Add glibc aliases to some math function

[Waldek Kozaczuk]

One of the libraries used by ffmpeg uses following symbols which is missing
on OSv:

***@9c76f35feabb:/git-repos/osv# readelf -s
apps/ffmpeg/ROOTFS/usr/lib/libx265.so.160 | grep finite
4: 0000000000000000 0 FUNC GLOBAL DEFAULT UND
***@GLIBC_2.15 (5)
22: 0000000000000000 0 FUNC GLOBAL DEFAULT UND
***@GLIBC_2.15 (5)
37: 0000000000000000 0 FUNC GLOBAL DEFAULT UND
***@GLIBC_2.15 (5)
40: 0000000000000000 0 FUNC GLOBAL DEFAULT UND
***@GLIBC_2.15 (5)
49: 0000000000000000 0 FUNC GLOBAL DEFAULT UND
***@GLIBC_2.15 (5)

Based on my research these seems to be aliases in glibc to pow, log10, etc
implementations. As I understand we need to add aliases (using weak_alias
macro) to OSv somehow. Given musl subrepo should not be modified we cannot
add it like this to musl source file like so:

diff --git a/src/math/pow.c b/src/math/pow.c
index f257814e..08c6fd22 100644
--- a/src/math/pow.c
+++ b/src/math/pow.c
@@ -314,3 +314,4 @@ double pow(double x, double y)
SET_HIGH_WORD(z, j);
return s*z;
}
+weak_alias(pow,__pow_finite);

I tried to create a corresponding pow.c file under libc, declare pow with
extern and define alias with weak_alias but the compiler complains. Is the
right way then to copy these files from musl dir to libc dir and add
week_alias statements there? Or is there a better way?

Waldek

[Waldek Kozaczuk]

Or maybe use defsym in linker script ? I read that weak_alias needs to be in the same translation unit.