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/*++
/* NAME
/* mail_stream 3
/* SUMMARY
/* mail stream management
/* SYNOPSIS
/* #include <mail_stream.h>
/*
/* typedef struct {
/* .in +4
/* VSTREAM *stream;
/* char *id;
/* private members...
/* .in -4
/* } MAIL_STREAM;
/*
/* MAIL_STREAM *mail_stream_file(queue, class, service, mode)
/* const char *queue;
/* const char *class;
/* const char *service;
/* int mode;
/*
/* MAIL_STREAM *mail_stream_service(class, service)
/* const char *class;
/* const char *service;
/*
/* MAIL_STREAM *mail_stream_command(command)
/* const char *command;
/*
/* void mail_stream_cleanup(info)
/* MAIL_STREAM *info;
/*
/* int mail_stream_finish(info, why)
/* MAIL_STREAM *info;
/* VSTRING *why;
/* DESCRIPTION
/* This module provides a generic interface to Postfix queue file
/* format messages to file, to Postfix server, or to external command.
/* The routines that open a stream return a handle with an initialized
/* stream and queue id member. The handle is either given to a cleanup
/* routine, to dispose of a failed request, or to a finish routine, to
/* complete the request.
/*
/* mail_stream_file() opens a mail stream to a newly-created file and
/* arranges for trigger delivery at finish time. This call never fails.
/* But it may take forever. The mode argument specifies additional
/* file permissions that will be OR-ed in.
/*
/* mail_stream_command() opens a mail stream to external command,
/* and receives queue ID information from the command. The result
/* is a null pointer when the initial handshake fails. The command
/* is given to the shell only when necessary. At finish time, the
/* command is expected to send a completion status.
/*
/* mail_stream_service() opens a mail stream to Postfix service,
/* and receives queue ID information from the command. The result
/* is a null pointer when the initial handshake fails. At finish
/* time, the daemon is expected to send a completion status.
/*
/* mail_stream_cleanup() cancels the operation that was started with
/* any of the mail_stream_xxx() routines, and destroys the argument.
/* It is up to the caller to remove incomplete file objects.
/*
/* mail_stream_finish() completes the operation that was started with
/* any of the mail_stream_xxx() routines, and destroys the argument.
/* The result is any of the status codes defined in <cleanup_user.h>.
/* It is up to the caller to remove incomplete file objects.
/* The why argument can be a null pointer.
/* LICENSE
/* .ad
/* .fi
/* The Secure Mailer license must be distributed with this software.
/* AUTHOR(S)
/* Wietse Venema
/* IBM T.J. Watson Research
/* P.O. Box 704
/* Yorktown Heights, NY 10598, USA
/*--*/
/* System library. */
#include <sys_defs.h>
#include <sys/stat.h>
#include <unistd.h>
#include <errno.h>
/* Utility library. */
#include <msg.h>
#include <mymalloc.h>
#include <vstring.h>
#include <vstream.h>
#include <stringops.h>
#include <argv.h>
/* Global library. */
#include <cleanup_user.h>
#include <mail_proto.h>
#include <mail_queue.h>
#include <opened.h>
#include <mail_params.h>
#include <mail_stream.h>
/* Application-specific. */
static VSTRING *id_buf;
#define FREE_AND_WIPE(free, arg) { if (arg) free(arg); arg = 0; }
/* mail_stream_cleanup - clean up after success or failure */
void mail_stream_cleanup(MAIL_STREAM * info)
{
FREE_AND_WIPE(info->close, info->stream);
FREE_AND_WIPE(myfree, info->id);
FREE_AND_WIPE(myfree, info->class);
FREE_AND_WIPE(myfree, info->service);
myfree((char *) info);
}
/* mail_stream_finish_file - finish file mail stream */
static int mail_stream_finish_file(MAIL_STREAM * info, VSTRING *unused_why)
{
int status = 0;
static char wakeup[] = {TRIGGER_REQ_WAKEUP};
/*
* Make sure the message makes it to file. Set the execute bit when no
* write error was detected. Some people believe that this code has a
* problem if the system crashes before fsync() returns; fchmod() could
* take effect before all the data blocks are written. Wietse claims that
* this is not a problem. Postfix rejects incomplete queue files, even
* when the +x attribute is set. Every Postfix queue file record has a
* type code and a length field. Files with missing records are rejected,
* as are files with unknown record type codes. Every Postfix queue file
* must end with an explicit END record. Postfix queue files without END
* record are discarded.
*/
if (vstream_fflush(info->stream)
|| fchmod(vstream_fileno(info->stream), 0700 | info->mode)
#ifdef HAS_FSYNC
|| fsync(vstream_fileno(info->stream))
#endif
)
status = (errno == EFBIG ? CLEANUP_STAT_SIZE : CLEANUP_STAT_WRITE);
/*
* Close the queue file and mark it as closed. Be prepared for
* vstream_fclose() to fail even after vstream_fflush() and fsync()
* reported no error. Reason: after a file is closed, some networked file
* systems copy the file out to another machine. Running the queue on a
* remote file system is not recommended, if only for performance
* reasons.
*/
if (info->close(info->stream))
status = (errno == EFBIG ? CLEANUP_STAT_SIZE : CLEANUP_STAT_WRITE);
info->stream = 0;
/*
* When all is well, notify the next service that a new message has been
* queued.
*/
if (status == CLEANUP_STAT_OK)
mail_trigger(info->class, info->service, wakeup, sizeof(wakeup));
/*
* Cleanup.
*/
mail_stream_cleanup(info);
return (status);
}
/* mail_stream_finish_ipc - finish IPC mail stream */
static int mail_stream_finish_ipc(MAIL_STREAM * info, VSTRING *why)
{
int status = CLEANUP_STAT_WRITE;
/*
* Receive the peer's completion status.
*/
if ((why && attr_scan(info->stream, ATTR_FLAG_STRICT,
ATTR_TYPE_NUM, MAIL_ATTR_STATUS, &status,
ATTR_TYPE_STR, MAIL_ATTR_WHY, why,
ATTR_TYPE_END) != 2)
|| (!why && attr_scan(info->stream, ATTR_FLAG_MISSING,
ATTR_TYPE_NUM, MAIL_ATTR_STATUS, &status,
ATTR_TYPE_END) != 1))
status = CLEANUP_STAT_WRITE;
/*
* Cleanup.
*/
mail_stream_cleanup(info);
return (status);
}
/* mail_stream_finish - finish action */
int mail_stream_finish(MAIL_STREAM * info, VSTRING *why)
{
return (info->finish(info, why));
}
/* mail_stream_file - destination is file */
MAIL_STREAM *mail_stream_file(const char *queue, const char *class,
const char *service, int mode)
{
MAIL_STREAM *info;
VSTREAM *stream;
stream = mail_queue_enter(queue, 0600 | mode);
if (msg_verbose)
msg_info("open %s", VSTREAM_PATH(stream));
info = (MAIL_STREAM *) mymalloc(sizeof(*info));
info->stream = stream;
info->finish = mail_stream_finish_file;
info->close = vstream_fclose;
info->id = mystrdup(basename(VSTREAM_PATH(stream)));
info->class = mystrdup(class);
info->service = mystrdup(service);
info->mode = mode;
return (info);
}
/* mail_stream_service - destination is service */
MAIL_STREAM *mail_stream_service(const char *class, const char *name)
{
VSTREAM *stream;
MAIL_STREAM *info;
if (id_buf == 0)
id_buf = vstring_alloc(10);
stream = mail_connect_wait(class, name);
if (attr_scan(stream, ATTR_FLAG_MISSING,
ATTR_TYPE_STR, MAIL_ATTR_QUEUEID, id_buf, 0) != 1) {
vstream_fclose(stream);
return (0);
} else {
info = (MAIL_STREAM *) mymalloc(sizeof(*info));
info->stream = stream;
info->finish = mail_stream_finish_ipc;
info->close = vstream_fclose;
info->id = mystrdup(vstring_str(id_buf));
info->class = 0;
info->service = 0;
return (info);
}
}
/* mail_stream_command - destination is command */
MAIL_STREAM *mail_stream_command(const char *command)
{
VSTREAM *stream;
MAIL_STREAM *info;
ARGV *export_env;
if (id_buf == 0)
id_buf = vstring_alloc(10);
/*
* Treat fork() failure as a transient problem. Treat bad handshake as a
* permanent error.
*
* XXX Are we invoking a Postfix process or a non-Postfix process? In the
* former case we can share the full environment; in the latter case only
* a restricted environment should be propagated. Even though we are
* talking a Postfix-internal protocol there is no way we can tell what
* is being executed except by duplicating a lot of existing code.
*/
export_env = argv_split(var_export_environ, ", \t\r\n");
while ((stream = vstream_popen(O_RDWR,
VSTREAM_POPEN_COMMAND, command,
VSTREAM_POPEN_EXPORT, export_env->argv,
VSTREAM_POPEN_END)) == 0) {
msg_warn("fork: %m");
sleep(10);
}
argv_free(export_env);
vstream_control(stream,
VSTREAM_CTL_PATH, command,
VSTREAM_CTL_END);
if (attr_scan(stream, ATTR_FLAG_MISSING,
ATTR_TYPE_STR, MAIL_ATTR_QUEUEID, id_buf, 0) != 1) {
vstream_pclose(stream);
return (0);
} else {
info = (MAIL_STREAM *) mymalloc(sizeof(*info));
info->stream = stream;
info->finish = mail_stream_finish_ipc;
info->close = vstream_pclose;
info->id = mystrdup(vstring_str(id_buf));
info->class = 0;
info->service = 0;
return (info);
}
}
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