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local.c
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local.c
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/*
* Copyright (c) 2008-2014, Simon Schubert <[email protected]>.
* Copyright (c) 2008 The DragonFly Project. All rights reserved.
*
* This code is derived from software contributed to The DragonFly Project
* by Simon Schubert <[email protected]>.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name of The DragonFly Project nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific, prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/types.h>
#include <sys/wait.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <paths.h>
#include <signal.h>
#include <stdint.h>
#include <stdio.h>
#include <syslog.h>
#include <unistd.h>
#include "dma.h"
static int
create_mbox(const char *name)
{
struct sigaction sa, osa;
pid_t child, waitchild;
int status;
int i;
long maxfd;
int e;
int r = -1;
/*
* We need to enable SIGCHLD temporarily so that waitpid works.
*/
bzero(&sa, sizeof(sa));
sa.sa_handler = SIG_DFL;
sigaction(SIGCHLD, &sa, &osa);
do_timeout(100, 0);
child = fork();
switch (child) {
case 0:
/* child */
maxfd = sysconf(_SC_OPEN_MAX);
if (maxfd == -1)
maxfd = 1024; /* what can we do... */
for (i = 3; i <= maxfd; ++i)
close(i);
execl(LIBEXEC_PATH "/dma-mbox-create", "dma-mbox-create", name, NULL);
syslog(LOG_ERR, "cannot execute "LIBEXEC_PATH"/dma-mbox-create: %m");
exit(EX_SOFTWARE);
default:
/* parent */
waitchild = waitpid(child, &status, 0);
e = errno;
do_timeout(0, 0);
if (waitchild == -1 && e == EINTR) {
syslog(LOG_ERR, "hung child while creating mbox `%s': %m", name);
break;
}
if (waitchild == -1) {
syslog(LOG_ERR, "child disappeared while creating mbox `%s': %m", name);
break;
}
if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
syslog(LOG_ERR, "error creating mbox `%s'", name);
break;
}
/* success */
r = 0;
break;
case -1:
/* error */
syslog(LOG_ERR, "error creating mbox");
break;
}
sigaction(SIGCHLD, &osa, NULL);
return (r);
}
int
deliver_local(struct qitem *it)
{
char fn[PATH_MAX+1];
char line[1000];
const char *sender;
const char *newline = "\n";
size_t linelen;
int tries = 0;
int mbox;
int error;
int hadnl = 0;
off_t mboxlen;
time_t now = time(NULL);
error = snprintf(fn, sizeof(fn), "%s/%s", _PATH_MAILDIR, it->addr);
if (error < 0 || (size_t)error >= sizeof(fn)) {
syslog(LOG_NOTICE, "local delivery deferred: %m");
return (1);
}
retry:
/* wait for a maximum of 100s to get the lock to the file */
do_timeout(100, 0);
/* don't use O_CREAT here, because we might be running as the wrong user. */
mbox = open_locked(fn, O_WRONLY|O_APPEND);
if (mbox < 0) {
int e = errno;
do_timeout(0, 0);
switch (e) {
case EACCES:
case ENOENT:
/*
* The file does not exist or we can't access it.
* Call dma-mbox-create to create it and fix permissions.
*/
if (tries > 0 || create_mbox(it->addr) != 0) {
syslog(LOG_ERR, "local delivery deferred: can not create `%s'", fn);
return (1);
}
++tries;
goto retry;
case EINTR:
syslog(LOG_NOTICE, "local delivery deferred: can not lock `%s'", fn);
break;
default:
syslog(LOG_NOTICE, "local delivery deferred: can not open `%s': %m", fn);
break;
}
return (1);
}
do_timeout(0, 0);
mboxlen = lseek(mbox, 0, SEEK_END);
/* New mails start with \nFrom ...., unless we're at the beginning of the mbox */
if (mboxlen == 0)
newline = "";
/* If we're bouncing a message, claim it comes from MAILER-DAEMON */
sender = it->sender;
if (strcmp(sender, "") == 0)
sender = "MAILER-DAEMON";
if (fseek(it->mailf, 0, SEEK_SET) != 0) {
syslog(LOG_NOTICE, "local delivery deferred: can not seek: %m");
goto out;
}
error = snprintf(line, sizeof(line), "%sFrom %s\t%s", newline, sender, ctime(&now));
if (error < 0 || (size_t)error >= sizeof(line)) {
syslog(LOG_NOTICE, "local delivery deferred: can not write header: %m");
goto out;
}
if (write(mbox, line, error) != error)
goto wrerror;
while (!feof(it->mailf)) {
if (fgets(line, sizeof(line), it->mailf) == NULL)
break;
linelen = strlen(line);
if (linelen == 0 || line[linelen - 1] != '\n') {
syslog(LOG_CRIT, "local delivery failed: corrupted queue file");
snprintf(errmsg, sizeof(errmsg), "corrupted queue file");
error = -1;
goto chop;
}
/*
* mboxro processing:
* - escape lines that start with "From " with a > sign.
* - be reversable by escaping lines that contain an arbitrary
* number of > signs, followed by "From ", i.e. />*From / in regexp.
* - strict mbox processing only requires escaping after empty lines,
* yet most MUAs seem to relax this requirement and will treat any
* line starting with "From " as the beginning of a new mail.
*/
if ((!MBOX_STRICT || hadnl) &&
strncmp(&line[strspn(line, ">")], "From ", 5) == 0) {
const char *gt = ">";
if (write(mbox, gt, 1) != 1)
goto wrerror;
hadnl = 0;
} else if (strcmp(line, "\n") == 0) {
hadnl = 1;
} else {
hadnl = 0;
}
if ((size_t)write(mbox, line, linelen) != linelen)
goto wrerror;
}
close(mbox);
return (0);
wrerror:
syslog(LOG_ERR, "local delivery failed: write error: %m");
error = 1;
chop:
if (ftruncate(mbox, mboxlen) != 0)
syslog(LOG_WARNING, "error recovering mbox `%s': %m", fn);
out:
close(mbox);
return (error);
}