It turns out that the path normalization that our brand new copy of
dirname(3) does is actually not allowed by the draft version of the
upcoming version of POSIX. It has to behave identically to the
dirname(1) utility.
This change replaces our new dirname(3) implementation by yet another
version that doesn't implement the path normalization logic; it merely
looks for the end of the directory name and overwrites that with a null
byte.
More details: See note #3370 at http://austingroupbugs.net/view.php?id=1073
PR: 212193
Reviewed by: emaste, jilles
Differential Revision: https://reviews.freebsd.org/D7790
As the xinstall(8) utility had to be patched up to work with the POSIXly
correct basename()/dirname() prototypes, we make it pretty hard to build
previous versions of FreeBSD on HEAD. xinstall(8) is part of the
bootstrap tools.
Add some logic to <libgen.h> to automatically detect bad calls to
dirname() based on the type of the argument. If the argument is of type
'const char *', we simply fall back to calling into dirname@FBSD_1.0
directly.
I'll also give basename() similar treatment when importing the
thread-safe version of that function.
Tested by: bdrewery, madpilot (thanks!)
Now that we've updated the prototypes of the basename(3) and dirname(3)
functions to conform to POSIX, let's go ahead and reimplement dirname(3)
in such a way that it's thread-safe, but also guaranteed to succeed. C
libraries like glibc, musl and the one that's part of Solaris already
follow such an approach.
Move the existing implementation to another source file,
freebsd11_dirname.c to keep existing users of the API that pass in a
constant string happy, using symbol versioning.
Put a new version of the function in dirname.c, obtained from CloudABI's
C library. This version scans through the pathname string from left to
right, normalizing it, while discarding the last pathname component.
Reviewed by: emaste, jilles
Differential Revision: https://reviews.freebsd.org/D7355
POSIX allows these functions to be implemented in a way that the
resulting string is stored in the input buffer. Though some may find
this annoying, this has the advantage that it makes it possible to
implement this function in a thread-safe way. It also means that they
can be implemented in a way that they work for paths of arbitrary
length, as the output string of these functions is never longer than
max(1, len(input)).
Portable code already needs to be written with this in mind, so in my
opinion it makes very little sense to allow the existing behaviour.
Prevent the base system from falling back to this by switching over to
POSIX prototypes.
I'm not going to bump the __FreeBSD_version for this. The reason is that
it's possible to account for this change in a portable way, without
depending on a specific version of FreeBSD. An exp-run was done some
time ago. As far as I know, all regressions as a result of this have
already been fixed.
I'll give this change some time to settle. In the long run I want to
replace our copies by ones that are thread-safe and don't depend on
PATH_MAX/MAXPATHLEN.
a pointer and lack a prototype will have the return value (assumed
to be an integer) zero-extended to a pointer. On ia64 this is
unconditionally fatal as it zeroes-out the region bits, forming an
invalid pointer. Fix the sigsegv by including <stdlib.h>.
Pointy hat: bbraun
commit.
Fixed related style bugs:
basename.c: misplaced '#if 0'
dirname.c: misplaced '#if 0'
getgrent.c: missing '#if 0', and tab lossage in vendor id (the previous
commit fixed the complete corruption of the vendor id but
lost a tab)
getpwent.c: missing '#if 0'
