[libmicrohttpd] libmicrohttpd running into indefinite loops

[Alexander Couzens]

Hi,

I'm running nodogsplash on serveral small routers. Nodogsplash is a
wifi splashpage portal. In version v2 (upcoming release) we switched to
libmicrohttpd.
libmicrohttpd is used without ssl support. These system runs OpenWrt
15.05 on 32Mb ram, 4mb flash. As libc it's using musl libc.

kernel: 3.18.36
libmicrohttpd: 0.9.50

nodogsplash is using mhd threading+epoll. On some devices the
libmicrohttpd thread taking all CPU running into the following
indefinite loop traced with strace.

[...]
clock_gettime(CLOCK_MONOTONIC, {147525, 556733385}) = 0
clock_gettime(CLOCK_MONOTONIC, {147525, 556850090}) = 0
sendfile64(121, 127, [0], 4294967295)   = -1 EINVAL (Invalid argument)
send(121, "", 0, MSG_NOSIGNAL)          = 0
[...]

I think this is exactly the code called by daemon.c
send_param_adapter(). 
send_param_adapter() / send_cls() was called with a zero length as
parameter.

Any further ideas?

best,
lynxis
-- 
Alexander Couzens

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