open file descriptor in remote process

Yarin · 10-14-2009, 01:08 PM

Is it possible to open up a file descriptor in my program. And then pass it to a child process for use (along with permissions)? I know each process has it's own list of descriptors, so I don't know how this would be done.

Kennedy · 10-14-2009, 01:20 PM

yes. This is common. What many programs do is to open some file to which they need access and then chroot and change userID (to a lesser user) to do processing. This is for security's sake.

brewbuck · 10-14-2009, 01:37 PM

File descriptors remain valid after a call to fork(). Normally, they also remain valid after a call to exec(), unless the FD_CLOEXEC flag is set of that descriptor.

So the answer is yes.

Yarin · 10-14-2009, 05:36 PM

Great. Thanks.
I didn't know exec() did that.

10-14-2009, 01:08 PM	#1
Yarin Unregistered User Join Date: Jul 2007 Posts: 925	open file descriptor in remote process Is it possible to open up a file descriptor in my program. And then pass it to a child process for use (along with permissions)? I know each process has it's own list of descriptors, so I don't know how this would be done. __________________ GCC 4.4.0, Code::Blocks 8.02, Fedora 11, x64
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10-14-2009, 01:20 PM	#2
Kennedy Jaxom's & Imriel's Dad Join Date: Aug 2006 Location: Alabama Posts: 801	yes. This is common. What many programs do is to open some file to which they need access and then chroot and change userID (to a lesser user) to do processing. This is for security's sake.
Kennedy is offline

10-14-2009, 01:37 PM	#3
brewbuck Senior software engineer Join Date: Mar 2007 Location: Portland, OR Posts: 5,381	File descriptors remain valid after a call to fork(). Normally, they also remain valid after a call to exec(), unless the FD_CLOEXEC flag is set of that descriptor. So the answer is yes. __________________ "Congratulations on your purchase. To begin using your quantum computer, set the power switch to both off and on simultaneously." -- raftpeople@slashdot
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10-14-2009, 05:36 PM	#4
Yarin Unregistered User Join Date: Jul 2007 Posts: 925	Great. Thanks. I didn't know exec() did that. __________________ GCC 4.4.0, Code::Blocks 8.02, Fedora 11, x64
Yarin is offline

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