Standardize logging with bgpd OK claudio@

Convert various reyk proc.c daemons over to new imsgbuf_init and imsgbuf_allow_fdpass. OK tb@

Convert the common imsgbuf_read calls to the post EAGAIN world. OK tb@

Use imsgbuf_queuelen() instead of accessing the w.queue member. OK tb@

Rename imsg_init, imsg_clear, imsg_read, imsg_write and imsg_flush to imsgbuf_init, imsgbuf_clear, imsgbuf_read, imsgbuf_write and imsgbuf_flush. This separates the imsgbuf API from the per-imsg API. OK tb@

Convert imsg_write() callers to the new simplified return logic. OK tb@

Introduce imsg_write() and use it instead of msgbuf_write(). imsg_write() is just a thin wrapper around msgbuf_write(). So this is mostly search and replace. OK tb@

imsg_flush no longer returns EAGAIN. Simplify proc_flush_imsg() accordingly. Issue spotted by op@

Use imsg_get_fd() As usual proc_forward_imsg() is never forwarding a file descriptor so just use -1 there. This should be replaced by imsg_forward(). All other changes are simple conversions. OK tb@

proc_ispeer() is not used anywhere anymore so remove it everywhere. ok florian@ bluhm@ ok for vmd mlarkin@

Move the daemon() call in the parent process from after forking the children to just before. That way the parent disasociates from its controling terminal and shell, but not from its children. Remove the dup2() bits that were copied from daemon() to solve the problem that the children still had the stdio fds open. This is now done in the parent earlier. Remove the setsid() and setpgid(). It is unclear what their intent was, but they dont seem to make sense, as daemon() covers this as well and there seems to be no reason the cildren procs need to do that. ok claudio@ bluhm@

relayd(8): don't create sockets between CAs and RELAYs. CA and RELAY process types don't need to communicate with other CA or RELAY processes respectively, so don't create and distribute ipc socketpairs. Tested by and ok denis@

Move TAILQ initialization to files where they are used. These priv-sep daemons all follow a similar design and use TAILQs for tracking control process connections. In most cases, the TAILQs are initialized separate from where they are used. Since the scope of use is generally confined to a specific control process file, this commit also removes any extern definitions and exposing the TAILQ structures to other compilation units. ok bluhm@, tb@

During the fork+exec implementation, daemon(3) was moved after proc_init(). As a consequence httpd(8) and relayd(8) child processes did not detach from the terminal anymore. Dup /dev/null to the stdio file descriptors in the children. OK benno@

use __func__ in log messages. fix some whitespace while here. From Hiltjo Posthuma hiltjo -AT codemadness -DOT- org, thanks! ok florian, claudio

Stop accessing verbose and debug variables from log.c directly. This replaces log_verbose() and "extern int verbose" with the two functions log_setverbose() and log_getverbose(). Pointed out by benno@ OK krw@ eric@ gilles@ (OK gilles@ for the snmpd bits as well)

The new fork+exec mode used too many fds in the parent process on startup, for a short time, so we needed a rlimit hack in relayd.c. Sync the fix from httpd: rzalamena@ has fixed proc.c and I added the proc_flush_imsg() mechanism that makes sure that each fd is immediately closed after forwarding it to a child process instead of queueing it up. OK rzalamena@ jca@ benno@

Sync with httpd(8) proc file. Check for dup2() usage to avoid oldd == newd and remove the CLOEXEC with fcntl() if necessary. ok reyk@

Call setsid() to create a new session for the executed processes. From deraadt@ OK rzalamena@

sync proc.c with vmd: add p_pw to specify a non-standard user for a process. OK rzalamena@

sync proc.c incl. the p_env removal

Replace [RELAY|SERVER]_MAXPROC with the new PROC_MAX_INSTANCES variable and limit it from 128 to 32 instances (the old value). While here, move a few PROC_ defines around. OK rzalamena@

Use the fork+exec privsep model in relayd; based on rzalamena@'s work for httpd with some (current and previous) changes for relayd. Once again, both daemons now share the same proc.c where most of the privsep "magic" happens. OK benno@ rzalamena@

style nit as done in httpd

As done in httpd, remove ps_ninstances and p_instance. OK benno@ rzalamena@