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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2018-04-03 16:26:05 -0400 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2018-04-03 16:26:05 -0400 |
| commit | dddfc4cb2edcfa5497f5d50190a7fb046c51da16 (patch) | |
| tree | 3e98745d3ccd730a3fd190281a5fcba246f50e01 /src/interfaces/ecpg/compatlib | |
| parent | d4a4c3d5b433513fc38ce60e454d2c86e8bd0ed4 (diff) | |
| download | postgresql-dddfc4cb2edcfa5497f5d50190a7fb046c51da16.tar.gz postgresql-dddfc4cb2edcfa5497f5d50190a7fb046c51da16.zip | |
Prevent accidental linking of system-supplied copies of libpq.so etc.
We were being careless in some places about the order of -L switches in
link command lines, such that -L switches referring to external directories
could come before those referring to directories within the build tree.
This made it possible to accidentally link a system-supplied library, for
example /usr/lib/libpq.so, in place of the one built in the build tree.
Hilarity ensued, the more so the older the system-supplied library is.
To fix, break LDFLAGS into two parts, a sub-variable LDFLAGS_INTERNAL
and the main LDFLAGS variable, both of which are "recursively expanded"
so that they can be incrementally adjusted by different makefiles.
Establish a policy that -L switches for directories in the build tree
must always be added to LDFLAGS_INTERNAL, while -L switches for external
directories must always be added to LDFLAGS. This is sufficient to
ensure a safe search order. For simplicity, we typically also put -l
switches for the respective libraries into those same variables.
(Traditional make usage would have us put -l switches into LIBS, but
cleaning that up is a project for another day, as there's no clear
need for it.)
This turns out to also require separating SHLIB_LINK into two variables,
SHLIB_LINK and SHLIB_LINK_INTERNAL, with a similar rule about which
switches go into which variable. And likewise for PG_LIBS.
Although this change might appear to affect external users of pgxs.mk,
I think it doesn't; they shouldn't have any need to touch the _INTERNAL
variables.
In passing, tweak src/common/Makefile so that the value of CPPFLAGS
recorded in pg_config lacks "-DFRONTEND" and the recorded value of
LDFLAGS lacks "-L../../../src/common". Both of those things are
mistakes, apparently introduced during prior code rearrangements,
as old versions of pg_config don't print them. In general we don't
want anything that's specific to the src/common subdirectory to
appear in those outputs.
This is certainly a bug fix, but in view of the lack of field
complaints, I'm unsure whether it's worth the risk of back-patching.
In any case it seems wise to see what the buildfarm makes of it first.
Discussion: https://postgr.es/m/25214.1522604295@sss.pgh.pa.us
Diffstat (limited to 'src/interfaces/ecpg/compatlib')
| -rw-r--r-- | src/interfaces/ecpg/compatlib/Makefile | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/src/interfaces/ecpg/compatlib/Makefile b/src/interfaces/ecpg/compatlib/Makefile index cd03af56a98..ebfd89544aa 100644 --- a/src/interfaces/ecpg/compatlib/Makefile +++ b/src/interfaces/ecpg/compatlib/Makefile @@ -22,8 +22,8 @@ override CPPFLAGS := -I../include -I$(top_srcdir)/src/interfaces/ecpg/include \ -I$(libpq_srcdir) -DFRONTEND $(CPPFLAGS) override CFLAGS += $(PTHREAD_CFLAGS) -SHLIB_LINK = -L../ecpglib -lecpg -L../pgtypeslib -lpgtypes $(libpq) \ - $(filter -lintl -lm, $(LIBS)) $(PTHREAD_LIBS) +SHLIB_LINK_INTERNAL = -L../ecpglib -lecpg -L../pgtypeslib -lpgtypes $(libpq) +SHLIB_LINK = $(filter -lintl -lm, $(LIBS)) $(PTHREAD_LIBS) SHLIB_PREREQS = submake-ecpglib submake-pgtypeslib SHLIB_EXPORTS = exports.txt |