CODEWITHSUNDEEP
openssllinker
Bart Friederichs
Bart Friederichs

Reputation: 33511

How to compile an application against the static OpenSSL library?

I have an application that I want to link statically to the OpenSSL library (because the OS-provided version is too old).

I have built the OpenSSL library for this device (it is an old ARM embedded device), and linking against the .so files works fine:

~$ /usr/local/arm-linux/bin/arm-linux-gcc «my own objects» -ldl  -lresolv -lsms -lssl -Wall -o «binary»

Now, I want to build against the .a files, but I don't seem to get the right command. The best I get it this:

~$ /usr/local/arm-linux/bin/arm-linux-gcc «my own objects» -ldl  -lresolv -lsms -Wall /usr/local/arm-linux/lib/libssl.a /usr/local/arm-linux/lib/libcrypto.a -o «binary»

But, this gives the following unfound references:

digest.o(.text+0x48): In function `digest_get_hash':
: undefined reference to `OPENSSL_init_crypto'
digest.o(.text+0x78): In function `digest_get_hash':
: undefined reference to `EVP_MD_CTX_new'
digest.o(.text+0xf4): In function `digest_get_hash':
: undefined reference to `EVP_MD_CTX_free'
ssl.o(.text+0x1c): In function `_ssl_initialise_context':
: undefined reference to `OPENSSL_init_crypto'
ssl.o(.text+0x2c): In function `_ssl_initialise_context':
: undefined reference to `OPENSSL_init_ssl'
ssl.o(.text+0x30): In function `_ssl_initialise_context':
: undefined reference to `TLS_client_method'
ssl.o(.text+0xc0): In function `ssl_init':
: undefined reference to `OPENSSL_init_ssl'
collect2: ld returned 1 exit status

Different commands, in where I change the order, or plainly leave out libcrypto.a or libssl.a yield different results (all undefined references).

How can I link statically against the OpenSSL .a libraries?

Update When I unpack the .a files using ar x «library.a», and link against the resulting .o files, the build succeeds.

Update This is the output of gcc -v:

[bf@localhost src]$ /usr/local/arm-linux/bin/arm-linux-gcc -v
Reading specs from /usr/local/arm-linux/bin/../lib/gcc-lib/arm-linux/3.3.2/specs
Configured with: ../configure --target=arm-linux --disable-shared --with-headers=/home/gerg/new-wave.xscale/linux-2.4.x/include --with-gnu-as --with-gnu-ld --enable-multilib
Thread model: posix
gcc version 3.3.2

Upvotes: 0

Views: 1752

Answers (1)

Employed Russian
Employed Russian

Reputation: 213516

How can I link statically against the OpenSSL .a libraries?

Your library order is wrong: libcrypto.a depends on libssl.a, so it must be listed before libssl.a on the link line.

See this post for detailed explanation.

Upvotes: 1

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