ldd是否也显示依赖关系的依赖关系？

Question

我有一个二进制文件，其中ldd显示了意外的依赖项和libicuuc（来自“ icu”）。

#ldd A
[...]
libxml2.so.2 => /usr/lib64/libxml2.so.2 (0x00007faaf9722000)
libicuuc.so.49 => /usr/lib64/libicuuc.so.49 (0x00007faaf5689000)

由于在该系统上libxml动态依赖于libicuuc，因此ldd最终会找到它是有意义的，但是是否期望libicuuc也出现在A的ldd输出中？是否有一些命令仅检索链接为依赖项依赖关系的库？

Answer 1

ldd 显示启动应用程序或加载共享库时需要加载的所有库。

readelf -d 仅显示二进制文件的直接依赖项。

$ readelf -d /opt/google/chrome/chrome | grep NEEDED
 0x0000000000000001 (NEEDED)             Shared library: [libX11.so.6]
 0x0000000000000001 (NEEDED)             Shared library: [libXrandr.so.2]
 0x0000000000000001 (NEEDED)             Shared library: [libXrender.so.1]
 0x0000000000000001 (NEEDED)             Shared library: [libXss.so.1]
 0x0000000000000001 (NEEDED)             Shared library: [libXext.so.6]
 0x0000000000000001 (NEEDED)             Shared library: [librt.so.1]
 0x0000000000000001 (NEEDED)             Shared library: [libdl.so.2]
 0x0000000000000001 (NEEDED)             Shared library: [libgobject-2.0.so.0]
 0x0000000000000001 (NEEDED)             Shared library: [libgthread-2.0.so.0]
 0x0000000000000001 (NEEDED)             Shared library: [libglib-2.0.so.0]
 0x0000000000000001 (NEEDED)             Shared library: [libgtk-x11-2.0.so.0]
 0x0000000000000001 (NEEDED)             Shared library: [libgdk-x11-2.0.so.0]
 0x0000000000000001 (NEEDED)             Shared library: [libatk-1.0.so.0]
 0x0000000000000001 (NEEDED)             Shared library: [libgdk_pixbuf-2.0.so.0]
 0x0000000000000001 (NEEDED)             Shared library: [libpangocairo-1.0.so.0]
 0x0000000000000001 (NEEDED)             Shared library: [libcairo.so.2]
 0x0000000000000001 (NEEDED)             Shared library: [libpango-1.0.so.0]
 0x0000000000000001 (NEEDED)             Shared library: [libfreetype.so.6]
 0x0000000000000001 (NEEDED)             Shared library: [libfontconfig.so.1]
 0x0000000000000001 (NEEDED)             Shared library: [libnss3.so]
 0x0000000000000001 (NEEDED)             Shared library: [libnssutil3.so]
 0x0000000000000001 (NEEDED)             Shared library: [libsmime3.so]
 0x0000000000000001 (NEEDED)             Shared library: [libplc4.so]
 0x0000000000000001 (NEEDED)             Shared library: [libnspr4.so]
 0x0000000000000001 (NEEDED)             Shared library: [libpthread.so.0]
 0x0000000000000001 (NEEDED)             Shared library: [libgconf-2.so.4]
 0x0000000000000001 (NEEDED)             Shared library: [libdbus-1.so.3]
 0x0000000000000001 (NEEDED)             Shared library: [libXcomposite.so.1]
 0x0000000000000001 (NEEDED)             Shared library: [libasound.so.2]
 0x0000000000000001 (NEEDED)             Shared library: [libXfixes.so.3]
 0x0000000000000001 (NEEDED)             Shared library: [libcups.so.2]
 0x0000000000000001 (NEEDED)             Shared library: [libgcrypt.so.11]
 0x0000000000000001 (NEEDED)             Shared library: [libbz2.so.1.0]
 0x0000000000000001 (NEEDED)             Shared library: [libexpat.so.1]
 0x0000000000000001 (NEEDED)             Shared library: [libudev.so.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]
 0x0000000000000001 (NEEDED)             Shared library: [ld-linux-x86-64.so.2]

$ ldd /opt/google/chrome/chrome
    linux-vdso.so.1 =>  (0x00007fff9d3ff000)
    libX11.so.6 => /lib64/libX11.so.6 (0x00007f93186dc000)
    libXrandr.so.2 => /lib64/libXrandr.so.2 (0x00007f93184d3000)
    libXrender.so.1 => /lib64/libXrender.so.1 (0x00007f93182c9000)
    libXss.so.1 => /lib64/libXss.so.1 (0x00007f93180c5000)
    libXext.so.6 => /lib64/libXext.so.6 (0x00007f9317eb2000)
    librt.so.1 => /lib64/librt.so.1 (0x00007f9317caa000)
    libdl.so.2 => /lib64/libdl.so.2 (0x00007f9317aa6000)
    libgobject-2.0.so.0 => /lib64/libgobject-2.0.so.0 (0x00007f9317858000)
    libgthread-2.0.so.0 => /lib64/libgthread-2.0.so.0 (0x00007f9317656000)
    libglib-2.0.so.0 => /lib64/libglib-2.0.so.0 (0x00007f9317336000)
    libgtk-x11-2.0.so.0 => /lib64/libgtk-x11-2.0.so.0 (0x00007f9316cbf000)
    libgdk-x11-2.0.so.0 => /lib64/libgdk-x11-2.0.so.0 (0x00007f9316a00000)
    libatk-1.0.so.0 => /lib64/libatk-1.0.so.0 (0x00007f93167de000)
    libgdk_pixbuf-2.0.so.0 => /lib64/libgdk_pixbuf-2.0.so.0 (0x00007f93165bb000)
    libpangocairo-1.0.so.0 => /lib64/libpangocairo-1.0.so.0 (0x00007f93163ae000)
    libcairo.so.2 => /lib64/libcairo.so.2 (0x00007f9316103000)
    libpango-1.0.so.0 => /lib64/libpango-1.0.so.0 (0x00007f9315eb7000)
    libfreetype.so.6 => /usr/lib64/freetype-freeworld/libfreetype.so.6 (0x00007f9315c15000)
    libfontconfig.so.1 => /lib64/libfontconfig.so.1 (0x00007f93159e0000)
    libnss3.so => /lib64/libnss3.so (0x00007f93156a4000)
    libnssutil3.so => /lib64/libnssutil3.so (0x00007f9315479000)
    libsmime3.so => /lib64/libsmime3.so (0x00007f931524c000)
    libplc4.so => /lib64/libplc4.so (0x00007f9315046000)
    libnspr4.so => /lib64/libnspr4.so (0x00007f9314e09000)
    libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f9314bed000)
    libgconf-2.so.4 => /lib64/libgconf-2.so.4 (0x00007f93149bc000)
    libdbus-1.so.3 => /lib64/libdbus-1.so.3 (0x00007f9314778000)
    libXcomposite.so.1 => /lib64/libXcomposite.so.1 (0x00007f9314575000)
    libasound.so.2 => /lib64/libasound.so.2 (0x00007f9314294000)
    libXfixes.so.3 => /lib64/libXfixes.so.3 (0x00007f931408e000)
    libcups.so.2 => /lib64/libcups.so.2 (0x00007f9313e33000)
    libgcrypt.so.11 => /lib64/libgcrypt.so.11 (0x00007f9313bba000)
    libbz2.so.1.0 => not found
    libexpat.so.1 => /lib64/libexpat.so.1 (0x00007f9313991000)
    libudev.so.0 => /lib64/libudev.so.0 (0x00007f9313782000)
    libstdc++.so.6 => /lib64/libstdc++.so.6 (0x00007f931347f000)
    libm.so.6 => /lib64/libm.so.6 (0x00007f9313184000)
    libgcc_s.so.1 => /lib64/libgcc_s.so.1 (0x00007f9312f6e000)
    libc.so.6 => /lib64/libc.so.6 (0x00007f9312bb7000)
    /lib64/ld-linux-x86-64.so.2 (0x0000003c7a000000)
    libxcb.so.1 => /lib64/libxcb.so.1 (0x00007f9312999000)
    libffi.so.5 => /lib64/libffi.so.5 (0x00007f9312790000)
    libgmodule-2.0.so.0 => /lib64/libgmodule-2.0.so.0 (0x00007f931258c000)
    libgio-2.0.so.0 => /lib64/libgio-2.0.so.0 (0x00007f931223f000)
    libpangoft2-1.0.so.0 => /lib64/libpangoft2-1.0.so.0 (0x00007f9312012000)
    libXinerama.so.1 => /lib64/libXinerama.so.1 (0x00007f9311e0f000)
    libXi.so.6 => /lib64/libXi.so.6 (0x00007f9311c00000)
    libXcursor.so.1 => /lib64/libXcursor.so.1 (0x00007f93119f4000)
    libXdamage.so.1 => /lib64/libXdamage.so.1 (0x00007f93117f1000)
    libpng15.so.15 => /lib64/libpng15.so.15 (0x00007f93115c7000)
    libpixman-1.so.0 => /lib64/libpixman-1.so.0 (0x00007f9311340000)
    libz.so.1 => /lib64/libz.so.1 (0x00007f9311129000)
    libplds4.so => /lib64/libplds4.so (0x00007f9310f24000)
    libdbus-glib-1.so.2 => /lib64/libdbus-glib-1.so.2 (0x00007f9310cfd000)
    libgssapi_krb5.so.2 => /lib64/libgssapi_krb5.so.2 (0x00007f9310ab8000)
    libkrb5.so.3 => /lib64/libkrb5.so.3 (0x00007f93107d3000)
    libk5crypto.so.3 => /lib64/libk5crypto.so.3 (0x00007f93105a8000)
    libcom_err.so.2 => /lib64/libcom_err.so.2 (0x00007f93103a3000)
    libgnutls.so.26 => /lib64/libgnutls.so.26 (0x00007f93100eb000)
    libgpg-error.so.0 => /lib64/libgpg-error.so.0 (0x00007f930fee7000)
    libavahi-common.so.3 => /lib64/libavahi-common.so.3 (0x00007f930fcd9000)
    libavahi-client.so.3 => /lib64/libavahi-client.so.3 (0x00007f930fac8000)
    libcrypt.so.1 => /lib64/libcrypt.so.1 (0x00007f930f891000)
    libXau.so.6 => /lib64/libXau.so.6 (0x00007f930f68c000)
    libselinux.so.1 => /lib64/libselinux.so.1 (0x00007f930f46b000)
    libresolv.so.2 => /lib64/libresolv.so.2 (0x00007f930f251000)
    libkrb5support.so.0 => /lib64/libkrb5support.so.0 (0x00007f930f046000)
    libkeyutils.so.1 => /lib64/libkeyutils.so.1 (0x00007f930ee42000)
    libtasn1.so.3 => /lib64/libtasn1.so.3 (0x00007f930ec31000)
    libp11-kit.so.0 => /lib64/libp11-kit.so.0 (0x00007f930ea1e000)
    libfreebl3.so => /lib64/libfreebl3.so (0x00007f930e7b3000)

是否有一些命令仅检索链接为依赖项依赖关系的库？

您可以设置ldd和readelf -d输出的差。