Re: httpd generating: read_errdoc entries in syslog

[Carsten Reith]

On Sat, Feb 10, 2024 at 06:21:03PM -0500, J Doe wrote:
> In /var/www I have created:
> 
>     /err              root:daemon     chmod 0755
> 
> Within /var/www/err I have created:
> 
>     err.html          www:www         chmod 0444
> 
> In my httpd.conf I have a global configuration that points to this:
> 
>     /etc/httpd.conf
>         . . .
>         errdocs "/err"
> 
> When I cause an error with httpd, the error document template I have
> created gets rendered to the client, but I get entries in syslog like
> the following:
> 
>     serv1 httpd[23368]: read_errdoc: open: No such file or directory
> 
> This also happens if a create a copy of err.html and name it 404.html.
> 
> How can I modify my configuration to stop the: read_errdoc entries in
> syslog ?
> 
> Thanks,
> 
> - J
>

This is probably not a configuration error. 

As far as I can see, the following line in server_http.c cause the problem:

if ((body = read_errdoc(srv_conf->errdocroot, cstr)) == NULL &&
    (body = read_errdoc(srv_conf->errdocroot, HTTPD_ERRDOCTEMPLATE) ==
        NULL)

The read_errdoc function tries to open the file (<code>.html
first, then err.html) and writes the syslog message, if the file can't be
found. (If none can be found a default body is created.

I attach a diff, which fixes the issue for me.

This is the first diff I submit, so anybody with more experience
is welcome to improve or reject it.

Carsten


Index: server_http.c
===================================================================
RCS file: /cvs/src/usr.sbin/httpd/server_http.c,v
retrieving revision 1.153
diff -u -p -u -p -r1.153 server_http.c
--- server_http.c       21 Sep 2022 05:55:18 -0000      1.153
+++ server_http.c       11 Feb 2024 12:11:27 -0000
@@ -893,6 +893,7 @@ server_abort_http(struct client *clt, un
        char                     buf[IBUF_READ_SIZE];
        char                    *escapedmsg = NULL;
        char                     cstr[5];
+       char                    *path;
        ssize_t                  bodylen;
 
        if (code == 0) {
@@ -974,10 +975,21 @@ server_abort_http(struct client *clt, un
        if ((size_t)snprintf(cstr, sizeof(cstr), "%03u", code) >= sizeof(cstr))
                goto builtin;
 
-       if ((body = read_errdoc(srv_conf->errdocroot, cstr)) == NULL &&
-           (body = read_errdoc(srv_conf->errdocroot, HTTPD_ERRDOCTEMPLATE))
-           == NULL)
+       if (asprintf(&path, "%s/%s.html", srv_conf->errdocroot, cstr) == -1)
+                               fatal("asprintf");
+
+       if (access(path, R_OK) == 0) {
+               if ((body = read_errdoc(srv_conf->errdocroot, cstr)) == NULL) {
+                       free(path);
+                       goto builtin;
+               }
+       }
+       else if ((body = read_errdoc(srv_conf->errdocroot, 
+                                    HTTPD_ERRDOCTEMPLATE)) == NULL) {
+               free(path);
                goto builtin;
+       }
+       free(path);
 
        body = replace_var(body, "$HTTP_ERROR", httperr);
        body = replace_var(body, "$RESPONSE_CODE", cstr);