset(dest, 0, prologue);
memcpy(dest+prologue, src, seg.file_size);
memset(dest+prologue+seg.file_size, 0, epilogue);
// end of segment
uintptr_t eos = image_base + seg.vaddr + seg.mem_size + prologue;
if (eos > eop)
eop = eos;
uintptr_t start_addr = (image_base + seg.vaddr) & ~0xfffull;
j6::syslog("Mapping segment from %s at %012lx - %012lx", path, start_addr, start_addr+seg.mem_size);
res = j6_vma_map(sub_vma, proc, &start_addr, j6_vm_flag_exact);
if (res != j6_status_ok) {
j6::syslog(" ** error loading ELF '%s': mapping sub vma to child: %lx", path, res);
return 0;
}
res = j6_vma_unmap(sub_vma, 0);
if (res != j6_status_ok) {
j6::syslog(" ** error loading ELF '%s': unmapping sub vma: %lx", path, res);
return 0;
}
}
return eop;
}
static bool
give_handle(j6_handle_t proc, j6_handle_t h, const char *name)
{
if (h != j6_handle_invalid) {
j6_status_t res = j6_process_give_handle(proc, h);
if (res != j6_status_ok) {
j6::syslog(" ** error loading program: giving %s handle: %lx", name, res);
return false;
}
}
return true;
}
static j6_handle_t
create_process(j6_handle_t sys, j6_handle_t slp, j6_handle_t vfs)
{
j6_handle_t proc = j6_handle_invalid;
j6_status_t res = j6_process_create(&proc);
if (res != j6_status_ok) {
j6::syslog(" ** error loading program: creating process: %lx", res);
return j6_handle_invalid;
}
if (!give_handle(proc, sys, "system")) return j6_handle_invalid;
if (!give_handle(proc, slp, "SLP")) return j6_handle_invalid;
if (!give_handle(proc, vfs, "VFS")) return j6_handle_invalid;
return proc;
}
static util::buffer
load_file(const j6romfs::fs &fs, const char *path)
{
const j6romfs::inode *in = fs.lookup_inode(path);
if (!in || in->type != j6romfs::inode_type::file)
return {};
j6::syslog(" Loading file: %s", path);
uint8_t *data = new uint8_t [in->size];
util::buffer program {data, in->size};
fs.load_inode_data(in, program);
return program;
}
bool
load_program(
const char *path, const j6romfs::fs &fs,
j6_handle_t sys, j6_handle_t slp, j6_handle_t vfs,
const module *arg)
{
j6::syslog("Loading program '%s' into new process", path);
util::buffer program_data = load_file(fs, path);
if (!program_data.pointer)
return false;
elf::file program_elf {program_data};
bool dyn = program_elf.type() == elf::filetype::shared;
uintptr_t program_image_base = 0;
if (dyn)
program_image_base = (rng.next() & 0xffe0 + 16) << 20;
if (!program_elf.valid(dyn ? elf::filetype::shared : elf::filetype::executable)) {
j6::syslog(" ** error loading program '%s': ELF is invalid", path);
return false;
}
j6_handle_t proc = create_process(sys, slp, vfs);
uintptr_t eop = load_program_into(proc, program_elf, program_image_base, path);
if (!eop)
return false;
uintptr_t stack_addr = 0;
j6_handle_t stack_vma = j6_handle_invalid;
j6_status_t res = j6_vma_create_map(&stack_vma, stack_size, &stack_addr, j6_vm_flag_write);
if (res != j6_status_ok) {
j6::syslog(" ** error loading program '%s': creating stack vma: %lx", path, res);
return false;
}
stack_pusher stack {
reinterpret_cast<uint8_t*>(stack_addr + stack_size),
stack_top,
};
// Push program's arg sentinel
stack.push_arg<j6_arg_none>();
j6_arg_handles *handles_arg = stack.push_arg<j6_arg_handles>(3 * sizeof(j6_arg_handle_entry));
handles_arg->nhandles = 3;
handles_arg->handles[0].handle = sys;
handles_arg->handles[0].proto = 0;
handles_arg->handles[1].handle = slp;
handles_arg->handles[1].proto = j6::proto::sl::id;
handles_arg->handles[2].handle = vfs;
handles_arg->handles[2].proto = j6::proto::vfs::id;
if (arg) {
size_t data_size = arg->bytes - sizeof(*arg);
j6_arg_driver *driver_arg = stack.push_arg<j6_arg_driver>(data_size);
driver_arg->device = arg->type_id;
const uint8_t *arg_data = arg->data<uint8_t>();
memcpy(driver_arg->data, arg_data, data_size);
}
// Add an aligned pointer to the program's args list
stack.push_current_pointer();
uintptr_t entrypoint = program_elf.entrypoint() + program_image_base;
if (dyn) {
// Push loaders's arg sentinel
stack.push_arg<j6_arg_none>();
j6_arg_loader *loader_arg = stack.push_arg<j6_arg_loader>();
loader_arg->image_base = program_image_base;
loader_arg->entrypoint = program_elf.entrypoint(); // ld.so will offset the entrypoint, don't do it here.
const elf::section_header *got_section = program_elf.get_section_by_name(".got.plt");
if (got_section)
loader_arg->got = reinterpret_cast<uintptr_t*>(program_image_base + got_section->addr);
// Add an aligned pointer to the loaders's args list
stack.push_current_pointer();
uintptr_t ldso_image_base = (eop & ~(MiB-1)) + MiB;
for (auto seg : program_elf.segments()) {
if (seg.type == elf::segment_type::interpreter) {
const char *ldso_path = reinterpret_cast<const char*>(program_elf.base() + seg.offset);
util::buffer ldso_data = load_file(fs, ldso_path);
if (!ldso_data.pointer)
return false;
elf::file ldso_elf {ldso_data};
if (!ldso_elf.valid(elf::filetype::shared)) {
j6::syslog(" ** error loading dynamic linker for program '%s': ELF is invalid", path);
return false;
}
uintptr_t eop = load_program_into(proc, ldso_elf, ldso_image_base, ldso_path);
eop = (eop & ~0xfffffull) + 0x100000;
loader_arg->loader_base = ldso_image_base;
loader_arg->start_addr = eop;
entrypoint = ldso_elf.entrypoint() + ldso_image_base;
delete [] reinterpret_cast<uint8_t*>(ldso_data.pointer);
break;
}
}
}
uintptr_t stack_base = stack_top-stack_size;
res = j6_vma_map(stack_vma, proc, &stack_base, j6_vm_flag_exact);
if (res != j6_status_ok) {
j6::syslog(" ** error loading program '%s': mapping stack vma: %lx", path, res);
return false;
}
res = j6_vma_unmap(stack_vma, 0);
if (res != j6_status_ok) {
j6::syslog(" ** error loading program '%s': unmapping stack vma: %lx", path, res);
return false;
}
j6_handle_t thread = j6_handle_invalid;
res = j6_thread_create(&thread, proc, stack.child_pointer(), entrypoint, program_image_base, 0);
if (res != j6_status_ok) {
j6::syslog(" ** error loading program '%s': creating thread: %lx", path, res);
return false;
}
// TODO: smart pointer this, it's a memory leak if we return early
delete [] reinterpret_cast<uint8_t*>(program_data.pointer);
return true;
}