Fix GNU/Hurd build. Bug 3044

[exim.git] / src / src / log.c

diff --git a/src/src/log.c b/src/src/log.c
index 755119813494913315de7a968db25acb3d86b9ea..1a77f2cdbb5d7081f5bd1ba619426535518d84b4 100644 (file)
--- a/src/src/log.c
+++ b/src/src/log.c
@@ -2,8 +2,10 @@
 *     Exim - an Internet mail transport agent    *
 *************************************************/
 
 *     Exim - an Internet mail transport agent    *
 *************************************************/
 

+/* Copyright (c) The Exim Maintainers 2020 - 2023 */

 /* Copyright (c) University of Cambridge 1995 - 2018 */
 /* See the file NOTICE for conditions of use and distribution. */
 /* Copyright (c) University of Cambridge 1995 - 2018 */
 /* See the file NOTICE for conditions of use and distribution. */

+/* SPDX-License-Identifier: GPL-2.0-or-later */

 
 /* Functions for writing log files. The code for maintaining datestamped
 log files was originally contributed by Tony Sheen. */
 
 /* Functions for writing log files. The code for maintaining datestamped
 log files was originally contributed by Tony Sheen. */


@@ -11,7 +13,6 @@ log files was originally contributed by Tony Sheen. */
 
 #include "exim.h"
 
 
 #include "exim.h"
 

-#define LOG_NAME_SIZE 256

 #define MAX_SYSLOG_LEN 870
 
 #define LOG_MODE_FILE   1
 #define MAX_SYSLOG_LEN 870
 
 #define LOG_MODE_FILE   1


@@ -29,7 +30,6 @@ static uschar *log_names[] = { US"main", US"reject", US"panic", US"debug" };
 
 static uschar mainlog_name[LOG_NAME_SIZE];
 static uschar rejectlog_name[LOG_NAME_SIZE];
 
 static uschar mainlog_name[LOG_NAME_SIZE];
 static uschar rejectlog_name[LOG_NAME_SIZE];

-static uschar debuglog_name[LOG_NAME_SIZE];

 
 static uschar *mainlog_datestamp = NULL;
 static uschar *rejectlog_datestamp = NULL;
 
 static uschar *mainlog_datestamp = NULL;
 static uschar *rejectlog_datestamp = NULL;


@@ -54,64 +54,68 @@ static size_t pid_position[2];
 number definitions in macros.h */
 
 static const uschar * exim_errstrings[] = {
 number definitions in macros.h */
 
 static const uschar * exim_errstrings[] = {

-  US"",
-  US"unknown error",
-  US"user slash",
-  US"exist race",
-  US"not regular",
-  US"not directory",
-  US"bad ugid",
-  US"bad mode",
-  US"inode changed",
-  US"lock failed",
-  US"bad address2",
-  US"forbid pipe",
-  US"forbid file",
-  US"forbid reply",
-  US"missing pipe",
-  US"missing file",
-  US"missing reply",
-  US"bad redirect",
-  US"smtp closed",
-  US"smtp format",
-  US"spool format",
-  US"not absolute",
-  US"Exim-imposed quota",
-  US"held",
-  US"Delivery filter process failure",
-  US"Delivery add/remove header failure",
-  US"Delivery write incomplete error",
-  US"Some expansion failed",
-  US"Failed to get gid",
-  US"Failed to get uid",
-  US"Unset or non-existent transport",
-  US"MBX length mismatch",
-  US"Lookup failed routing or in smtp tpt",
-  US"Can't match format in appendfile",
-  US"Creation outside home in appendfile",
-  US"Can't check a list; lookup defer",
-  US"DNS lookup defer",
-  US"Failed to start TLS session",
-  US"Mandatory TLS session not started",
-  US"Failed to chown a file",
-  US"Failed to create a pipe",
-  US"When verifying",
-  US"When required by client",
-  US"Used internally in smtp transport",
-  US"RCPT gave 4xx error",
-  US"MAIL gave 4xx error",
-  US"DATA gave 4xx error",
-  US"Negotiation failed for proxy configured host",
-  US"Authenticator 'other' failure",
-  US"target not supporting SMTPUTF8",
-  US"",
-
-  US"Not time for routing",
-  US"Not time for local delivery",
-  US"Not time for any remote host",
-  US"Local-only delivery",
-  US"Domain in queue_domains",
-  US"Transport concurrency limit",
+  [0] = US"",
+  [- ERRNO_UNKNOWNERROR] =     US"unknown error",
+  [- ERRNO_USERSLASH] =                US"user slash",
+  [- ERRNO_EXISTRACE] =                US"exist race",
+  [- ERRNO_NOTREGULAR] =       US"not regular",
+  [- ERRNO_NOTDIRECTORY] =     US"not directory",
+  [- ERRNO_BADUGID] =          US"bad ugid",
+  [- ERRNO_BADMODE] =          US"bad mode",
+  [- ERRNO_INODECHANGED] =     US"inode changed",
+  [- ERRNO_LOCKFAILED] =       US"lock failed",
+  [- ERRNO_BADADDRESS2] =      US"bad address2",
+  [- ERRNO_FORBIDPIPE] =       US"forbid pipe",
+  [- ERRNO_FORBIDFILE] =       US"forbid file",
+  [- ERRNO_FORBIDREPLY] =      US"forbid reply",
+  [- ERRNO_MISSINGPIPE] =      US"missing pipe",
+  [- ERRNO_MISSINGFILE] =      US"missing file",
+  [- ERRNO_MISSINGREPLY] =     US"missing reply",
+  [- ERRNO_BADREDIRECT] =      US"bad redirect",
+  [- ERRNO_SMTPCLOSED] =       US"smtp closed",
+  [- ERRNO_SMTPFORMAT] =       US"smtp format",
+  [- ERRNO_SPOOLFORMAT] =      US"spool format",
+  [- ERRNO_NOTABSOLUTE] =      US"not absolute",
+  [- ERRNO_EXIMQUOTA] =                US"Exim-imposed quota",
+  [- ERRNO_HELD] =             US"held",
+  [- ERRNO_FILTER_FAIL] =      US"Delivery filter process failure",
+  [- ERRNO_CHHEADER_FAIL] =    US"Delivery add/remove header failure",
+  [- ERRNO_WRITEINCOMPLETE] =  US"Delivery write incomplete error",
+  [- ERRNO_EXPANDFAIL] =       US"Some expansion failed",
+  [- ERRNO_GIDFAIL] =          US"Failed to get gid",
+  [- ERRNO_UIDFAIL] =          US"Failed to get uid",
+  [- ERRNO_BADTRANSPORT] =     US"Unset or non-existent transport",
+  [- ERRNO_MBXLENGTH] =                US"MBX length mismatch",
+  [- ERRNO_UNKNOWNHOST] =      US"Lookup failed routing or in smtp tpt",
+  [- ERRNO_FORMATUNKNOWN] =    US"Can't match format in appendfile",
+  [- ERRNO_BADCREATE] =                US"Creation outside home in appendfile",
+  [- ERRNO_LISTDEFER] =                US"Can't check a list; lookup defer",
+  [- ERRNO_DNSDEFER] =         US"DNS lookup defer",
+  [- ERRNO_TLSFAILURE] =       US"Failed to start TLS session",
+  [- ERRNO_TLSREQUIRED] =      US"Mandatory TLS session not started",
+  [- ERRNO_CHOWNFAIL] =                US"Failed to chown a file",
+  [- ERRNO_PIPEFAIL] =         US"Failed to create a pipe",
+  [- ERRNO_CALLOUTDEFER] =     US"When verifying",
+  [- ERRNO_AUTHFAIL] =         US"When required by client",
+  [- ERRNO_CONNECTTIMEOUT] =   US"Used internally in smtp transport",
+  [- ERRNO_RCPT4XX] =          US"RCPT gave 4xx error",
+  [- ERRNO_MAIL4XX] =          US"MAIL gave 4xx error",
+  [- ERRNO_DATA4XX] =          US"DATA gave 4xx error",
+  [- ERRNO_PROXYFAIL] =                US"Negotiation failed for proxy configured host",
+  [- ERRNO_AUTHPROB] =         US"Authenticator 'other' failure",
+  [- ERRNO_UTF8_FWD] =         US"target not supporting SMTPUTF8",
+  [- ERRNO_HOST_IS_LOCAL] =    US"host is local",
+  [- ERRNO_TAINT] =            US"tainted filename",
+
+  [- ERRNO_RRETRY] =           US"Not time for routing",
+
+  [- ERRNO_LRETRY] =           US"Not time for local delivery",
+  [- ERRNO_HRETRY] =           US"Not time for any remote host",
+  [- ERRNO_LOCAL_ONLY] =       US"Local-only delivery",
+  [- ERRNO_QUEUE_DOMAIN] =     US"Domain in queue_domains",
+  [- ERRNO_TRETRY] =           US"Transport concurrency limit",
+
+  [- ERRNO_EVENT] =            US"Event requests alternate response",

 };
 
 
 };
 
 


@@ -134,33 +138,36 @@ can get here if there is a failure to open the panic log.)
 
 Arguments:
   priority       syslog priority
 
 Arguments:
   priority       syslog priority

-  s              the string to be written, the string may be modified!
+  s              the string to be written

 
 Returns:         nothing
 */
 
 static void
 
 Returns:         nothing
 */
 
 static void

-write_syslog(int priority, uschar *s)
+write_syslog(int priority, const uschar *s)

 {
 {

-int len, pass;
+int len;

 int linecount = 0;
 
 int linecount = 0;
 

-if (running_in_test_harness) return;
-
-if (!syslog_timestamp) s += log_timezone ? 26 : 20;

 if (!syslog_pid && LOGGING(pid))
 if (!syslog_pid && LOGGING(pid))

-    memmove(s + pid_position[0], s + pid_position[1], pid_position[1] - pid_position[0]);
+  s = string_sprintf("%.*s%s", (int)pid_position[0], s, s + pid_position[1]);
+if (!syslog_timestamp)
+  {
+  len = log_timezone ? 26 : 20;
+  if (LOGGING(millisec)) len += 4;
+  s += len;
+  }

 
 len = Ustrlen(s);
 
 #ifndef NO_OPENLOG
 
 len = Ustrlen(s);
 
 #ifndef NO_OPENLOG

-if (!syslog_open)
+if (!syslog_open && !f.running_in_test_harness)

   {
   {

-  #ifdef SYSLOG_LOG_PID
+# ifdef SYSLOG_LOG_PID

   openlog(CS syslog_processname, LOG_PID|LOG_CONS, syslog_facility);
   openlog(CS syslog_processname, LOG_PID|LOG_CONS, syslog_facility);

-  #else
+# else

   openlog(CS syslog_processname, LOG_CONS, syslog_facility);
   openlog(CS syslog_processname, LOG_CONS, syslog_facility);

-  #endif
+# endif

   syslog_open = TRUE;
   }
 #endif
   syslog_open = TRUE;
   }
 #endif


@@ -168,31 +175,37 @@ if (!syslog_open)
 /* First do a scan through the message in order to determine how many lines
 it is going to end up as. Then rescan to output it. */
 
 /* First do a scan through the message in order to determine how many lines
 it is going to end up as. Then rescan to output it. */
 

-for (pass = 0; pass < 2; pass++)
+for (int pass = 0; pass < 2; pass++)

   {
   {

-  int i;
-  int tlen;
-  uschar *ss = s;
-  for (i = 1, tlen = len; tlen > 0; i++)
+  const uschar * ss = s;
+  for (int i = 1, tlen = len; tlen > 0; i++)

     {
     int plen = tlen;
     uschar *nlptr = Ustrchr(ss, '\n');
     if (nlptr != NULL) plen = nlptr - ss;
     {
     int plen = tlen;
     uschar *nlptr = Ustrchr(ss, '\n');
     if (nlptr != NULL) plen = nlptr - ss;

-    #ifndef SYSLOG_LONG_LINES
+#ifndef SYSLOG_LONG_LINES

     if (plen > MAX_SYSLOG_LEN) plen = MAX_SYSLOG_LEN;
     if (plen > MAX_SYSLOG_LEN) plen = MAX_SYSLOG_LEN;

-    #endif
+#endif

     tlen -= plen;
     if (ss[plen] == '\n') tlen--;    /* chars left */
 
     tlen -= plen;
     if (ss[plen] == '\n') tlen--;    /* chars left */
 

-    if (pass == 0) linecount++; else
-      {
+    if (pass == 0)
+      linecount++;
+    else if (f.running_in_test_harness)
+      if (linecount == 1)
+        fprintf(stderr, "SYSLOG: '%.*s'\n", plen, ss);
+      else
+        fprintf(stderr, "SYSLOG: '[%d%c%d] %.*s'\n", i,
+          ss[plen] == '\n' && tlen != 0 ? '\\' : '/',
+          linecount, plen, ss);
+    else

       if (linecount == 1)
         syslog(priority, "%.*s", plen, ss);
       else
         syslog(priority, "[%d%c%d] %.*s", i,
       if (linecount == 1)
         syslog(priority, "%.*s", plen, ss);
       else
         syslog(priority, "[%d%c%d] %.*s", i,

-          (ss[plen] == '\n' && tlen != 0)? '\\' : '/',
+          ss[plen] == '\n' && tlen != 0 ? '\\' : '/',

           linecount, plen, ss);
           linecount, plen, ss);

-      }
+

     ss += plen;
     if (*ss == '\n') ss++;
     }
     ss += plen;
     if (*ss == '\n') ss++;
     }


@@ -227,12 +240,12 @@ if (s1)
   {
   write_syslog(LOG_CRIT, s1);
   if (debug_file) debug_printf("%s\n", s1);
   {
   write_syslog(LOG_CRIT, s1);
   if (debug_file) debug_printf("%s\n", s1);

-  if (log_stderr != NULL && log_stderr != debug_file)
+  if (log_stderr && log_stderr != debug_file)

     fprintf(log_stderr, "%s\n", s1);
   }
     fprintf(log_stderr, "%s\n", s1);
   }

-if (receive_call_bombout) receive_bomb_out(NULL, s2);  /* does not return */
+if (f.receive_call_bombout) receive_bomb_out(NULL, s2);  /* does not return */

 if (smtp_input) smtp_closedown(s2);
 if (smtp_input) smtp_closedown(s2);

-exim_exit(EXIT_FAILURE, NULL);
+exim_exit(EXIT_FAILURE);

 }
 
 
 }
 
 


@@ -253,14 +266,19 @@ overwrite it temporarily if it is necessary to create the directory.
 Returns:       a file descriptor, or < 0 on failure (errno set)
 */
 
 Returns:       a file descriptor, or < 0 on failure (errno set)
 */
 

-int
-log_create(uschar *name)
+static int
+log_open_already_exim(const uschar * const name)

 {
 {

-int fd = Uopen(name,
-#ifdef O_CLOEXEC
-       O_CLOEXEC |
-#endif
-       O_CREAT|O_APPEND|O_WRONLY, LOG_MODE);
+int fd = -1;
+const int flags = O_WRONLY | O_APPEND | O_CREAT | O_NONBLOCK;
+
+if (geteuid() != exim_uid)
+  {
+  errno = EACCES;
+  return -1;
+  }
+
+fd = Uopen(name, flags, LOG_MODE);

 
 /* If creation failed, attempt to build a log directory in case that is the
 problem. */
 
 /* If creation failed, attempt to build a log directory in case that is the
 problem. */


@@ -271,14 +289,13 @@ if (fd < 0 && errno == ENOENT)
   uschar *lastslash = Ustrrchr(name, '/');
   *lastslash = 0;
   created = directory_make(NULL, name, LOG_DIRECTORY_MODE, FALSE);
   uschar *lastslash = Ustrrchr(name, '/');
   *lastslash = 0;
   created = directory_make(NULL, name, LOG_DIRECTORY_MODE, FALSE);

-  DEBUG(D_any) debug_printf("%s log directory %s\n",
-    created ? "created" : "failed to create", name);
+  DEBUG(D_any)
+    if (created)
+      debug_printf("created log directory %s\n", name);
+    else
+      debug_printf("failed to create log directory %s: %s\n", name, strerror(errno));

   *lastslash = '/';
   *lastslash = '/';

-  if (created) fd = Uopen(name,
-#ifdef O_CLOEXEC
-                       O_CLOEXEC |
-#endif
-                       O_CREAT|O_APPEND|O_WRONLY, LOG_MODE);
+  if (created) fd = Uopen(name, flags, LOG_MODE);

   }
 
 return fd;
   }
 
 return fd;


@@ -286,6 +303,79 @@ return fd;
 
 
 
 
 
 

+/* Inspired by OpenSSH's mm_send_fd(). Thanks!
+Send fd over socketpair.
+Return: true iff good.
+*/
+
+static BOOL
+log_send_fd(const int sock, const int fd)
+{
+struct msghdr msg;
+union {
+  struct cmsghdr hdr;
+  char buf[CMSG_SPACE(sizeof(int))];
+} cmsgbuf;
+struct cmsghdr *cmsg;
+char ch = 'A';
+struct iovec vec = {.iov_base = &ch, .iov_len = 1};
+ssize_t n;
+
+memset(&msg, 0, sizeof(msg));
+memset(&cmsgbuf, 0, sizeof(cmsgbuf));
+msg.msg_control = &cmsgbuf.buf;
+msg.msg_controllen = sizeof(cmsgbuf.buf);
+
+cmsg = CMSG_FIRSTHDR(&msg);
+cmsg->cmsg_len = CMSG_LEN(sizeof(int));
+cmsg->cmsg_level = SOL_SOCKET;
+cmsg->cmsg_type = SCM_RIGHTS;
+*(int *)CMSG_DATA(cmsg) = fd;
+
+msg.msg_iov = &vec;
+msg.msg_iovlen = 1;
+
+while ((n = sendmsg(sock, &msg, 0)) == -1 && errno == EINTR);
+return n == 1;
+}
+
+/* Inspired by OpenSSH's mm_receive_fd(). Thanks!
+Return fd passed over socketpair, or -1 on error.
+*/
+
+static int
+log_recv_fd(const int sock)
+{
+struct msghdr msg;
+union {
+  struct cmsghdr hdr;
+  char buf[CMSG_SPACE(sizeof(int))];
+} cmsgbuf;
+struct cmsghdr *cmsg;
+char ch = '\0';
+struct iovec vec = {.iov_base = &ch, .iov_len = 1};
+ssize_t n;
+int fd;
+
+memset(&msg, 0, sizeof(msg));
+msg.msg_iov = &vec;
+msg.msg_iovlen = 1;
+
+memset(&cmsgbuf, 0, sizeof(cmsgbuf));
+msg.msg_control = &cmsgbuf.buf;
+msg.msg_controllen = sizeof(cmsgbuf.buf);
+
+while ((n = recvmsg(sock, &msg, 0)) == -1 && errno == EINTR) ;
+if (n != 1 || ch != 'A') return -1;
+
+if (!(cmsg = CMSG_FIRSTHDR(&msg))) return -1;
+if (cmsg->cmsg_type != SCM_RIGHTS) return -1;
+if ((fd = *(const int *)CMSG_DATA(cmsg)) < 0) return -1;
+return fd;
+}
+
+
+

 /*************************************************
 *     Create a log file as the exim user         *
 *************************************************/
 /*************************************************
 *     Create a log file as the exim user         *
 *************************************************/


@@ -301,41 +391,56 @@ Returns:       a file descriptor, or < 0 on failure (errno set)
 */
 
 int
 */
 
 int

-log_create_as_exim(uschar *name)
+log_open_as_exim(const uschar * const name)

 {
 {

-pid_t pid = fork();
-int status = 1;

 int fd = -1;
 int fd = -1;

+const uid_t euid = geteuid();

 
 

-/* In the subprocess, change uid/gid and do the creation. Return 0 from the
-subprocess on success. If we don't check for setuid failures, then the file
-can be created as root, so vulnerabilities which cause setuid to fail mean
-that the Exim user can use symlinks to cause a file to be opened/created as
-root. We always open for append, so can't nuke existing content but it would
-still be Rather Bad. */
-
-if (pid == 0)
+if (euid == exim_uid)
+  fd = log_open_already_exim(name);
+else if (euid == root_uid)

   {
   {

-  if (setgid(exim_gid) < 0)
-    die(US"exim: setgid for log-file creation failed, aborting",
-      US"Unexpected log failure, please try later");
-  if (setuid(exim_uid) < 0)
-    die(US"exim: setuid for log-file creation failed, aborting",
-      US"Unexpected log failure, please try later");
-  _exit((log_create(name) < 0)? 1 : 0);
-  }
-
-/* If we created a subprocess, wait for it. If it succeeded, try the open. */
+  int sock[2];
+  if (socketpair(AF_UNIX, SOCK_STREAM, 0, sock) == 0)
+    {
+    const pid_t pid = fork();
+    if (pid == 0)
+      {
+      (void)close(sock[0]);
+      if (  setgroups(1, &exim_gid) != 0
+         || setgid(exim_gid) != 0
+         || setuid(exim_uid) != 0
+
+         || getuid() != exim_uid || geteuid() != exim_uid
+         || getgid() != exim_gid || getegid() != exim_gid
+
+         || (fd = log_open_already_exim(name)) < 0
+         || !log_send_fd(sock[1], fd)
+        ) _exit(EXIT_FAILURE);
+      (void)close(sock[1]);
+      _exit(EXIT_SUCCESS);
+      }

 
 

-while (pid > 0 && waitpid(pid, &status, 0) != pid);
-if (status == 0) fd = Uopen(name,
-#ifdef O_CLOEXEC
-                       O_CLOEXEC |
-#endif
-                       O_APPEND|O_WRONLY, LOG_MODE);
+    (void)close(sock[1]);
+    if (pid > 0)
+      {
+      fd = log_recv_fd(sock[0]);
+      while (waitpid(pid, NULL, 0) == -1 && errno == EINTR);
+      }
+    (void)close(sock[0]);
+    }
+  }

 
 

-/* If we failed to create a subprocess, we are in a bad way. We return
-with fd still < 0, and errno set, letting the caller handle the error. */
+if (fd >= 0)
+  {
+  int flags;
+  flags = fcntl(fd, F_GETFD);
+  if (flags != -1) (void)fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
+  flags = fcntl(fd, F_GETFL);
+  if (flags != -1) (void)fcntl(fd, F_SETFL, flags & ~O_NONBLOCK);
+  }
+else
+  errno = EACCES;

 
 return fd;
 }
 
 return fd;
 }


@@ -351,7 +456,7 @@ return fd;
 it does not exist. This may be called recursively on failure, in order to open
 the panic log.
 
 it does not exist. This may be called recursively on failure, in order to open
 the panic log.
 

-The directory is in the static variable file_path. This is static so that it
+The directory is in the static variable file_path. This is static so that

 the work of sorting out the path is done just once per Exim process.
 
 Exim is normally configured to avoid running as root wherever possible, the log
 the work of sorting out the path is done just once per Exim process.
 
 Exim is normally configured to avoid running as root wherever possible, the log


@@ -369,7 +474,7 @@ Returns:   nothing
 */
 
 static void
 */
 
 static void

-open_log(int *fd, int type, uschar *tag)
+open_log(int * fd, int type, const uschar * tag)

 {
 uid_t euid;
 BOOL ok, ok2;
 {
 uid_t euid;
 BOOL ok, ok2;


@@ -386,61 +491,64 @@ people want, I hope. */
 
 ok = string_format(buffer, sizeof(buffer), CS file_path, log_names[type]);
 
 
 ok = string_format(buffer, sizeof(buffer), CS file_path, log_names[type]);
 

-/* Save the name of the mainlog for rollover processing. Without a datestamp,
-it gets statted to see if it has been cycled. With a datestamp, the datestamp
-will be compared. The static slot for saving it is the same size as buffer,
-and the text has been checked above to fit, so this use of strcpy() is OK. */
-
-if (type == lt_main && string_datestamp_offset >= 0)
+switch (type)

   {
   {

-  Ustrcpy(mainlog_name, buffer);
-  mainlog_datestamp = mainlog_name + string_datestamp_offset;
-  }
-
-/* Ditto for the reject log */
-
-else if (type == lt_reject && string_datestamp_offset >= 0)
-  {
-  Ustrcpy(rejectlog_name, buffer);
-  rejectlog_datestamp = rejectlog_name + string_datestamp_offset;
-  }
-
-/* and deal with the debug log (which keeps the datestamp, but does not
-update it) */
+  case lt_main:
+    /* Save the name of the mainlog for rollover processing. Without a datestamp,
+    it gets statted to see if it has been cycled. With a datestamp, the datestamp
+    will be compared. The static slot for saving it is the same size as buffer,
+    and the text has been checked above to fit, so this use of strcpy() is OK. */
+    Ustrcpy(mainlog_name, buffer);
+    if (string_datestamp_offset > 0)
+      mainlog_datestamp = mainlog_name + string_datestamp_offset;
+    break;

 
 

-else if (type == lt_debug)
-  {
-  Ustrcpy(debuglog_name, buffer);
-  if (tag)
-    {
-    /* this won't change the offset of the datestamp */
-    ok2 = string_format(buffer, sizeof(buffer), "%s%s",
-      debuglog_name, tag);
-    if (ok2)
-      Ustrcpy(debuglog_name, buffer);
-    }
-  }
+  case lt_reject:
+    /* Ditto for the reject log */
+    Ustrcpy(rejectlog_name, buffer);
+    if (string_datestamp_offset > 0)
+      rejectlog_datestamp = rejectlog_name + string_datestamp_offset;
+    break;

 
 

-/* Remove any datestamp if this is the panic log. This is rare, so there's no
-need to optimize getting the datestamp length. We remove one non-alphanumeric
-char afterwards if at the start, otherwise one before. */
+  case lt_debug:
+    /* and deal with the debug log (which keeps the datestamp, but does not
+    update it) */
+    Ustrcpy(debuglog_name, buffer);
+    if (tag)
+      {
+      if (is_tainted(tag))
+       die(US"exim: tainted tag for debug log filename",
+             US"Logging failure; please try later");
+
+      /* this won't change the offset of the datestamp */
+      ok2 = string_format(buffer, sizeof(buffer), "%s%s",
+        debuglog_name, tag);
+      if (ok2)
+        Ustrcpy(debuglog_name, buffer);
+      }
+    break;

 
 

-else if (string_datestamp_offset >= 0)
-  {
-  uschar *from = buffer + string_datestamp_offset;
-  uschar *to = from + string_datestamp_length;
-  if (from == buffer || from[-1] == '/')
-    {
-    if (!isalnum(*to)) to++;
-    }
-  else
-    {
-    if (!isalnum(from[-1])) from--;
-    }
+  default:
+    /* Remove any datestamp if this is the panic log. This is rare, so there's no
+    need to optimize getting the datestamp length. We remove one non-alphanumeric
+    char afterwards if at the start, otherwise one before. */
+    if (string_datestamp_offset >= 0)
+      {
+      uschar * from = buffer + string_datestamp_offset;
+      uschar * to = from + string_datestamp_length;

 
 

-  /* This strcpy is ok, because we know that to is a substring of from. */
+      if (from == buffer || from[-1] == '/')
+        {
+        if (!isalnum(*to)) to++;
+        }
+      else
+        if (!isalnum(from[-1])) from--;

 
 

-  Ustrcpy(from, to);
+      /* This copy is ok, because we know that to is a substring of from. But
+      due to overlap we must use memmove() not Ustrcpy(). */
+      memmove(from, to, Ustrlen(to)+1);
+      }
+    break;

   }
 
 /* If the file name is too long, it is an unrecoverable disaster */
   }
 
 /* If the file name is too long, it is an unrecoverable disaster */


@@ -449,59 +557,20 @@ if (!ok)
   die(US"exim: log file path too long: aborting",
       US"Logging failure; please try later");
 
   die(US"exim: log file path too long: aborting",
       US"Logging failure; please try later");
 

-/* We now have the file name. Try to open an existing file. After a successful
-open, arrange for automatic closure on exec(), and then return. */
+/* We now have the file name. After a successful open, return. */

 
 

-*fd = Uopen(buffer,
-#ifdef O_CLOEXEC
-               O_CLOEXEC |
-#endif
-               O_APPEND|O_WRONLY, LOG_MODE);
-
-if (*fd >= 0)
-  {
-#ifndef O_CLOEXEC
-  (void)fcntl(*fd, F_SETFD, fcntl(*fd, F_GETFD) | FD_CLOEXEC);
-#endif
+if ((*fd = log_open_as_exim(buffer)) >= 0)

   return;
   return;

-  }
-
-/* Open was not successful: try creating the file. If this is a root process,
-we must do the creating in a subprocess set to exim:exim in order to ensure
-that the file is created with the right ownership. Otherwise, there can be a
-race if another Exim process is trying to write to the log at the same time.
-The use of SIGUSR1 by the exiwhat utility can provoke a lot of simultaneous
-writing. */

 
 euid = geteuid();
 
 
 euid = geteuid();
 

-/* If we are already running as the Exim user (even if that user is root),
-we can go ahead and create in the current process. */
-
-if (euid == exim_uid) *fd = log_create(buffer);
-
-/* Otherwise, if we are root, do the creation in an exim:exim subprocess. If we
-are neither exim nor root, creation is not attempted. */
-
-else if (euid == root_uid) *fd = log_create_as_exim(buffer);
-
-/* If we now have an open file, set the close-on-exec flag and return. */
-
-if (*fd >= 0)
-  {
-#ifndef O_CLOEXEC
-  (void)fcntl(*fd, F_SETFD, fcntl(*fd, F_GETFD) | FD_CLOEXEC);
-#endif
-  return;
-  }
-

 /* Creation failed. There are some circumstances in which we get here when
 the effective uid is not root or exim, which is the problem. (For example, a
 non-setuid binary with log_arguments set, called in certain ways.) Rather than
 just bombing out, force the log to stderr and carry on if stderr is available.
 */
 
 /* Creation failed. There are some circumstances in which we get here when
 the effective uid is not root or exim, which is the problem. (For example, a
 non-setuid binary with log_arguments set, called in certain ways.) Rather than
 just bombing out, force the log to stderr and carry on if stderr is available.
 */
 

-if (euid != root_uid && euid != exim_uid && log_stderr != NULL)
+if (euid != root_uid && euid != exim_uid && log_stderr)

   {
   *fd = fileno(log_stderr);
   return;
   {
   *fd = fileno(log_stderr);
   return;


@@ -510,7 +579,9 @@ if (euid != root_uid && euid != exim_uid && log_stderr != NULL)
 /* Otherwise this is a disaster. This call is deliberately ONLY to the panic
 log. If possible, save a copy of the original line that was being logged. If we
 are recursing (can't open the panic log either), the pointer will already be
 /* Otherwise this is a disaster. This call is deliberately ONLY to the panic
 log. If possible, save a copy of the original line that was being logged. If we
 are recursing (can't open the panic log either), the pointer will already be

-set. */
+set.  Also, when we had to use a subprocess for the create we didn't retrieve
+errno from it, so get the error from the open attempt above (which is often
+meaningful enough, so leave it). */

 
 if (!panic_save_buffer)
   if ((panic_save_buffer = US malloc(LOG_BUFFER_SIZE)))
 
 if (!panic_save_buffer)
   if ((panic_save_buffer = US malloc(LOG_BUFFER_SIZE)))


@@ -530,6 +601,22 @@ if (type == lt_debug) unlink(CS debuglog_name);
 
 
 
 
 
 

+/* Append to a gstring, in no-extend (or rebuffer) mode
+and without taint-checking.  Thanks to the no-extend, the
+gstring struct never needs reallocation; we ignore the
+infore that the initial space allocation for the string
+was exceeded, and just leave it potentially truncated. */
+
+static void
+string_fmt_append_noextend(gstring * g, char * fmt, ...)
+{
+va_list ap;
+va_start(ap, fmt);
+/* can return NULL if it truncates; just ignore */
+(void) string_vformat(g, SVFMT_TAINT_NOCHK, fmt, ap);
+va_end(ap);
+}
+

 /*************************************************
 *     Add configuration file info to log line    *
 *************************************************/
 /*************************************************
 *     Add configuration file info to log line    *
 *************************************************/


@@ -538,29 +625,28 @@ if (type == lt_debug) unlink(CS debuglog_name);
 once for real).
 
 Arguments:
 once for real).
 
 Arguments:

-  ptr         pointer to the end of the line we are building
-  flags       log flags
+  g            extensible-string referring to static buffer,
+               usable after return
+  flags                log flags

 
 

-Returns:      updated pointer
+Returns:      nothing

 */
 
 */
 

-static uschar *
-log_config_info(uschar *ptr, int flags)
+static void
+log_config_info(gstring * g, int flags)

 {
 {

-Ustrcpy(ptr, "Exim configuration error");
-ptr += 24;
+string_fmt_append_noextend(g, "Exim configuration error");

 
 

-if ((flags & (LOG_CONFIG_FOR & ~LOG_CONFIG)) != 0)
+if (flags & (LOG_CONFIG_FOR & ~LOG_CONFIG))
+  string_fmt_append_noextend(g, " for ");
+else

   {
   {

-  Ustrcpy(ptr, " for ");
-  return ptr + 5;
-  }
-
-if ((flags & (LOG_CONFIG_IN & ~LOG_CONFIG)) != 0)
-  ptr += sprintf(CS ptr, " in line %d of %s", config_lineno, config_filename);
+  if (flags & (LOG_CONFIG_IN & ~LOG_CONFIG))
+    string_fmt_append_noextend(g, " in line %d of %s",
+                                 config_lineno, config_filename);

 
 

-Ustrcpy(ptr, ":\n  ");
-return ptr + 4;
+  string_fmt_append_noextend(g, ":\n  ");
+  }

 }
 
 
 }
 
 


@@ -618,11 +704,11 @@ Returns:
   length actually written, persisting an errno from write()
 */
 ssize_t
   length actually written, persisting an errno from write()
 */
 ssize_t

-write_to_fd_buf(int fd, const uschar *buf, size_t length)
+write_to_fd_buf(int fd, const uschar * buf, size_t length)

 {
 ssize_t wrote;
 size_t total_written = 0;
 {
 ssize_t wrote;
 size_t total_written = 0;

-const uschar *p = buf;
+const uschar * p = buf;

 size_t left = length;
 
 while (1)
 size_t left = length;
 
 while (1)


@@ -645,6 +731,12 @@ while (1)
 return total_written;
 }
 
 return total_written;
 }
 

+static inline ssize_t
+write_gstring_to_fd_buf(int fd, const gstring * g)
+{
+return write_to_fd_buf(fd, g->s, g->ptr);
+}
+

 
 
 static void
 
 
 static void


@@ -662,10 +754,17 @@ while ((t = string_nextinlist(&tt, &sep, log_buffer, LOG_BUFFER_SIZE)))
 }
 
 
 }
 
 

+/* Close mainlog, unless we do not see a chance to open the file mainlog later
+again.  This will happen if we log from a transport process (which has dropped
+privs); something we traditionally avoid, but the introduction of taint-tracking
+and resulting detection of errors is makinng harder. */
+

 void
 mainlog_close(void)
 {
 void
 mainlog_close(void)
 {

-if (mainlogfd < 0) return;
+if (mainlogfd < 0
+   || !(geteuid() == 0 || geteuid() == exim_uid))
+  return;

 (void)close(mainlogfd);
 mainlogfd = -1;
 mainlog_inode = 0;
 (void)close(mainlogfd);
 mainlogfd = -1;
 mainlog_inode = 0;


@@ -731,10 +830,10 @@ Returns:    nothing
 void
 log_write(unsigned int selector, int flags, const char *format, ...)
 {
 void
 log_write(unsigned int selector, int flags, const char *format, ...)
 {

-uschar * ptr;
-int length;

 int paniclogfd;
 ssize_t written_len;
 int paniclogfd;
 ssize_t written_len;

+gstring gs = { .size = LOG_BUFFER_SIZE-2, .ptr = 0, .s = log_buffer };
+gstring * g = &gs;

 va_list ap;
 
 /* If panic_recurseflag is set, we have failed to open the panic log. This is
 va_list ap;
 
 /* If panic_recurseflag is set, we have failed to open the panic log. This is


@@ -744,11 +843,11 @@ original log line that caused the problem. Afterwards, expire. */
 
 if (panic_recurseflag)
   {
 
 if (panic_recurseflag)
   {

-  uschar *extra = (panic_save_buffer == NULL)? US"" : panic_save_buffer;
-  if (debug_file != NULL) debug_printf("%s%s", extra, log_buffer);
-  if (log_stderr != NULL && log_stderr != debug_file)
+  uschar * extra = panic_save_buffer ? panic_save_buffer : US"";
+  if (debug_file) debug_printf("%s%s", extra, log_buffer);
+  if (log_stderr && log_stderr != debug_file)

     fprintf(log_stderr, "%s%s", extra, log_buffer);
     fprintf(log_stderr, "%s%s", extra, log_buffer);

-  if (*extra != 0) write_syslog(LOG_CRIT, extra);
+  if (*extra) write_syslog(LOG_CRIT, extra);

   write_syslog(LOG_CRIT, log_buffer);
   die(US"exim: could not open panic log - aborting: see message(s) above",
     US"Unexpected log failure, please try later");
   write_syslog(LOG_CRIT, log_buffer);
   die(US"exim: could not open panic log - aborting: see message(s) above",
     US"Unexpected log failure, please try later");


@@ -761,7 +860,7 @@ if (!log_buffer)
   if (!(log_buffer = US malloc(LOG_BUFFER_SIZE)))
     {
     fprintf(stderr, "exim: failed to get store for log buffer\n");
   if (!(log_buffer = US malloc(LOG_BUFFER_SIZE)))
     {
     fprintf(stderr, "exim: failed to get store for log buffer\n");

-    exim_exit(EXIT_FAILURE, NULL);
+    exim_exit(EXIT_FAILURE);

     }
 
 /* If we haven't already done so, inspect the setting of log_file_path to
     }
 
 /* If we haven't already done so, inspect the setting of log_file_path to


@@ -785,12 +884,14 @@ if (!path_inspected)
     int sep = ':';              /* Fixed separator - outside use */
     uschar *s;
     const uschar *ss = log_file_path;
     int sep = ':';              /* Fixed separator - outside use */
     uschar *s;
     const uschar *ss = log_file_path;

+

     logging_mode = 0;
     while ((s = string_nextinlist(&ss, &sep, log_buffer, LOG_BUFFER_SIZE)))
       {
       if (Ustrcmp(s, "syslog") == 0)
         logging_mode |= LOG_MODE_SYSLOG;
     logging_mode = 0;
     while ((s = string_nextinlist(&ss, &sep, log_buffer, LOG_BUFFER_SIZE)))
       {
       if (Ustrcmp(s, "syslog") == 0)
         logging_mode |= LOG_MODE_SYSLOG;

-      else if ((logging_mode & LOG_MODE_FILE) != 0) multiple = TRUE;
+      else if (logging_mode & LOG_MODE_FILE)
+       multiple = TRUE;

       else
         {
         logging_mode |= LOG_MODE_FILE;
       else
         {
         logging_mode |= LOG_MODE_FILE;


@@ -820,7 +921,7 @@ if (!path_inspected)
   /* Set up the ultimate default if necessary. Then revert to the old store
   pool, and record that we've sorted out the path. */
 
   /* Set up the ultimate default if necessary. Then revert to the old store
   pool, and record that we've sorted out the path. */
 

-  if ((logging_mode & LOG_MODE_FILE) != 0 && file_path[0] == 0)
+  if (logging_mode & LOG_MODE_FILE  &&  !file_path[0])

     file_path = string_sprintf("%s/log/%%slog", spool_directory);
   store_pool = old_pool;
   path_inspected = TRUE;
     file_path = string_sprintf("%s/log/%%slog", spool_directory);
   store_pool = old_pool;
   path_inspected = TRUE;


@@ -833,59 +934,66 @@ if (!path_inspected)
       "More than one path given in log_file_path: using %s", file_path);
   }
 
       "More than one path given in log_file_path: using %s", file_path);
   }
 

+/* Optionally trigger debug */
+
+if (flags & LOG_PANIC && dtrigger_selector & BIT(DTi_panictrigger))
+  debug_trigger_fire();
+

 /* If debugging, show all log entries, but don't show headers. Do it all
 in one go so that it doesn't get split when multi-processing. */
 
 DEBUG(D_any|D_v)
   {
 /* If debugging, show all log entries, but don't show headers. Do it all
 in one go so that it doesn't get split when multi-processing. */
 
 DEBUG(D_any|D_v)
   {

-  int i;
-  ptr = log_buffer;
-
-  Ustrcpy(ptr, "LOG:");
-  ptr += 4;
+  string_fmt_append_noextend(g, "LOG:");

 
   /* Show the selector that was passed into the call. */
 
 
   /* Show the selector that was passed into the call. */
 

-  for (i = 0; i < log_options_count; i++)
+  for (int i = 0; i < log_options_count; i++)

     {
     unsigned int bitnum = log_options[i].bit;
     if (bitnum < BITWORDSIZE && selector == BIT(bitnum))
     {
     unsigned int bitnum = log_options[i].bit;
     if (bitnum < BITWORDSIZE && selector == BIT(bitnum))

-      {
-      *ptr++ = ' ';
-      Ustrcpy(ptr, log_options[i].name);
-      while (*ptr) ptr++;
-      }
+      string_fmt_append_noextend(g, " %s", log_options[i].name);

     }
 
     }
 

-  ptr += sprintf(CS ptr, "%s%s%s%s\n  ",
-    ((flags & LOG_MAIN) != 0)?    " MAIN"   : "",
-    ((flags & LOG_PANIC) != 0)?   " PANIC"  : "",
-    ((flags & LOG_PANIC_DIE) == LOG_PANIC_DIE)? " DIE" : "",
-    ((flags & LOG_REJECT) != 0)?  " REJECT" : "");
+  string_fmt_append_noextend(g, "%s%s%s%s\n  ",
+    flags & LOG_MAIN ?    " MAIN"   : "",
+    flags & LOG_PANIC ?   " PANIC"  : "",
+    (flags & LOG_PANIC_DIE) == LOG_PANIC_DIE ? " DIE" : "",
+    flags & LOG_REJECT ?  " REJECT" : "");

 
 

-  if ((flags & LOG_CONFIG) != 0) ptr = log_config_info(ptr, flags);
+  if (flags & LOG_CONFIG) log_config_info(g, flags);
+
+  /* We want to be able to log tainted info, but log_buffer is directly
+  malloc'd.  So use deliberately taint-nonchecking routines to build into
+  it, trusting that we will never expand the results. */

 
   va_start(ap, format);
 
   va_start(ap, format);

-  if (!string_vformat(ptr, LOG_BUFFER_SIZE - (ptr-log_buffer)-1, format, ap))
-    Ustrcpy(ptr, "**** log string overflowed log buffer ****");
+  if (!string_vformat(g, SVFMT_TAINT_NOCHK, format, ap))
+    {
+    uschar * s = US"**** log string overflowed log buffer ****";
+    gstring_trim(g, Ustrlen(s));
+    string_fmt_append_noextend(g, "%s", s);
+    }

   va_end(ap);
 
   va_end(ap);
 

-  while(*ptr) ptr++;
-  Ustrcat(ptr, "\n");
-  debug_printf("%s", log_buffer);
-  }
+  debug_printf("%Y\n", g);
+
+  /* Having used the buffer for debug output, reset it for the real use. */

 
 

+  gstring_reset(g);
+  }

 /* If no log file is specified, we are in a mess. */
 
 /* If no log file is specified, we are in a mess. */
 

-if ((flags & (LOG_MAIN|LOG_PANIC|LOG_REJECT)) == 0)
+if (!(flags & (LOG_MAIN|LOG_PANIC|LOG_REJECT)))

   log_write(0, LOG_MAIN|LOG_PANIC_DIE, "log_write called with no log "
     "flags set");
 
 /* There are some weird circumstances in which logging is disabled. */
 
   log_write(0, LOG_MAIN|LOG_PANIC_DIE, "log_write called with no log "
     "flags set");
 
 /* There are some weird circumstances in which logging is disabled. */
 

-if (disable_logging)
+if (f.disable_logging)

   {
   DEBUG(D_any) debug_printf("log writing disabled\n");
   {
   DEBUG(D_any) debug_printf("log writing disabled\n");

+  if ((flags & LOG_PANIC_DIE) == LOG_PANIC_DIE) exim_exit(EXIT_FAILURE);

   return;
   }
 
   return;
   }
 


@@ -896,69 +1004,80 @@ if (!write_rejectlog) flags &= ~LOG_REJECT;
 /* Create the main message in the log buffer. Do not include the message id
 when called by a utility. */
 
 /* Create the main message in the log buffer. Do not include the message id
 when called by a utility. */
 

-ptr = log_buffer;
-ptr += sprintf(CS ptr, "%s ", tod_stamp(tod_log));
+string_fmt_append_noextend(&gs, "%s ", tod_stamp(tod_log));

 
 if (LOGGING(pid))
   {
 
 if (LOGGING(pid))
   {

-  if (!syslog_pid) pid_position[0] = ptr - log_buffer; /* remember begin … */
-  ptr += sprintf(CS ptr, "[%d] ", (int)getpid());
-  if (!syslog_pid) pid_position[1] = ptr - log_buffer; /*  … and end+1 of the PID */
+  if (!syslog_pid) pid_position[0] = g->ptr;           /* remember begin … */
+  string_fmt_append_noextend(g, "[%ld] ", (long)getpid());
+  if (!syslog_pid) pid_position[1] = g->ptr;           /*  … and end+1 of the PID */

   }
 
   }
 

-if (really_exim && message_id[0] != 0)
-  ptr += sprintf(CS ptr, "%s ", message_id);
+if (f.really_exim && message_id[0])
+  string_fmt_append_noextend(g, "%s ", message_id);

 
 

-if ((flags & LOG_CONFIG) != 0) ptr = log_config_info(ptr, flags);
+if (flags & LOG_CONFIG)
+  log_config_info(g, flags);

 
 va_start(ap, format);
 
 va_start(ap, format);

-if (!string_vformat(ptr, LOG_BUFFER_SIZE - (ptr-log_buffer)-1, format, ap))
-  Ustrcpy(ptr, "**** log string overflowed log buffer ****\n");
-while(*ptr) ptr++;
+  {
+  /* We want to be able to log tainted info, but log_buffer is directly
+  malloc'd.  So use deliberately taint-nonchecking routines to build into
+  it, trusting that we will never expand the results. */
+
+  if (!string_vformat(g, SVFMT_TAINT_NOCHK, format, ap))
+    {
+    uschar * s = US"**** log string overflowed log buffer ****\n";
+    gstring_trim(g, Ustrlen(s));
+    string_fmt_append_noextend(g, "%s", s);
+    }
+  }

 va_end(ap);
 
 /* Add the raw, unrewritten, sender to the message if required. This is done
 this way because it kind of fits with LOG_RECIPIENTS. */
 
 va_end(ap);
 
 /* Add the raw, unrewritten, sender to the message if required. This is done
 this way because it kind of fits with LOG_RECIPIENTS. */
 

-if ((flags & LOG_SENDER) != 0 &&
-    ptr < log_buffer + LOG_BUFFER_SIZE - 10 - Ustrlen(raw_sender))
-  ptr += sprintf(CS ptr, " from <%s>", raw_sender);
+if (flags & LOG_SENDER)
+  string_fmt_append_noextend(g, " from <%s>", raw_sender);

 
 /* Add list of recipients to the message if required; the raw list,
 before rewriting, was saved in raw_recipients. There may be none, if an ACL
 discarded them all. */
 
 
 /* Add list of recipients to the message if required; the raw list,
 before rewriting, was saved in raw_recipients. There may be none, if an ACL
 discarded them all. */
 

-if ((flags & LOG_RECIPIENTS) != 0 && ptr < log_buffer + LOG_BUFFER_SIZE - 6 &&
-     raw_recipients_count > 0)
+if (flags & LOG_RECIPIENTS && raw_recipients_count > 0)

   {
   {

-  int i;
-  ptr += sprintf(CS ptr, " for");
-  for (i = 0; i < raw_recipients_count; i++)
-    {
-    uschar * s = raw_recipients[i];
-    if (log_buffer + LOG_BUFFER_SIZE - ptr < Ustrlen(s) + 3) break;
-    ptr += sprintf(CS ptr, " %s", s);
+  string_fmt_append_noextend(g, " for");
+  for (int i = 0; i < raw_recipients_count; i++)
+    if (!string_fmt_append_f(g, SVFMT_TAINT_NOCHK, " %s", raw_recipients[i]))
+      {
+    uschar * s = US"<trunc>";
+    gstring_trim(g, Ustrlen(s));
+    string_fmt_append_noextend(g, "%s", s);
+    break;

     }
   }
 
     }
   }
 

-ptr += sprintf(CS  ptr, "\n");
-length = ptr - log_buffer;
+/* actual size, now we are placing the newline (and space for NUL) */
+gs.size = LOG_BUFFER_SIZE;
+string_fmt_append_noextend(g, "\n");
+string_from_gstring(g);

 
 /* Handle loggable errors when running a utility, or when address testing.
 Write to log_stderr unless debugging (when it will already have been written),
 or unless there is no log_stderr (expn called from daemon, for example). */
 
 
 /* Handle loggable errors when running a utility, or when address testing.
 Write to log_stderr unless debugging (when it will already have been written),
 or unless there is no log_stderr (expn called from daemon, for example). */
 

-if (!really_exim || log_testing_mode)
+if (!f.really_exim || f.log_testing_mode)

   {
   {

-  if (debug_selector == 0 && log_stderr != NULL &&
-      (selector == 0 || (selector & log_selector[0]) != 0))
-    {
+  if (  !debug_selector
+     && log_stderr
+     && (selector == 0 || (selector & log_selector[0]) != 0)
+    )

     if (host_checking)
       fprintf(log_stderr, "LOG: %s", CS(log_buffer + 20));  /* no timestamp */
     else
       fprintf(log_stderr, "%s", CS log_buffer);
     if (host_checking)
       fprintf(log_stderr, "LOG: %s", CS(log_buffer + 20));  /* no timestamp */
     else
       fprintf(log_stderr, "%s", CS log_buffer);

-    }
-  if ((flags & LOG_PANIC_DIE) == LOG_PANIC_DIE) exim_exit(EXIT_FAILURE, US"");
+
+  if ((flags & LOG_PANIC_DIE) == LOG_PANIC_DIE) exim_exit(EXIT_FAILURE);

   return;
   }
 
   return;
   }
 


@@ -1014,10 +1133,9 @@ if (  flags & LOG_MAIN
 
     /* Failing to write to the log is disastrous */
 
 
     /* Failing to write to the log is disastrous */
 

-    written_len = write_to_fd_buf(mainlogfd, log_buffer, length);
-    if (written_len != length)
+    if ((written_len = write_gstring_to_fd_buf(mainlogfd, g)) != g->ptr)

       {
       {

-      log_write_failed(US"main log", length, written_len);
+      log_write_failed(US"main log", g->ptr, written_len);

       /* That function does not return */
       }
     }
       /* That function does not return */
       }
     }


@@ -1028,74 +1146,56 @@ which case the flags are altered above. If there are any header lines (i.e. if
 the rejection is happening after the DATA phase), log the recipients and the
 headers. */
 
 the rejection is happening after the DATA phase), log the recipients and the
 headers. */
 

-if ((flags & LOG_REJECT) != 0)
+if (flags & LOG_REJECT)

   {
   {

-  header_line *h;
-
-  if (header_list != NULL && LOGGING(rejected_header))
+  if (header_list && LOGGING(rejected_header))

     {
     {

+    int i;
+

     if (recipients_count > 0)
       {
     if (recipients_count > 0)
       {

-      int i;
-

       /* List the sender */
 
       /* List the sender */
 

-      string_format(ptr, LOG_BUFFER_SIZE - (ptr-log_buffer),
-        "Envelope-from: <%s>\n", sender_address);
-      while (*ptr) ptr++;
+      string_fmt_append_noextend(g,
+                       "Envelope-from: <%s>\n", sender_address);

 
       /* List up to 5 recipients */
 
 
       /* List up to 5 recipients */
 

-      string_format(ptr, LOG_BUFFER_SIZE - (ptr-log_buffer),
-        "Envelope-to: <%s>\n", recipients_list[0].address);
-      while (*ptr) ptr++;
+      string_fmt_append_noextend(g,
+                       "Envelope-to: <%s>\n", recipients_list[0].address);

 
       for (i = 1; i < recipients_count && i < 5; i++)
 
       for (i = 1; i < recipients_count && i < 5; i++)

-        {
-        string_format(ptr, LOG_BUFFER_SIZE - (ptr-log_buffer), "    <%s>\n",
-          recipients_list[i].address);
-        while (*ptr) ptr++;
-        }
+        string_fmt_append_noextend(g,
+                       "    <%s>\n", recipients_list[i].address);

 
       if (i < recipients_count)
 
       if (i < recipients_count)

-        {
-        (void)string_format(ptr, LOG_BUFFER_SIZE - (ptr-log_buffer),
-          "    ...\n");
-        while (*ptr) ptr++;
-        }
+        string_fmt_append_noextend(g, "    ...\n", NULL);

       }
 
       }
 

-    /* A header with a NULL text is an unfilled in Received: header */
+    /* A header with a NULL text is an unfilled-in Received: header */

 
 

-    for (h = header_list; h; h = h->next) if (h->text)
-      {
-      BOOL fitted = string_format(ptr, LOG_BUFFER_SIZE - (ptr-log_buffer),
-        "%c %s", h->type, h->text);
-      while(*ptr) ptr++;
-      if (!fitted)         /* Buffer is full; truncate */
-        {
-        ptr -= 100;        /* For message and separator */
-        if (ptr[-1] == '\n') ptr--;
-        Ustrcpy(ptr, "\n*** truncated ***\n");
-        while (*ptr) ptr++;
+    for (header_line * h = header_list; h; h = h->next) if (h->text)
+      if (!string_fmt_append_f(g, SVFMT_TAINT_NOCHK,
+                       "%c %s", h->type, h->text))
+        {                              /* Buffer is full; truncate */
+       gstring_trim(g, 100);           /* space for message and separator */
+       gstring_trim_trailing(g, '\n');
+        string_fmt_append_noextend(g, "\n*** truncated ***\n");

         break;
         }
         break;
         }

-      }
-
-    length = ptr - log_buffer;

     }
 
   /* Write to syslog or to a log file */
 
     }
 
   /* Write to syslog or to a log file */
 

-  if ((logging_mode & LOG_MODE_SYSLOG) != 0 &&
-      (syslog_duplication || (flags & LOG_PANIC) == 0))
-    write_syslog(LOG_NOTICE, log_buffer);
+  if (  logging_mode & LOG_MODE_SYSLOG
+     && (syslog_duplication || !(flags & LOG_PANIC)))
+    write_syslog(LOG_NOTICE, string_from_gstring(g));

 
   /* Check for a change to the rejectlog file name when datestamping is in
   operation. This happens at midnight, at which point we want to roll over
   the file. Closing it has the desired effect. */
 
 
   /* Check for a change to the rejectlog file name when datestamping is in
   operation. This happens at midnight, at which point we want to roll over
   the file. Closing it has the desired effect. */
 

-  if ((logging_mode & LOG_MODE_FILE) != 0)
+  if (logging_mode & LOG_MODE_FILE)

     {
     struct stat statbuf;
 
     {
     struct stat statbuf;
 


@@ -1117,7 +1217,6 @@ if ((flags & LOG_REJECT) != 0)
     happening. */
 
     if (rejectlogfd >= 0)
     happening. */
 
     if (rejectlogfd >= 0)

-      {

       if (Ustat(rejectlog_name, &statbuf) < 0 ||
            statbuf.st_ino != rejectlog_inode)
         {
       if (Ustat(rejectlog_name, &statbuf) < 0 ||
            statbuf.st_ino != rejectlog_inode)
         {


@@ -1125,7 +1224,6 @@ if ((flags & LOG_REJECT) != 0)
         rejectlogfd = -1;
         rejectlog_inode = 0;
         }
         rejectlogfd = -1;
         rejectlog_inode = 0;
         }

-      }

 
     /* Open the file if necessary, and write the data */
 
 
     /* Open the file if necessary, and write the data */
 


@@ -1135,10 +1233,9 @@ if ((flags & LOG_REJECT) != 0)
       if (fstat(rejectlogfd, &statbuf) >= 0) rejectlog_inode = statbuf.st_ino;
       }
 
       if (fstat(rejectlogfd, &statbuf) >= 0) rejectlog_inode = statbuf.st_ino;
       }
 

-    written_len = write_to_fd_buf(rejectlogfd, log_buffer, length);
-    if (written_len != length)
+    if ((written_len = write_gstring_to_fd_buf(rejectlogfd, g)) != g->ptr)

       {
       {

-      log_write_failed(US"reject log", length, written_len);
+      log_write_failed(US"reject log", g->ptr, written_len);

       /* That function does not return */
       }
     }
       /* That function does not return */
       }
     }


@@ -1150,37 +1247,33 @@ open, there will be a recursive call to log_write(). We detect this above and
 attempt to write to the system log as a last-ditch try at telling somebody. In
 all cases except mua_wrapper, try to write to log_stderr. */
 
 attempt to write to the system log as a last-ditch try at telling somebody. In
 all cases except mua_wrapper, try to write to log_stderr. */
 

-if ((flags & LOG_PANIC) != 0)
+if (flags & LOG_PANIC)

   {
   {

-  if (log_stderr != NULL && log_stderr != debug_file && !mua_wrapper)
-    fprintf(log_stderr, "%s", CS log_buffer);
+  if (log_stderr && log_stderr != debug_file && !mua_wrapper)
+    fprintf(log_stderr, "%s", CS string_from_gstring(g));

 
 

-  if ((logging_mode & LOG_MODE_SYSLOG) != 0)
+  if (logging_mode & LOG_MODE_SYSLOG)

     write_syslog(LOG_ALERT, log_buffer);
 
   /* If this panic logging was caused by a failure to open the main log,
   the original log line is in panic_save_buffer. Make an attempt to write it. */
 
     write_syslog(LOG_ALERT, log_buffer);
 
   /* If this panic logging was caused by a failure to open the main log,
   the original log line is in panic_save_buffer. Make an attempt to write it. */
 

-  if ((logging_mode & LOG_MODE_FILE) != 0)
+  if (logging_mode & LOG_MODE_FILE)

     {
     panic_recurseflag = TRUE;
     open_log(&paniclogfd, lt_panic, NULL);  /* Won't return on failure */
     panic_recurseflag = FALSE;
 
     {
     panic_recurseflag = TRUE;
     open_log(&paniclogfd, lt_panic, NULL);  /* Won't return on failure */
     panic_recurseflag = FALSE;
 

-    if (panic_save_buffer != NULL)
-      {
-      int i = write(paniclogfd, panic_save_buffer, Ustrlen(panic_save_buffer));
-      i = i;   /* compiler quietening */
-      }
+    if (panic_save_buffer)
+      (void) write(paniclogfd, panic_save_buffer, Ustrlen(panic_save_buffer));

 
 

-    written_len = write_to_fd_buf(paniclogfd, log_buffer, length);
-    if (written_len != length)
+    if ((written_len = write_gstring_to_fd_buf(paniclogfd, g)) != g->ptr)

       {
       int save_errno = errno;
       write_syslog(LOG_CRIT, log_buffer);
       sprintf(CS log_buffer, "write failed on panic log: length=%d result=%d "
       {
       int save_errno = errno;
       write_syslog(LOG_CRIT, log_buffer);
       sprintf(CS log_buffer, "write failed on panic log: length=%d result=%d "

-        "errno=%d (%s)", length, (int)written_len, save_errno, strerror(save_errno));
-      write_syslog(LOG_CRIT, log_buffer);
+        "errno=%d (%s)", g->ptr, (int)written_len, save_errno, strerror(save_errno));
+      write_syslog(LOG_CRIT, string_from_gstring(g));

       flags |= LOG_PANIC_DIE;
       }
 
       flags |= LOG_PANIC_DIE;
       }
 


@@ -1190,7 +1283,10 @@ if ((flags & LOG_PANIC) != 0)
   /* Give up if the DIE flag is set */
 
   if ((flags & LOG_PANIC_DIE) != LOG_PANIC)
   /* Give up if the DIE flag is set */
 
   if ((flags & LOG_PANIC_DIE) != LOG_PANIC)

-    die(NULL, US"Unexpected failure, please try later");
+    if (panic_coredump)
+      kill(getpid(), SIGSEGV); /* deliberate trap */
+    else
+      die(NULL, US"Unexpected failure, please try later");

   }
 }
 
   }
 }
 


@@ -1275,18 +1371,19 @@ Returns:         nothing on success - bomb out on failure
 */
 
 void
 */
 
 void

-decode_bits(unsigned int *selector, size_t selsize, int *notall,
-  uschar *string, bit_table *options, int count, uschar *which, int flags)
+decode_bits(unsigned int * selector, size_t selsize, int * notall,
+  const uschar * string, bit_table * options, int count, uschar * which,
+  int flags)

 {
 uschar *errmsg;
 {
 uschar *errmsg;

-if (string == NULL) return;
+if (!string) return;

 
 if (*string == '=')
   {
   char *end;    /* Not uschar */
   memset(selector, 0, sizeof(*selector)*selsize);
 
 if (*string == '=')
   {
   char *end;    /* Not uschar */
   memset(selector, 0, sizeof(*selector)*selsize);

-  *selector = strtoul(CS string+1, &end, 0);
-  if (*end == 0) return;
+  *selector = strtoul(CCS string+1, &end, 0);
+  if (!*end) return;

   errmsg = string_sprintf("malformed numeric %s_selector setting: %s", which,
     string);
   goto ERROR_RETURN;
   errmsg = string_sprintf("malformed numeric %s_selector setting: %s", which,
     string);
   goto ERROR_RETURN;


@@ -1297,12 +1394,12 @@ if (*string == '=')
 else for(;;)
   {
   BOOL adding;
 else for(;;)
   {
   BOOL adding;

-  uschar *s;
+  const uschar * s;

   int len;
   int len;

-  bit_table *start, *end;
+  bit_table * start, * end;

 
 

-  while (isspace(*string)) string++;
-  if (*string == 0) return;
+  Uskip_whitespace(&string);
+  if (!*string) return;

 
   if (*string != '+' && *string != '-')
     {
 
   if (*string != '+' && *string != '-')
     {


@@ -1324,7 +1421,6 @@ else for(;;)
     bit_table *middle = start + (end - start)/2;
     int c = Ustrncmp(s, middle->name, len);
     if (c == 0)
     bit_table *middle = start + (end - start)/2;
     int c = Ustrncmp(s, middle->name, len);
     if (c == 0)

-      {

       if (middle->name[len] != 0) c = -1; else
         {
         unsigned int bit = middle->bit;
       if (middle->name[len] != 0) c = -1; else
         {
         unsigned int bit = middle->bit;


@@ -1346,7 +1442,6 @@ else for(;;)
 
         break;  /* Out of loop to match selector name */
         }
 
         break;  /* Out of loop to match selector name */
         }

-      }

     if (c < 0) end = middle; else start = middle + 1;
     }  /* Loop to match selector name */
 
     if (c < 0) end = middle; else start = middle + 1;
     }  /* Loop to match selector name */
 


@@ -1390,13 +1485,15 @@ misconfiguration.
 
 The first use of this is in ACL logic, "control = debug/tag=foo/opts=+expand"
 which can be combined with conditions, etc, to activate extra logging only
 
 The first use of this is in ACL logic, "control = debug/tag=foo/opts=+expand"
 which can be combined with conditions, etc, to activate extra logging only

-for certain sources. The second use is inetd wait mode debug preservation. */
+for certain sources. The second use is inetd wait mode debug preservation.
+
+It might be nice, in ACL-initiated pretrigger mode, to not create the file
+immediately but only upon a trigger - but we'd need another cmdline option
+to pass the name through child_exxec_exim(). */

 
 void
 
 void

-debug_logging_activate(uschar *tag_name, uschar *opts)
+debug_logging_activate(const uschar * tag_name, const uschar * opts)

 {
 {

-int fd = -1;
-

 if (debug_file)
   {
   debug_printf("DEBUGGING ACTIVATED FROM WITHIN CONFIG.\n"
 if (debug_file)
   {
   debug_printf("DEBUGGING ACTIVATED FROM WITHIN CONFIG.\n"


@@ -1404,7 +1501,7 @@ if (debug_file)
   return;
   }
 
   return;
   }
 

-if (tag_name != NULL && (Ustrchr(tag_name, '/') != NULL))
+if (tag_name && (Ustrchr(tag_name, '/') != NULL))

   {
   log_write(0, LOG_MAIN|LOG_PANIC, "debug tag may not contain a '/' in: %s",
       tag_name);
   {
   log_write(0, LOG_MAIN|LOG_PANIC, "debug tag may not contain a '/' in: %s",
       tag_name);


@@ -1422,25 +1519,47 @@ do not segfault; note that nondefault log locations will not work */
 
 if (!*file_path) set_file_path();
 
 
 if (!*file_path) set_file_path();
 

-open_log(&fd, lt_debug, tag_name);
+open_log(&debug_fd, lt_debug, tag_name);

 
 

-if (fd != -1)
-  debug_file = fdopen(fd, "w");
+if (debug_fd != -1)
+  debug_file = fdopen(debug_fd, "w");

 else
   log_write(0, LOG_MAIN|LOG_PANIC, "unable to open debug log");
 }
 
 
 void
 else
   log_write(0, LOG_MAIN|LOG_PANIC, "unable to open debug log");
 }
 
 
 void

-debug_logging_stop(void)
+debug_logging_from_spool(const uschar * filename)
+{
+if (debug_fd < 0)
+  {
+  Ustrncpy(debuglog_name, filename, sizeof(debuglog_name));
+  if ((debug_fd = log_open_as_exim(filename)) >= 0)
+    debug_file = fdopen(debug_fd, "w");
+  DEBUG(D_deliver) debug_printf("debug enabled by spoolfile\n");
+  }
+/*
+else DEBUG(D_deliver)
+  debug_printf("debug already active; ignoring spoolfile '%s'\n", filename);
+*/
+}
+
+
+void
+debug_logging_stop(BOOL kill)

 {
 {

+debug_printf("debug terminated by %s\n", kill ? "kill" : "stop");
+debug_pretrigger_discard();

 if (!debug_file || !debuglog_name[0]) return;
 
 debug_selector = 0;
 fclose(debug_file);
 debug_file = NULL;
 if (!debug_file || !debuglog_name[0]) return;
 
 debug_selector = 0;
 fclose(debug_file);
 debug_file = NULL;

-unlink_log(lt_debug);
+debug_fd = -1;
+if (kill) unlink_log(lt_debug);

 }
 
 
 /* End of log.c */
 }
 
 
 /* End of log.c */

+/* vi: sw ai sw=2
+*/