[bug#50882] [PATCH] gnu: services: Add darkhttpd service

[bug#50882] [PATCH] gnu: services: Add darkhttpd service

[jgart via Guix-patches via]

Hi Guixers,

Heres a WIP service for darkhttpd along with texinfo documentation for how it
works.

I'd appreciate feedback and testing if you have the time to do that.

all the best,

jgart

3B1D 7F19 E36B B60C 0F5B 2CA9 A52A A2B4 77B6 DD35

[bug#50882] [PATCH] services: Add darkhttpd service.

[jgart via Guix-patches via]

* gnu/services/web.scm (<darkhttpd-configuration>): New record type.
(darkhttpd-accounts, darkhttpd-shepherd-service): New procedures.
(darkhttpd-service-type): New variable.
* doc/guix.texi (Web Services): Adds documentation for darkhttpd.
---
 doc/guix.texi        | 124 +++++++++++++++++++++++++++++
 gnu/services/web.scm | 184 ++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 306 insertions(+), 2 deletions(-)

diff --git a/doc/guix.texi b/doc/guix.texi
index 3124ed2ef8..6f22edba2e 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -26259,6 +26259,130 @@ The file which should store the logging output of Agate.
 @end table
 @end deftp
 
+@subsubheading darkhttpd
+
+@cindex darkhttpd
+@uref{https://unix4lyfe.org/darkhttpd/, darkhttpd} is a web server with a 
+focus on security and having a small memory footprint.
+
+Some security features are the following:
+
+@itemize
+@item Logging accesses, including Referer and User-Agent.
+@item Can chroot.
+@item Can drop privileges.
+@item Impervious to /../ sniffing.
+@item Times out idle connections.
+@item Drops overly long requests.
+@end itemize 
+
+@deffn {Scheme Variable} darkhttpd-service-type
+This is the type of the darkhttpd service, whose value should be a
+@code{darkhttpd-service-type} object, as in this example:
+
+@lisp
+(service darkhttpd-service-type
+	 (darkhttpd-configuration
+	   (content "/var/www/localhost/blog")
+	   (port 4567)
+	   (no-server-id? #t)
+	   (enable-ipv6? #t)
+	   (chroot? #f)))
+@end lisp
+
+The example above shows @code{content} directory modified as 
+well as @code{port}, @code{no-server-id?}, and @code{enable-ipv6?} 
+enabled and @code{chroot?} disabled.
+
+A minimal config might look like the following:
+
+@lisp
+(service darkhttpd-service-type)
+@end lisp
+
+@deftp {Data Type} darkhttpd-configuration
+Data type representing the configuration of darkhttpd.
+
+@table @asis
+@item @code{package} (default: @code{darkhttpd})
+The package object of the darkhttpd server.
+
+@item @code{content} (default: @file{"/srv/gemini"})
+The directory from which Agate will serve files.
+
+@item @code{port} (default: @code{"80"})
+Specifies which port to listen on for connections.
+Assign 0 to let the system choose any free port for you.
+
+@item @code{address} (default: @code{"all"})
+If multiple interfaces are present, specifies
+which one to bind the listening port to.
+
+@item @code{maximum-connections} (default: @code{#f})
+Specifies how many concurrent connections to accept.
+
+@item @code{log-file} (default: @file{"/var/log/darkhttpd.log"})
+The file which should store the logging output of @code{darkhttpd}.
+
+@item @code{chroot?} (default: @code{#t})
+Locks the web server into the content directory for added security.
+
+@item @code{daemonize?} (default: @code{#t})
+Detach from the controlling terminal and run in the background.
+
+@item @code{index-file} (default: @code{"index.html"})
+Default file to serve when a directory is requested.
+
+@item @code{do-not-serve-listing?} (default: @code{#f})
+Do not serve listing if directory is requested.
+
+@item @code{mimetypes} (default: @code{#f})
+This option is optional. @code{mimetypes} parses the 
+specified file for extension-MIME associations.
+
+@item @code{default-mimetype} (default: @code{"application/octet-stream"})
+Files with unknown extensions are served as this mimetype.
+
+@item @code{drop-user-privileges?} (default: @code{#t})
+Drops privileges to given uid after initialization.
+
+@item @code{drop-group-privileges?} (default: @code{#t})
+Drops privileges to given gid after initialization.
+
+@item @code{write-pid-file} (default: @code{#f})
+Write PID to the specified file.  Note that if you are
+using @{chroot?}, then the pidfile will be set relative
+to the directory set with the @{content} option.
+
+@item @code{disable-keep-alive?} (default: @code{#f})
+Disables HTTP Keep-Alive functionality.
+
+@item @code{forward} (default: @code{#f})
+By default, @{darkhttpd} does not forward requests.
+This option allows requests to the host to be redirected 
+to the corresponding url given as an argument.
+@{forward} may be specified multiple times, in which case
+the host is matched in order of appearance.
+
+@item @code{forward-all} (default: @code{#f})
+@{forward-all} is similar to @{forward} but all 
+requests are redirected to the url given as an argument.
+
+@item @code{no-server-id?} (default: @code{#f})
+Do not identify the server type in headers or 
+directory listings.
+
+@item @code{enable-ipv6?} (default: @code{#f})
+Listen on IPv6 address.
+
+@item @code{user} (default: @code{"darkhttpd"})
+Owner of the @code{darkhttpd} process.
+
+@item @code{group} (default: @code{"darkhttpd"})
+Owner's group of the @code{darkhttpd} process.
+
+@end table
+@end deftp
 @node Certificate Services
 @subsection Certificate Services
 
diff --git a/gnu/services/web.scm b/gnu/services/web.scm
index bb42eacf83..68afba3cad 100644
--- a/gnu/services/web.scm
+++ b/gnu/services/web.scm
@@ -281,8 +281,35 @@
             agate-configuration-group
             agate-configuration-log-file
 
-            agate-service-type))
-
+            agate-service-type
+            
+            darkhttpd-configuration
+            darkhttpd-configuration?
+            darkhttpd-configuration-package
+            darkhttpd-configuration-content
+            darkhttpd-configuration-port
+            darkhttpd-configuration-address
+            darkhttpd-configuration-maximum-connections
+            darkhttpd-configuration-log-file
+            darkhttpd-configuration-chroot
+            darkhttpd-configuration-daemonize
+            darkhttpd-configuration-index-file
+            darkhttpd-configuration-do-not-serve-listing
+            darkhttpd-configuration-mimetypes
+            darkhttpd-configuration-default-mimetype
+            darkhttpd-configuration-drop-user-privileges
+            darkhttpd-configuration-drop-group-privileges
+            darkhttpd-configuration-write-pid-file
+            darkhttpd-configuration-disable-keep-alive
+            darkhttpd-configuration-forward
+            darkhttpd-configuration-forward-all
+            darkhttpd-configuration-no-server-id
+            darkhttpd-configuration-enable-ipv6
+            darkhttpd-configuration-user
+            darkhttpd-configuration-group
+
+            darkhttpd-service-type))
+            
 ;;; Commentary:
 ;;;
 ;;; Web services.
@@ -1993,3 +2020,156 @@ root=/srv/gemini
           (service-extension shepherd-root-service-type
                              agate-shepherd-service)))
    (default-value (agate-configuration))))
+
+(define-record-type* <darkhttpd-configuration>
+  darkhttpd-configuration make-darkhttpd-configuration
+  darkhttpd-configuration?
+  (package                 darkhttpd-configuration-package
+                           (default darkhttpd))
+  (content                 darkhttpd-configuration-content
+                           (default "/var/www/localhost/htdocs"))
+  (port                    darkhttpd-configuration-port
+                           (default "80"))
+  (address                 darkhttpd-configuration-address
+                           (default "all"))
+  (maximum-connections     darkhttpd-configuration-maximum-connections
+                           (default #f))
+  (log-file                darkhttpd-configuration-log-file
+                           (default "access.log"))
+  (chroot?                 darkhttpd-configuration-chroot
+                           (default #t))
+  (daemonize?              darkhttpd-configuration-daemonize
+                           (default #t))
+  (index-file              darkhttpd-configuration-index-file
+                           (default "index.html"))
+  (do-not-serve-listing?   darkhttpd-configuration-do-not-serve-listing
+                           (default #f))
+  (mimetypes               darkhttpd-configuration-mimetypes
+                           (default #f))
+  (default-mimetype        darkhttpd-configuration-default-mimetype
+                           (default "application/octet-stream"))
+  (drop-user-privileges?   darkhttpd-configuration-drop-user-privileges
+                           (default #t))
+  (drop-group-privileges?  darkhttpd-configuration-drop-group-privileges
+                           (default #t))
+  (write-pid-file          darkhttpd-configuration-write-pid-file
+                           (default #f))
+  (disable-keep-alive?     darkhttpd-configuration-disable-keep-alive
+                           (default #f))
+  (forward                 darkhttpd-configuration-forward
+                           (default #f))
+  (forward-all             darkhttpd-configuration-forward-all
+                           (default #f))
+  (no-server-id?           darkhttpd-configuration-no-server-id
+                           (default #f))
+  (enable-ipv6?            darkhttpd-configuration-enable-ipv6
+                           (default #f))
+  (user                    darkhttpd-configuration-user
+                           (default "darkhttpd"))
+  (group                   darkhttpd-configuration-group
+                           (default "www-data")))
+
+(define darkhttpd-shepherd-service
+  (match-lambda
+    (($ <darkhttpd-configuration> package content port address 
+                                  maximum-connections log-file chroot? 
+                                  daemonize? index-file do-not-serve-listing?
+                                  mimetypes default-mimetype 
+                                  drop-user-priviledges drop-group-priviledges 
+                                  write-pid-file disable-keep-alive? 
+                                  forward forward-all 
+                                  no-server-id? enable-ipv6? 
+                                  user group)
+     (list (shepherd-service
+            (provision '(darkhttpd))
+            (requirement '(networking))
+            (documentation "Run the darkhttpd web server.")
+            (start (let ((darkhttpd (file-append package "/bin/darkhttpd")))
+                     #~(make-forkexec-constructor
+                        (list #$darkhttpd 
+                              #$content
+                              #$@(if port
+                                     (list "--port" (number->string port))
+                                     '())
+                              #$@(if address
+                                     (list "--addr" address)
+                                     '())
+                              #$@(if maximum-connections
+                                     (list "--maxconn" maximum-connections)
+                                     '())
+                              #$@(if log-file
+                                     (list "--log" 
+                                           (string-append "/var/log/darkhttpd/" 
+                                                          log-file)
+                                     '()))
+                              #$@(if chroot? '("--chroot") '())
+                              #$@(if daemonize? '("--daemon") '())
+                              #$@(if index-file
+                                     (list "--index" index-file)
+                                     '())
+                              #$@(if do-not-serve-listing?
+                                     (list "--no-listing" 
+                                           do-not-serve-listing?)
+                                     '())
+                              #$@(if mimetypes '("--mimetypes" mimetypes) '())
+                              #$@(if default-mimetype 
+                                     (list "--default-mimetype" 
+                                           default-mimetype) 
+                                     '())
+                              #$@(if drop-user-privileges? 
+                                     '("--uid" user) '())
+                              #$@(if drop-group-privileges? 
+                                     '("--gid" group) '())
+                              ;; if using --chroot, then the pidfile must be 
+                              ;; relative to, and inside the wwwroot.
+                              #$@(if write-pid-file 
+                                     "--pidfile" 
+                                     (if (and chroot? write-pid-file)
+                                            '(string-append content 
+                                                            "/"
+                                                            write-pid-file)
+                                         write-pid-file)
+                                     '())                                     
+                              #$@(if disable-keep-alive? 
+                                     (list "--no-keepalive" 
+                                           disable-keep-alive?) 
+                                     '())
+                              #$@(if forward '("--forward" forward) '())
+                              #$@(if forward-all
+                                     (list "--forward-all" forward-all) 
+                                     '())
+                              #$@(if no-server-id? '("--no-server-id") '())
+                              #$@(if enable-ipv6? '("--ipv6") '())
+                        #:user #$user #:group #$group))))
+            (stop #~(make-kill-destructor)))))))
+
+(define darkhttpd-accounts
+  (match-lambda
+    (($ <darkhttpd-configuration> _ _ _ _ _ _ _ _ 
+                                  _ _ _ _ _ _ _ _ 
+                                  _ _ user group)
+     `(,@(if (equal? group "darkhttpd")
+             '()
+             (list (user-group (name "darkhttpd") (system? #t))))
+       ,(user-group
+         (name group)
+         (system? #t))
+       ,(user-account
+         (name user)
+         (group group)
+         (supplementary-groups '("darkhttpd"))
+         (system? #t)
+         (comment "darkhttpd server user")
+         (home-directory "/var/empty")
+         (shell (file-append shadow "/sbin/nologin")))))))
+
+(define darkhttpd-service-type
+  (service-type
+   (name 'guix)
+   (extensions
+    (list (service-extension account-service-type
+                             darkhttpd-accounts)
+          (service-extension shepherd-root-service-type
+                             darkhttpd-shepherd-service)))
+   (default-value (darkhttpd-configuration))))
+
-- 
2.33.0

[bug#50882] [PATCH] gnu: services: Add darkhttpd service

[Ludovic Courtès]

Hi,

jgart <jgart@dismail.de> skribis:

> * gnu/services/web.scm (<darkhttpd-configuration>): New record type.
> (darkhttpd-accounts, darkhttpd-shepherd-service): New procedures.
> (darkhttpd-service-type): New variable.
> * doc/guix.texi (Web Services): Adds documentation for darkhttpd.

Overall LGTM!  Some comments and suggestions below.

> +@cindex darkhttpd
> +@uref{https://unix4lyfe.org/darkhttpd/, darkhttpd} is a web server with a 
> +focus on security and having a small memory footprint.
> +
> +Some security features are the following:
> +
> +@itemize
> +@item Logging accesses, including Referer and User-Agent.
> +@item Can chroot.
> +@item Can drop privileges.
> +@item Impervious to /../ sniffing.
> +@item Times out idle connections.
> +@item Drops overly long requests.
> +@end itemize 

I’d replace the bullet list with a simple sentence like: “Among other
things, it can change root directories, drop privileges, it times out on
idle connections and can drop overly long requests.”

> +@deffn {Scheme Variable} darkhttpd-service-type
> +This is the type of the darkhttpd service, whose value should be a
> +@code{darkhttpd-service-type} object, as in this example:
> +
> +@lisp
> +(service darkhttpd-service-type
> +	 (darkhttpd-configuration

Please don’t use tabs.

> +@end table
> +@end deftp
>  @node Certificate Services

Missing newline before @node.  :-)

> +  (mimetypes               darkhttpd-configuration-mimetypes
> +                           (default #f))
> +  (default-mimetype        darkhttpd-configuration-default-mimetype

Rather ‘mime-type’ (two words).

> +(define darkhttpd-shepherd-service
> +  (match-lambda
> +    (($ <darkhttpd-configuration> package content port address 
> +                                  maximum-connections log-file chroot? 
> +                                  daemonize? index-file do-not-serve-listing?
> +                                  mimetypes default-mimetype 
> +                                  drop-user-priviledges drop-group-priviledges 
> +                                  write-pid-file disable-keep-alive? 
> +                                  forward forward-all 
> +                                  no-server-id? enable-ipv6? 
> +                                  user group)

Rather use ‘match-record’ here, to make sure we’re getting the right
fields.

> +(define darkhttpd-accounts
> +  (match-lambda
> +    (($ <darkhttpd-configuration> _ _ _ _ _ _ _ _ 
> +                                  _ _ _ _ _ _ _ _ 
> +                                  _ _ user group)

In such a case, simply call ‘darkhttpd-configuration-user’ and
‘darkhttpd-configuration-group’; it’s much less error-prone!

> +(define darkhttpd-service-type
> +  (service-type
> +   (name 'guix)
> +   (extensions
> +    (list (service-extension account-service-type
> +                             darkhttpd-accounts)
> +          (service-extension shepherd-root-service-type
> +                             darkhttpd-shepherd-service)))
> +   (default-value (darkhttpd-configuration))))

Please add a ‘description’ field.

Could you also add a system test, under (gnu tests web)?  You can start
by copying the nginx test; it should take around ~20 lines.

TIA!

Ludo’.

[bug#50882] [PATCH] gnu: services: Add darkhttpd service

[Maxim Cournoyer]

tag 50882 moreinfo
thanks

Hello jgart,

Ludovic Courtès <ludo@gnu.org> writes:

> Hi,
>
> jgart <jgart@dismail.de> skribis:
>
>> * gnu/services/web.scm (<darkhttpd-configuration>): New record type.
>> (darkhttpd-accounts, darkhttpd-shepherd-service): New procedures.
>> (darkhttpd-service-type): New variable.
>> * doc/guix.texi (Web Services): Adds documentation for darkhttpd.
>
> Overall LGTM!  Some comments and suggestions below.
>
>> +@cindex darkhttpd
>> +@uref{https://unix4lyfe.org/darkhttpd/, darkhttpd} is a web server with a 
>> +focus on security and having a small memory footprint.
>> +
>> +Some security features are the following:
>> +
>> +@itemize
>> +@item Logging accesses, including Referer and User-Agent.
>> +@item Can chroot.
>> +@item Can drop privileges.
>> +@item Impervious to /../ sniffing.
>> +@item Times out idle connections.
>> +@item Drops overly long requests.
>> +@end itemize 
>
> I’d replace the bullet list with a simple sentence like: “Among other
> things, it can change root directories, drop privileges, it times out on
> idle connections and can drop overly long requests.”
>
>> +@deffn {Scheme Variable} darkhttpd-service-type
>> +This is the type of the darkhttpd service, whose value should be a
>> +@code{darkhttpd-service-type} object, as in this example:
>> +
>> +@lisp
>> +(service darkhttpd-service-type
>> +	 (darkhttpd-configuration
>
> Please don’t use tabs.
>
>> +@end table
>> +@end deftp
>>  @node Certificate Services
>
> Missing newline before @node.  :-)
>
>> +  (mimetypes               darkhttpd-configuration-mimetypes
>> +                           (default #f))
>> +  (default-mimetype        darkhttpd-configuration-default-mimetype
>
> Rather ‘mime-type’ (two words).
>
>> +(define darkhttpd-shepherd-service
>> +  (match-lambda
>> +    (($ <darkhttpd-configuration> package content port address 
>> +                                  maximum-connections log-file chroot? 
>> +                                  daemonize? index-file do-not-serve-listing?
>> +                                  mimetypes default-mimetype 
>> +                                  drop-user-priviledges drop-group-priviledges 
>> +                                  write-pid-file disable-keep-alive? 
>> +                                  forward forward-all 
>> +                                  no-server-id? enable-ipv6? 
>> +                                  user group)
>
> Rather use ‘match-record’ here, to make sure we’re getting the right
> fields.
>
>> +(define darkhttpd-accounts
>> +  (match-lambda
>> +    (($ <darkhttpd-configuration> _ _ _ _ _ _ _ _ 
>> +                                  _ _ _ _ _ _ _ _ 
>> +                                  _ _ user group)
>
> In such a case, simply call ‘darkhttpd-configuration-user’ and
> ‘darkhttpd-configuration-group’; it’s much less error-prone!
>
>> +(define darkhttpd-service-type
>> +  (service-type
>> +   (name 'guix)
>> +   (extensions
>> +    (list (service-extension account-service-type
>> +                             darkhttpd-accounts)
>> +          (service-extension shepherd-root-service-type
>> +                             darkhttpd-shepherd-service)))
>> +   (default-value (darkhttpd-configuration))))
>
> Please add a ‘description’ field.
>
> Could you also add a system test, under (gnu tests web)?  You can start
> by copying the nginx test; it should take around ~20 lines.

Friendly ping about the above requests from Ludovic :-).

Thanks,

Maxim

[bug#50882] [PATCH] gnu: services: Add darkhttpd service

[jgart via Guix-patches via]

On Thu, 07 Jul 2022 14:02:36 -0400 Maxim Cournoyer <maxim.cournoyer@gmail.com> wrote:
> tag 50882 moreinfo
> thanks
> 
> Hello jgart,
> 
> Ludovic Courtès <ludo@gnu.org> writes:
> 
> > Hi,
> >
> > jgart <jgart@dismail.de> skribis:
> >
> >> * gnu/services/web.scm (<darkhttpd-configuration>): New record type.
> >> (darkhttpd-accounts, darkhttpd-shepherd-service): New procedures.
> >> (darkhttpd-service-type): New variable.
> >> * doc/guix.texi (Web Services): Adds documentation for darkhttpd.
> >
> > Overall LGTM!  Some comments and suggestions below.
> >
> >> +@cindex darkhttpd
> >> +@uref{https://unix4lyfe.org/darkhttpd/, darkhttpd} is a web server with a 
> >> +focus on security and having a small memory footprint.
> >> +
> >> +Some security features are the following:
> >> +
> >> +@itemize
> >> +@item Logging accesses, including Referer and User-Agent.
> >> +@item Can chroot.
> >> +@item Can drop privileges.
> >> +@item Impervious to /../ sniffing.
> >> +@item Times out idle connections.
> >> +@item Drops overly long requests.
> >> +@end itemize 
> >
> > I’d replace the bullet list with a simple sentence like: “Among other
> > things, it can change root directories, drop privileges, it times out on
> > idle connections and can drop overly long requests.”
> >
> >> +@deffn {Scheme Variable} darkhttpd-service-type
> >> +This is the type of the darkhttpd service, whose value should be a
> >> +@code{darkhttpd-service-type} object, as in this example:
> >> +
> >> +@lisp
> >> +(service darkhttpd-service-type
> >> +	 (darkhttpd-configuration
> >
> > Please don’t use tabs.
> >
> >> +@end table
> >> +@end deftp
> >>  @node Certificate Services
> >
> > Missing newline before @node.  :-)
> >
> >> +  (mimetypes               darkhttpd-configuration-mimetypes
> >> +                           (default #f))
> >> +  (default-mimetype        darkhttpd-configuration-default-mimetype
> >
> > Rather ‘mime-type’ (two words).
> >
> >> +(define darkhttpd-shepherd-service
> >> +  (match-lambda
> >> +    (($ <darkhttpd-configuration> package content port address 
> >> +                                  maximum-connections log-file chroot? 
> >> +                                  daemonize? index-file do-not-serve-listing?
> >> +                                  mimetypes default-mimetype 
> >> +                                  drop-user-priviledges drop-group-priviledges 
> >> +                                  write-pid-file disable-keep-alive? 
> >> +                                  forward forward-all 
> >> +                                  no-server-id? enable-ipv6? 
> >> +                                  user group)
> >
> > Rather use ‘match-record’ here, to make sure we’re getting the right
> > fields.
> >
> >> +(define darkhttpd-accounts
> >> +  (match-lambda
> >> +    (($ <darkhttpd-configuration> _ _ _ _ _ _ _ _ 
> >> +                                  _ _ _ _ _ _ _ _ 
> >> +                                  _ _ user group)
> >
> > In such a case, simply call ‘darkhttpd-configuration-user’ and
> > ‘darkhttpd-configuration-group’; it’s much less error-prone!
> >
> >> +(define darkhttpd-service-type
> >> +  (service-type
> >> +   (name 'guix)
> >> +   (extensions
> >> +    (list (service-extension account-service-type
> >> +                             darkhttpd-accounts)
> >> +          (service-extension shepherd-root-service-type
> >> +                             darkhttpd-shepherd-service)))
> >> +   (default-value (darkhttpd-configuration))))
> >
> > Please add a ‘description’ field.
> >
> > Could you also add a system test, under (gnu tests web)?  You can start
> > by copying the nginx test; it should take around ~20 lines.
> 
> Friendly ping about the above requests from Ludovic :-).

Arun Isaac convinced me to not write a service for this one since it's
common usage is for quick serving by simply running `darkhttpd ...` from
the command line. I think that guile bindings for every CLI feature of
darkhttpd doesn't add to that aim. I might change my mind later on this.
Feel free to close this one for now.

It was a fun exercise though. 

Ludo, thanks for the review. It was much appreciated!

all best,

jgart

https://whereis.みんな/

bug#50882: [PATCH] gnu: services: Add darkhttpd service

[Maxim Cournoyer]

Hello,

[...]

>> Friendly ping about the above requests from Ludovic :-).
>
> Arun Isaac convinced me to not write a service for this one since it's
> common usage is for quick serving by simply running `darkhttpd ...` from
> the command line. I think that guile bindings for every CLI feature of
> darkhttpd doesn't add to that aim. I might change my mind later on this.
> Feel free to close this one for now.
>
> It was a fun exercise though. 
>
> Ludo, thanks for the review. It was much appreciated!

OK, if you do reopen a ticket for it, please incorporate Ludovic's and
others comments in this issue in the to be submitted code, to avoid
duplicating efforts.

Closing; thanks!

Maxim