" so“如何加载具有固定地址的so？

Question

在我的程序中，两个"so“- libcpss.so和libhelper.so必须加载到一个固定的虚拟地址，这是由ld脚本完成的，

SECTIONS
{
/* Code section, access rights RX */
. = 0x14600000;
…
}

readelf -l libhelper.so | less

Elf文件类型是DYN (共享目标文件)入口点0x14607ad8有8个程序头，从偏移量64开始

Program Headers:
  Type           Offset             VirtAddr           PhysAddr
                 FileSiz            MemSiz              Flags  Align
  LOAD           0x0000000000010000 0x0000000014600000 0x0000000014600000
                 0x000000000001aaec 0x000000000001aaec  R E    0x10000

一个elf程序链接了这两个".so"，我们可以看到这两个确实被加载到了预期的固定地址中，

LDD./appDemo

linux-vdso.so.1 => (0x0000ffff917ec000)
libcpss.so => ./libcpss.so (0x0000000010000000)
libhelper.so => ./libhelper.so (0x0000000014600000)
libpthread.so.0 => /lib/aarch64-linux-gnu/libpthread.so.0 (0x0000ffff917b5000)
librt.so.1 => /lib/aarch64-linux-gnu/librt.so.1 (0x0000ffff9179d000)
libdl.so.2 => /lib/aarch64-linux-gnu/libdl.so.2 (0x0000ffff91789000)
libm.so.6 => /lib/aarch64-linux-gnu/libm.so.6 (0x0000ffff916d7000)
libc.so.6 => /lib/aarch64-linux-gnu/libc.so.6 (0x0000ffff91583000)
/lib/ld-linux-aarch64.so.1 (0x0000aaaadd94f000)

然而，我构建了另一个" so“，使得链接(依赖于)这两个so，似乎无法将这两个so加载到适当的固定地址，如下所示-

Ldd./libtestScript.so

linux-vdso.so.1 => (0x0000ffff8d87c000)
libcpss.so => ./libcpss.so (0x0000ffff89d50000)
libhelper.so => ./libhelper.so (0x0000ffff5e350000)
libpthread.so.0 => /lib/aarch64-linux-gnu/libpthread.so.0 (0x0000ffff5e31c000)
librt.so.1 => /lib/aarch64-linux-gnu/librt.so.1 (0x0000ffff5e304000)
libdl.so.2 => /lib/aarch64-linux-gnu/libdl.so.2 (0x0000ffff5e2f0000)
libm.so.6 => /lib/aarch64-linux-gnu/libm.so.6 (0x0000ffff5e23e000)
libc.so.6 => /lib/aarch64-linux-gnu/libc.so.6 (0x0000ffff5e0ea000)
/lib/ld-linux-aarch64.so.1 (0x0000aaaae0958000)

在构建“联合.so”的过程中，我是否遗漏了一些LD标志?我看到elf主程序和“联合”的唯一区别是“-shared”的标志，那么为什么“联合.so”遗漏了两个独立的so的加载地址的信息？当ld.so加载“联合.so”并试图解析并加载两个依赖项".so“时，它没有将它们加载到固定地址(0x10000000/ 0x14600000)

NOK: LD_DEBUG=all LDD./libtestScript.so

  2349:     file=libhelper.so [0];  generating link map
  2349:       dynamic: 0x0000ffff5d581ba0  base: 0x0000ffff48f57000   size: 0x000000002b9ff004
  2349:         entry: 0x0000ffff5d55ead8  phdr: 0x0000ffff8ca6fcc0  phnum:                  8

OK: LD_DEBUG=all ldd./appDemo

  2289:       trying file=./libhelper.so
  2289:
  2289:     file=libhelper.so [0];  generating link map
  2289:       dynamic: 0x000000001462aba0  base: 0x0000000000000000   size: 0x000000002b9ff004
  2289:         entry: 0x0000000014607ad8  phdr: 0x0000ffffb2e24cc0  phnum:                  8

readelf -h ./libhelper.so

ELF Header:
  Magic:   7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00 
  Class:                             ELF64
  Data:                              2's complement, little endian
  Version:                           1 (current)
  OS/ABI:                            UNIX - System V
  ABI Version:                       0
  Type:                              DYN (Shared object file)
  Machine:                           AArch64
  Version:                           0x1
  Entry point address:               0x14607ad8
  Start of program headers:          64 (bytes into file)
  Start of section headers:          228680 (bytes into file)
  Flags:                             0x0
  Size of this header:               64 (bytes)
  Size of program headers:           56 (bytes)
  Number of program headers:         8
  Size of section headers:           64 (bytes)
  Number of section headers:         34
  Section header string table index: 31

如果你能帮我的话我会很感激的。向陈星豪致以良好的问候

Answer 1

添加-Wl标志后，生成libtestScript.so时-Ttext-segment=0xXXXXXXXX(如0x70000000)，结果如预期：

ldd libtestScript.so
        linux-vdso.so.1 (0x0000007fa6f04000)
        libcpss.so => ./libcpss.so (0x0000000010000000)
        libhelper.so => ./libhelper.so (0x0000000014600000)
        libpthread.so.0 => /lib/aarch64-linux-gnu/libpthread.so.0 (0x0000007fa6ece000)
        librt.so.1 => /lib/aarch64-linux-gnu/librt.so.1 (0x0000007fa6eb7000)
        libdl.so.2 => /lib/aarch64-linux-gnu/libdl.so.2 (0x0000007fa6ea2000)
        libm.so.6 => /lib/aarch64-linux-gnu/libm.so.6 (0x0000007fa6de6000)
        libc.so.6 => /lib/aarch64-linux-gnu/libc.so.6 (0x0000007fa6c8d000)
        /lib/ld-linux-aarch64.so.1 (0x0000005565c4c000)