almost got the term emu working and shell

kernel/elf.c

@@ -0,0 +1,65 @@
+#include "elf.h"
+#include "vfs.h"
+#include "memory/mm.h"
+
+#include <lib/memory.h>
+
+uint32_t load_elf_program(const char* prgm) {
+    int fd = open(prgm, 0);
+    if (fd == -1) {
+        return -1;
+    }
+
+    elf_header_t* e_hdr = kalloc(sizeof(elf_header_t));
+    memset((void*)e_hdr, 0, sizeof(elf_header_t));
+
+    uint32_t bytes_rd = read(fd, e_hdr, sizeof(elf_header_t));
+    if (bytes_rd <= 0) {
+        return -1;
+    }
+
+    uint32_t ph_table_ptr = e_hdr->e_phoff;
+    elf_program_header_t* ph = kalloc(sizeof(elf_program_header_t));
+    uint32_t heap_start = 0;
+
+    for (uint32_t i = 0; i < e_hdr->e_phnum; i++) {
+        fseek(fd, ph_table_ptr);
+        memset((void*)ph, 0, sizeof(elf_program_header_t));
+        read(fd, ph, sizeof(elf_program_header_t));
+
+        if (ph->p_type == PT_LOAD) {
+            uint32_t vstart = ph->p_vaddr;
+            uint32_t vend = vstart + ph->p_memsz;
+
+            if (vend > heap_start) {
+                heap_start = vend;
+            }
+
+            uint32_t page_start = vstart & ~(PAGE_SIZE - 1);
+            uint32_t page_end = (vend + PAGE_SIZE - 1) & ~(PAGE_SIZE - 1);
+
+            for (uint32_t v = page_start; v < page_end; v += PAGE_SIZE) {
+                void* phys_frame = p_alloc_frame();
+                map_page(v, (uint32_t)phys_frame, PAGE_PRESENT | PAGE_WRITABLE | PAGE_USER);
+            }
+
+            uint32_t data_ptr = ph->p_offset;
+            fseek(fd, data_ptr);
+            read(fd, (void*)vstart, ph->p_filesz);
+
+            // 0 out bss
+            if (ph->p_memsz > ph->p_filesz) {
+                size_t bss_size = ph->p_memsz - ph->p_filesz;
+                memset((void*)(vstart + ph->p_filesz), 0, bss_size);
+            }
+        }
+
+        ph_table_ptr += sizeof(elf_program_header_t);
+    }
+
+    uint32_t eip = e_hdr->e_entry;
+    kfree(ph);
+    kfree(e_hdr);
+
+    return eip;
+}