From 62470498cca9a209aa9904668c1949f5229123af Mon Sep 17 00:00:00 2001

From: Felix Kaechele <felix@kaechele.ca>

Date: Tue, 20 Apr 2021 21:28:18 -0400

Subject: [PATCH 2/2] fix PIDFile handling

Corresponding RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=1869026

Rejected upstream: https://trac.nginx.org/nginx/ticket/1897

Taken from: https://git.launchpad.net/ubuntu/+source/nginx/tree/debian/patches/nginx-fix-pidfile.patch

From original patch:

Author: Tj <ubuntu@iam.tj>

Bug-Ubuntu: https://bugs.launchpad.net/ubuntu/+source/nginx/+bug/1581864

Bug-Debian: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=876365

iLast-Update: 2020-06-24

Signed-off-by: Felix Kaechele <felix@kaechele.ca>

---

 src/core/nginx.c         | 24 +++++++++++++++++++++---

 src/os/unix/ngx_daemon.c |  8 ++++++--

 2 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/src/core/nginx.c b/src/core/nginx.c

index 48a20e9..32c0afe 100644

--- a/src/core/nginx.c

+++ b/src/core/nginx.c

@@ -339,14 +339,21 @@ main(int argc, char *const *argv)

         ngx_process = NGX_PROCESS_MASTER;

     }

+    /* tell-tale to detect if this is parent or child process */

+    ngx_int_t child_pid = NGX_BUSY;

+

 #if !(NGX_WIN32)

     if (ngx_init_signals(cycle->log) != NGX_OK) {

         return 1;

     }

+    /* tell-tale that this code has been executed */

+    child_pid--;

+

     if (!ngx_inherited && ccf->daemon) {

-        if (ngx_daemon(cycle->log) != NGX_OK) {

+        child_pid = ngx_daemon(cycle->log);

+        if (child_pid == NGX_ERROR) {

             return 1;

         }

@@ -359,8 +366,19 @@ main(int argc, char *const *argv)

 #endif

-    if (ngx_create_pidfile(&ccf->pid, cycle->log) != NGX_OK) {

-        return 1;

+    /* If ngx_daemon() returned the child's PID in the parent process

+     * after the fork() set ngx_pid to the child_pid, which gets

+     * written to the PID file, then exit.

+     * For NGX_WIN32 always write the PID file

+     * For others, only write it from the parent process */

+    if (child_pid < NGX_OK || child_pid > NGX_OK) {

+	ngx_pid = child_pid > NGX_OK ? child_pid : ngx_pid;

+        if (ngx_create_pidfile(&ccf->pid, cycle->log) != NGX_OK) {

+            return 1;

+	}

+    }

+    if (child_pid > NGX_OK) {

+        exit(0);

     }

     if (ngx_log_redirect_stderr(cycle) != NGX_OK) {

diff --git a/src/os/unix/ngx_daemon.c b/src/os/unix/ngx_daemon.c

index 385c49b..3719854 100644

--- a/src/os/unix/ngx_daemon.c

+++ b/src/os/unix/ngx_daemon.c

@@ -7,14 +7,17 @@

 #include <ngx_config.h>

 #include <ngx_core.h>

+#include <unistd.h>

 ngx_int_t

 ngx_daemon(ngx_log_t *log)

 {

     int  fd;

+    /* retain the return value for passing back to caller */

+    pid_t pid_child = fork();

-    switch (fork()) {

+    switch (pid_child) {

     case -1:

         ngx_log_error(NGX_LOG_EMERG, log, ngx_errno, "fork() failed");

         return NGX_ERROR;

@@ -23,7 +26,8 @@ ngx_daemon(ngx_log_t *log)

         break;

     default:

-        exit(0);

+        /* let caller do the exit() */

+        return pid_child;

     }

     ngx_parent = ngx_pid;

-- 

2.31.1