Re: The right way to invoke sh from a freebsd makefile?
On Sun, Sep 22, 2013 at 05:56:07PM -0600, Ian Lepore wrote: > > You can hard-code /bin/sh directly, but what I was getting at with the > > '#!/usr/bin/env sh' is that the 'sh' interpreter of the build > > environment could be used (instead of /bin/sh directly). Then you don't > > need to worry about the path to sh(1). > > > > My point is that the #! isn't used at all in this case, it doesn't > matter what's there. Try this... > > echo "echo foo" >/tmp/foo > sh /tmp/foo > > Not only does it not need the hashbang, the script doesn't even have to > be executable when you launch sh and name a script on the command line, > which is just what's needed to run a script from a directory mounted > with the noexec flag. > Ah - maybe it's just late. I see what you mean now. Thanks. Glen pgpPhTPHL9FbJ.pgp Description: PGP signature
Re: The right way to invoke sh from a freebsd makefile?
On Sun, 2013-09-22 at 19:45 -0400, Glen Barber wrote:
> On Sun, Sep 22, 2013 at 05:37:51PM -0600, Ian Lepore wrote:
> > On Sun, 2013-09-22 at 19:27 -0400, Glen Barber wrote:
> > > On Sun, Sep 22, 2013 at 05:18:25PM -0600, Ian Lepore wrote:
> > > > What's the right way to launch the bourne shell from a makefile? I had
> > > > assumed the ${SHELL} variable would be set to "the right" copy
> > > > of /bin/sh (like maybe the one in tmp or legacy at various stages). It
> > > > appears that that's not the case, and ${SHELL} is whatever comes from
> > > > the environment, which can lead to using csh or bash or whatever.
> > > >
> > > > I see some of our makefiles use just a bare "sh" which seems reasonable
> > > > to me, but I don't want to glitch this in src/include/Makefile again.
> > > > The goal is to run a script in src/include/Makefile by launching sh with
> > > > the script name (as opposed to launching the script and letting the #!
> > > > do its thing, which doesn't work if the source dir is mounted noexec).
> > > >
> > >
> > > I think BUILDENV_SHELL is what you are looking for. For this specific
> > > case, I think instead of '#!/bin/sh', maybe '#!/usr/bin/env sh' may be
> > > preferable.
> > >
> > > Glen
> > >
> >
> > No, BUILDENV_SHELL is a special thing... it's used when you "make
> > buildenv" to chroot into a cross-build environment to work
> > interactively. I added that long ago because I can't live in a csh
> > shell (I mean, I can't do anything, I'm totally lost), and I wanted a
> > way to have "make buildenv" put me right into bash (of course, you have
> > to have bash in the chroot).
> >
>
> Ah, right. Thanks for the sanity check.
>
> > The flavor of hashbang to use shouldn't matter, since what I'm after
> > here is launching the shell to run the script without using the hashbang
> > mechanism.
> >
>
> You can hard-code /bin/sh directly, but what I was getting at with the
> '#!/usr/bin/env sh' is that the 'sh' interpreter of the build
> environment could be used (instead of /bin/sh directly). Then you don't
> need to worry about the path to sh(1).
>
> Glen
>
My point is that the #! isn't used at all in this case, it doesn't
matter what's there. Try this...
echo "echo foo" >/tmp/foo
sh /tmp/foo
Not only does it not need the hashbang, the script doesn't even have to
be executable when you launch sh and name a script on the command line,
which is just what's needed to run a script from a directory mounted
with the noexec flag.
-- Ian
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Re: The right way to invoke sh from a freebsd makefile?
On Sun, Sep 22, 2013 at 05:37:51PM -0600, Ian Lepore wrote:
> On Sun, 2013-09-22 at 19:27 -0400, Glen Barber wrote:
> > On Sun, Sep 22, 2013 at 05:18:25PM -0600, Ian Lepore wrote:
> > > What's the right way to launch the bourne shell from a makefile? I had
> > > assumed the ${SHELL} variable would be set to "the right" copy
> > > of /bin/sh (like maybe the one in tmp or legacy at various stages). It
> > > appears that that's not the case, and ${SHELL} is whatever comes from
> > > the environment, which can lead to using csh or bash or whatever.
> > >
> > > I see some of our makefiles use just a bare "sh" which seems reasonable
> > > to me, but I don't want to glitch this in src/include/Makefile again.
> > > The goal is to run a script in src/include/Makefile by launching sh with
> > > the script name (as opposed to launching the script and letting the #!
> > > do its thing, which doesn't work if the source dir is mounted noexec).
> > >
> >
> > I think BUILDENV_SHELL is what you are looking for. For this specific
> > case, I think instead of '#!/bin/sh', maybe '#!/usr/bin/env sh' may be
> > preferable.
> >
> > Glen
> >
>
> No, BUILDENV_SHELL is a special thing... it's used when you "make
> buildenv" to chroot into a cross-build environment to work
> interactively. I added that long ago because I can't live in a csh
> shell (I mean, I can't do anything, I'm totally lost), and I wanted a
> way to have "make buildenv" put me right into bash (of course, you have
> to have bash in the chroot).
>
Ah, right. Thanks for the sanity check.
> The flavor of hashbang to use shouldn't matter, since what I'm after
> here is launching the shell to run the script without using the hashbang
> mechanism.
>
You can hard-code /bin/sh directly, but what I was getting at with the
'#!/usr/bin/env sh' is that the 'sh' interpreter of the build
environment could be used (instead of /bin/sh directly). Then you don't
need to worry about the path to sh(1).
Glen
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Re: The right way to invoke sh from a freebsd makefile?
On Sun, 2013-09-22 at 19:27 -0400, Glen Barber wrote:
> On Sun, Sep 22, 2013 at 05:18:25PM -0600, Ian Lepore wrote:
> > What's the right way to launch the bourne shell from a makefile? I had
> > assumed the ${SHELL} variable would be set to "the right" copy
> > of /bin/sh (like maybe the one in tmp or legacy at various stages). It
> > appears that that's not the case, and ${SHELL} is whatever comes from
> > the environment, which can lead to using csh or bash or whatever.
> >
> > I see some of our makefiles use just a bare "sh" which seems reasonable
> > to me, but I don't want to glitch this in src/include/Makefile again.
> > The goal is to run a script in src/include/Makefile by launching sh with
> > the script name (as opposed to launching the script and letting the #!
> > do its thing, which doesn't work if the source dir is mounted noexec).
> >
>
> I think BUILDENV_SHELL is what you are looking for. For this specific
> case, I think instead of '#!/bin/sh', maybe '#!/usr/bin/env sh' may be
> preferable.
>
> Glen
>
No, BUILDENV_SHELL is a special thing... it's used when you "make
buildenv" to chroot into a cross-build environment to work
interactively. I added that long ago because I can't live in a csh
shell (I mean, I can't do anything, I'm totally lost), and I wanted a
way to have "make buildenv" put me right into bash (of course, you have
to have bash in the chroot).
The flavor of hashbang to use shouldn't matter, since what I'm after
here is launching the shell to run the script without using the hashbang
mechanism.
-- Ian
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Re: The right way to invoke sh from a freebsd makefile?
On Sun, Sep 22, 2013 at 05:18:25PM -0600, Ian Lepore wrote:
> What's the right way to launch the bourne shell from a makefile? I had
> assumed the ${SHELL} variable would be set to "the right" copy
> of /bin/sh (like maybe the one in tmp or legacy at various stages). It
> appears that that's not the case, and ${SHELL} is whatever comes from
> the environment, which can lead to using csh or bash or whatever.
>
> I see some of our makefiles use just a bare "sh" which seems reasonable
> to me, but I don't want to glitch this in src/include/Makefile again.
> The goal is to run a script in src/include/Makefile by launching sh with
> the script name (as opposed to launching the script and letting the #!
> do its thing, which doesn't work if the source dir is mounted noexec).
>
I think BUILDENV_SHELL is what you are looking for. For this specific
case, I think instead of '#!/bin/sh', maybe '#!/usr/bin/env sh' may be
preferable.
Glen
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Re: The right way to invoke sh from a freebsd makefile?
On 9/22/2013 6:18 PM, Ian Lepore wrote:
> What's the right way to launch the bourne shell from a makefile? I had
> assumed the ${SHELL} variable would be set to "the right" copy
> of /bin/sh (like maybe the one in tmp or legacy at various stages). It
> appears that that's not the case, and ${SHELL} is whatever comes from
> the environment, which can lead to using csh or bash or whatever.
>
> I see some of our makefiles use just a bare "sh" which seems reasonable
> to me, but I don't want to glitch this in src/include/Makefile again.
> The goal is to run a script in src/include/Makefile by launching sh with
> the script name (as opposed to launching the script and letting the #!
> do its thing, which doesn't work if the source dir is mounted noexec).
>
> -- Ian
>
Grepping the Makefiles in the tree, 'sh' is the very common. I see
around 157 users of this pattern. 13 use /bin/sh directly. Also consider
that it is highly likely, if not required, that a /bin/sh will exist.
Calling 'sh' specifically is definitely more proper than ${SHELL} since
it is an sh script.
--
Regards,
Bryan Drewery
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