From 13cb638cbde60f3187030ca428b4428e3c04561a Mon Sep 17 00:00:00 2001
From: Jeff Trawick <trawick@apache.org>
Date: Wed, 2 Dec 2009 14:24:18 +0000
Subject: [PATCH] Add OmitPID keyword on Mutex directive to suppress the
 addition of the parent pid to the generated lock file name.

Change the Mutex directive syntax from

  Mutex default|mutex-name mechanism

to

  Mutex mechanism [default|mutex-name] ... [OmitPID]

as suggested by wrowe.  (Thanks!)



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@886154 13f79535-47bb-0310-9956-ffa450edef68
---
 docs/manual/mod/core.xml | 122 ++++++++++++++++++++-------------------
 include/util_mutex.h     |   3 +-
 server/core.c            |   4 +-
 server/util_mutex.c      |  81 +++++++++++++++++++-------
 4 files changed, 127 insertions(+), 83 deletions(-)

diff --git a/docs/manual/mod/core.xml b/docs/manual/mod/core.xml
index debba51780..c778bb6ad6 100644
--- a/docs/manual/mod/core.xml
+++ b/docs/manual/mod/core.xml
@@ -2232,8 +2232,8 @@ connection</description>
 <name>Mutex</name>
 <description>Configures mutex mechanism and lock file directory for all
 or specified mutexes</description>
-<syntax>Mutex <var>default|mutex-name</var> <var>mechanism</var></syntax>
-<default>Mutex default default</default>
+<syntax>Mutex <var>mechanism</var> [default|<var>mutex-name</var>] ... [OmitPID]</syntax>
+<default>Mutex default</default>
 <contextlist><context>server config</context></contextlist>
 <compatibility>Available in Apache 2.3.4 and later</compatibility>
 
@@ -2266,61 +2266,6 @@ or specified mutexes</description>
     can be configured if this directive is supported.</p>
     </note>
 
-    <p>The following table documents the names of mutexes used by httpd
-    and bundled modules.</p>
-
-    <table border="1" style="zebra">
-        <tr>
-            <th>Mutex name</th>
-            <th>Module(s)</th>
-            <th>Protected resource</th>
-	</tr>
-        <tr>
-            <td><code>mpm-accept</code></td>
-            <td><module>prefork</module> and <module>worker</module> MPMs</td>
-            <td>incoming connections, to avoid the thundering herd problem;
-            for more information, refer to the
-            <a href="../misc/perf-tuning.html">performance tuning</a>
-            documentation</td>
-	</tr>
-        <tr>
-            <td><code>authdigest-client</code></td>
-            <td><module>mod_auth_digest</module></td>
-            <td>client list in shared memory</td>
-	</tr>
-        <tr>
-            <td><code>authdigest-opaque</code></td>
-            <td><module>mod_auth_digest</module></td>
-            <td>counter in shared memory</td>
-	</tr>
-        <tr>
-            <td><code>ldap-cache</code></td>
-            <td><module>mod_ldap</module></td>
-            <td>LDAP result cache</td>
-	</tr>
-        <tr>
-            <td><code>rewrite-map</code></td>
-            <td><module>mod_rewrite</module></td>
-            <td>communication with external mapping programs, to avoid
-            intermixed I/O from multiple requests</td>
-	</tr>
-        <tr>
-            <td><code>ssl-cache</code></td>
-            <td><module>mod_ssl</module></td>
-            <td>SSL session cache</td>
-	</tr>
-        <tr>
-            <td><code>ssl-stapling</code></td>
-            <td><module>mod_ssl</module></td>
-            <td>OCSP stapling response cache</td>
-	</tr>
-        <tr>
-            <td><code>watchdog-callback</code></td>
-            <td><module>mod_watchdog</module></td>
-            <td>callback function of a particular client module</td>
-	</tr>
-    </table>
-
     <p>The following mutex <em>mechanisms</em> are available:</p>
     <ul>
         <li><code>default | yes</code>
@@ -2416,8 +2361,9 @@ or specified mutexes</description>
     <directive module="core">ServerRoot</directive>.  Always use a local disk
     filesystem for <code>/path/to/mutex</code> and never a directory residing
     on a NFS- or AFS-filesystem.  The basename of the file will be the mutex
-    type, an optional instance string provided by the module, with the process
-    id of the httpd parent process appended to to make it unique, avoiding
+    type, an optional instance string provided by the module, and unless the
+    <code>OmitPID</code> keyword is specified, the process id of the httpd 
+    parent process will be appended to to make the file name unique, avoiding
     conflicts when multiple httpd instances share a lock file directory.  For
     example, if the mutex name is <code>mpm-accept</code> and the lock file
     directory is <code>/var/httpd/locks</code>, the lock file name for the
@@ -2432,6 +2378,64 @@ or specified mutexes</description>
     to create.</p>
     </note>
 
+    <p>The following table documents the names of mutexes used by httpd
+    and bundled modules.</p>
+
+    <table border="1" style="zebra">
+        <tr>
+            <th>Mutex name</th>
+            <th>Module(s)</th>
+            <th>Protected resource</th>
+	</tr>
+        <tr>
+            <td><code>mpm-accept</code></td>
+            <td><module>prefork</module> and <module>worker</module> MPMs</td>
+            <td>incoming connections, to avoid the thundering herd problem;
+            for more information, refer to the
+            <a href="../misc/perf-tuning.html">performance tuning</a>
+            documentation</td>
+	</tr>
+        <tr>
+            <td><code>authdigest-client</code></td>
+            <td><module>mod_auth_digest</module></td>
+            <td>client list in shared memory</td>
+	</tr>
+        <tr>
+            <td><code>authdigest-opaque</code></td>
+            <td><module>mod_auth_digest</module></td>
+            <td>counter in shared memory</td>
+	</tr>
+        <tr>
+            <td><code>ldap-cache</code></td>
+            <td><module>mod_ldap</module></td>
+            <td>LDAP result cache</td>
+	</tr>
+        <tr>
+            <td><code>rewrite-map</code></td>
+            <td><module>mod_rewrite</module></td>
+            <td>communication with external mapping programs, to avoid
+            intermixed I/O from multiple requests</td>
+	</tr>
+        <tr>
+            <td><code>ssl-cache</code></td>
+            <td><module>mod_ssl</module></td>
+            <td>SSL session cache</td>
+	</tr>
+        <tr>
+            <td><code>ssl-stapling</code></td>
+            <td><module>mod_ssl</module></td>
+            <td>OCSP stapling response cache</td>
+	</tr>
+        <tr>
+            <td><code>watchdog-callback</code></td>
+            <td><module>mod_watchdog</module></td>
+            <td>callback function of a particular client module</td>
+	</tr>
+    </table>
+
+    <p>The <code>OmitPID</code> keyword suppresses the addition of the httpd
+    parent process id from the lock file name.</p>
+
     <p>In the following example, the mutex mechanism for the MPM accept
     mutex will be changed from the compiled-in default to <code>fcntl</code>,
     with the associated lock file created in directory
diff --git a/include/util_mutex.h b/include/util_mutex.h
index b27c7364da..e9dde52705 100644
--- a/include/util_mutex.h
+++ b/include/util_mutex.h
@@ -101,8 +101,7 @@ AP_DECLARE(apr_status_t) ap_parse_mutex(const char *arg, apr_pool_t *pool,
 
 /* private function to process the Mutex directive */
 AP_DECLARE_NONSTD(const char *) ap_set_mutex(cmd_parms *cmd, void *dummy,
-                                             const char *typelist,
-                                             const char *mechfile);
+                                             const char *arg);
 
 /**
  * option flags for ap_mutex_register(), ap_global_mutex_create(), and
diff --git a/server/core.c b/server/core.c
index cac5b4f373..e97a103dc8 100644
--- a/server/core.c
+++ b/server/core.c
@@ -3319,8 +3319,8 @@ AP_INIT_TAKE1("LimitRequestBody", set_limit_req_body,
 AP_INIT_TAKE1("LimitXMLRequestBody", set_limit_xml_req_body, NULL, OR_ALL,
               "Limit (in bytes) on maximum size of an XML-based request "
               "body"),
-AP_INIT_TAKE2("Mutex", ap_set_mutex, NULL, RSRC_CONF,
-              "mutex (or \"default\") and mechanism"),
+AP_INIT_RAW_ARGS("Mutex", ap_set_mutex, NULL, RSRC_CONF,
+                 "mutex (or \"default\") and mechanism"),
 
 /* System Resource Controls */
 #ifdef RLIMIT_CPU
diff --git a/server/util_mutex.c b/server/util_mutex.c
index 8607a7d2ab..a3ea1d617c 100644
--- a/server/util_mutex.c
+++ b/server/util_mutex.c
@@ -125,6 +125,7 @@ typedef struct {
     apr_int32_t options;
     int set;
     int none;
+    int omit_pid;
     apr_lockmech_e mech;
     const char *dir;
 } mutex_cfg_t;
@@ -165,27 +166,30 @@ static void mx_hash_init(apr_pool_t *p)
 }
 
 AP_DECLARE_NONSTD(const char *)ap_set_mutex(cmd_parms *cmd, void *dummy,
-                                            const char *type,
-                                            const char *mechdir)
+                                            const char *arg)
 {
     apr_pool_t *p = cmd->pool;
+    const char **elt;
+    const char *mechdir;
+    const char *type;
+    int no_mutex = 0, omit_pid = 0;
+    apr_array_header_t *type_list;
     apr_lockmech_e mech;
     apr_status_t rv;
     const char *mutexdir;
-    mutex_cfg_t *mxcfg = apr_hash_get(mxcfg_by_type, type,
-                                      APR_HASH_KEY_STRING);
+    mutex_cfg_t *mxcfg;
     const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
 
     if (err != NULL) {
         return err;
     }
 
-    if (!mxcfg) {
-        return apr_psprintf(p, "Mutex type %s is not valid", type);
+    mechdir = ap_getword_conf(cmd->pool, &arg);
+    if (*mechdir == NULL) {
+        return "Mutex requires at least a mechanism argument (" 
+               AP_ALL_AVAILABLE_MUTEXES_STRING ")";
     }
 
-    mxcfg->none = 0; /* in case that was the default */
-
     rv = ap_parse_mutex(mechdir, p, &mech, &mutexdir);
     if (rv == APR_ENOTIMPL) {
         return apr_pstrcat(p, "Invalid Mutex argument ", mechdir,
@@ -196,20 +200,55 @@ AP_DECLARE_NONSTD(const char *)ap_set_mutex(cmd_parms *cmd, void *dummy,
         return apr_pstrcat(p, "Invalid Mutex directory in argument ",
                            mechdir, NULL);
     }
+    else if (rv == APR_ENOLOCK) { /* "none" */
+        no_mutex = 1;
+    }
+
+    /* "OmitPID" can appear at the end of the list, so build a list of
+     * mutex type names while looking for "OmitPID" (anywhere) or the end
+     */
+    type_list = apr_array_make(cmd->pool, 4, sizeof(char *));
+    while (*arg) {
+        char *s = ap_getword_conf(cmd->pool, &arg);
 
-    mxcfg->set = 1;
-    if (rv == APR_ENOLOCK) { /* "none" */
-        if (!(mxcfg->options & AP_MUTEX_ALLOW_NONE)) {
-            return apr_psprintf(p,
-                                "None is not allowed for mutex type %s",
-                                type);
+        if (!strcasecmp(s, "omitpid")) {
+            omit_pid = 1;
+        }
+        else {
+            char **new_type = (char **)apr_array_push(type_list);
+            *new_type = s;
         }
-        mxcfg->none = 1;
     }
-    else {
-        mxcfg->mech = mech;
-        if (mutexdir) { /* retain mutex default if not configured */
-            mxcfg->dir = mutexdir;
+
+    if (apr_is_empty_array(type_list)) { /* no mutex type?  assume "default" */
+        char **new_type = (char **)apr_array_push(type_list);
+        *new_type = "default";
+    }
+
+    while ((elt = (const char **)apr_array_pop(type_list)) != NULL) {
+        const char *type = *elt;
+        mxcfg = apr_hash_get(mxcfg_by_type, type, APR_HASH_KEY_STRING);
+        if (!mxcfg) {
+            return apr_psprintf(p, "Mutex type %s is not valid", type);
+        }
+
+        mxcfg->none = 0; /* in case that was the default */
+        mxcfg->omit_pid = omit_pid;
+
+        mxcfg->set = 1;
+        if (no_mutex) {
+            if (!(mxcfg->options & AP_MUTEX_ALLOW_NONE)) {
+                return apr_psprintf(p,
+                                    "None is not allowed for mutex type %s",
+                                    type);
+            }
+            mxcfg->none = 1;
+        }
+        else {
+            mxcfg->mech = mech;
+            if (mutexdir) { /* retain mutex default if not configured */
+                mxcfg->dir = mutexdir;
+            }
         }
     }
 
@@ -265,7 +304,9 @@ static const char *get_mutex_filename(apr_pool_t *p, mutex_cfg_t *mxcfg,
     }
 
 #if HAVE_UNISTD_H
-    pid_suffix = apr_psprintf(p, ".%" APR_PID_T_FMT, getpid());
+    if (!mxcfg->omit_pid) {
+        pid_suffix = apr_psprintf(p, ".%" APR_PID_T_FMT, getpid());
+    }
 #endif
 
     return ap_server_root_relative(p,
-- 
2.50.1