-/* $Cambridge: exim/src/src/log.c,v 1.15 2010/06/06 00:27:52 pdp Exp $ */
-
/*************************************************
* Exim - an Internet mail transport agent *
*************************************************/
-/* Copyright (c) University of Cambridge 1995 - 2009 */
+/* Copyright (c) University of Cambridge 1995 - 2012 */
/* See the file NOTICE for conditions of use and distribution. */
/* Functions for writing log files. The code for maintaining datestamped
#define LOG_MODE_FILE 1
#define LOG_MODE_SYSLOG 2
-enum { lt_main, lt_reject, lt_panic, lt_debug, lt_process };
+enum { lt_main, lt_reject, lt_panic, lt_debug };
-static uschar *log_names[] = { US"main", US"reject", US"panic", US"debug", US"process" };
+static uschar *log_names[] = { US"main", US"reject", US"panic", US"debug" };
*/
static int
-create_log(uschar *name)
+log_create(uschar *name)
{
int fd = Uopen(name, O_CREAT|O_APPEND|O_WRONLY, LOG_MODE);
+/*************************************************
+* Create a log file as the exim user *
+*************************************************/
+
+/* This function is called when we are root to spawn an exim:exim subprocess
+in which we can create a log file. It must be signal-safe since it is called
+by the usr1_handler().
+
+Arguments:
+ name the file name
+
+Returns: a file descriptor, or < 0 on failure (errno set)
+*/
+
+int
+log_create_as_exim(uschar *name)
+{
+pid_t pid = fork();
+int status = 1;
+int fd = -1;
+
+/* 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 (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. */
+
+while (pid > 0 && waitpid(pid, &status, 0) != pid);
+if (status == 0) fd = Uopen(name, O_APPEND|O_WRONLY, LOG_MODE);
+
+/* 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. */
+
+return fd;
+}
+
+
+
/*************************************************
* Open a log file *
*************************************************/
-/* This function opens one of a number of logs, which all (except for the
-"process log") reside in the same directory, creating the directory if it does
-not exist. This may be called recursively on failure, in order to open the
-panic log.
+/* This function opens one of a number of logs, creating the log directory if
+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 work of sorting out the path is done just once per Exim process.
Arguments:
fd where to return the resulting file descriptor
- type lt_main, lt_reject, lt_panic, lt_debug or lt_process
+ type lt_main, lt_reject, lt_panic, or lt_debug
tag optional tag to include in the name (only hooked up for debug)
Returns: nothing
BOOL ok, ok2;
uschar buffer[LOG_NAME_SIZE];
-/* Sort out the file name. This depends on the type of log we are opening. The
-process "log" is written in the spool directory by default, but a path name can
-be specified in the configuration. */
+/* The names of the log files are controlled by file_path. The panic log is
+written to the same directory as the main and reject logs, but its name does
+not have a datestamp. The use of datestamps is indicated by %D/%M in file_path.
+When opening the panic log, if %D or %M is present, we remove the datestamp
+from the generated name; if it is at the start, remove a following
+non-alphanumeric character as well; otherwise, remove a preceding
+non-alphanumeric character. This is definitely kludgy, but it sort of does what
+people want, I hope. */
+
+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_process)
+if (type == lt_main)
{
- if (process_log_path == NULL)
- ok = string_format(buffer, sizeof(buffer), "%s/exim-process.info",
- spool_directory);
- else
- ok = string_format(buffer, sizeof(buffer), "%s", process_log_path);
+ Ustrcpy(mainlog_name, buffer);
+ mainlog_datestamp = mainlog_name + string_datestamp_offset;
}
-/* The names of the other three logs are controlled by file_path. The panic log
-is written to the same directory as the main and reject logs, but its name does
-not have a datestamp. The use of datestamps is indicated by %D in file_path.
-When opening the panic log, if %D is present, we remove the datestamp from the
-generated name; if it is at the start, remove a following non-alphameric
-character as well; otherwise, remove a preceding non-alphameric character. This
-is definitely kludgy, but it sort of does what people want, I hope. */
+/* Ditto for the reject log */
-else
+else if (type == lt_reject)
{
- ok = string_format(buffer, sizeof(buffer), CS file_path, log_names[type]);
+ Ustrcpy(rejectlog_name, buffer);
+ rejectlog_datestamp = rejectlog_name + string_datestamp_offset;
+ }
- /* 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. */
+/* and deal with the debug log (which keeps the datestamp, but does not
+update it) */
- if (type == lt_main)
+else if (type == lt_debug)
+ {
+ Ustrcpy(debuglog_name, buffer);
+ if (tag)
{
- Ustrcpy(mainlog_name, buffer);
- mainlog_datestamp = mainlog_name + string_datestamp_offset;
+ /* 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);
}
+ }
- /* Ditto for the reject log */
+/* 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. */
- else if (type == lt_reject)
+else if (string_datestamp_offset >= 0)
+ {
+ uschar *from = buffer + string_datestamp_offset;
+ uschar *to = from + string_datestamp_length;
+ if (from == buffer || from[-1] == '/')
{
- Ustrcpy(rejectlog_name, buffer);
- rejectlog_datestamp = rejectlog_name + string_datestamp_offset;
+ if (!isalnum(*to)) to++;
}
-
- /* and deal with the debug log (which keeps the datestamp, but does not
- update it) */
-
- else if (type == lt_debug)
+ else
{
- 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);
- }
+ if (!isalnum(from[-1])) from--;
}
- /* 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. */
-
- else if (string_datestamp_offset >= 0)
- {
- uschar *from = buffer + string_datestamp_offset;
- uschar *to = from + Ustrlen(tod_stamp(tod_log_datestamp));
- if (from == buffer || from[-1] == '/')
- {
- if (!isalnum(*to)) to++;
- }
- else
- {
- if (!isalnum(from[-1])) from--;
- }
-
- /* This strcpy is ok, because we know that to is a substring of from. */
+ /* This strcpy is ok, because we know that to is a substring of from. */
- Ustrcpy(from, to);
- }
+ Ustrcpy(from, to);
}
/* If the file name is too long, it is an unrecoverable disaster */
/* 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 = create_log(buffer);
+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)
- {
- int status;
- pid_t pid = fork();
-
- /* In the subprocess, change uid/gid and do the creation. Return 0 from the
- subprocess on success. There doesn't seem much point in testing for setgid
- and setuid errors. */
-
- if (pid == 0)
- {
- (void)setgid(exim_gid);
- (void)setuid(exim_uid);
- _exit((create_log(buffer) < 0)? 1 : 0);
- }
-
- /* If we created a subprocess, wait for it. If it succeeded retry the open. */
-
- if (pid > 0)
- {
- while (waitpid(pid, &status, 0) != pid);
- if (status == 0) *fd = Uopen(buffer, O_APPEND|O_WRONLY, LOG_MODE);
- }
-
- /* If we failed to create a subprocess, we are in a bad way. We fall through
- with *fd still < 0, and errno set, letting the code below handle the error. */
- }
+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. */
We try to save the relevant message in the panic_save buffer before crashing
out.
+The potential invoker should probably not call us for EINTR -1 writes. But
+otherwise, short writes are bad as we don't do non-blocking writes to fds
+subject to flow control. (If we do, that's new and the logic of this should
+be reconsidered).
+
Arguments:
name the name of the log being written
length the string length being written
+/*************************************************
+* Write to an fd, retrying after signals *
+*************************************************/
+
+/* Basic write to fd for logs, handling EINTR.
+
+Arguments:
+ fd the fd to write to
+ buf the string to write
+ length the string length being written
+
+Returns:
+ length actually written, persisting an errno from write()
+*/
+ssize_t
+write_to_fd_buf(int fd, const uschar *buf, size_t length)
+{
+ssize_t wrote;
+size_t total_written = 0;
+const uschar *p = buf;
+size_t left = length;
+
+while (1)
+ {
+ wrote = write(fd, p, left);
+ if (wrote == (ssize_t)-1)
+ {
+ if (errno == EINTR) continue;
+ return wrote;
+ }
+ total_written += wrote;
+ if (wrote == left)
+ break;
+ else
+ {
+ p += wrote;
+ left -= wrote;
+ }
+ }
+return total_written;
+}
+
+
/*************************************************
* Write message to log file *
*************************************************/
log_file_path = "syslog" write to syslog
log_file_path = "syslog : xxx" write to syslog and to files (any order)
-The one exception to this is messages containing LOG_PROCESS. These are always
-written to exim-process.info in the spool directory. They aren't really log
-messages in the same sense as the others.
-
The message always gets '\n' added on the end of it, since more than one
process may be writing to the log at once and we don't want intermingling to
happen in the middle of lines. To be absolutely sure of this we write the data
LOG_REJECT write to reject log or syslog LOG_NOTICE
LOG_PANIC write to panic log or syslog LOG_ALERT
LOG_PANIC_DIE write to panic log or LOG_ALERT and then crash
- LOG_PROCESS write to process log (always a file)
format a printf() format
... arguments for format
*/
void
-log_write(unsigned int selector, int flags, char *format, ...)
+log_write(unsigned int selector, int flags, const char *format, ...)
{
uschar *ptr;
-int length, rc;
+int length;
int paniclogfd;
+ssize_t written_len;
va_list ap;
/* If panic_recurseflag is set, we have failed to open the panic log. This is
}
}
- sprintf(CS ptr, "%s%s%s%s%s\n ",
+ 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_PROCESS) != 0)? " PROCESS": "",
((flags & LOG_REJECT) != 0)? " REJECT" : "");
while(*ptr) ptr++;
/* If no log file is specified, we are in a mess. */
-if ((flags & (LOG_MAIN|LOG_PANIC|LOG_REJECT|LOG_PROCESS)) == 0)
+if ((flags & (LOG_MAIN|LOG_PANIC|LOG_REJECT)) == 0)
log_write(0, LOG_MAIN|LOG_PANIC_DIE, "log_write called with no log "
"flags set");
if (!write_rejectlog) flags &= ~LOG_REJECT;
-/* Create the main message in the log buffer, including the message
-id except for the process log and 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;
sprintf(CS ptr, "%s ", tod_stamp(tod_log));
while (*ptr) ptr++;
}
-if (really_exim && (flags & LOG_PROCESS) == 0 && message_id[0] != 0)
+if (really_exim && message_id[0] != 0)
{
sprintf(CS ptr, "%s ", message_id);
while(*ptr) ptr++;
if (mainlog_datestamp != NULL)
{
- uschar *nowstamp = tod_stamp(tod_log_datestamp);
+ uschar *nowstamp = tod_stamp(string_datestamp_type);
if (Ustrncmp (mainlog_datestamp, nowstamp, Ustrlen(nowstamp)) != 0)
{
(void)close(mainlogfd); /* Close the file */
/* Failing to write to the log is disastrous */
- if ((rc = write(mainlogfd, log_buffer, length)) != length)
+ written_len = write_to_fd_buf(mainlogfd, log_buffer, length);
+ if (written_len != length)
{
- log_write_failed(US"main log", length, rc);
+ log_write_failed(US"main log", length, written_len);
/* That function does not return */
}
}
if (rejectlog_datestamp != NULL)
{
- uschar *nowstamp = tod_stamp(tod_log_datestamp);
+ uschar *nowstamp = tod_stamp(string_datestamp_type);
if (Ustrncmp (rejectlog_datestamp, nowstamp, Ustrlen(nowstamp)) != 0)
{
(void)close(rejectlogfd); /* Close the file */
if (fstat(rejectlogfd, &statbuf) >= 0) rejectlog_inode = statbuf.st_ino;
}
- if ((rc = write(rejectlogfd, log_buffer, length)) != length)
+ written_len = write_to_fd_buf(rejectlogfd, log_buffer, length);
+ if (written_len != length)
{
- log_write_failed(US"reject log", length, rc);
+ log_write_failed(US"reject log", length, written_len);
/* That function does not return */
}
}
}
-/* Handle the process log file, where exim processes can be made to dump
-details of what they are doing by sending them a USR1 signal. Note that
-a message id is not automatically added above. This information is always
-written to a file - never to syslog. */
-
-if ((flags & LOG_PROCESS) != 0)
- {
- int processlogfd;
- open_log(&processlogfd, lt_process, NULL); /* No return on error */
- if ((rc = write(processlogfd, log_buffer, length)) != length)
- {
- log_write_failed(US"process log", length, rc);
- /* That function does not return */
- }
- (void)close(processlogfd);
- }
-
-
/* Handle the panic log, which is not kept open like the others. If it fails to
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
if (panic_save_buffer != NULL)
(void) write(paniclogfd, panic_save_buffer, Ustrlen(panic_save_buffer));
- if ((rc = write(paniclogfd, log_buffer, length)) != length)
+ written_len = write_to_fd_buf(paniclogfd, log_buffer, length);
+ if (written_len != length)
{
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, rc, save_errno, strerror(save_errno));
+ "errno=%d (%s)", length, (int)written_len, save_errno, strerror(save_errno));
write_syslog(LOG_CRIT, log_buffer);
flags |= LOG_PANIC_DIE;
}
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. */
+for certain sources. The second use is inetd wait mode debug preservation. */
void
debug_logging_activate(uschar *tag_name, uschar *opts)
if (debug_file)
{
debug_printf("DEBUGGING ACTIVATED FROM WITHIN CONFIG.\n"
- "DEBUG: Tag=\"%s\" Opts=\"%s\"\n", tag_name, opts);
+ "DEBUG: Tag=\"%s\" Opts=\"%s\"\n", tag_name, opts ? opts : US"");
return;
}
git://git.exim.org / exim.git / blobdiff