Question

我有这样的目录结构：指向目录的symlink和指向库的符号链接：

$ libtrotl.so -> /usr/local/lib64/tora-3.1/../libtrotl.so
$ instantclient -> /usr/lib/oracle/12.1/client64/lib

当我dlopen库libtrotl.so时，所有依赖库都被解析并加载。感谢RPATH。

$ readelf -d libtrotl.so

Dynamic section at offset 0x17e7a8 contains 31 entries:
  Tag        Type                         Name/Value
 0x0000000000000001 (NEEDED)             Shared library: [libclntsh.so.12.1]
 0x0000000000000001 (NEEDED)             Shared library: [libboost_system.so.1.60.0]
 0x0000000000000001 (NEEDED)             Shared library: [libstdc++.so.6]
 0x0000000000000001 (NEEDED)             Shared library: [libm.so.6]
 0x0000000000000001 (NEEDED)             Shared library: [libgcc_s.so.1]
 0x0000000000000001 (NEEDED)             Shared library: [libc.so.6]
 0x000000000000000e (SONAME)             Library soname: [libtrotl.so]
 0x000000000000000f (RPATH)              Library rpath: [$ORIGIN/instantclient/]
 0x000000000000000c (INIT)               0xe7898

$ ldd libtrotl.so 
    linux-vdso.so.1 (0x00007ffdc25d1000)
    libclntsh.so.12.1 => /home/ivan/.TOra3/poracle/./instantclient/libclntsh.so.12.1 (0x00007f6cd0c37000)
    libboost_system.so.1.60.0 => /lib64/libboost_system.so.1.60.0 (0x00007f6cd0a24000)
    libstdc++.so.6 => /lib64/libstdc++.so.6 (0x00007f6cd069c000)
    libm.so.6 => /lib64/libm.so.6 (0x00007f6cd0393000)
    libgcc_s.so.1 => /lib64/libgcc_s.so.1 (0x00007f6cd017b000)
    libc.so.6 => /lib64/libc.so.6 (0x00007f6ccfdb9000)
    libmql1.so => /home/ivan/.TOra3/poracle/./instantclient/libmql1.so (0x00007f6ccfb43000)
    libipc1.so => /home/ivan/.TOra3/poracle/./instantclient/libipc1.so (0x00007f6ccf7c4000)
    libnnz12.so => /home/ivan/.TOra3/poracle/./instantclient/libnnz12.so (0x00007f6ccf0ba000)

我只使用-Wl,-rpath,"\$ORIGIN/instantclient/"作为编译标志，它可以在任何地方使用 - 除了Gentoo。

Gentoo链接器（GNU gold（Gentoo 2.25.1 p1.1 2.25.1）1.11）添加了RPATH的RUNPATH insead。

 0x000000000000001d (RUNPATH)            Library runpath: [$ORIGIN/instantclient/]

然后动态链接器不解析库。

(Gentoo)$ ldd libtrotl.so 
    linux-vdso.so.1 (0x00007ffe5c3e9000)
    libclntsh.so.12.1 => /home/ivan/.TOra3/poracle/./instantclient/libclntsh.so.12.1 (0x00007f245dc9e000)
    libstdc++.so.6 => /usr/lib/gcc/x86_64-pc-linux-gnu/4.9.4/libstdc++.so.6 (0x00007f245d933000)
    libm.so.6 => /lib64/libm.so.6 (0x00007f245d62e000)
    libgcc_s.so.1 => /usr/lib/gcc/x86_64-pc-linux-gnu/4.9.4/libgcc_s.so.1 (0x00007f245d417000)
    libc.so.6 => /lib64/libc.so.6 (0x00007f245d07d000)
    libmql1.so => not found
    libipc1.so => not found
    libnnz12.so => not found
    libons.so => not found

正如您所看到的，在第二种情况下，libmql1.so虽然存在于instantclient子目录中，但未找到它。如何在Gentoo上设置RPATH？

Answer 1

不推荐使用

DT_RPATH标记，DT_RUNPATH是具有两种不同语义的现代实现。 Gentoo链接编辑器（ld和gold）默认情况下不会生成已弃用的标记。您可以（但可能不应该）通过传递-Wl,--disable-new-dtags来禁用这些功能，但我建议不要这样做。

Qt中有一个较旧的底池解释了使用插件时这两者的区别：http://blog.qt.io/blog/2011/10/28/rpath-and-runpath/

当-Wl使用-rpath时，Gentoo ld在库中生成RUNPATH

1 个答案: