Dump nginx config from running process?

You need a gdb installed to dump memory regions of running process.

# Set pid of nginx master process here
pid=8192

# generate gdb commands from the process's memory mappings using awk
cat /proc/$pid/maps | awk '$6 !~ "^/" {split ($1,addrs,"-"); print "dump memory mem_" addrs[1] " 0x" addrs[1] " 0x" addrs[2] ;}END{print "quit"}' > gdb-commands

# use gdb with the -x option to dump these memory regions to mem_* files
gdb -p $pid -x gdb-commands

# look for some (any) nginx.conf text
grep worker_connections mem_*
grep server_name mem_*

You should get something like "Binary file mem_086cb000 matches". Open this file in editor, search for config (e.g. "worker_connections" directive), copy&paste. Profit!

Update: This method isn't entirely reliable. It's based on assumption that nginx process will read configuration and don't overwrite/reuse this memory area later. Master nginx process gives us best chances for that I guess.

This will not help on this request, but might help other reaching here for the same reason. Newer nginx versions have the -T option to dump the nginx config read from all nginx config files, not from memory:

nginx -T

This can be useful to confirm that a config file is being read, to compare with other server or search for configs.

Again, this will not dump the config from the running process, only what a new process would load.

The ngx_conf_t is a type of a structure used for configuration parsing. It only exists during configuration parsing, and obviously you can't access it after configuration parsing is complete.

the ideal way is to look for the ngx_conf_t struct from nginx process image.

It is defined here

http://trac.nginx.org/nginx/browser/nginx/trunk/src/core/ngx_conf_file.h#L166

My C & gdb sucks so home someone else could come up with a solution.