Quote:
Originally Posted by Niraj Kulkarni
Hi,
I am facing "mq_open-> Permission denied" problem while trying to open POSIX message queue. Can any one tell me why "Permission denied". Here are related information:
1. I am using Linux ubuntu 2.6.32-33.
2. Args passed to mq_open : mq_path = /root/mq,
oflag = O_CREAT|O_WRONLY,
mode = 0666
mq_attribute->mq_maxmsg = 1;
mq_attribute->mq_msgsize = 10;
mq_attribute->mq_flags = 0;
mq_attribute->mq_curmsgs = 0;
3. I am root.
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There are a few solutions posted, one on this site, but they center around (obviously enough), a permissions issue on the object, specifically either the mode or oflag:
http://www.linuxquestions.org/questi...ileges-867954/
http://manpages.ubuntu.com/manpages/....2freebsd.html
http://www.freag.net/en/t/3aaw7/mq_open_permiss
From the documentation:
Quote:
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Originally Posted by mq_open Docs
O_WRONLY
Open the queue for sending messages. The process can use the returned message queue descriptor with the mq_send subroutine but not the mq_receive subroutine. A message queue may be open multiple times in the same or different processes for sending messages.
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...and depending on how your program is working, that may explain it. If you're trying to use the mq_receive subroutine, it'll fail, but the send will work. Have you tried O_RDWR instead of O_WRONLY?
