[Bluez-devel] bluez-utils 3.30, uClibc, hcid, plugin handling

[Bluez-devel] bluez-utils 3.30, uClibc, hcid, plugin handling

[Wolfram Joost]

Hello,

I had some trouble using hcid from bluez-utils 3.30 on my openwrt-router.
Openwrt uses uClibc, not glibc.

I discovered the following two problems:

1. In eglib/gmodule.c, function g_module_open, line 29 dlopen is used.
The flags for dlopen come from hcid/plugin.c, function plugin_init, line 94.
The flag-value is 0. According to the manpage of dlopen
(http://www.kernel.org/pub/linux/docs/manpages/man-pages-2.79.tar.bz2),
one of RTLD_LAZY or RTLD_NOW has to be set. uClibc checks this and returns an error.

2. hcid needs to be linked with -rdynamic or --export-dynamic. Some functions
in the hcid-executable are used by the plugins. Without -rdynamic uClibc
doesn't resolve the symbols in the plugins resulting in a NULL pointer
dereference and a SIGSEGV. Again, its documented in the man-page of
dlopen.

Wolfram

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Re: [Bluez-devel] bluez-utils 3.30, uClibc, hcid, plugin handling

[Marcel Holtmann]

Hi Wolfram,

> I had some trouble using hcid from bluez-utils 3.30 on my openwrt-router.
> Openwrt uses uClibc, not glibc.
> 
> I discovered the following two problems:
> 
> 1. In eglib/gmodule.c, function g_module_open, line 29 dlopen is used.
> The flags for dlopen come from hcid/plugin.c, function plugin_init, line 94.
> The flag-value is 0. According to the manpage of dlopen
> (http://www.kernel.org/pub/linux/docs/manpages/man-pages-2.79.tar.bz2),
> one of RTLD_LAZY or RTLD_NOW has to be set. uClibc checks this and returns an error.
> 
> 2. hcid needs to be linked with -rdynamic or --export-dynamic. Some functions
> in the hcid-executable are used by the plugins. Without -rdynamic uClibc
> doesn't resolve the symbols in the plugins resulting in a NULL pointer
> dereference and a SIGSEGV. Again, its documented in the man-page of
> dlopen.

this has been fixed a long time ago. However we just recently released
bluez-utils-3.31 and that should be fine.

Regards

Marcel



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