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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 12:06:34 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 12:06:34 +0000 |
commit | 5e61585d76ae77fd5e9e96ebabb57afa4d74880d (patch) | |
tree | 2b467823aaeebc7ef8bc9e3cabe8074eaef1666d /src/master/master_monitor.c | |
parent | Initial commit. (diff) | |
download | postfix-5e61585d76ae77fd5e9e96ebabb57afa4d74880d.tar.xz postfix-5e61585d76ae77fd5e9e96ebabb57afa4d74880d.zip |
Adding upstream version 3.5.24.upstream/3.5.24upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/master/master_monitor.c')
-rw-r--r-- | src/master/master_monitor.c | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/src/master/master_monitor.c b/src/master/master_monitor.c new file mode 100644 index 0000000..403d07e --- /dev/null +++ b/src/master/master_monitor.c @@ -0,0 +1,100 @@ +/*++ +/* NAME +/* master_monitor 3 +/* SUMMARY +/* Postfix master - start-up monitoring +/* SYNOPSIS +/* #include "master.h" +/* +/* int master_monitor(time_limit) +/* int time_limit; +/* DESCRIPTION +/* master_monitor() forks off a background child process, and +/* returns in the child. The result value is the file descriptor +/* on which the child process must write one byte after it +/* completes successful initialization as a daemon process. +/* +/* The foreground process waits for the child's completion for +/* a limited amount of time. It terminates with exit status 0 +/* in case of success, non-zero otherwise. +/* DIAGNOSTICS +/* Fatal errors: system call failure. +/* BUGS +/* SEE ALSO +/* LICENSE +/* .ad +/* .fi +/* The Secure Mailer license must be distributed with this software. +/* AUTHOR(S) +/* Wietse Venema +/* IBM T.J. Watson Research +/* P.O. Box 704 +/* Yorktown Heights, NY 10598, USA +/*--*/ + +/* System library. */ + +#include <sys_defs.h> +#include <signal.h> +#include <unistd.h> +#include <stdlib.h> + +/* Utility library. */ + +#include <msg.h> +#include <iostuff.h> + +/* Application-specific. */ + +#include <master.h> + +/* master_monitor - fork off a foreground monitor process */ + +int master_monitor(int time_limit) +{ + pid_t pid; + int pipes[2]; + char buf[1]; + + /* + * Sanity check. + */ + if (time_limit <= 0) + msg_panic("master_monitor: bad time limit: %d", time_limit); + + /* + * Set up the plumbing for child-to-parent communication. + */ + if (pipe(pipes) < 0) + msg_fatal("pipe: %m"); + close_on_exec(pipes[0], CLOSE_ON_EXEC); + close_on_exec(pipes[1], CLOSE_ON_EXEC); + + /* + * Fork the child, and wait for it to report successful initialization. + */ + switch (pid = fork()) { + case -1: + /* Error. */ + msg_fatal("fork: %m"); + case 0: + /* Child. Initialize as daemon in the background. */ + close(pipes[0]); + return (pipes[1]); + default: + /* Parent. Monitor the child in the foreground. */ + close(pipes[1]); + switch (timed_read(pipes[0], buf, 1, time_limit, (void *) 0)) { + default: + /* The child process still runs, but something is wrong. */ + (void) kill(pid, SIGKILL); + /* FALLTHROUGH */ + case 0: + /* The child process exited prematurely. */ + msg_fatal("daemon initialization failure"); + case 1: + /* The child process initialized successfully. */ + exit(0); + } + } +} |