justin/jsix
1
1
Fork 0
mirror of https://github.com/justinian/jsix.git synced 2025-12-10 00:14:32 -08:00
Code Issues Packages Projects Releases Wiki Activity

[ld.so] Add dynamic library linking

Browse Source 
ld.so will now go through all DT_NEEDED entries in the dynamic table and load and relocate
those shared libraries as well. Lazy linking of functions via the PLT is not yet supported,
all PLT entries are looked up ahead of time by ld.so.
This commit is contained in:
Justin C. Miller
2024-02-18 17:39:42 -08:00
parent c27f8baa31
commit c245949ea4
17 changed files with 607 additions and 203 deletions
Download Patch File Download Diff File Expand all files Collapse all files

63
src/user/ld.so/main.cpp
View File

@@ -3,32 +3,16 @@
#include <elf/headers.h>
#include <j6/init.h>
#include <j6/protocols/vfs.hh>
#include <j6/syslog.hh>
#include <util/pointers.h>
#include "relocate.h"
uintptr_t
locate_dyn_section(uintptr_t base, uintptr_t phdr, size_t phdr_size, size_t phdr_count)
{
if (!phdr || !phdr_count)
return 0;
#include "image.h"
const elf::segment_header *ph_base =
reinterpret_cast<const elf::segment_header*>(phdr + base);
for (size_t i = 0; i < phdr_count; ++i) {
const elf::segment_header *ph =
util::offset_pointer(ph_base, i*phdr_size);
if (ph->type == elf::segment_type::dynamic)
return ph->vaddr;
}
return 0;
}
image_list all_images;
extern "C" uintptr_t
ldso_init(j6_arg_header *stack_args, uintptr_t const *got)
ldso_init(j6_arg_header *stack_args, uintptr_t *got)
{
j6_arg_loader *arg_loader = nullptr;
j6_arg_handles *arg_handles = nullptr;
@@ -57,14 +41,37 @@ ldso_init(j6_arg_header *stack_args, uintptr_t const *got)
exit(127);
}
relocate_image(arg_loader->loader_base, got[0]);
j6_handle_t vfs = j6_handle_invalid;
if (arg_handles) {
for (size_t i = 0; i < arg_handles->nhandles; ++i) {
j6_arg_handle_entry &ent = arg_handles->handles[i];
if (ent.proto == j6::proto::vfs::id) {
vfs = ent.handle;
break;
}
}
}
uintptr_t dyn_section = locate_dyn_section(
arg_loader->image_base,
arg_loader->phdr,
arg_loader->phdr_size,
arg_loader->phdr_count);
relocate_image(arg_loader->image_base, dyn_section);
// First relocate ld.so itself. It cannot have any dependencies
image_list::item_type ldso_image;
ldso_image.base = arg_loader->loader_base;
ldso_image.got = got;
ldso_image.read_dyn_table(
reinterpret_cast<const dyn_entry*>(got[0] + arg_loader->loader_base));
image_list just_ldso;
just_ldso.push_back(&ldso_image);
ldso_image.relocate(just_ldso);
image_list::item_type target_image;
target_image.base = arg_loader->image_base;
target_image.got = arg_loader->got;
target_image.read_dyn_table(
reinterpret_cast<const dyn_entry*>(arg_loader->got[0] + arg_loader->image_base));
all_images.push_back(&target_image);
all_images.load(vfs, 0xb00'0000);
return arg_loader->entrypoint + arg_loader->image_base;
}
}