Elf loader added

4 files changed, 108 insertions, 3 deletions

diff --git a/src/stem/Makefile b/src/stem/Makefile
index d212216..41b5368 100644
--- a/src/stem/Makefile
+++ b/src/stem/Makefile
@@ -12,7 +12,8 @@ OBJECTS = core/loader_.o core/kmain.o core/sys.o \
 		  core/monitor.o task/timer.o \
 		  task/idt.o task/idt_.o task/task.o task/task_.o task/syscall.o \
 		  lib/stdlib.o lib/bitset.o \
-		  mem/mem.o mem/paging.o mem/gdt.o mem/heap.o mem/seg.o
+		  mem/mem.o mem/paging.o mem/gdt.o mem/heap.o mem/seg.o \
+		  linker/elf.o
 OUT = stem.elf
 
 all: $(OBJECTS)
diff --git a/src/stem/linker/elf.c b/src/stem/linker/elf.c
new file mode 100644
index 0000000..62030ee
--- /dev/null
+++ b/src/stem/linker/elf.c
@@ -0,0 +1,31 @@
+#include "elf.h"
+#include <mem/paging.h>
+#include <mem/seg.h>
+#include <stdlib.h>
+
+int elf_check(uint8_t *data) {
+	struct elf_ehdr *h = (struct elf_ehdr*)data;
+	if (h->e_ident[0] == 0x7F && h->e_ident[1] == 'E' && h->e_ident[2] == 'L' && h->e_ident[3] == 'F') return 0;
+	return 1;
+}
+
+thread_entry elf_load(uint8_t *data, struct process* process) {
+	struct elf_ehdr *ehdr = (struct elf_ehdr*)data;
+	struct elf_phdr *phdr;
+	int i;
+	if (elf_check(data)) return 0;
+
+	pagedir_switch(process->pagedir);
+
+	phdr = (struct elf_phdr*)((uint8_t*)(data + ehdr->e_phoff));
+	for (i = 0; i < ehdr->e_phnum; i++) {
+		if (phdr[i].p_type == PT_LOAD) {
+			seg_map(simpleseg_make(phdr[i].p_vaddr, phdr[i].p_memsz, (phdr[i].p_flags & PF_W) != 0), process->pagedir);
+			memcpy((uint8_t*)phdr[i].p_vaddr, data + phdr[i].p_offset, phdr[i].p_filesz);
+			if (phdr[i].p_memsz > phdr[i].p_filesz) {
+				memset((uint8_t*)phdr[i].p_vaddr + phdr[i].p_memsz, 0, phdr[i].p_memsz - phdr[i].p_filesz);
+			}
+		}
+	}
+	return (thread_entry)ehdr->e_entry;
+}
diff --git a/src/stem/linker/elf.h b/src/stem/linker/elf.h
new file mode 100644
index 0000000..f84bb62
--- /dev/null
+++ b/src/stem/linker/elf.h
@@ -0,0 +1,63 @@
+#ifndef DEF_ELF_H
+#define DEF_ELF_H
+
+#include <types.h>
+#include <task/task.h>
+
+/* elf_phdr_t :: p_type : program header entries types */
+#define	PT_NULL             0
+#define	PT_LOAD             1
+#define	PT_DYNAMIC          2
+#define	PT_INTERP           3
+#define	PT_NOTE             4
+#define	PT_SHLIB            5
+#define	PT_PHDR             6
+#define	PT_LOPROC  0x70000000
+#define	PT_HIPROC  0x7fffffff
+ 
+/* elf_phdr_t :: p_flags : program header entries flags */
+#define PF_X	(1 << 0)
+#define PF_W	(1 << 1)
+#define PF_R	(1 << 2)
+
+struct elf_ehdr {
+	uint8_t e_ident[16];      /* ELF identification */
+	uint16_t e_type;             /* 2 (exec file) */
+	uint16_t e_machine;          /* 3 (intel architecture) */
+	uint32_t e_version;          /* 1 */
+	uint32_t e_entry;            /* starting point */
+	uint32_t e_phoff;            /* program header table offset */
+	uint32_t e_shoff;            /* section header table offset */
+	uint32_t e_flags;            /* various flags */
+	uint16_t e_ehsize;           /* ELF header (this) size */
+
+	uint16_t e_phentsize;        /* program header table entry size */
+	uint16_t e_phnum;            /* number of entries */
+
+	uint16_t e_shentsize;        /* section header table entry size */
+	uint16_t e_shnum;            /* number of entries */
+
+	uint16_t e_shstrndx;         /* index of the section name string table */
+};
+ 
+struct elf_phdr {
+	uint32_t p_type;             /* type of segment */
+	uint32_t p_offset;
+	uint32_t p_vaddr;
+	uint32_t p_paddr;
+	uint32_t p_filesz;
+	uint32_t p_memsz;
+	uint32_t p_flags;
+	uint32_t p_align;
+};
+ 
+struct phdr {
+	struct elf_phdr h;
+	uint8_t* data;
+};
+
+int elf_check(uint8_t *data);	//0 if ok, 1 if not a valid ELF
+thread_entry elf_load(uint8_t *data, struct process* process);	//Load an ELF to a process, return entry point
+struct process* elf_exec(uint8_t *data);	//Creates a new process and a thread for running ELF file
+
+#endif
diff --git a/src/stem/stem.map b/src/stem/stem.map
index c35b1ee..a919c01 100644
--- a/src/stem/stem.map
+++ b/src/stem/stem.map
@@ -26,7 +26,7 @@ Linker script and memory map
                 0x00100000                loader
                 0xe010003a                . = (. + 0xe0000000)
 
-.text           0xe0100040     0x3395 load address 0x00100040
+.text           0xe0100040     0x355a load address 0x00100040
  *(.text)
  .text          0xe0100040       0x25 core/loader_.o
  *fill*         0xe0100065        0x3 00
@@ -178,8 +178,12 @@ Linker script and memory map
                 0xe01032e8                simpleseg_unmap
                 0xe010333b                simpleseg_handleFault
                 0xe01033d0                simpleseg_delete
+ *fill*         0xe01033d5        0x3 00
+ .text          0xe01033d8      0x1c2 linker/elf.o
+                0xe01033d8                elf_check
+                0xe010341d                elf_load
 
-.iplt           0xe01033d8        0x0 load address 0x001033d5
+.iplt           0xe010359c        0x0 load address 0x0010359a
  .iplt          0x00000000        0x0 core/loader_.o
 
 .rodata         0xe0104000      0x395 load address 0x00104000
@@ -216,6 +220,7 @@ Linker script and memory map
  .data          0xe0105024        0x0 mem/gdt.o
  .data          0xe0105024        0x0 mem/heap.o
  .data          0xe0105024        0x0 mem/seg.o
+ .data          0xe0105024        0x0 linker/elf.o
 
 .igot.plt       0xe0105024        0x0 load address 0x00105024
  .igot.plt      0x00000000        0x0 core/loader_.o
@@ -258,6 +263,7 @@ Linker script and memory map
  *fill*         0xe01159ae        0x2 00
  .bss           0xe01159b0        0x0 mem/heap.o
  .bss           0xe01159b0        0x0 mem/seg.o
+ .bss           0xe01159b0        0x0 linker/elf.o
                 0xe01159b0                ebss = .
                 0xe01159b0                end = .
                 0xe01159b0                _end = .
@@ -279,6 +285,7 @@ LOAD mem/paging.o
 LOAD mem/gdt.o
 LOAD mem/heap.o
 LOAD mem/seg.o
+LOAD linker/elf.o
 OUTPUT(stem.elf elf32-i386)
 
 .comment        0x00000000       0x11
@@ -297,6 +304,7 @@ OUTPUT(stem.elf elf32-i386)
  .comment       0x00000000       0x12 mem/gdt.o
  .comment       0x00000000       0x12 mem/heap.o
  .comment       0x00000000       0x12 mem/seg.o
+ .comment       0x00000000       0x12 linker/elf.o
 
 .note.GNU-stack
                 0x00000000        0x0
@@ -328,3 +336,5 @@ OUTPUT(stem.elf elf32-i386)
                 0x00000000        0x0 mem/heap.o
  .note.GNU-stack
                 0x00000000        0x0 mem/seg.o
+ .note.GNU-stack
+                0x00000000        0x0 linker/elf.o