[exim-cvs] log_write EINTR handling on write()

Gitweb: http://git.exim.org/exim.git/commitdiff/23ecb73de01ae47e2282790a75c7e07114bd5702

Commit:     23ecb73de01ae47e2282790a75c7e07114bd5702
Parent:     c6fa5dfa8280de53bfbfd4921bc8bb5945dd5f19
Author:     Phil Pennock <pdp@???>
AuthorDate: Sun Nov 13 23:51:43 2011 -0500
Committer:  Phil Pennock <pdp@???>
CommitDate: Sun Nov 13 23:51:43 2011 -0500

    log_write EINTR handling on write()
---
 src/src/log.c |   15 +++++++++++++--
 1 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/src/log.c b/src/src/log.c
index a3ec18d..2be1ff2 100644
--- a/src/src/log.c
+++ b/src/src/log.c
@@ -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
@@ -571,6 +576,7 @@ log_write(unsigned int selector, int flags, const char *format, ...)
 uschar *ptr;
 int length, rc;
 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 +892,14 @@ if ((flags & LOG_MAIN) != 0 &&

     /* Failing to write to the log is disastrous */

-    if ((rc = write(mainlogfd, log_buffer, length)) != length)
+    while (
+        ((written_len = write(mainlogfd, log_buffer, length)) == (ssize_t)-1)
+        &&
+        (errno == EINTR)
+        ) /**/;
+    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 */
       }
     }