Hi,
I've seen similar complain. What was the end of this patch? Did this
discussion continue off-list ?
Michal
On 29.10.2012 12:11, Dr. Werner Fink wrote:
On Fri, Oct 26, 2012 at 04:42:17PM +0200, Roland Mainz wrote:
On Fri, Oct 26, 2012 at 3:47 PM, Dr. Werner Fink <[email protected]> wrote:
I had a customer which had reported that the ksh run into problem if
the /tmp partition on his system had no space left due to a process
gone wild:
Last login: Tue Oct 23 15:12:00 2012 from ...
/etc/profile: line 12: write to 1 failed [No space left on device]
/etc/profile: line 41: write to 1 failed [No space left on device]
/etc/profile: line 87: write to 1 failed [No space left on device]
/etc/profile: line 88: write to 1 failed [No space left on device]
/etc/profile: line 91: write to 1 failed [No space left on device]
/etc/profile: line 92: write to 1 failed [No space left on device]
/etc/profile: line 93: write to 1 failed [No space left on device]
/usr/bin/manpath: can't set the locale; make sure $LC_* and $LANG are correct
/etc/profile: line 207: write to 1 failed [No space left on device]
/etc/profile[324]: .: line 606: write to 4 failed [No space left on device]
also the ksh93u-2012-02-29 sometimes crash in src/cmd/ksh93/sh/subshell.c
which seems to be fixed in current ksh. Nevertheless IMHO the ksh should
check not only if access is allowed in /tmp or /usr/tmp (which points to
/var/tmp) but also if there is enough room left. If no space is left on
the temporary device it would be perfect to use pipe() as fallback for
stdout.
Uhm... for which shell constructs would you like to use |pipe()| ?
if ! is=$(/bin/ls -l /proc/$$/exe 2>/dev/null) ; then
[...]
tty=`tty 2> /dev/null`
[...]
test -z "$UID" && readonly UID=`id -ur 2> /dev/null`
test -z "$EUID" && readonly EUID=`id -u 2> /dev/null`
[...]
test -z "$HOST" && HOST=`/bin/hostname -s 2> /dev/null`
test -z "$CPU" && CPU=`/bin/uname -m 2> /dev/null`
test -z "$HOSTNAME" && HOSTNAME=`/bin/hostname 2> /dev/null`
[...]
MANPATH="`test -x /usr/bin/manpath && /usr/bin/manpath -q`"
[...]
Btw: from src/cmd/ksh93/sh/subshell.c you can see in sh_subtmpfile() that
if the creation of a tmp fd fails a pipe is usesd:
/* popping a discipline forces a /tmp file create */
sfdisc(sfstdout,SF_POPDISC);
if((fd=sffileno(sfstdout))<0)
{
/* unable to create the /tmp file so use a pipe */
[...]
See the attached patch for a suggested solution. The change in
src/lib/libast/path/pathtemp.c uses statvfs() to check if the device
has at least space of the sitze of one page left. The change in
src/lib/libast/sfio/sftmp.c use the /dev/shm tmpfs which is used for
POSIX shared memory objects. One could use shm_open()/shm_unlink()
but the file descriptor then has FD_CLOEXEC set in its flags.
A different solution (since /dev/shm is not portable) may be to probe
various locations for temporary files and check if there is space left
(e.g. /tmp (preferred because this is usually a ramdisk-like
filesystem on newer Unixes), /var/tmp and /usr/tmp (the traditional
location)) and check if at least a page (MMU default page size) is
available (a better algorithm may be 8*default_mmu_page_size) ... if
all locations do not have enough space then ksh93 should bail-out with
a fatal error...
With glibc there exists also the functions shm_open(3) and shm_unlink(3)
but the open for POSIX SHM will set the FD_CLOEXEC flag on the fd. Both
shm_open(3) and shm_unlink(3) handle files relatively to /dev/shm.
Werner
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