${hexquote: expansion operator

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

diff --git a/src/src/log.c b/src/src/log.c
index a3ec18d9f79036a313d9d6eec91fcb796accc287..1523874d9a780a88e03575350546fca6100e2ad3 100644 (file)
--- a/src/src/log.c
+++ b/src/src/log.c
@@ -2,7 +2,7 @@
 *     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
@@ -179,7 +179,7 @@ overwrite it temporarily if it is necessary to create the directory.
 Returns:       a file descriptor, or < 0 on failure (errno set)
 */
 
-static int
+int
 log_create(uschar *name)
 {
 int fd = Uopen(name, O_CREAT|O_APPEND|O_WRONLY, LOG_MODE);
@@ -480,6 +480,11 @@ log, which can happen if a disk gets full or a file gets too large or whatever.
 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
@@ -508,6 +513,49 @@ log_write(0, LOG_PANIC_DIE, "failed to write to %s: length=%d result=%d "
 
 
 
+/*************************************************
+*     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           *
 *************************************************/
@@ -569,8 +617,9 @@ void
 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
@@ -886,9 +935,10 @@ if ((flags & LOG_MAIN) != 0 &&
 
     /* 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 */
       }
     }
@@ -1008,9 +1058,10 @@ if ((flags & LOG_REJECT) != 0)
       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 */
       }
     }
@@ -1042,14 +1093,18 @@ if ((flags & LOG_PANIC) != 0)
     panic_recurseflag = FALSE;
 
     if (panic_save_buffer != NULL)
-      (void) write(paniclogfd, panic_save_buffer, Ustrlen(panic_save_buffer));
+      {
+      int i = write(paniclogfd, panic_save_buffer, Ustrlen(panic_save_buffer));
+      i = i;   /* compiler quietening */
+      }
 
-    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;
       }
@@ -1254,7 +1309,7 @@ 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
-for certain sources. */
+for certain sources. The second use is inetd wait mode debug preservation. */
 
 void
 debug_logging_activate(uschar *tag_name, uschar *opts)
@@ -1264,7 +1319,7 @@ int fd = -1;
 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;
   }