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re PR libgcj/31228 (Race condition between setting close-on-exec and Runtime.exec())

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PR libgcj/31228
	* configure.ac: Add checks for getrlimit and sys/resource.h.
	* include/posix.h (_Jv_platform_close_on_exec): Remove.
	* include/config.h.in: Regenerate.
	* configure: Regenerate.
	* gnu/java/nio/channels/natFileChannelPosix.cc (open): Remove call to
	_Jv_platform_close_on_exec;
	* gnu/java/net/natPlainSocketImplPosix.cc (create): Likewise.
	(accept): Likewise.
	* gnu/java/net/natPlainDatagramSocketImplPosix.cc (create):Likewise.
	* java/lang/natPosixProcess.cc: Include sys/resource.h.
	(nativeSpawn): Close all file descriptors.  Don't set FD_CLOEXEC on
	pipes.

From-SVN: r123138
This commit is contained in:
David Daney 2007-03-23 00:06:41 +00:00 • committed by David Daney
parent 92ef5cf999
commit 46ecc2bc5c
9 changed files with 56 additions and 30 deletions
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37
libjava/java/lang/natPosixProcess.cc
View file

@ -17,6 +17,9 @@ details. */
#include <fcntl.h>
#include <sys/types.h>
#include <sys/wait.h>
#ifdef HAVE_SYS_RESOURCE_H
#include <sys/resource.h>
#endif
#include <signal.h>
#include <string.h>
#include <stdlib.h>
@ -352,7 +355,31 @@ java::lang::PosixProcess::nativeSpawn ()
_exit (127);
}
}
// Make sure all file descriptors are closed. In
// multi-threaded programs, there is a race between when a
// descriptor is obtained, when we can set FD_CLOEXEC, and
// fork(). If the fork occurs before FD_CLOEXEC is set, the
// descriptor would leak to the execed process if we did not
// manually close it. So that is what we do. Since we
// close all the descriptors, it is redundant to set
// FD_CLOEXEC on them elsewhere.
int max_fd;
#ifdef HAVE_GETRLIMIT
rlimit rl;
int rv = getrlimit(RLIMIT_NOFILE, &rl);
if (rv == 0)
max_fd = rl.rlim_max - 1;
else
max_fd = 1024 - 1;
#else
max_fd = 1024 - 1;
#endif
while(max_fd > 2)
{
if (max_fd != msgp[1])
close (max_fd);
max_fd--;
}
// Make sure that SIGCHLD is unblocked for the new process.
sigset_t mask;
sigemptyset (&mask);
@ -438,12 +465,4 @@ java::lang::PosixProcess::nativeSpawn ()
myclose (msgp[0]);
cleanup (args, env, path);
if (exception == NULL)
{
fcntl (outp[1], F_SETFD, FD_CLOEXEC);
fcntl (inp[0], F_SETFD, FD_CLOEXEC);
if (! redirect)
fcntl (errp[0], F_SETFD, FD_CLOEXEC);
}
}