c - 构建的库目录未添加到 libtool 包装器脚本中的 LD_LIBRARY_PATH

Question

构建后我无法轻易测试我的程序:

$ ./src/rap/rap -h
/home/il/workspace/rap/src/rap/.libs/lt-rap: error while loading shared libraries: libpmclient.so: cannot open shared object file: No such file or directory

libpmclient.so 位于 ./src/nsreclient/x86_64-unknown-linux-gnu/ 中，正确的 -L 标志是链接时使用

Automake 使用 libtool 构建我的二进制文件。它创建一个包装器脚本 src/rap/rap。

我的预期是:在生成脚本时，libtool 会忽略 LD_LIBRARY_PATH 的当前值。运行脚本时，它会将构建树中所需的目录附加到 LD_LIBRARY_PATH 的现有值。例如，执行:

LD_LIBRARY_PATH=/foo ./src/rap/rap

结果:

LD_LIBRARY_PATH=/foo:/home/il/workspace/rap/src/nsreclient/x86_64-unknown-linux-gnu ./src/rap/.libs/lt-rap

但 libtool 的作用恰恰相反:它将 LD_LIBRARY_PATH 的当前值硬编码到生成的脚本中:

LD_LIBRARY_PATH=/opt/oracle/product/11.2.0/client_64/lib:/lib:/usr/lib:/usr/local/lib; export LD_LIBRARY_PATH;

没有意义。为什么它不在那里添加构建树目录？

这里是 make 命令的格式化输出:

/bin/sh ../../libtool  --tag=CC   --mode=link gcc  -Werror-implicit-function-declaration -O2 \
    -pthread   -o rap rap.o \
    librap.a \
    ../liclib/liblic.a \
    ../fget-1.3.3/lib/libfget.a \
    ../lib_mt/libppb.la \
    ../sgplib/libsgp.la \
    ../../variations/asn1lib/ebuf_lib_mt/libasn1cebuf.la \
    -L../../src/nsreclient/x86_64-unknown-linux-gnu -lpmclient \
    -L/opt/oracle/product/11.2.0/client_64/lib -lclntsh \
    -L/usr/lib -lexpat \
    -lssl \
    -lcrypto  \
    -lm


libtool: link: gcc -Werror-implicit-function-declaration -O2 -pthread -o .libs/rap rap.o  librap.a ../liclib/liblic.a ../fget-1.3.3/lib/libfget.a \
    ../lib_mt/.libs/libppb.so \
    ../sgplib/.libs/libsgp.so \
    ../../variations/asn1lib/ebuf_lib_mt/.libs/libasn1cebuf.so \
    -L../../src/nsreclient/x86_64-unknown-linux-gnu -lpmclient \
    -L/opt/oracle/product/11.2.0/client_64/lib -lclntsh \
    -L/usr/lib /usr/lib/libexpat.so \
    -lssl -lcrypto -lm -pthread -Wl,-rpath -Wl,/usr/local/lib

Answer 1

包装器脚本根本不设置 LD_LIBRARY_PATH。它假定包含所需库的子目录已添加到实际二进制文件的 RPATH。

当-lfoo 标志传递给libtool 时，它首先尝试打开相应的文件libfoo.la。如果该文件不存在，libtool 会退回到将标志传递给 gcc 而不改变。

如果 .la 文件存在并指向共享库，libtool 告诉链接器将包含该库的目录添加到 RPATH输出二进制文件。

许多软件包将它们的 .la 文件安装到 /usr/lib/。这意味着较新的 ​​libtool 将能够解析由以前版本创建的文件。为预编译的.so 文件手动编写.la 文件而不是每次都生成它们一定是完全安全的。

我创建了文件 ./src/nsreclient/x86_64-unknown-linux-gnu/libpmclient.la :

# libpmclient.la - a libtool library file
# Generated by ltmain.sh - GNU libtool 1.5.22 (1.1220.2.365 2005/12/18 22:14:06)
#
# Please DO NOT delete this file!
# It is necessary for linking the library.

# The name that we can dlopen(3).
dlname='libpmclient.so'

# Names of this library.
library_names='libpmclient.so'

# The name of the static archive.
old_library='libpmclient.a'

# Linker flags that cannot go in dependency_libs.
inherited_linker_flags=' -pthread'

# Libraries that this one depends upon.
dependency_libs=''

# Names of additional weak libraries provided by this library
weak_library_names=''

# Version information for libpmclient.
current=0
age=0
revision=0

# Is this an already installed library?
installed=no

# Should we warn about portability when linking against -modules?
shouldnotlink=no

# Files to dlopen/dlpreopen
dlopen=''
dlpreopen=''

# Directory that this library needs to be installed in:
libdir='/usr/local/lib'

重建后，我的包装器脚本不再报错。