ELF virtual header and file offset

Question

I know the relationship between them:

virtual address mod page alignment == file alignment mod page alignment

But can anyone tell me in which direction these two numbers are calculated?

Is the virtual address computed from the file offset according to the relation above, or vice versa?

Update

Here are some more details: when the linker writes the header of the ELF file, it sets the virtual address and offset of the program header file. (segments)

For example, the output readelf -l someELFfile:

Elf file type is EXEC (Executable file)
Entry point 0x8048094
Program Headers:
  Type           Offset   VirtAddr   PhysAddr   FileSiz MemSiz  Flg Align
  LOAD           0x000000 0x08048000 0x08048000 0x00154 0x00154 R E 0x1000
  LOAD           0x000154 0x08049154 0x08049154 0x00004 0x00004 RW  0x1000
  GNU_STACK      0x000000 0x00000000 0x00000000 0x00000 0x00000 RW  0x10

We see 2 segments of LOAD.

The virtual address of the first LOAD ends with 0x8048154, and the second LOAD starts with 0x8049154.

ELF LOAD LOAD 0x00154, , ELF , 0x1000 LOAD.

? , LOAD 0x80489000? 0x1000 LOAD?

, LOAD :

mod == mod

, .

Answer 1

0x1000 LOAD?

, 0x08048154, : LOAD , ( PROT_READ|PROT_EXEC, PROT_READ|PROTO_WRITE. ( ) , . .

==
, .

LOAD mmap ed . LOAD, , ( strace , ):

mmap(0x08049000, 0x158, PROT_READ|PROT_WRITE, MAP_PRIVATE, $fd, 0)

, , mmap EINVAL. , VirtAddr Offset modulo Align, , .

, LOAD ( ). - [0x08049000,0x08049154). , , "" LOAD ( , LOAD ).

. mmap man page.