158920 - build fails if cygwin mount prefix is not /cygdrive

Status: RESOLVED FIXED

(SeaMonkey :: Build Config, defect, P3)

Description

[hacker formerly known as [e-mail]]

I thought that we had fixed this at one point but it seems to have been
resurrected with the fix of bug 141834.  Cygwin uses /cygdrive/X/foo/bar to
denote the path to files on drive X, if X is a cyg-mounted drive.  If the drive
is unmounted, cygwin uses /X/foo/bar/.  Both conventions already screw up
non-cygwin programs but this is doubly annoying.  While both are easy enough to
check for via sed, the first has far less of a chance of hitting a false positive.  

Using `cygpath -w` to translate either type of path into a regular dos path
seems to work.  However, we do not use cygpath in the cygwin-wrapper script
since cygpath only works on a single argument, not a list of arguments.  Instead
we assume that /cygdrive/ is used which breaks when the drive isn't cyg-mounted.

Potential solutions:
1) Start using cygpath in the wrapper script.  This is nasty as it means
invoking a separate process for *each* argument passed through the script.

2) Skip the wrapper script altogether.  In the main build, we use the script as
little as possible.  It's still used for a handful of things though, namely
running rc, perl & nsinstall.  nsinstall is the main sore spot as it can accept
a variable number of filename args which each would need to be checked. NSPR &
LDAP use the wrapper pretty much everywhere.

3) Hack cygpath to accept multiple args so that we could use cygpath in the
wrapper in lieu of sed.  This means yet another entry from wintools or hoping
that cygnus will accept the changes and bump the minimum rev of the cygwin tools
required.

Comment 1

[Wan-Teh Chang]

I vote for solution 3.

Comment 2

[hacker formerly known as [e-mail]]

I forgot to mention the obvious but potentially unfriendly option of requiring
that the drive be cygwin mounted before we can build.  I don't know of any
immediate side-effects of mounting but people aren't going to like the extra step.

Comment 3

[cls]

So, um, I'm not sure how to naturally reproduce this bug.  When I converted one
of my linux partitions into a ntfs partition, it showed up in my mount table as
/cygdrive/e/ automatically. It also has a noumount attribute and I can't seem to
umount it.  This is on w2k.

Comment 4

[Chak Nanga]

I think the cygwin installer records the mount information in the Windows registry.

On my installation this is at:
HKEY_CURRENT_USER\Software\Cygnus Solutions\Cygwin\mounts v2

You should be able to use regedit.exe to edit the registry entries to get rid of
the mount points.

Comment 5

[hacker formerly known as [e-mail]]

It must be keeping these particular drive mount points elsewhere.  Under that
registry space, I see the mount points for /, /usr/bin & /usr/lib.  I do not see
any drive mount points.  Even if I log in as Administrator and do a 'umount -A'
(or 'umount -S') which should unmount all mountpoints, the /cygdrive/{c,e} mount
points still exist. 

I'm starting to wonder if requiring a /cygdrive/ mount point is really all that
inconvenient...seeing as I can't even get rid of mine to reproduce the problem. :-/

Comment 6

[Chak Nanga]

Hi Chris : Requiring a /cygdrive/ mount point does not seem to be all that
inconvenient. Maybe all that's needed here is to add this part to the build
instructions?

Comment 7

[hacker formerly known as [e-mail]]

Chak: I added a note about the /cygdrive issue to the "Common Sticking Points"
of the updated win32 build instructions.  Out of curiosity, what does "mount -p"
return as the mount prefix for your drives?  I'm still wondering where the
option to change the mount prefix comes from as I haven't seen it.  Was this a
fresh install of cygwin or an update of a previous release (like b20.1)?

Comment 8

[Chak Nanga]

C:\WINNT> mount -p
Prefix              Type         Flags
/                   user         textmode

Here's what i remember regarding the mount stuff:

1. I had installed Cygwin a while ago (sorry i do not remember which version)
2. After the install, I had used the istructions at
http://cygwin.com/faq/faq.html#SEC53 to change the mount prefix(Specifically the
part which talks about "You can avoid the ambiguity of Windows paths, and avoid
typing "/cygdrive", by explicitly mounting drives to posix paths". 
I mainly did this save myself some typing in bash windows as the note says.
3. I had to undo the part(in 2 above) to get Mozilla building with gmake per you
suggestion

Comment 9

[Lapo Luchini]

Just to shread a little light on the subject:

Cygwin has its own mount table (as seen in the registry):
$ mount
C:\Cygwin\bin on /usr/bin type system (binmode)
C:\Cygwin\lib on /usr/lib type system (binmode)
C:\Cygwin on / type system (binmode)
c: on /cygdrive/c type user (binmode,noumount)
d: on /cygdrive/d type user (binmode,noumount)
e: on /cygdrive/e type user (binmode,noumount)
f: on /cygdrive/f type user (binmode,noumount)
h: on /cygdrive/h type user (binmode,noumount)
k: on /cygdrive/k type user (binmode,noumount)
l: on /cygdrive/l type user (binmode,noumount)
x: on /cygdrive/x type user (binmode,noumount)

The /cygdrive/?/ are *not* mounted directories but Cygwin simply "map" each
windows drive automatically in that directory, so that a program can access each
windows file and not only "mounted" directories.

/cygdrive/?/ is just a nifty 'hack', though very useful.
By default it is installed in binmode, which is the right default (textmode
means "by default open files ni text mode" and leads to many problems if the
program doesn't use "rt" or "wt").

What is thwe problem in using always the /cygdrive/x/path method? That can be
easily converted in x:\path using sed, no need to mount everyting as the
/cygdrive/ tree has nothing different from "real" mounted directories... AFAIK.

Anyway, I'm downloading the source so that I can test and do a better report on
the problem.

Comment 10

[hacker formerly known as [e-mail]]

Attachment: v1.0

This patch fixes the /cygdrive assumptions in the code by checking what mount
prefix is returned by 'mount -p'.  It will slow down the cygwin-wrapper
slightly.

Comment 11

[hacker formerly known as [e-mail]]

FYI, this patch still won't fix the problem of building on a mountpoint that
doesn't use the default mount prefix.  That can only be fixed by calling cygpath
on each individual arg.

Nor will it solve the problem of building under the cygwin install point
(c:\cygwin\).  That problem could be fixed if cygwin make didn't auto-translate
the paths used in automatic variables ($^).

Comment 12

[Johnny Stenback (:jst)]

Attachment: Possible alternate approach...

This is what I've had in my tree for a while and it works for me, but I've
never tried it in any other environments. Have a look, and ignore this if you
don't like it.

Comment 13

[hacker formerly known as [e-mail]]

Comment on attachment 119133 [details] [diff] [review]
Possible alternate approach...

The only problem I see with it is that it only addresses mountprefix ==
/cygdrive & mountprefix == /.  (Granted, those are the only ones I've tested
with as well but I wouldn't be surprised if others were used.)

Comment 14

[Kyle Yuan]

In my environment, mount -p shows:
$ mount -p
Prefix              Type         Flags
/cygdrive           user         binmode
/cygdrive           system       binmode

so mount -p | grep ^/ | awk '{ print $1 }' will get
/cygdrive
/cygdrive

and it breaks my build. Is that a cygwin bug?

Comment 15

[hacker formerly known as [e-mail]]

Attachment: handle multiple mount points

No, that's not a bug.  Cygwin allows you to have separate user defined mount
points as well as system defined ones.	Try this patch.  It should pick the
first system defined mount prefix.

Comment 16

[Johnny Stenback (:jst)]

On my system I get this from mount -p

Prefix              Type         Flags
/cygdrive           system       textmode

but I've got plenty more mount points than that, mount gives this:

C:\cygwin\bin on /usr/bin type system (textmode)
C:\cygwin\lib on /usr/lib type system (textmode)
C:\cygwin on / type system (textmode)
c: on /c type user (textmode)
e: on /e type user (textmode)
e: on /e type system (textmode)
f: on /f type user (textmode)
g: on /cygdrive/g type system (textmode)
g: on /g type system (textmode)
h: on /h type system (textmode)
d: on /cygdrive/d type user (textmode,noumount)

Comment 17

[hacker formerly known as [e-mail]]

Attachment: fix make-jars.pl too

Comment 18

[Ere Maijala (slow)]

Something about this was checked in and I suspect it broke my build. I had to
manually apply the patch for nsprpub/build/cygwin-wrapper to make it build. 

Comment 19

[hacker formerly known as [e-mail]]

Attachment: again

Bah.  Apparently, some people (or maybe it's just timeless) only have a user
defined mount prefix so we're taking whichever comes first.

Comment 20

[(not reading, please use [e-mail] instead)]

that patch worked for me.

see news://news.mozilla.org:119/[e-mail]

Comment 21

[Dan M]

Attachment: another version of the "again" patch

I had the same problem. This is what I used to get a build this morning. It's
similar, but it's possibly a little faster since it doesn't have to add another
pipe.

For some reason, and I had never realized this before today, my cygwin
installation has multiple base mount points, so mount -p says:

$ mount -p
Prefix		    Type	 Flags
/cygdrive	    user	 textmode
/cygdrive	    system	 binmode
$

And it's still that way even after I tried rebuilding all my mount points using
regedit.

Comment 22

[Dan M]

Oh. looking closer: no fewer pipes in my version after all.

Comment 23

[Dan M]

mount -p|awk '{if(/^\//) {print $1; exit}}'

Comment 24

[hacker formerly known as [e-mail]]

danm, I checked in your change.  Less pipes and creature hit the perl/bin/head
problem.  All of my boxes, which were all installed within the past 3 months,
only have the single system mount prefix.

jst, 'mount -p' just shows the default mount prefix used when mapping a new
drive for cygwin.  I'm surprised that you have a default of /cygdrive but the
rest use / .  I assume you changed those.  You can have an many mount points as
you want but I think there's only a single default mount prefix for each mount
type (system & user).

Comment 25

[Johnny Stenback (:jst)]

FYI, this didn't fix the build problems for me. I'm still stuck with my own
version of this (attachment #119133 [details] [diff] [review]), which I've lived with now for months...
Maybe my mountpoints are messed up, all I did was to mount my drives as /<drive
letter>, I didn't mess with the default mount prefix, didn't even know there was
one.

/me points out that he really doesn't like cygwin's dealings with mount points.

Comment 26

[hacker formerly known as [e-mail]]

jst, given your mount table listed in comment #16, the checked in changes won't
work for you unless you're building on drive d or g due to the reasons I pointed
out in comment #11.  You could have avoided mounting those drives individually
by just changing the default mount prefix and rebooting.

Comment 27

[Bernd]

I am just trying to run the layout regression tests and get:
C:\moz_sour\mozilla\mozilla\layout\html\tests\block>sh rtest.sh baseline
testbase
/cygdrive/c/moz_sour/mozilla/mozilla/layout/html/tests/block/../../../../..
Running baseline in base
sed: -e expression #1, char 7: Unterminated `s' command
/cygdrive/c/moz_sour/mozilla/mozilla/layout/html/tests/block/runtests.sh -m base
line -f
baseline
backing out the changes to runtests.sh make the whole thing running again. Have
you ever tested that the layout regression test did survive the change under winxx?