First useful jump to userspace!

3 files changed, 92 insertions, 10 deletions

diff --git a/common/elf.c b/common/elf.c
index c6a37e0..c73d56c 100644
--- a/common/elf.c
+++ b/common/elf.c
@@ -1,12 +1,83 @@
 #include <apos/elf.h>
 #include <apos/vmem.h>
+#include <apos/bytes.h>
+#include <apos/string.h>
 
-vm_t bin_entry(vm_t bin)
+static void __map_exec(struct tcb *t, vm_t bin, uint8_t ei_c, vm_t phstart, size_t phnum, size_t phsize)
 {
-	struct elf_header *e = (struct elf_header *)bin;
-	/* TODO: check that address points to a valid ELF executable */
-	/* oh yeah, this only works for DYN objects, fuck */
-	/* eh, fuck it, I'll fix this later, today has been a decently
-	 * productive day as is */
-	return ((vm_t)e->e_entry) + bin;
+	/* TODO: take alignment into consideration? */
+	vm_t runner = phstart;
+	for(size_t i = 0; i < phnum; ++i, runner += phsize){
+		if(program_header_prop(ei_c, runner, p_type) != PT_LOAD)
+			continue;
+
+		vm_t va = program_header_prop(ei_c, runner, p_vaddr);
+		size_t vsz = program_header_prop(ei_c, runner, p_memsz);
+
+		vm_t start = 0;
+		if(!(start = alloc_fixed_region(&t->sp_r, va, vsz, 0)))
+				return; /* out of memory or something */
+
+		uint8_t vflags = VM_V | VM_U;
+		uint8_t bflags = program_header_prop(ei_c, runner, p_flags);
+		if(bflags & PF_X)
+			vflags |= VM_X;
+
+		if(bflags & PF_W)
+			vflags |= VM_W;
+
+		if(bflags & PF_R)
+			vflags |= VM_R;
+
+		map_fill_region(t->b_r, start, vsz, VM_V | VM_X | VM_R | VM_W | VM_U);
+
+		vm_t vo = bin + program_header_prop(ei_c, runner, p_offset);
+		vm_t vfz = program_header_prop(ei_c, runner, p_filesz);
+		memcpy((void *)va, (void *)vo, vfz);
+
+		/* skip while testing
+		pm_t paddr = 0;
+		stat_vmem(t->b_r, va, &paddr, 0, 0);
+		mod_vmem(t->b_r, va, paddr, vflags);
+		*/
+	}
+}
+
+static vm_t __map_dyn(struct tcb *t, vm_t bin, uint8_t ei_c, vm_t phstart, size_t phnum, size_t phsize)
+{
+	/* TODO */
+}
+
+static vm_t __prepare_proc(struct tcb *t, uint8_t ei_c, vm_t elf)
+{
+	short e_type = elf_header_prop(ei_c, elf, e_type);
+	if(e_type != ET_DYN && e_type != ET_EXEC)
+		return 0;
+
+	vm_t phstart = ptradd(elf, elf_header_prop(ei_c, elf, e_phoff));
+	size_t phnum = elf_header_prop(ei_c, elf, e_phnum);
+	size_t phsize = elf_header_prop(ei_c, elf, e_phentsize);
+
+	vm_t entry = elf_header_prop(ei_c, elf, e_entry);
+	if(e_type == ET_EXEC){
+		__map_exec(t, elf, ei_c, phstart, phnum, phsize);
+		return entry;
+	} else {
+		vm_t o = __map_dyn(t, elf, ei_c, phstart, phnum, phsize);
+		return o + entry;
+	}
+}
+
+/* sets up all memory regions etc, returns the entry address */
+vm_t prepare_proc(struct tcb *t, vm_t p)
+{
+	struct elf_ident *i = (struct elf_ident *)p;
+	if(i->ei_magic != cpu_to_be32(EI_MAGIC))
+		return 0;
+
+	if(i->ei_class != ELFCLASS32 && i->ei_class != ELFCLASS64)
+			return 0;
+
+	/* more sanity checks? */
+	return __prepare_proc(t, i->ei_class, p);
 }
diff --git a/common/initrd.c b/common/initrd.c
index 61aaaff..18db836 100644
--- a/common/initrd.c
+++ b/common/initrd.c
@@ -86,6 +86,14 @@ size_t get_init_size(void *fdt)
 	return convnum(cp->c_filesize, 8, 16);
 }
 
+vm_t get_init_base(void *fdt)
+{
+	char *c = (char *)get_initrdbase(fdt);
+	struct cpio_header *cp = find_file(c, init_n, init_nlen);
+	size_t name_len = convnum(cp->c_namesize, 8, 16);
+	return ((vm_t)cp) + align_up(sizeof(struct cpio_header) + name_len, 4);
+}
+
 void move_init(void *fdt, void *target)
 {
 	char *c = (char *)get_initrdbase(fdt);
diff --git a/common/vmem.c b/common/vmem.c
index 7b1fa4f..229963c 100644
--- a/common/vmem.c
+++ b/common/vmem.c
@@ -299,8 +299,11 @@ vm_t alloc_region(struct sp_reg_root *r,
 vm_t alloc_fixed_region(struct sp_reg_root *r,
 		vm_t start, size_t size, size_t *actual_size)
 {
-	*actual_size = align_up(size, BASE_PAGE_SIZE);
-	size_t pages = __page(*actual_size);
+	size_t asize = align_up(size, BASE_PAGE_SIZE);
+	if(actual_size)
+		*actual_size = asize;
+
+	size_t pages = __page(asize);
 	start = __page(start);
 
 	struct sp_mem *m = sp_find_used_closest(r, start);
@@ -309,7 +312,7 @@ vm_t alloc_fixed_region(struct sp_reg_root *r,
 
 	/* locate actual region where start is between the region start and end */
 	while(!((m->start <= start) && (start <= m->end))){
-		if(start < m->start)
+		if(start > m->start)
 			m = m->next;
 		else
 			m = m->prev;