Package: gcc-3.2
Version: 1:3.2.1-0pre3
Severity: normal
Now that I think about it, I see no good reason to export $CDPATH from a shell,
as I was doing. But if for whatever reason one does export a non-null value of
$CDPATH while building gcc-3.2, say, with "debuild", the build is going to
fail. The gcc-3.2 makefiles could be more robust, to prevent this failure,
which will occur in such situations whenever $CDPATH is exported and non-null.
To explain, let me first review how Bash handles the "cd" command.
Fact 1: Quoting from bash-2.05b/builtins/cd.def:
/* POSIX.2 says that if a nonempty directory from CDPATH
is used to find the directory to change to, the new
directory name is echoed to stdout, whether or not
the shell is interactive. */
Fact 2: Bash considers strings starting with "./" and "../" to be
absolute. (There is no mention in the source (general.c) whether this is a
POSIX spec.)
Consequently, the following:
Suppose it is possible to cd to a subdirectory "MySubdir" of the
current directory.
When bash is in POSIX mode and either interactive or not,
cd ./MySubdir
never echoes the new directory, and
cd MySubdir
always echoes it, when the command is successful. The command is successful
when $CDPATH is null or unset, or is set and contains ".".
Now consider the following rule from gcc-3.2-3.2.2ds4/build/gcc/Makefile:
pascal.real-install-doc: pascal.install-dir $(srcdir)/p/README \
$(srcdir)/p/NEWS $(srcdir)/p/FAQ $(srcdir)/p/AUTHORS \
$(srcdir)/p/COPYING $(srcdir)/p/COPYING.LIB $(srcdir)/p/COPYING.FDL
$(srcdir)/p/test/README pascal.docdemos
for f in README NEWS INSTALL FAQ AUTHORS COPYING COPYING.LIB
COPYING.FDL; do \
rm -f "$(p_inst_docdir)/$$f"; \
$(INSTALL_DATA) "$(srcdir)/p/$$f" "$(p_inst_docdir)/$$f" || exit
1; \
chmod a-x "$(p_inst_docdir)/$$f"; \
done
rm -f "$(p_inst_docdir)/BUGS"
$(INSTALL_DATA) "$(srcdir)/p/test/README" "$(p_inst_docdir)/BUGS"
for f in `cd "$(srcdir)/p/demos" && echo *`; do \
if [ "$$f" != CVS ]; then \
rm -f "$(p_inst_demodir)/$$f"; \
$(INSTALL_DATA) "$(srcdir)/p/demos/$$f" "$(p_inst_demodir)/$$f"
|| exit 1; \
fi \
done
chmod a-x "$(p_inst_docdir)/BUGS" "$(p_inst_demodir)"/*
if [ "`cd p/docdemos && echo a*`" != "a*" ]; then \
(cd "$(p_inst_docdemodir)"; for f in *; do rm -f "$$f"; done) && \
for f in `cd p/docdemos && echo *`; do \
rm -f "$(p_inst_docdemodir)/$$f"; \
$(INSTALL_DATA) "p/docdemos/$$f" "$(p_inst_docdemodir)/$$f" && \
chmod a-x "$(p_inst_docdemodir)/$$f" || exit 1; \
done; \
fi
In particular, observe the construction
for f in `cd p/docdemos && echo *`; do
which is used twice in this rule ($(srcdir) happens to be absolute) -- and
probably elsewhere.
The makefile will behave in one of three ways:
1) If $CDPATH is set and contains "." then the absolute pathname of the
subdirectory itself will be the first value of $f in the loop, and
the "install" command will fail.
2) If $CDPATH is set but does not contain ".", the subdirectory will not be
found by the "cd" command.
3) If $CDPATH is null or unset, the Makefile will succeed as intended.
Conclusion:
The makefile would be more robust if it replaced constructions like
for f in `cd p/docdemos && echo *`; do
with
for f in `cd ./p/docdemos && echo *`; do
that is, add a "./" before "p/docdemos".
Moral:
Export as few envariables as you can get away with!
-- System Information:
Debian Release: testing/unstable
Architecture: i386
Kernel: Linux beth 2.4.20 #1 Wed Jan 15 16:59:59 EST 2003 i686
Locale: LANG=C, LC_CTYPE=C
Versions of packages gcc-3.2 depends on:
ii binutils 2.13.90.0.10-1 The GNU assembler, linker and bina
ii cpp-3.2 1:3.2.1-0pre3 The GNU C preprocessor.
ii gcc-3.2-base 1:3.2.1-0pre3 The GNU Compiler Collection (base
ii libc6 2.2.5-14.3 GNU C Library: Shared libraries an
ii libgcc1 1:3.2.1-0pre3 GCC support library.
-- no debconf information
-- System Information:
Debian Release: testing/unstable
Architecture: i386
Kernel: Linux beth 2.4.20 #1 Wed Jan 15 16:59:59 EST 2003 i686
Locale: LANG=C, LC_CTYPE=C
Versions of packages gcc-3.2 depends on:
ii binutils 2.13.90.0.10-1 The GNU assembler, linker and bina
ii cpp-3.2 1:3.2.1-0pre3 The GNU C preprocessor.
ii gcc-3.2-base 1:3.2.1-0pre3 The GNU Compiler Collection (base
ii libc6 2.2.5-14.3 GNU C Library: Shared libraries an
ii libgcc1 1:3.2.1-0pre3 GCC support library.
-- no debconf information
