67fbb903b6
The original pattern for creating the pid file was:
open_create(pid_file)
write(pid_file, pid)
close(pid_file)
But if a power outage occurs between open_create and write, the file will
be empty and httpd will refuse to start afterwards unless the corrupt pid
file is removed.
This patch uses the pattern:
open_create(temp_pid_file)
write(temp_pid_file)
close(temp_pid_file)
rename(temp_pid_file, pid_file)
which is guaranteed to be atomic, provided that temp_pid_file and pid_file
are located in the same file system, which this patch does by creating
a temporary file name with the pattern:
pid_file_name + random_suffix
Patch is upstream as of
dd10a9352e,
which will be in the next 2.5.x version.
Signed-off-by: Nicolas Carrier <nicolas.carrier@orolia.com>
[Thomas: update to use upstreamed patch.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
78 lines
2.9 KiB
Diff
78 lines
2.9 KiB
Diff
From 5b95d256387b45fbe33f7ee7890ae35afdd5c371 Mon Sep 17 00:00:00 2001
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From: Joe Orton <jorton@apache.org>
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Date: Fri, 13 Mar 2020 14:34:18 +0000
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Subject: [PATCH] * server/log.c (ap_log_pid): Use a temporary file, then
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rename once successfully written; also add error checking. Avoids startup
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failures if a previous httpd invocation crashed while writing the pidfile.
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Submitted by: Nicolas Carrier <carrier.nicolas0 gmail.com>, jorton
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Github: closes #100, closes #69
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PR: 63140
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git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1875153 13f79535-47bb-0310-9956-ffa450edef68
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Signed-off-by: Nicolas Carrier <nicolas.carrier@orolia.com>
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---
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server/log.c | 33 ++++++++++++++++++++++++++-------
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1 file changed, 26 insertions(+), 7 deletions(-)
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diff --git a/server/log.c b/server/log.c
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index f0bde6e4b8..8d54b4e057 100644
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--- a/server/log.c
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+++ b/server/log.c
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@@ -1598,6 +1598,9 @@ AP_DECLARE(void) ap_log_pid(apr_pool_t *p, const char *filename)
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pid_t mypid;
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apr_status_t rv;
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const char *fname;
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+ char *temp_fname;
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+ apr_fileperms_t perms;
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+ char pidstr[64];
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if (!filename) {
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return;
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@@ -1626,19 +1629,35 @@ AP_DECLARE(void) ap_log_pid(apr_pool_t *p, const char *filename)
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fname);
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}
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- if ((rv = apr_file_open(&pid_file, fname,
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- APR_WRITE | APR_CREATE | APR_TRUNCATE,
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- APR_UREAD | APR_UWRITE | APR_GREAD | APR_WREAD, p))
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- != APR_SUCCESS) {
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+ temp_fname = apr_pstrcat(p, fname, ".XXXXXX", NULL);
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+ rv = apr_file_mktemp(&pid_file, temp_fname,
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+ APR_FOPEN_WRITE | APR_FOPEN_CREATE | APR_FOPEN_TRUNCATE, p);
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+ if (rv != APR_SUCCESS) {
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ap_log_error(APLOG_MARK, APLOG_ERR, rv, NULL, APLOGNO(00099)
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- "could not create %s", fname);
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+ "could not create %s", temp_fname);
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ap_log_error(APLOG_MARK, APLOG_ERR, 0, NULL, APLOGNO(00100)
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"%s: could not log pid to file %s",
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ap_server_argv0, fname);
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exit(1);
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}
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- apr_file_printf(pid_file, "%" APR_PID_T_FMT APR_EOL_STR, mypid);
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- apr_file_close(pid_file);
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+
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+ apr_snprintf(pidstr, sizeof pidstr, "%" APR_PID_T_FMT APR_EOL_STR, mypid);
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+
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+ perms = APR_UREAD | APR_UWRITE | APR_GREAD | APR_WREAD;
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+ rv = apr_file_perms_set(temp_fname, perms);
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+ if (rv == APR_SUCCESS)
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+ rv = apr_file_write_full(pid_file, pidstr, strlen(pidstr), NULL);
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+ if (rv == APR_SUCCESS)
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+ rv = apr_file_close(pid_file);
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+ if (rv == APR_SUCCESS)
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+ rv = apr_file_rename(temp_fname, fname, p);
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+ if (rv != APR_SUCCESS) {
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+ ap_log_error(APLOG_MARK, APLOG_ERR, rv, NULL, APLOGNO(10231)
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+ "%s: Failed creating pid file %s",
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+ ap_server_argv0, temp_fname);
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+ exit(1);
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+ }
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+
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saved_pid = mypid;
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}
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--
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2.25.2
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