Put upx stub loader at high end of ELF output file on linux,

and allow for block-by-block specification of filter and parameters.
	linker.cpp linker.h mem.cpp mem.h p_elf.h
	p_lx_elf.cpp p_lx_elf.h
	p_lx_exc.cpp p_lx_exc.h
	p_lx_sh.cpp  p_lx_sh.h
	p_unix.cpp p_unix.h
	packer.cpp packer.h
	stub/fold_elf86.asm stub/fold_exec86.asm stub/fold_sh86.asm
	stub/l_lx_elf.c  stub/l_lx_elf86.asm  stub/l_lx_elf86.lds
	stub/l_lx_exec.c stub/l_lx_exec86.asm stub/l_lx_exec86.lds
	stub/l_lx_sh.c   stub/l_lx_sh86.asm   stub/l_lx_sh86.lds
	stub/linux.hh

committer: jreiser <jreiser> 981084316 +0000

src/stub/l_lx_elf86.asm

@@ -116,7 +116,6 @@ decompress:
 
 ;__LEXEC020__
 
-%define PAGE_MASK (~0<<12)
 %define PAGE_SIZE ( 1<<12)
 
 %define MAP_FIXED     0x10
@@ -126,7 +125,6 @@ decompress:
 %define PROT_WRITE     2
 %define PROT_EXEC      4
 %define __NR_mmap     90
-%define __NR_munmap   91
 
 ; Decompress the rest of this loader, and jump to it
 unfold:
@@ -135,10 +133,7 @@ unfold:
         lodsd
         push eax  ; sz_uncompressed  (junk, actually)
         push esp  ; &sz_uncompressed
-        mov eax, ebp  ; &decompress
-        and eax, dword PAGE_MASK  ; &my_elfhdr
-        mov edx, eax  ; need my_elfhdr later
-        mov ah,0  ; round down to 64KB boundary
+        mov eax, 0x400000
         push eax  ; &destination
 
                 ; mmap a page to hold the decompressed program
@@ -148,16 +143,19 @@ unfold:
         mov ch, PAGE_SIZE >> 8
         push byte MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS
         push byte PROT_READ | PROT_WRITE | PROT_EXEC
-        push ecx
+        push ecx  ; length
         push eax  ; destination
+        mov ebx, esp  ; address of parameter vector for __NR_mmap
         push byte __NR_mmap
         pop eax
-        mov ebx, esp
         int 0x80
+        xchg eax, ebx
+        mov bh, PAGE_SIZE>>8  ; ebx= 0x401000
         add esp, byte 6*4  ; discard args to mmap
 
         lodsd
         push eax  ; sz_compressed
+        lodsd  ; junk cto8, algo, unused[2]
         push esi  ; &compressed_data
         call ebp  ; decompress(&src, srclen, &dst, &dstlen)
         pop eax  ; discard &compressed_data