Date: Sat, 17 Jun 1995 16:01:36 +0300 From: "Gennady B. Sorokopud" <gena@NetVision.net.il> To: Peter Dufault <dufault@hda.com> Cc: <hackers@FreeBSD.org>, <gena@NetVision.net.il> Subject: Re: SCIOCCOMMAND ioctl - permission denied Message-ID: <XFMail.950617154730.gena@NetVision.net.il> In-Reply-To: <199506171138.HAA11954@hda.com>
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In message <199506171138.HAA11954@hda.com> Peter Dufault writes: >Gennady B. Sorokopud writes: >> >> Hello! >> >> I'm author of xmcd port to FreeBSD platform. >> I received some reports from users that claims that xmcd SCSI >> interface does not work any more on 2.0.5R. >> >> After some checking i find out that SCIOCCOMMAND ioctl always fail >> with "permission denied". >> >> Looking at /sys/scsi/scsi_ioctl.c line 260: >> >> /* If we can't write the device we can't permit much: >> */ >> if (cmd != SCIOCIDENTIFY && !(flags & FWRITE)) >> return EACCES; >> >> After commenting out this 2 lines and recompiling the kernel >> xmcd started to work fine. >> >> All i need to know is how to call this ioctl so it will not fail. > >You are probably opening the device O_RDONLY. The SCIOCCOMMAND You right! How stupid i was :-(. Thanks. >ioctl beginning in 2.05 is considered 'destructive' and requires >write access to the device (even for a CD-ROM). This is different >from write permission to open the device. > >This is because I can't tell which SCIOCCOMMANDs do things (change >the mode on the device, eject the CD, etc) that you want to restrict. >Otherwise someone could open the CD device read-only, allow removal, >change the modes, eject the device, etc. > >I can't protect based on whether you read or write data, since many >destructive commands don't transfer data. > >Sorry, I should have considered this problem with existing programs. >I hate to see your program break this way on 2.05. Are there any >ideas for better ways to handle this? > >Peter > >-- >Peter Dufault Real Time Machine Control and Simulation >HD Associates, Inc. Voice: 508 433 6936 >dufault@hda.com Fax: 508 433 5267 -------- Gennady B. Sorokopud - System programmer at NetVision Israel. E-Mail: gena@NetVision.net.il Homepage: http://www.netvision.net.il/~gena This message was sent at 06/17/95 15:47:30 by XF-Mail
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