66 lines
1.8 KiB
C
66 lines
1.8 KiB
C
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#include "elf.h"
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#include "vfs.h"
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#include "memory/mm.h"
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#include <lib/memory.h>
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uint32_t load_elf_program(const char* prgm) {
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int fd = open(prgm, 0);
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if (fd == -1) {
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return -1;
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}
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elf_header_t* e_hdr = kalloc(sizeof(elf_header_t));
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memset((void*)e_hdr, 0, sizeof(elf_header_t));
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uint32_t bytes_rd = read(fd, e_hdr, sizeof(elf_header_t));
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if (bytes_rd <= 0) {
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return -1;
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}
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uint32_t ph_table_ptr = e_hdr->e_phoff;
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elf_program_header_t* ph = kalloc(sizeof(elf_program_header_t));
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uint32_t heap_start = 0;
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for (uint32_t i = 0; i < e_hdr->e_phnum; i++) {
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fseek(fd, ph_table_ptr);
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memset((void*)ph, 0, sizeof(elf_program_header_t));
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read(fd, ph, sizeof(elf_program_header_t));
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if (ph->p_type == PT_LOAD) {
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uint32_t vstart = ph->p_vaddr;
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uint32_t vend = vstart + ph->p_memsz;
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if (vend > heap_start) {
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heap_start = vend;
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}
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uint32_t page_start = vstart & ~(PAGE_SIZE - 1);
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uint32_t page_end = (vend + PAGE_SIZE - 1) & ~(PAGE_SIZE - 1);
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for (uint32_t v = page_start; v < page_end; v += PAGE_SIZE) {
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void* phys_frame = p_alloc_frame();
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map_page(v, (uint32_t)phys_frame, PAGE_PRESENT | PAGE_WRITABLE | PAGE_USER);
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}
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uint32_t data_ptr = ph->p_offset;
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fseek(fd, data_ptr);
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read(fd, (void*)vstart, ph->p_filesz);
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// 0 out bss
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if (ph->p_memsz > ph->p_filesz) {
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size_t bss_size = ph->p_memsz - ph->p_filesz;
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memset((void*)(vstart + ph->p_filesz), 0, bss_size);
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}
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}
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ph_table_ptr += sizeof(elf_program_header_t);
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}
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uint32_t eip = e_hdr->e_entry;
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kfree(ph);
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kfree(e_hdr);
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return eip;
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}
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