commit da831afcf2f6c0d3ed1ea3128a6208f548a05d8f
Author: Eric Blake <eblake@redhat.com>
Date:   Tue May 29 17:47:58 2012 -0600

    command: avoid double close bugs
    
    KAMEZAWA Hiroyuki reported a nasty double-free bug when virCommand
    is used to convert a string into input to a child command.  The
    problem is that the poll() loop of virCommandProcessIO would close()
    the write end of the pipe in order to let the child see EOF, then
    the caller virCommandRun() would also close the same fd number, with
    the second close possibly nuking an fd opened by some other thread
    in the meantime.  This in turn can have all sorts of bad effects.
    
    The bug has been present since the introduction of virCommand in
    commit f16ad06f.
    
    This is based on his first attempt at a patch, at
    https://bugzilla.redhat.com/show_bug.cgi?id=823716
    
    * src/util/command.c (_virCommand): Drop inpipe member.
    (virCommandProcessIO): Add argument, to avoid closing caller's fd
    without informing caller.
    (virCommandRun, virCommandNewArgs): Adjust clients.

diff --git a/src/util/command.c b/src/util/command.c
index 5b94f1e..1a22508 100644
--- a/src/util/command.c
+++ b/src/util/command.c
@@ -83,7 +83,6 @@ struct _virCommand {
     char **errbuf;
 
     int infd;
-    int inpipe;
     int outfd;
     int errfd;
     int *outfdptr;
@@ -788,7 +787,6 @@ virCommandNewArgs(const char *const*args)
     cmd->handshakeNotify[1] = -1;
 
     cmd->infd = cmd->outfd = cmd->errfd = -1;
-    cmd->inpipe = -1;
     cmd->pid = -1;
 
     virCommandAddArgSet(cmd, args);
@@ -1676,7 +1674,7 @@ virCommandTranslateStatus(int status)
  * Manage input and output to the child process.
  */
 static int
-virCommandProcessIO(virCommandPtr cmd)
+virCommandProcessIO(virCommandPtr cmd, int *inpipe)
 {
     int infd = -1, outfd = -1, errfd = -1;
     size_t inlen = 0, outlen = 0, errlen = 0;
@@ -1687,7 +1685,7 @@ virCommandProcessIO(virCommandPtr cmd)
      * via pipe */
     if (cmd->inbuf) {
         inlen = strlen(cmd->inbuf);
-        infd = cmd->inpipe;
+        infd = *inpipe;
     }
 
     /* With out/err buffer, the outfd/errfd have been filled with an
@@ -1808,10 +1806,9 @@ virCommandProcessIO(virCommandPtr cmd)
                 } else {
                     inoff += done;
                     if (inoff == inlen) {
-                        int tmpfd ATTRIBUTE_UNUSED;
-                        tmpfd = infd;
-                        if (VIR_CLOSE(infd) < 0)
-                            VIR_DEBUG("ignoring failed close on fd %d", tmpfd);
+                        if (VIR_CLOSE(*inpipe) < 0)
+                            VIR_DEBUG("ignoring failed close on fd %d", infd);
+                        infd = -1;
                     }
                 }
             }
@@ -1938,7 +1935,6 @@ virCommandRun(virCommandPtr cmd, int *exitstatus)
             return -1;
         }
         cmd->infd = infd[0];
-        cmd->inpipe = infd[1];
     }
 
     /* If caller requested the same string for stdout and stderr, then
@@ -1981,7 +1977,7 @@ virCommandRun(virCommandPtr cmd, int *exitstatus)
     }
 
     if (string_io)
-        ret = virCommandProcessIO(cmd);
+        ret = virCommandProcessIO(cmd, &infd[1]);
 
     if (virCommandWait(cmd, exitstatus) < 0)
         ret = -1;