RE: What is the difference between 'login: root' and 'su -' ?

[PVotruba@Chemoprojekt.cz]

Hi,

BTW, /dev/hdc4, is that a regular hard disk partition? I was always used to
create /dev/hda1, /dev/hda5, /dev/hda6 etc.  as normal partitions (via
fdisk). 

Is your /dev/hda hard disk drive or some other device?

Just for my curiosity :)

Regards
Petr


> -----Původní zpráva-----
> Od:	Peter Seiderer [SMTP:Peter.Seiderer@ciselant.de]
> Odesláno:	8. listopadu 2001 9:47
> Komu:	linux-kernel@vger.kernel.org
> Kopie:	Ville Herva
> Předmět:	Re: What is the difference between 'login: root' and 'su -'
> ?
> 
> Hello,
> in both cases file descriptor 4 is from 'open("/dev/hdc4", O_RDWR) = 4'
> ....
> Peter
> 
> On Thu, Nov 08, 2001 at 08:10:07AM +0200, Ville Herva wrote:
> > On Wed, Nov 07, 2001 at 11:40:25PM +0100, you [Peter Seiderer] claimed:
> > > Mhhh,
> > > the strace output from the 'login: root' one (the one which was good)
> > > looks the same till the EFBIG place:
> > > 
> > > 	write(1, "\10\10\10\10\10", 5)          = 5
> > > 	write(1, "16/44", 5)                    = 5
> > > 	_llseek(4, 18446744071562084352, [2147500032], SEEK_SET) = 0
> > > 	write(4,
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 32768) =
> 32768
> > > 	_llseek(4, 18446744071562117120, [2147532800], SEEK_SET) = 0
> > > 	write(4,
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 32768) =
> 32768
> > > 	_llseek(4, 18446744071562149888, [2147565568], SEEK_SET) = 0
> > > 	write(4,
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 32768) =
> 32768
> > > 	_llseek(4, 18446744071562182656, [2147598336], SEEK_SET) = 0
> > > 	write(4,
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 32768) =
> 32768
> > 
> > Weird. Perhaps strace gets that wrong and the problem is elsewhere.
> > 
> > Did you make sure that fd 4 is the same _partition_ in both cases (using
> > strace)? The only thing I could imagine exposing 2GB limit is writing to
> a
> > file.
> > 
> > > > > 	zodiak login: seiderer
> > > > > 	Password:
> > > > > 	seiderer@zodiak:~ > su -
> > > > > 	Password:
> > > > > 	zodiak:~ #
> > > > > 	zodiak:~ # mkfs.ext2 /dev/hdc4
> > > > > 	mke2fs 1.18, 11-Nov-1999 for EXT2 FS 0.5b, 95/08/09
> > > > > 	Filesystem label=
> > > > > 	OS type: Linux
> > > > > 	Block size=4096 (log=2)
> > > > > 	Fragment size=4096 (log=2)
> > > > > 	716672 inodes, 1432116 blocks
> > > > > 	71605 blocks (5.00%) reserved for the super user
> > > > > 	First data block=0
> > > > > 	44 block groups
> > > > > 	32768 blocks per group, 32768 fragments per group
> > > > > 	16288 inodes per group
> > > > > 	Superblock backups stored on blocks:
> > > > > 	        32768, 98304, 163840, 229376, 294912, 819200, 884736
> > > > > 
> > > > > 	Writing inode tables: 16/44File size limit exceeded
> > > > > 
> > > > > strace showed that write returned wit EFBIG and the process ended
> with SIGXFSZ:
> > > > > 
> > > > > 	write(1, "\10\10\10\10\10", 5)          = 5
> > > > > 	write(1, "16/44", 5)                    = 5
> > > > > 	_llseek(4, 18446744071562084352, [2147500032], SEEK_SET) = 0
> > > > > 	write(4,
> "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 32768) = -1
> EFBIG (File too large)
> > > > > 	--- SIGXFSZ (File size limit exceeded) ---
> > > > > 	+++ killed by SIGXFSZ +++
> > > > 
> > > > Hmm, 18446744071562084352 = 0xffffffff80004000, 2147500032 =
> 0x80004000...
> > > > It looks a tad like llseek's offset_high would have been
> corrupted...
> > > > Strange.
> > > > 
> > > > 1432116 blocks * 4096 bytes/block * 16/44 written = 2133071685.81818
> so
> > > > 2147500032 looks sane(ish).
> > 
> > -- v --
> > 
> > v@iki.fi
> 
> -
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