10.12.2. Contents of The Multiarch Wrapper
Installed programs:
multiarch_wrapper
The Multiarch Wrapper is used to wrap certain binaries that have hardcoded paths to libraries or are architecture specific.
Create the source file:
cat > multiarch_wrapper.c << "EOF" #include <unistd.h> #include <stdlib.h> #include <errno.h> #include <string.h> #ifndef USE_ARCH #define USE_ARCH "64" #endif int main(int argc, char **argv) { char *filename; char *use_arch; if(!(use_arch = getenv("USE_ARCH"))) use_arch = USE_ARCH; filename = (char *) malloc(strlen(argv[0]) + strlen(use_arch) + 2); strcpy(filename, argv[0]); strcat(filename, "-"); strcat(filename, use_arch); execvp(filename, argv); perror(argv[0]); free(filename); } EOF
Compile and Install the Multiarch Wrapper:
gcc ${BUILD64} multiarch_wrapper.c -o /usr/bin/multiarch_wrapper
This multiarch wrapper is going to be used later on in the book with Perl. It will also be very useful outside of the base CLFS system.
Create a testcase:
echo 'echo "32bit Version"' > test-32 echo 'echo "64bit Version"' > test-64 chmod 755 test-32 test-64 ln -sv /usr/bin/multiarch_wrapper test
Test the wrapper:
USE_ARCH=32 ./test USE_ARCH=64 ./test
The output of the above command should be:
32bit Version 64bit Version