[exim-cvs] cvs commit: exim/exim-doc/doc-txt ChangeLog exim…

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Autor: Philip Hazel
Data:  
Para: exim-cvs
Assunto: [exim-cvs] cvs commit: exim/exim-doc/doc-txt ChangeLog exim/exim-src/src log.c
ph10 2005/03/29 16:19:25 BST

  Modified files:
    exim-doc/doc-txt     ChangeLog 
    exim-src/src         log.c 
  Log:
  Test for failure of the fork() when a root process creates a log file.


  Revision  Changes    Path
  1.105     +9 -0      exim/exim-doc/doc-txt/ChangeLog
  1.3       +12 -5     exim/exim-src/src/log.c


  Index: ChangeLog
  ===================================================================
  RCS file: /home/cvs/exim/exim-doc/doc-txt/ChangeLog,v
  retrieving revision 1.104
  retrieving revision 1.105
  diff -u -r1.104 -r1.105
  --- ChangeLog    29 Mar 2005 14:53:09 -0000    1.104
  +++ ChangeLog    29 Mar 2005 15:19:25 -0000    1.105
  @@ -1,4 +1,4 @@
  -$Cambridge: exim/exim-doc/doc-txt/ChangeLog,v 1.104 2005/03/29 14:53:09 ph10 Exp $
  +$Cambridge: exim/exim-doc/doc-txt/ChangeLog,v 1.105 2005/03/29 15:19:25 ph10 Exp $


Change log file for Exim from version 4.21
-------------------------------------------
@@ -98,6 +98,15 @@

   PH/18 Installed Lars Mainka's patch for the support of CRL collections in
         files or directories, for OpenSSL.
  +
  +PH/19 When an Exim process that is running as root has to create an Exim log
  +      file, it does so in a subprocess that runs as exim:exim so as to get the
  +      ownership right at creation (otherwise, other Exim processes might see
  +      the file with the wrong ownership). There was no test for failure of this
  +      fork() call, which would lead to the process getting stuck as it waited
  +      for a non-existent subprocess. Forks do occasionally fail when resources
  +      run out. I reviewed all the other calls to fork(); they all seem to check
  +      for failure.



A note about Exim versions 4.44 and 4.50

  Index: log.c
  ===================================================================
  RCS file: /home/cvs/exim/exim-src/src/log.c,v
  retrieving revision 1.2
  retrieving revision 1.3
  diff -u -r1.2 -r1.3
  --- log.c    4 Jan 2005 10:00:42 -0000    1.2
  +++ log.c    29 Mar 2005 15:19:25 -0000    1.3
  @@ -1,4 +1,4 @@
  -/* $Cambridge: exim/exim-src/src/log.c,v 1.2 2005/01/04 10:00:42 ph10 Exp $ */
  +/* $Cambridge: exim/exim-src/src/log.c,v 1.3 2005/03/29 15:19:25 ph10 Exp $ */


   /*************************************************
   *     Exim - an Internet mail transport agent    *
  @@ -321,8 +321,9 @@
   /* 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 an 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. */
  +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();

  @@ -350,10 +351,16 @@
       _exit((create_log(buffer) < 0)? 1 : 0);
       }


- /* Wait for the subprocess. If it succeeded retry the open. */
+ /* If we created a subprocess, wait for it. If it succeeded retry the open. */

  -  while (waitpid(pid, &status, 0) != pid);
  -  if (status == 0) *fd = Uopen(buffer, O_APPEND|O_WRONLY, LOG_MODE);
  +  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. */
     }


/* If we now have an open file, set the close-on-exec flag and return. */