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[master] Move the check for another server to be earlier

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[rt38078] Move the check for another server to be earlier

    Move the code that checks if there is already a server
    running to be executed earlier in the process.  This
    puts it before the server touches the database which
    should avoid problems with rewriting a database from
    under a running server.
This commit is contained in:
Shawn Routhier 2014-12-16 08:36:57 -08:00
parent 913d69f6c9
commit 992dc76542
2 changed files with 39 additions and 23 deletions
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7
RELNOTES
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@ -202,6 +202,13 @@ by Eric Young (eay@cryptsoft.com).
leae expiration code.
[ISC-Bugs #38002]
- Move the check for a PID file and process to be before we rewrite the
lease file. This avoids the possibility of starting a second instance
of a server which changes the current lease file confusing the first
instance. This check is only included if the admin hasn't disabled PID
files.
[ISC-Bugs #38078]
Changes since 4.3.1b1
- Modify the linux and openwrt dhclient scripts to process information

55
server/dhcpd.c
View File

@ -621,6 +621,34 @@ main(int argc, char **argv) {
if (cftest && !lftest)
exit(0);
/*
* First part of dealing with pid files. Check to see if
* we should continue running or not. We run if:
* - we are testing the lease file out
* - we don't have a pid file to check
* - there is no other process running
*/
if ((lftest == 0) && (no_pid_file == ISC_FALSE)) {
/*Read previous pid file. */
if ((i = open(path_dhcpd_pid, O_RDONLY)) >= 0) {
status = read(i, pbuf, (sizeof pbuf) - 1);
close(i);
if (status > 0) {
pbuf[status] = 0;
pid = atoi(pbuf);
/*
* If there was a previous server process and
* it is still running, abort
*/
if (!pid ||
(pid != getpid() && kill(pid, 0) == 0))
log_fatal("There's already a "
"DHCP server running.");
}
}
}
group_write_hook = group_writer;
/* Start up the database... */
@ -696,34 +724,15 @@ main(int argc, char **argv) {
}
/*
* Deal with pid files. If the user told us
* not to write a file we don't read one either
* Second part of dealing with pid files. Now
* that we have forked we can write our pid if
* appropriate.
*/
if (no_pid_file == ISC_FALSE) {
/*Read previous pid file. */
if ((i = open (path_dhcpd_pid, O_RDONLY)) >= 0) {
status = read(i, pbuf, (sizeof pbuf) - 1);
close (i);
if (status > 0) {
pbuf[status] = 0;
pid = atoi(pbuf);
/*
* If there was a previous server process and
* it is still running, abort
*/
if (!pid ||
(pid != getpid() && kill(pid, 0) == 0))
log_fatal("There's already a "
"DHCP server running.");
}
}
/* Write new pid file. */
i = open(path_dhcpd_pid, O_WRONLY|O_CREAT|O_TRUNC, 0644);
if (i >= 0) {
sprintf(pbuf, "%d\n", (int) getpid());
IGNORE_RET (write(i, pbuf, strlen(pbuf)));
IGNORE_RET(write(i, pbuf, strlen(pbuf)));
close(i);
} else {
log_error("Can't create PID file %s: %m.",