The error CANNOT LINK EXECUTABLE "./openconnect": library "libopenconnect.so" not found on x86-64 LineageOS Termux—despite the file libopenconnect.so being present—is a classic dynamic linker issue. Here’s a structured breakdown of the problem and how to resolve it:

Root Cause: Dynamic Linker Search Path

The dynamic linker (ld) cannot find libopenconnect.so because:

• It is not in a standard library search path (e.g., /system/lib64, /vendor/lib64, or Termux’s $PREFIX/lib).
• The library is likely in the current directory or a custom path, but the linker does not search the current directory by default for security reasons.

Why ldd Fails to Find It

• ldd uses the same search paths as the dynamic linker.
• If libopenconnect.so is in the same directory as the openconnect binary, the linker will not look there unless explicitly told to do so.

Solutions

1. Set LD_LIBRARY_PATH

Temporarily tell the linker where to find the library:

export LD_LIBRARY_PATH=$(pwd):$LD_LIBRARY_PATH
./openconnect

• This adds the current directory to the linker’s search path.
• Note: This is temporary and only affects the current shell session.

2. Use -rpath During Compilation

If you compiled openconnect yourself, ensure the library path is embedded in the binary:

gcc -o openconnect openconnect.c -lopenconnect -Wl,-rpath=$(pwd)

• -rpath embeds the library path into the executable, so the linker will look there at runtime.

3. Copy the Library to a Standard Path

Copy libopenconnect.so to a directory in the default linker search path:

cp libopenconnect.so $PREFIX/lib

• In Termux, $PREFIX is usually /data/data/com.termux/files/usr.
• After copying, run ldconfig (if available) to update the linker cache:
  bash

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  ldconfig

4. Use Absolute Path for the Library

If you don’t want to move the library, you can symlink it to a standard path:

ln -s $(pwd)/libopenconnect.so $PREFIX/lib/libopenconnect.so

5. Check Library Permissions

Ensure the library is readable:

chmod +r libopenconnect.so

6. Verify Architecture Compatibility

• Your libopenconnect.so is x86-64 (as per file output).
• Ensure your Termux environment and the openconnect binary are also x86-64.
• If your device is ARM64, you cannot use x86-64 libraries. You need an ARM64 build of libopenconnect.so.

7. Check for Missing Dependencies

Even if libopenconnect.so is found, it may depend on other libraries. Use:

ldd libopenconnect.so

• If other libraries are missing, you’ll need to install them (e.g., via pkg install in Termux).

Termux-Specific Notes

• Termux uses a custom prefix ($PREFIX). Libraries should ideally be placed in $PREFIX/lib.
• If you installed openconnect via pkg install openconnect, the package should have placed the library in the correct location. If not, reinstall it:
  bash

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  pkg reinstall openconnect

Debugging Steps

1. Check where the linker looks for libraries:

   bash

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   getconf -a | grep LD_LIBRARY_PATH

   or

   bash

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   env | grep LD_LIBRARY_PATH

2. List all library paths:

   bash

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   cat /etc/ld.so.conf
   ldconfig -p

3. Run with verbose linker output:

   bash

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   LD_DEBUG=libs ./openconnect

   • This will show exactly where the linker is searching for libopenconnect.so.

Summary Table

Next Step: Try export LD_LIBRARY_PATH=$(pwd):$LD_LIBRARY_PATH and rerun ./openconnect. If that works, you can make it permanent by adding it to your ~/.bashrc. If not, let me know the output of LD_DEBUG=libs ./openconnect for further debugging.