Attachment #163813 for bug #235785






#------------------------------------------------------------------------------
# On systems which support dynamic loading of shared libraries, Exim can
# load a local_scan function specified in its config file instead of having
# to be recompiled with the desired local_scan function. For a full
# description of the API to this function, see the Exim specification.

DLOPEN_LOCAL_SCAN=yes

# If you set DLOPEN_LOCAL_SCAN, then you need to include -rdynamic in the
# linker flags.  Without it, the loaded .so won't be able to access any
# functions from exim.

LFLAGS=-rdynamic
if ${OSTYPE} == "Linux"; then \
    LFLAGS="${LFLAGS} -ldl"; \
fi

#------------------------------------------------------------------------------
# The default distribution of Exim contains only the plain text form of the
# documentation. Other forms are available separately. If you want to install
# the documentation in "info" format, first fetch the Texinfo documentation

Lines 20-25 Link Here

(-)src/config.h.defaults (+2 lines)
20	#define AUTH_PLAINTEXT	20	#define AUTH_PLAINTEXT
21	#define AUTH_SPA	21	#define AUTH_SPA
22		22
		23	#define DLOPEN_LOCAL_SCAN
		24
23	#define BIN_DIRECTORY	25	#define BIN_DIRECTORY
24		26
25	#define CONFIGURE_FILE	27	#define CONFIGURE_FILE

Lines 109-114 Link Here

(-)src/globals.c (+4 lines)
109	uschar *tls_verify_hosts = NULL;	109	uschar *tls_verify_hosts = NULL;
110	#endif	110	#endif
111		111
		112	#ifdef DLOPEN_LOCAL_SCAN
		113	uschar *local_scan_path = NULL;
		114	#endif
		115
112		116
113	/* Input-reading functions for messages, so we can use special ones for	117	/* Input-reading functions for messages, so we can use special ones for
114	incoming TCP/IP. The defaults use stdin. We never need these for any	118	incoming TCP/IP. The defaults use stdin. We never need these for any

Lines 73-78 Link Here

(-)src/globals.h (+3 lines)
73	extern uschar tls_verify_hosts; / Mandatory client verification */	73	extern uschar tls_verify_hosts; / Mandatory client verification */
74	#endif	74	#endif
75		75
		76	#ifdef DLOPEN_LOCAL_SCAN
		77	extern uschar local_scan_path; / Path to local_scan() library */
		78	#endif
76		79
77	/* Input-reading functions for messages, so we can use special ones for	80	/* Input-reading functions for messages, so we can use special ones for
78	incoming TCP/IP. */	81	incoming TCP/IP. */




/* Copyright (c) University of Cambridge 1995 - 2004 */
/* See the file NOTICE for conditions of use and distribution. */

#include "exim.h"

#ifdef DLOPEN_LOCAL_SCAN
#include <dlfcn.h>
static int (*local_scan_fn)(int fd, uschar **return_text) = NULL;
static int load_local_scan_library(void);
#endif

LOCAL_SCAN_SOURCE=Local/local_scan.c

in your Local/Makefile. This makes it easy to copy your version for use with
subsequent Exim releases.

For a full description of the API to this function, see the Exim specification.
******************************************************************************/


/* This is the only Exim header that you should include. The effect of
including any other Exim header is not defined, and may change from release to
release. Use only the documented interface! */

#include "local_scan.h"


/* This is a "do-nothing" version of a local_scan() function. The arguments
are:

  fd             The file descriptor of the open -D file, which contains the
                   body of the message. The file is open for reading and
                   writing, but modifying it is dangerous and not recommended.

  return_text    A pointer to an unsigned char* variable which you can set in
                   order to return a text string. It is initialized to NULL.

The return values of this function are:

  LOCAL_SCAN_ACCEPT
                 The message is to be accepted. The return_text argument is
                   saved in $local_scan_data.

  LOCAL_SCAN_REJECT
                 The message is to be rejected. The returned text is used
                   in the rejection message.

  LOCAL_SCAN_TEMPREJECT
                 This specifies a temporary rejection. The returned text
                   is used in the rejection message.
*/

int
local_scan(int fd, uschar **return_text)
{
fd = fd;                      /* Keep picky compilers happy */
return_text = return_text;
#ifdef DLOPEN_LOCAL_SCAN
/* local_scan_path is defined AND not the empty string */
if (local_scan_path && *local_scan_path)
  {
  if (!local_scan_fn)
    {
    if (!load_local_scan_library())
      {
        char *base_msg , *error_msg , *final_msg ;
        int final_length = -1 ;

        base_msg=US"Local configuration error - local_scan() library failure\n";
        error_msg = dlerror() ;

        final_length = strlen(base_msg) + strlen(error_msg) + 1 ;
        final_msg = (char*)malloc( final_length*sizeof(char) ) ;
        *final_msg = '\0' ;

        strcat( final_msg , base_msg ) ;
        strcat( final_msg , error_msg ) ;

        *return_text = final_msg ;
      return LOCAL_SCAN_TEMPREJECT;
      }
    }
    return local_scan_fn(fd, return_text);
  }
else
#endif
  return LOCAL_SCAN_ACCEPT;
}

#ifdef DLOPEN_LOCAL_SCAN

static int load_local_scan_library(void)
{
/* No point in keeping local_scan_lib since we'll never dlclose() anyway */
void *local_scan_lib = NULL;
int (*local_scan_version_fn)(void);
int vers_maj;
int vers_min;

local_scan_lib = dlopen(local_scan_path, RTLD_NOW);
if (!local_scan_lib)
  {
  log_write(0, LOG_MAIN|LOG_REJECT, "local_scan() library open failed - "
    "message temporarily rejected");
  return FALSE;
  }

local_scan_version_fn = dlsym(local_scan_lib, "local_scan_version_major");
if (!local_scan_version_fn)
  {
  dlclose(local_scan_lib);
  log_write(0, LOG_MAIN|LOG_REJECT, "local_scan() library doesn't contain "
    "local_scan_version_major() function - message temporarily rejected");
  return FALSE;
  }

/* The major number is increased when the ABI is changed in a non
   backward compatible way. */
vers_maj = local_scan_version_fn();

local_scan_version_fn = dlsym(local_scan_lib, "local_scan_version_minor");
if (!local_scan_version_fn)
  {
  dlclose(local_scan_lib);
  log_write(0, LOG_MAIN|LOG_REJECT, "local_scan() library doesn't contain "
    "local_scan_version_minor() function - message temporarily rejected");
  return FALSE;
  }

/* The minor number is increased each time a new feature is added (in a
   way that doesn't break backward compatibility) -- Marc */
vers_min = local_scan_version_fn();


if (vers_maj != LOCAL_SCAN_ABI_VERSION_MAJOR)
  {
  dlclose(local_scan_lib);
  local_scan_lib = NULL;
  log_write(0, LOG_MAIN|LOG_REJECT, "local_scan() has an incompatible major"
    "version number, you need to recompile your module for this version"
    "of exim (The module was compiled for version %d.%d and this exim provides"
    "ABI version %d.%d)", vers_maj, vers_min, LOCAL_SCAN_ABI_VERSION_MAJOR,
    LOCAL_SCAN_ABI_VERSION_MINOR);
  return FALSE;
  }
else if (vers_min > LOCAL_SCAN_ABI_VERSION_MINOR)
  {
  dlclose(local_scan_lib);
  local_scan_lib = NULL;
  log_write(0, LOG_MAIN|LOG_REJECT, "local_scan() has an incompatible minor"
    "version number, you need to recompile your module for this version"
    "of exim (The module was compiled for version %d.%d and this exim provides"
    "ABI version %d.%d)", vers_maj, vers_min, LOCAL_SCAN_ABI_VERSION_MAJOR,
    LOCAL_SCAN_ABI_VERSION_MINOR);
  return FALSE;
  }

local_scan_fn = dlsym(local_scan_lib, "local_scan");
if (!local_scan_fn)
  {
  dlclose(local_scan_lib);
  log_write(0, LOG_MAIN|LOG_REJECT, "local_scan() library doesn't contain "
    "local_scan() function - message temporarily rejected");
  return FALSE;
  }

return TRUE;
}

#endif /* DLOPEN_LOCAL_SCAN */

/* End of local_scan.c */

Lines 223-228 Link Here

(-)src/readconf.c (+3 lines)
223	{ "local_from_prefix", opt_stringptr, &local_from_prefix },	223	{ "local_from_prefix", opt_stringptr, &local_from_prefix },
224	{ "local_from_suffix", opt_stringptr, &local_from_suffix },	224	{ "local_from_suffix", opt_stringptr, &local_from_suffix },
225	{ "local_interfaces", opt_stringptr, &local_interfaces },	225	{ "local_interfaces", opt_stringptr, &local_interfaces },
		226	#ifdef DLOPEN_LOCAL_SCAN
		227	{ "local_scan_path", opt_stringptr, &local_scan_path },
		228	#endif
226	{ "local_scan_timeout", opt_time, &local_scan_timeout },	229	{ "local_scan_timeout", opt_time, &local_scan_timeout },
227	{ "local_sender_retain", opt_bool, &local_sender_retain },	230	{ "local_sender_retain", opt_bool, &local_sender_retain },
228	{ "localhost_number", opt_stringptr, &host_number_string },	231	{ "localhost_number", opt_stringptr, &host_number_string },

Return to bug 235785

Lines 615-620 Link Here

(-)src/EDITME (+17 lines)
615		615
616		616
617	#------------------------------------------------------------------------------	617	#------------------------------------------------------------------------------
		618	# On systems which support dynamic loading of shared libraries, Exim can
		619	# load a local_scan function specified in its config file instead of having
		620	# to be recompiled with the desired local_scan function. For a full
		621	# description of the API to this function, see the Exim specification.
		622
		623	DLOPEN_LOCAL_SCAN=yes
		624
		625	# If you set DLOPEN_LOCAL_SCAN, then you need to include -rdynamic in the
		626	# linker flags. Without it, the loaded .so won't be able to access any
		627	# functions from exim.
		628
		629	LFLAGS=-rdynamic
		630	if ${OSTYPE} == "Linux"; then \
		631	LFLAGS="${LFLAGS} -ldl"; \
		632	fi
		633
		634	#------------------------------------------------------------------------------
618	# The default distribution of Exim contains only the plain text form of the	635	# The default distribution of Exim contains only the plain text form of the
619	# documentation. Other forms are available separately. If you want to install	636	# documentation. Other forms are available separately. If you want to install
620	# the documentation in "info" format, first fetch the Texinfo documentation	637	# the documentation in "info" format, first fetch the Texinfo documentation

Lines 5-64 Link Here

(-)src/local_scan.c (-47 / +118 lines)
5	/* Copyright (c) University of Cambridge 1995 - 2004 */	5	/* Copyright (c) University of Cambridge 1995 - 2004 */
6	/* See the file NOTICE for conditions of use and distribution. */	6	/* See the file NOTICE for conditions of use and distribution. */
7		7
		8	#include "exim.h"
8		9
9	/******************************************************************************	10	#ifdef DLOPEN_LOCAL_SCAN
10	This file contains a template local_scan() function that just returns ACCEPT.	11	#include <dlfcn.h>
11	If you want to implement your own version, you should copy this file to, say	12	static int (local_scan_fn)(int fd, uschar *return_text) = NULL;
12	Local/local_scan.c, and edit the copy. To use your version instead of the	13	static int load_local_scan_library(void);
13	default, you must set	14	#endif
14
15	LOCAL_SCAN_SOURCE=Local/local_scan.c
16
17	in your Local/Makefile. This makes it easy to copy your version for use with
18	subsequent Exim releases.
19
20	For a full description of the API to this function, see the Exim specification.
21	******************************************************************************/
22
23
24	/* This is the only Exim header that you should include. The effect of
25	including any other Exim header is not defined, and may change from release to
26	release. Use only the documented interface! */
27
28	#include "local_scan.h"
29
30
31	/* This is a "do-nothing" version of a local_scan() function. The arguments
32	are:
33
34	fd The file descriptor of the open -D file, which contains the
35	body of the message. The file is open for reading and
36	writing, but modifying it is dangerous and not recommended.
37
38	return_text A pointer to an unsigned char* variable which you can set in
39	order to return a text string. It is initialized to NULL.
40
41	The return values of this function are:
42
43	LOCAL_SCAN_ACCEPT
44	The message is to be accepted. The return_text argument is
45	saved in $local_scan_data.
46
47	LOCAL_SCAN_REJECT
48	The message is to be rejected. The returned text is used
49	in the rejection message.
50
51	LOCAL_SCAN_TEMPREJECT
52	This specifies a temporary rejection. The returned text
53	is used in the rejection message.
54	*/
55		15
56	int	16	int
57	local_scan(int fd, uschar **return_text)	17	local_scan(int fd, uschar **return_text)
58	{	18	{
59	fd = fd; /* Keep picky compilers happy */	19	fd = fd; /* Keep picky compilers happy */
60	return_text = return_text;	20	return_text = return_text;
61	return LOCAL_SCAN_ACCEPT;	21	#ifdef DLOPEN_LOCAL_SCAN
		22	/* local_scan_path is defined AND not the empty string */
		23	if (local_scan_path && *local_scan_path)
		24	{
		25	if (!local_scan_fn)
		26	{
		27	if (!load_local_scan_library())
		28	{
		29	char base_msg , error_msg , *final_msg ;
		30	int final_length = -1 ;
		31
		32	base_msg=US"Local configuration error - local_scan() library failure\n";
		33	error_msg = dlerror() ;
		34
		35	final_length = strlen(base_msg) + strlen(error_msg) + 1 ;
		36	final_msg = (char)malloc( final_lengthsizeof(char) ) ;
		37	*final_msg = '\0' ;
		38
		39	strcat( final_msg , base_msg ) ;
		40	strcat( final_msg , error_msg ) ;
		41
		42	*return_text = final_msg ;
		43	return LOCAL_SCAN_TEMPREJECT;
		44	}
		45	}
		46	return local_scan_fn(fd, return_text);
		47	}
		48	else
		49	#endif
		50	return LOCAL_SCAN_ACCEPT;
		51	}
		52
		53	#ifdef DLOPEN_LOCAL_SCAN
		54
		55	static int load_local_scan_library(void)
		56	{
		57	/* No point in keeping local_scan_lib since we'll never dlclose() anyway */
		58	void *local_scan_lib = NULL;
		59	int (*local_scan_version_fn)(void);
		60	int vers_maj;
		61	int vers_min;
		62
		63	local_scan_lib = dlopen(local_scan_path, RTLD_NOW);
		64	if (!local_scan_lib)
		65	{
		66	log_write(0, LOG_MAIN\|LOG_REJECT, "local_scan() library open failed - "
		67	"message temporarily rejected");
		68	return FALSE;
		69	}
		70
		71	local_scan_version_fn = dlsym(local_scan_lib, "local_scan_version_major");
		72	if (!local_scan_version_fn)
		73	{
		74	dlclose(local_scan_lib);
		75	log_write(0, LOG_MAIN\|LOG_REJECT, "local_scan() library doesn't contain "
		76	"local_scan_version_major() function - message temporarily rejected");
		77	return FALSE;
		78	}
		79
		80	/* The major number is increased when the ABI is changed in a non
		81	backward compatible way. */
		82	vers_maj = local_scan_version_fn();
		83
		84	local_scan_version_fn = dlsym(local_scan_lib, "local_scan_version_minor");
		85	if (!local_scan_version_fn)
86	{
87	dlclose(local_scan_lib);
88	log_write(0, LOG_MAIN\|LOG_REJECT, "local_scan() library doesn't contain "
89	"local_scan_version_minor() function - message temporarily rejected");
90	return FALSE;
91	}
92
93	/* The minor number is increased each time a new feature is added (in a
94	way that doesn't break backward compatibility) -- Marc */
95	vers_min = local_scan_version_fn();
96
97
98	if (vers_maj != LOCAL_SCAN_ABI_VERSION_MAJOR)
99	{
100	dlclose(local_scan_lib);
101	local_scan_lib = NULL;
102	log_write(0, LOG_MAIN\|LOG_REJECT, "local_scan() has an incompatible major"
103	"version number, you need to recompile your module for this version"
104	"of exim (The module was compiled for version %d.%d and this exim provides"
105	"ABI version %d.%d)", vers_maj, vers_min, LOCAL_SCAN_ABI_VERSION_MAJOR,
106	LOCAL_SCAN_ABI_VERSION_MINOR);
107	return FALSE;
108	}
109	else if (vers_min > LOCAL_SCAN_ABI_VERSION_MINOR)
110	{
111	dlclose(local_scan_lib);
112	local_scan_lib = NULL;
113	log_write(0, LOG_MAIN\|LOG_REJECT, "local_scan() has an incompatible minor"
114	"version number, you need to recompile your module for this version"
115	"of exim (The module was compiled for version %d.%d and this exim provides"
116	"ABI version %d.%d)", vers_maj, vers_min, LOCAL_SCAN_ABI_VERSION_MAJOR,
117	LOCAL_SCAN_ABI_VERSION_MINOR);
118	return FALSE;
119	}
120
121	local_scan_fn = dlsym(local_scan_lib, "local_scan");
122	if (!local_scan_fn)
123	{
124	dlclose(local_scan_lib);
125	log_write(0, LOG_MAIN\|LOG_REJECT, "local_scan() library doesn't contain "
126	"local_scan() function - message temporarily rejected");
127	return FALSE;
128	}
129
130	return TRUE;
62	}	131	}
63		132
		133	#endif /* DLOPEN_LOCAL_SCAN */
		134
64	/* End of local_scan.c */	135	/* End of local_scan.c */