Well, I want to be able to restart processes on linux and so I looked into kill manpages for that. Apparently kill -l would list all the signals I could send to a process to do what I need, which are:
1) SIGHUP 2) SIGINT 3) SIGQUIT 4) SIGILL 5) SIGTRAP 6) SIGABRT 7) SIGBUS 8) SIGFPE 9) SIGKILL 10) SIGUSR1
11) SIGSEGV 12) SIGUSR2 13) SIGPIPE 14) SIGALRM 15) SIGTERM
16) SIGSTKFLT 17) SIGCHLD 18) SIGCONT 19) SIGSTOP 20) SIGTSTP
21) SIGTTIN 22) SIGTTOU 23) SIGURG 24) SIGXCPU 25) SIGXFSZ
26) SIGVTALRM 27) SIGPROF 28) SIGWINCH 29) SIGIO 30) SIGPWR
31) SIGSYS 34) SIGRTMIN 35) SIGRTMIN+1 36) SIGRTMIN+2 37) SIGRTMIN+3
38) SIGRTMIN+4 39) SIGRTMIN+5 40) SIGRTMIN+6 41) SIGRTMIN+7 42) SIGRTMIN+8
43) SIGRTMIN+9 44) SIGRTMIN+10 45) SIGRTMIN+11 46) SIGRTMIN+12 47) SIGRTMIN+13
48) SIGRTMIN+14 49) SIGRTMIN+15 50) SIGRTMAX-14 51) SIGRTMAX-13 52) SIGRTMAX-12
53) SIGRTMAX-11 54) SIGRTMAX-10 55) SIGRTMAX-9 56) SIGRTMAX-8 57) SIGRTMAX-7
58) SIGRTMAX-6 59) SIGRTMAX-5 60) SIGRTMAX-4 61) SIGRTMAX-3 62) SIGRTMAX-2
63) SIGRTMAX-1 64) SIGRTMAXI thought that I would get the desired effect by using SIGSTOP signal (number 19) and then SIGCONT signal (number 18) like this:
kill -19 $PID_NUMBER # It stops! nice, we are reaching just what we wanted.
kill -18 $PID_NUMBER # Ok... it continues to death... that isn't funny though.I also tried with signal number 1 : SIGHUP with pretty much the same results, am I missing something? Does anyone know what I need to reach what I want?
2 Answers
There is no “restart” signal. You need to record the environment (environ, cwd, cmdline, security context…) from /proc/<pid> and manually start the process again.
SIGHUP is close, but it is only used by convention to ask the program to reload its settings.
5There is a "RELOAD" signal.
Assume you have a squid process with pid 1 runs in container, if you restart the squid process the container will exit. but you can "RELOAD" it like this:
kill -HUP 1
