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configure: preserve various environment variables in config.status

PATCH Superseded Daniel P. Berrange 3 participants 6 messages Nov 17, 2015 – Nov 18, 2015

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Daniel P. Berrange

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#0 lore raw

PATCH 1/1 configure: preserve various environment variables in config.status

Suggested in

https://lists.gnu.org/archive/html/qemu-devel/2015-11/msg03298.html

The config.status script is auto-generated by configure upon completion. The intention is that config.status can be later invoked by the developer to re-detect the same environment that configure originally used. The current config.status script, however, only contains a record of the command line arguments to configure. Various environment variables have an effect on what configure will find. In particular the PKG_CONFIG_LIBDIR & PKG_CONFIG_PATH vars will affect what libraries pkg-config finds. The PATH var will affect what toolchain binaries and XXXX-config scripts are found. The LD_LIBRARY_PATH var will affect what libraries are found. All these key env variables should be recorded in the config.status script.

Signed-off-by Daniel P. Berrange <[email protected]>

---

Open question: are there more env vars we should preserve ?

 configure | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)
configure +18 -0
index d7472d7..9c9f6ac 100755
@@ -5925,6 +5925,24 @@ cat <<EOD >config.status
 # Compiler output produced by configure, useful for debugging
 # configure, is in config.log if it exists.
 EOD
+
+preserve_env() {
+    envname=$1
+
+    if test -n "${!envname}"
+    then
+	echo "$envname=\"${!envname}\"" >> config.status
+	echo "export $envname" >> config.status
+    fi
+}
+
+# Preserve various env variables that influence what
+# features/build target configure will detect
+preserve_env PATH
+preserve_env LD_LIBRARY_PATH
+preserve_env PKG_CONFIG_LIBDIR
+preserve_env PKG_CONFIG_PATH
+
 printf "exec" >>config.status
 printf " '%s'" "$0" "$@" >>config.status
 echo >>config.status
Signature · 1 line
2.5.0
Reviewed-by on v1 1/1
#1 lore raw

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Am 17.11.2015 um 18:59 schrieb Daniel P. Berrange:

Quoted 18 lines

Suggested in

https://lists.gnu.org/archive/html/qemu-devel/2015-11/msg03298.html

The config.status script is auto-generated by configure upon completion. The intention is that config.status can be later invoked by the developer to re-detect the same environment that configure originally used. The current config.status script, however, only contains a record of the command line arguments to configure. Various environment variables have an effect on what configure will find. In particular the PKG_CONFIG_LIBDIR & PKG_CONFIG_PATH vars will affect what libraries pkg-config finds. The PATH var will affect what toolchain binaries and XXXX-config scripts are found. The LD_LIBRARY_PATH var will affect what libraries are found. All these key env variables should be recorded in the config.status script.

Quoted 4 lines
Signed-off-by Daniel P. Berrange <[email protected]>

---

Open question: are there more env vars we should preserve ?

Probably yes. They can be added as soon as we discover them.

Quoted 10 lines
 configure | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)
configure +0 -0
index d7472d7..9c9f6ac 100755
@@ -5925,6 +5925,24 @@ cat <<EOD >config.status
 # Compiler output produced by configure, useful for debugging

configure cat <<EOD >config.status · line 5935

Quoted 10 lines
configure +8 -0
 # configure, is in config.log if it exists.
 EOD
+
+preserve_env() {
+    envname=$1
+
+    if test -n "${!envname}"
+    then
+    echo "$envname=\"${!envname}\"" >> config.status
+    echo "export $envname" >> config.status

else
echo "unset $envname" >>config.status

Quoted 4 lines
configure +3 -0
+    fi
+}
+

configure cat <<EOD >config.status · line 5948

Quoted 10 lines
configure +7 -0
+# Preserve various env variables that influence what
+# features/build target configure will detect
+preserve_env PATH
+preserve_env LD_LIBRARY_PATH
+preserve_env PKG_CONFIG_LIBDIR
+preserve_env PKG_CONFIG_PATH
+
 printf "exec" >>config.status
 printf " '%s'" "$0" "$@" >>config.status
 echo >>config.status

With the additional code for unset variables this
patch is nearly perfect. Even without it, it is a
reasonable improvement.

Reviewed-by Stefan Weil <[email protected]>

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#2 lore raw
In reply to Daniel P. Berrange
Quoted 18 lines · Daniel P. Berrange

Suggested in

https://lists.gnu.org/archive/html/qemu-devel/2015-11/msg03298.html

The config.status script is auto-generated by configure upon completion. The intention is that config.status can be later invoked by the developer to re-detect the same environment that configure originally used. The current config.status script, however, only contains a record of the command line arguments to configure. Various environment variables have an effect on what configure will find. In particular the PKG_CONFIG_LIBDIR & PKG_CONFIG_PATH vars will affect what libraries pkg-config finds. The PATH var will affect what toolchain binaries and XXXX-config scripts are found. The LD_LIBRARY_PATH var will affect what libraries are found. All these key env variables should be recorded in the config.status script.

Quoted 4 lines
Signed-off-by Daniel P. Berrange <[email protected]>

---

Open question: are there more env vars we should preserve ?

Yes - anything that autoconf would mark as precious. See below.

configure cat <<EOD >config.status · line 5932

Quoted 10 lines

+++ b/configure

configure +5 -0
@@ -5925,6 +5925,24 @@ cat <<EOD >config.status
 # Compiler output produced by configure, useful for debugging
 # configure, is in config.log if it exists.
 EOD
+
+preserve_env() {
+    envname=$1
+
+    if test -n "${!envname}"

Bashism, but configure is /bin/sh. This won't work on dash :(

I think you'll have to use eval, and we'll just have to audit that preserve_env can never be called with suspicious text where eval would open a security hole.

configure cat <<EOD >config.status · line 5934

Quoted 2 lines
configure +2 -0
+    then
+	echo "$envname=\"${!envname}\"" >> config.status

Another use of the bashism.

configure cat <<EOD >config.status · line 5945

Quoted 11 lines
configure +11 -0
+	echo "export $envname" >> config.status
+    fi
+}
+
+# Preserve various env variables that influence what
+# features/build target configure will detect
+preserve_env PATH
+preserve_env LD_LIBRARY_PATH
+preserve_env PKG_CONFIG_LIBDIR
+preserve_env PKG_CONFIG_PATH
+

Autoconf preserves CC, CFLAGS, LDFLAGS, LIBS, CPPFLAGS, and CPP by default. Also, PKG_CONFIG is typically preserved. If you run libvirt's './configure --help', you'll also notice a bunch of *_CFLAGS and *_LIBS in the precious list starting under the label "Some influential environment variables".

Signature · 2 lines
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org
author
#3 lore raw
Quoted 39 lines · Eric Blake
Quoted 18 lines · Daniel P. Berrange

Suggested in

https://lists.gnu.org/archive/html/qemu-devel/2015-11/msg03298.html

The config.status script is auto-generated by configure upon completion. The intention is that config.status can be later invoked by the developer to re-detect the same environment that configure originally used. The current config.status script, however, only contains a record of the command line arguments to configure. Various environment variables have an effect on what configure will find. In particular the PKG_CONFIG_LIBDIR & PKG_CONFIG_PATH vars will affect what libraries pkg-config finds. The PATH var will affect what toolchain binaries and XXXX-config scripts are found. The LD_LIBRARY_PATH var will affect what libraries are found. All these key env variables should be recorded in the config.status script.

Quoted 4 lines
Signed-off-by Daniel P. Berrange <[email protected]>

---

Open question: are there more env vars we should preserve ?

Yes - anything that autoconf would mark as precious. See below.

configure cat <<EOD >config.status · line 5932

Quoted 10 lines

+++ b/configure

configure +5 -0
@@ -5925,6 +5925,24 @@ cat <<EOD >config.status
 # Compiler output produced by configure, useful for debugging
 # configure, is in config.log if it exists.
 EOD
+
+preserve_env() {
+    envname=$1
+
+    if test -n "${!envname}"

Bashism, but configure is /bin/sh. This won't work on dash :(

Quoted 3 lines

I think you'll have to use eval, and we'll just have to audit that preserve_env can never be called with suspicious text where eval would open a security hole.

Ok, shouldn't be a big deal

Quoted 14 lines

configure cat <<EOD >config.status · line 5934

Quoted 2 lines
configure +2 -0
+    then
+	echo "$envname=\"${!envname}\"" >> config.status

Another use of the bashism.

Quoted 9 lines
configure +9 -0
+	echo "export $envname" >> config.status
+    fi
+}
+
+# Preserve various env variables that influence what
+# features/build target configure will detect
+preserve_env PATH
+preserve_env LD_LIBRARY_PATH
+preserve_env PKG_CONFIG_LIBDIR
Quoted 8 lines

configure cat <<EOD >config.status · line 5945

Quoted 2 lines
configure +2 -0
+preserve_env PKG_CONFIG_PATH
+

Autoconf preserves CC, CFLAGS, LDFLAGS, LIBS, CPPFLAGS, and CPP by default. Also, PKG_CONFIG is typically preserved. If you run libvirt's './configure --help', you'll also notice a bunch of *_CFLAGS and *_LIBS in the precious list starting under the label "Some influential environment variables".

I'll add in env vars for all the commands like CC, CPP, MAKE, etc that QEMU's configure uses. I've tried preserving various *FLAGS vars but the problem here is that configure will modify/augment those variables while it is running, so when we get to preserve the original flags we only have the munged version. In any case recommendation is to use --extra-cflags rather than CFLAGS, so I figure its not a big deal to skip preserving CFLAGS/LDFLAGS

Regards,
Daniel

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#4 lore raw
Quoted 7 lines · Daniel P. Berrange
Quoted 6 lines

Autoconf preserves CC, CFLAGS, LDFLAGS, LIBS, CPPFLAGS, and CPP by default. Also, PKG_CONFIG is typically preserved. If you run libvirt's './configure --help', you'll also notice a bunch of *_CFLAGS and *_LIBS in the precious list starting under the label "Some influential environment variables".

Quoted 7 lines

I'll add in env vars for all the commands like CC, CPP, MAKE, etc that QEMU's configure uses. I've tried preserving various *FLAGS vars but the problem here is that configure will modify/augment those variables while it is running, so when we get to preserve the original flags we only have the munged version. In any case recommendation is to use --extra-cflags rather than CFLAGS, so I figure its not a big deal to skip preserving CFLAGS/LDFLAGS

Just one more case where we (perhaps needlessly) diverge from autotools and make distro's life harder. Oh well, it's not your fault that we aren't using CFLAGS like other projects, and not preserving CFLAGS does not change that.

Signature · 2 lines
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org
#5 lore raw
In reply to Eric Blake

Am 17.11.2015 um 20:06 schrieb Eric Blake:

Quoted 1 line · Daniel P. Berrange

[...]

Quoted 12 lines

configure cat <<EOD >config.status · line 5932

Quoted 10 lines

+++ b/configure

configure +5 -0
@@ -5925,6 +5925,24 @@ cat <<EOD >config.status
 # Compiler output produced by configure, useful for debugging
 # configure, is in config.log if it exists.
 EOD
+
+preserve_env() {
+    envname=$1
+
+    if test -n "${!envname}"

Bashism, but configure is /bin/sh. This won't work on dash :(

Quoted 3 lines

I think you'll have to use eval, and we'll just have to audit that preserve_env can never be called with suspicious text where eval would open a security hole.

You could also call the function with two arguments ... preserve_env PATH "$PATH"
... and use the 2nd argument in the test.