Name

svscan — starts and monitors a collection of services

Synopsis

svscan [directory]

Description

svscan starts one supervise(1) process for each subdirectory of the current directory, up to a limit of 1000 subdirectories. svscan skips subdirectory names starting with dots. supervise(1) must be in svscan's path.

svscan optionally starts a pair of supervise(1) processes, one for a subdirectory s, one for s/log, with a pipe between them. It does this if the name s is at most 255 bytes long and s/log exists. (In versions 0.70 and below, it does this if s is sticky.) svscan needs two free descriptors for each pipe.

Every five seconds, svscan checks for subdirectories again. If it sees a new subdirectory, it starts a new supervise(1) process. If it sees an old subdirectory where a supervise(1) process has exited, it restarts the supervise(1) process. In the log case it reuses the same pipe so that no data is lost.

svscan is designed to run forever. If it has trouble creating a pipe or running supervise(1), it prints a message to stderr; it will try again five seconds later.

If svscan is given a command-line argument directory, it switches to that directory when it starts.

See also

supervise(1)
svc(1)
svok(1)
svstat(1)
svscanboot(1)
readproctitle(1)
fghack(1)
pgrphack(1)
multilog(1)
tai64n(1)
tai64nlocal(1)
setuidgid(1)
envuidgid(1)
envdir(1)
softlimit(1)
setlock(1)

Author

Original code and documentation by Daniel J. Bernstein. Converted to manual pages and updated by Gerrit Pape in 2000, 2001, and 2002. Converted to DocBook XML by Jonathan de Boyne Pollard.