mirror of
https://github.com/Mathewnd/Astral.git
synced 2026-10-27 12:48:22 +00:00
ELF: refactor loader
This commit is contained in:
Matheus
@@ -0,0 +1,9 @@
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#ifndef _ARCH_ELFMAGIC_INCLUDE
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#define _ARCH_ELFMAGIC_INCLUDE
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#define ARCH_ELF_BITS 2
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#define ARCH_ELF_ISA 0x3E
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#define ARCH_ELF_ENDIANNESS 1
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#endif
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@@ -7,9 +7,6 @@
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#include <stdint.h>
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#define ELF_MAGIC 0x464c457f // 0x7F ELF
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#define ELF_BITS_64 2
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#define ELF_ISA_X86_64 0x3E
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#define ELF_ENDIANNESS_LITTLE 1
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#define ELF_RELOCATABLE 1
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#define ELF_EXECUTABLE 2
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@@ -26,7 +23,7 @@
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#define ELF_FLAG_WRITABLE 2
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#define ELF_FLAG_READABLE 4
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#define STACK_TOP 0x800000000000
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#define STACK_TOP (void*)0x800000000000
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#define AT_NULL 0
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#define AT_PHDR 3
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@@ -34,6 +31,19 @@
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#define AT_PHNUM 5
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#define AT_ENTRY 9
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typedef struct{
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uint64_t a_type;
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uint64_t a_val;
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} auxv64_t;
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typedef struct {
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auxv64_t phdr;
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auxv64_t phnum;
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auxv64_t phent;
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auxv64_t entry;
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auxv64_t null;
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} auxv64_list;
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typedef struct{
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uint32_t magic;
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uint8_t bits;
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+124
-211
@@ -4,16 +4,7 @@
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#include <errno.h>
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#include <string.h>
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#include <arch/cls.h>
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typedef struct{
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uint64_t a_type;
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uint64_t a_val;
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} auxv64_t;
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typedef struct {
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auxv64_t phdr;
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auxv64_t null;
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} auxv64_list;
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#include <arch/elfmagic.h>
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static size_t phflagtommuflag(size_t phflags){
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@@ -33,31 +24,71 @@ static size_t phflagtommuflag(size_t phflags){
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}
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static bool check_header64(elf_header64* header){
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// XXX throw this into arch
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if(header->magic != ELF_MAGIC)
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return false;
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if(header->bits != ELF_BITS_64)
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if(header->bits != ARCH_ELF_BITS)
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return false;
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if(header->endianness != ELF_ENDIANNESS_LITTLE)
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if(header->endianness != ARCH_ELF_ENDIANNESS)
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return false;
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if(header->isa != ELF_ISA_X86_64)
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if(header->isa != ARCH_ELF_ISA)
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return false;
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return true;
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}
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static void* stacksetup(char* interp, char** argv, char** env, elf_header64 header, elf_ph64* phs){
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static int load(vnode_t* node, elf_ph64 ph){
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size_t mmuflags = phflagtommuflag(ph.flags);
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// allocate memory for the section
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if(!vmm_allocnowat((void*)ph.memaddr, mmuflags, ph.msize))
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return ENOMEM;
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// set up temporary mmu flags to copy data
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size_t pagesize = ph.msize / PAGE_SIZE + (ph.msize % PAGE_SIZE ? 1 : 0);
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arch_mmu_changeflags(arch_getcls()->context->context, (void*)ph.memaddr, ARCH_MMU_MAP_READ | ARCH_MMU_MAP_WRITE, pagesize);
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int err;
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size_t readc = vfs_read(&err, node, (void*)ph.memaddr, ph.fsize, ph.offset);
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if(err)
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return err;
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if(readc != ph.fsize)
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return EINVAL;
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// zero if needed
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size_t zerocount = ph.msize - ph.fsize;
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if(zerocount){
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void* zeroaddr = (void*)ph.memaddr + ph.fsize;
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memset(zeroaddr, 0, zerocount);
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}
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// reset proper mmu flags
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arch_mmu_changeflags(arch_getcls()->context->context, (void*)ph.memaddr, mmuflags, pagesize);
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return 0;
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}
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static void* stacksetup(char** argv, char** env, auxv64_list auxv){
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size_t argc = 0;
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size_t envc = 0;
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size_t initialsize = 0;
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size_t argdatasize = 0;
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size_t envdatasize = 0;
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size_t auxvsize = 5*16; // FIXME better way of keeping track of this
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while(argv[argc]){
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argdatasize += strlen(argv[argc]) + 1;
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@@ -87,45 +118,17 @@ static void* stacksetup(char* interp, char** argv, char** env, elf_header64 head
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char* argdatastart = STACK_TOP - argdatasize;
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char* envdatastart = argdatastart - envdatasize;
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auxv64_t* auxvstart = (void*)(((uintptr_t)envdatastart & (~0xF)) - auxvsize);
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auxv64_list* auxvstart = (void*)(((uintptr_t)envdatastart & (~0xF)) - sizeof(auxv));
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// count + 1 because of a null entry
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char** envstart = (void*)auxvstart - (envc + 1)*sizeof(char*);
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char** argstart = (void*)envstart - (argc + 1)*sizeof(char*);
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size_t* argcptr = (void*)argstart - sizeof(size_t);
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// auxv
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// AT_PHDR
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auxvstart->a_type = AT_PHDR;
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auxvstart->a_val = (uint64_t)phs;
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auxvstart++;
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// AT_PHENT
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auxvstart->a_type = AT_PHENT;
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auxvstart->a_val = header.ph_size;
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auxvstart++;
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// AT_PHNUM
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auxvstart->a_type = AT_PHNUM;
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auxvstart->a_val = header.ph_count;
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auxvstart++;
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// AT_ENTRY
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auxvstart->a_type = AT_ENTRY;
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auxvstart->a_val = header.entry;
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auxvstart++;
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// AT_NULL
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auxvstart->a_type = AT_NULL;
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auxvstart->a_val = 0;
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// copy the data
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memcpy(auxvstart, &auxv, sizeof(auxv));
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for(size_t i = 0; i < argc; ++i){
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@@ -154,206 +157,116 @@ static void* stacksetup(char* interp, char** argv, char** env, elf_header64 head
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int elf_load(thread_t* thread, vnode_t* node, char** argv, char** env){
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elf_header64 header;
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elf_header64 progheader;
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vnode_t* prognode = node;
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elf_ph64 ph;
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elf_header64 header;
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elf_ph64 phbuff;
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int err = 0;
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int readc = vfs_read(&err, node, &header, sizeof(elf_header64), 0);
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char* interp = NULL;
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if(err)
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return err;
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if(readc != sizeof(elf_header64) || (!check_header64(&header)))
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return EINVAL;
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progheader = header; // incase an interpreter exists
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auxv64_list auxv;
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auxv.null.a_type = AT_NULL;
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auxv.phdr.a_type = AT_PHDR;
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auxv.phnum.a_type = AT_PHNUM;
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auxv.phent.a_type = AT_PHENT;
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auxv.entry.a_type = AT_ENTRY;
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// find out if this needs an interpreter
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// and also save the executable's program headers
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// for auxv
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auxv.phnum.a_val = header.ph_count;
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auxv.phent.a_val = header.ph_size;
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auxv.entry.a_val = header.entry;
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elf_ph64* progphs;
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for(size_t currentph = 0; currentph < header.ph_count; ++currentph){
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readc = vfs_read(&err, node, &ph, header.ph_size, header.ph_pos + currentph*header.ph_size);
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char* interp = NULL; // interpreter name location in program image
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for(size_t pos = header.ph_pos, ph = 0; ph < header.ph_count; ++ph, pos += header.ph_size){
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readc = vfs_read(&err, node, &phbuff, header.ph_size, pos);
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if(err)
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return err;
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if(readc != header.ph_size)
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return EINVAL;
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if(ph.type == PH_TYPE_PHDR)
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progphs = (elf_ph64*)ph.memaddr;
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if(ph.type == PH_TYPE_INTERPRETER){
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// load the name and elf header of the interpreter
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progheader = header;
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interp = alloc(ph.fsize + 1);
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if(!interp)
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return ENOMEM;
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readc = vfs_read(&err, node, interp, ph.fsize, ph.offset);
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if(err){
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free(interp);
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return err;
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}
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if(ph.fsize != readc){
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free(interp);
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return EINVAL;
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}
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err = vfs_open(&node, thread->proc->root, interp);
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if(err){
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free(interp);
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return err;
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}
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readc = vfs_read(&err, node, &header, sizeof(elf_header64), 0);
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if(err)
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goto _fail;
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if(readc != sizeof(elf_header64) || (!check_header64(&header))){
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err = EINVAL;
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goto _fail;
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}
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switch(phbuff.type){
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case PH_TYPE_INTERPRETER:
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interp = (char*)phbuff.memaddr;
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break;
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case PH_TYPE_PHDR:
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auxv.phdr.a_val = phbuff.memaddr;
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break;
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case PH_TYPE_LOAD:
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err = load(node, phbuff);
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if(err)
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return err;
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break;
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}
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}
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// load program into memory
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for(size_t currentph = 0; currentph < header.ph_count; ++currentph){
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// load the interpreter if needed
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// read ph
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vnode_t* interfile;
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readc = vfs_read(&err, node, &ph, header.ph_size, header.ph_pos + currentph*header.ph_size);
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if(interp){
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err = vfs_open(&interfile, thread->proc->root, interp);
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if(err)
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return err;
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if(err) goto _fail;
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if(readc != header.ph_size){
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err = EINVAL;
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goto _fail;
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}
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if(ph.type != PH_TYPE_LOAD)
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continue;
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if(!vmm_allocnowat((void*)ph.memaddr, phflagtommuflag(ph.flags), ph.msize)){
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err = ENOMEM;
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goto _fail;
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}
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// set up temporary mmu flags to copy data
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arch_mmu_changeflags(arch_getcls()->context->context, ph.memaddr, ARCH_MMU_MAP_READ | ARCH_MMU_MAP_WRITE, ph.msize / PAGE_SIZE + (ph.msize % PAGE_SIZE ? 1 : 0));
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// read program data
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readc = vfs_read(&err, node, (void*)ph.memaddr, ph.fsize, ph.offset);
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readc = vfs_read(&err, interfile, &header, sizeof(elf_header64), 0);
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if(err)
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goto _fail;
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if(readc != ph.fsize){
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goto _interpfail;
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if(readc != sizeof(elf_header64)){
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err = EINVAL;
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goto _fail;
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}
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// zero if needed
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size_t zerocount = ph.msize - ph.fsize;
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if(zerocount){
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void* zeroaddr = ph.memaddr + ph.fsize;
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memset(zeroaddr, 0, zerocount);
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goto _interpfail;
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}
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// reset proper mmu flags
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arch_mmu_changeflags(arch_getcls()->context->context, ph.memaddr, phflagtommuflag(ph.flags), ph.msize / PAGE_SIZE + (ph.msize % PAGE_SIZE ? 1 : 0));
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for(size_t pos = header.ph_pos, ph = 0; ph < header.ph_count; ++ph, pos += header.ph_size){
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readc = vfs_read(&err, interfile, &phbuff, header.ph_size, pos);
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if(err)
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goto _interpfail;
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}
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// also load the executable memory image if we're using an interpreter
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if(interp){
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for(size_t currentph = 0; currentph < progheader.ph_count; ++currentph){
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// read ph
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readc = vfs_read(&err, prognode, &ph, progheader.ph_size, progheader.ph_pos + currentph*progheader.ph_size);
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if(err) goto _fail;
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if(readc != progheader.ph_size){
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if(readc != header.ph_size){
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err = EINVAL;
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goto _fail;
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goto _interpfail;
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}
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if(ph.type != PH_TYPE_LOAD)
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if(phbuff.type != PH_TYPE_LOAD)
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continue;
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if(!vmm_allocnowat((void*)ph.memaddr, phflagtommuflag(ph.flags), ph.msize)){
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err = ENOMEM;
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goto _fail;
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}
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// set up temporary mmu flags to copy data
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arch_mmu_changeflags(arch_getcls()->context->context, ph.memaddr, ARCH_MMU_MAP_READ | ARCH_MMU_MAP_WRITE, ph.msize / PAGE_SIZE + (ph.msize % PAGE_SIZE ? 1 : 0));
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// read program data
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readc = vfs_read(&err, prognode, (void*)ph.memaddr, ph.fsize, ph.offset);
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err = load(interfile, phbuff);
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if(err)
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goto _fail;
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goto _interpfail;
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}
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vfs_close(interfile);
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if(readc != ph.fsize){
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err = EINVAL;
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goto _fail;
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}
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// zero if needed
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size_t zerocount = ph.msize - ph.fsize;
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if(zerocount){
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void* zeroaddr = ph.memaddr + ph.fsize;
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memset(zeroaddr, 0, zerocount);
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}
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// reset proper mmu flags
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arch_mmu_changeflags(arch_getcls()->context->context, ph.memaddr, phflagtommuflag(ph.flags), ph.msize / PAGE_SIZE + (ph.msize % PAGE_SIZE ? 1 : 0));
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}
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}
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void* stack = stacksetup(interp, argv, env, progheader, progphs);
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void* stack = stacksetup(argv, env, auxv);
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arch_regs_setupuser(thread->regs, (void*)header.entry, stack, true);
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return 0;
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_fail:
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if(interp){
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free(interp);
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vfs_close(node);
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}
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return err;
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return 0;
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_interpfail:
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vfs_close(interfile);
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return err;
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}
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