0

我正在尝试在 x86_64 Debian 上使用musl 工具链v1.2.1 编译一个简单的 C 程序。

程序secgetenv.c如下：

#define _GNU_SOURCE
#include <stdlib.h> 
#include <stdio.h>

int main()
{
    char *res;

    res = secure_getenv("TEST_ENV_VAR");

    fprintf(stdout, "%s\n", res);

    return 0;
}

编译执行没有错误。但是运行ldd显示secure_getenv找不到该符号：

$ musl-ldd secgetenv-musl 
    /lib/ld-musl-x86_64.so.1 (0x7f7872779000)
    libc.so => /lib/ld-musl-x86_64.so.1 (0x7f7872779000)
Error relocating secgetenv-musl: secure_getenv: symbol not found

muslsecure_getenv在较早的补丁中添加了对的支持，我确实在以下位置看到了声明/usr/local/x86_64-linux-musl/include/stdlib.h：

#ifdef _GNU_SOURCE
...
char *secure_getenv(const char *);
...
#endif

有相应的定义src/env/secure_getenv.c：

#define _GNU_SOURCE
#include <stdlib.h>
#include "libc.h"

char *secure_getenv(const char *name)
{
    return libc.secure ? NULL : getenv(name);
}

此外，musllibc.so定义了符号：

$ readelf -s /usr/local/x86_64-linux-musl/lib/libc.so | grep secure
  1461: 0000000000020e0d    17 FUNC    GLOBAL DEFAULT    8 secure_getenv
   358: 0000000000000000     0 FILE    LOCAL  DEFAULT  ABS secure_getenv.c
  2275: 0000000000020e0d    17 FUNC    GLOBAL DEFAULT    8 secure_getenv

我尝试设置LD_LIBRARY_PATH指向/usr/local/x86_64-linux-musl/lib（musl的libc所在的位置）。但这似乎没有解决任何问题。我尝试了其他一些编译器选项，但似乎没有任何解决方法。难道我做错了什么？我该如何解决这个问题？

我认为如果我添加我的编译方式可能会很有用，所以这里是详细的输出：

$ /usr/local/bin/x86_64-linux-musl-gcc -v -o secgetenv-musl secgetenv.c -fPIC -ggdb
Using built-in specs.
COLLECT_GCC=/usr/local/bin/x86_64-linux-musl-gcc
COLLECT_LTO_WRAPPER=/usr/local/bin/../libexec/gcc/x86_64-linux-musl/9.2.0/lto-wrapper
Target: x86_64-linux-musl
Configured with: ../src_gcc/configure --enable-languages=c,c++ --enable-languages=c,c++ --enable-default-pie --disable-bootstrap --disable-assembly --disable-werror --target=x86_64-linux-musl --prefix= --libdir=/lib --disable-multilib --with-sysroot=/x86_64-linux-musl --enable-tls --disable-libmudflap --disable-libsanitizer --disable-gnu-indirect-function --disable-libmpx --enable-libstdcxx-time=rt --with-build-sysroot=/home/<user>/musl-cross-make/build/local/x86_64-linux-musl/obj_sysroot AR_FOR_TARGET=/home/<user>/musl-cross-make/build/local/x86_64-linux-musl/obj_binutils/binutils/ar AS_FOR_TARGET=/home/<user>/musl-cross-make/build/local/x86_64-linux-musl/obj_binutils/gas/as-new LD_FOR_TARGET=/home/<user>/musl-cross-make/build/local/x86_64-linux-musl/obj_binutils/ld/ld-new NM_FOR_TARGET=/home/<user>/musl-cross-make/build/local/x86_64-linux-musl/obj_binutils/binutils/nm-new OBJCOPY_FOR_TARGET=/home/<user>/musl-cross-make/build/local/x86_64-linux-musl/obj_binutils/binutils/objcopy OBJDUMP_FOR_TARGET=/home/<user>/musl-cross-make/build/local/x86_64-linux-musl/obj_binutils/binutils/objdump RANLIB_FOR_TARGET=/home/<user>/musl-cross-make/build/local/x86_64-linux-musl/obj_binutils/binutils/ranlib READELF_FOR_TARGET=/home/<user>/musl-cross-make/build/local/x86_64-linux-musl/obj_binutils/binutils/readelf STRIP_FOR_TARGET=/home/<user>/musl-cross-make/build/local/x86_64-linux-musl/obj_binutils/binutils/strip-new --build=x86_64-pc-linux-gnu --host=x86_64-pc-linux-gnu
Thread model: posix
gcc version 9.2.0 (GCC) 
COLLECT_GCC_OPTIONS='-v' '-o' 'secgetenv-musl' '-fPIC' '-ggdb' '-mtune=generic' '-march=x86-64'
 /usr/local/bin/../libexec/gcc/x86_64-linux-musl/9.2.0/cc1 -quiet -v -iprefix /usr/local/bin/../lib/gcc/x86_64-linux-musl/9.2.0/ -isysroot /usr/local/bin/../x86_64-linux-musl secgetenv.c -quiet -dumpbase secgetenv.c -mtune=generic -march=x86-64 -auxbase secgetenv -ggdb -version -fPIC -o /tmp/cczjeoUa.s
GNU C17 (GCC) version 9.2.0 (x86_64-linux-musl)
    compiled by GNU C version 8.3.0, GMP version 6.1.2, MPFR version 4.0.2, MPC version 1.1.0, isl version none
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
ignoring nonexistent directory "/usr/local/bin/../x86_64-linux-musl/usr/local/include"
ignoring duplicate directory "/usr/local/bin/../lib/gcc/../../lib/gcc/x86_64-linux-musl/9.2.0/../../../../x86_64-linux-musl/include"
ignoring nonexistent directory "/usr/local/bin/../x86_64-linux-musl/usr/include"
ignoring duplicate directory "/usr/local/bin/../lib/gcc/../../lib/gcc/x86_64-linux-musl/9.2.0/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/local/bin/../lib/gcc/x86_64-linux-musl/9.2.0/../../../../x86_64-linux-musl/include
 /usr/local/bin/../lib/gcc/x86_64-linux-musl/9.2.0/include
End of search list.
GNU C17 (GCC) version 9.2.0 (x86_64-linux-musl)
    compiled by GNU C version 8.3.0, GMP version 6.1.2, MPFR version 4.0.2, MPC version 1.1.0, isl version none
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 02d33dfe51251a8723bc0ce5bbca8406
COLLECT_GCC_OPTIONS='-v' '-o' 'secgetenv-musl' '-fPIC' '-ggdb' '-mtune=generic' '-march=x86-64'
 /usr/local/bin/../lib/gcc/x86_64-linux-musl/9.2.0/../../../../x86_64-linux-musl/bin/as -v --64 -o /tmp/ccMKBInY.o /tmp/cczjeoUa.s
GNU assembler version 2.33.1 (x86_64-linux-musl) using BFD version (GNU Binutils) 2.33.1
COMPILER_PATH=/usr/local/bin/../libexec/gcc/x86_64-linux-musl/9.2.0/:/usr/local/bin/../libexec/gcc/:/usr/local/bin/../lib/gcc/x86_64-linux-musl/9.2.0/../../../../x86_64-linux-musl/bin/
LIBRARY_PATH=/usr/local/bin/../lib/gcc/x86_64-linux-musl/9.2.0/:/usr/local/bin/../lib/gcc/:/usr/local/bin/../lib/gcc/x86_64-linux-musl/9.2.0/../../../../x86_64-linux-musl/lib/:/usr/local/bin/../x86_64-linux-musl/lib/
COLLECT_GCC_OPTIONS='-v' '-o' 'secgetenv-musl' '-fPIC' '-ggdb' '-mtune=generic' '-march=x86-64'
 /usr/local/bin/../libexec/gcc/x86_64-linux-musl/9.2.0/collect2 -plugin /usr/local/bin/../libexec/gcc/x86_64-linux-musl/9.2.0/liblto_plugin.so -plugin-opt=/usr/local/bin/../libexec/gcc/x86_64-linux-musl/9.2.0/lto-wrapper -plugin-opt=-fresolution=/tmp/ccjHWTRL.res -plugin-opt=-pass-through=-lgcc -plugin-opt=-pass-through=-lgcc_s -plugin-opt=-pass-through=-lc -plugin-opt=-pass-through=-lgcc -plugin-opt=-pass-through=-lgcc_s --sysroot=/usr/local/bin/../x86_64-linux-musl --eh-frame-hdr -m elf_x86_64 -dynamic-linker /lib/ld-musl-x86_64.so.1 -pie -o secgetenv-musl /usr/local/bin/../lib/gcc/x86_64-linux-musl/9.2.0/../../../../x86_64-linux-musl/lib/Scrt1.o /usr/local/bin/../lib/gcc/x86_64-linux-musl/9.2.0/../../../../x86_64-linux-musl/lib/crti.o /usr/local/bin/../lib/gcc/x86_64-linux-musl/9.2.0/crtbeginS.o -L/usr/local/bin/../lib/gcc/x86_64-linux-musl/9.2.0 -L/usr/local/bin/../lib/gcc -L/usr/local/bin/../lib/gcc/x86_64-linux-musl/9.2.0/../../../../x86_64-linux-musl/lib -L/usr/local/bin/../x86_64-linux-musl/lib /tmp/ccMKBInY.o -lgcc --push-state --as-needed -lgcc_s --pop-state -lc -lgcc --push-state --as-needed -lgcc_s --pop-state /usr/local/bin/../lib/gcc/x86_64-linux-musl/9.2.0/crtendS.o /usr/local/bin/../lib/gcc/x86_64-linux-musl/9.2.0/../../../../x86_64-linux-musl/lib/crtn.o
COLLECT_GCC_OPTIONS='-v' '-o' 'secgetenv-musl' '-fPIC' '-ggdb' '-mtune=generic' '-march=x86-64'
4

2 回答 2

0

然而，运行 ldd 显示未找到符号 secure_getenv：

$ musl-ldd secgetenv-musl 
    /lib/ld-musl-x86_64.so.1 (0x7f7872779000)
    libc.so => /lib/ld-musl-x86_64.so.1 (0x7f7872779000)
Error relocating secgetenv-musl: secure_getenv: symbol not found

ldd 似乎揭示的不仅仅是找不到符号。这似乎表明某些东西，也许是musl-ldd它本身，严重损坏了。输出表明libc.so正在解析不是 MUSL 的 libc，甚至不是系统的默认 libc，而是 MUSL 的运行时动态链接器。自然，这并不能提供所需的符号本身。

如果尽管收到了投诉，程序仍按预期运行musl-ldd，那么问题很可能出现在musl-ldd. 如果程序没有按预期运行（可能在您尝试时报告相同的重定位错误），那么问题可能出在您的 MUSL 副本中，特别是在其运行时动态链接器 /lib/ld-musl-x86_64.so 中。 1.

附录：

假设对此答案的评论是正确的，即 MUSL 程序解释器包含 C 库的副本，那么仍然可以得出这里存在严重问题，无论是在库的副本中musl-ldd还是在您的库副本中，特别是在/lib/ld-musl-x86_64.so.1. 例如，后者可能与库不同步。此类问题可能是由于同时存在两个或多个不同 MUSL 安装的组件，或者具有与已安装的 MUSL 版本不同步的 MUSL 编译器工具链的结果。

于 2020-10-15T18:33:24.143 回答
0

/lib/ld-musl-x86_64.so.1symlinked to /lib/x86_64-linux-musl/libc.sowhich 没有定义符号。这个 libc 是在我安装 musl-tools 或类似的东西时引入的。它使用 musl 版本 1.1.21，它没有secure_getenv消除此错误所需的补丁。将 ld 符号链接libc.so到我在安装 musl-cross-make 时得到的更新的 musl 解决了我的问题。

于 2020-11-17T20:39:58.193 回答