utmpx is specified by POSIX as an XSI extension. That's more portable
than utmp, which is unavailable for example in musl libc. The manual
page specifies that in Linux (but it probably means in glibc), utmp and
utmpx (and the functions that use them) are identical, so this commit
shouldn't affect glibc systems.
Assume utmpx is always present.
Also, if utmpx is present, POSIX guarantees that some members exist:
- ut_user
- ut_id
- ut_line
- ut_pid
- ut_type
- ut_tv
So, rely on them unconditionally.
Fixes: 170b76cdd1 ("Disable utmpx permanently")
Closes: <https://github.com/shadow-maint/shadow/issues/945>
Reported-by: Firas Khalil Khana <firasuke@gmail.com>
Reported-by: "A. Wilfox" <https://github.com/awilfox>
Tested-by: Firas Khalil Khana <firasuke@gmail.com>
Reviewed-by: Iker Pedrosa <ipedrosa@redhat.com>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
Cherry-picked-from: 64bcb54fa9 ("lib/, src/, configure.ac: Use utmpx instead of utmp")
Signed-off-by: Alejandro Colomar <alx@kernel.org>
This fixes build with glibc-2.33 (newer glibc merged libdl and libpthread
into libc):
```
libtool: link: x86_64-pc-linux-gnu-gcc -isystem /usr/include/bsd -DLIBBSD_OVERLAY -O2 -pipe -Wl,-O1 -o login login.o login_nopam.o -Wl,--as-needed ../lib/.libs/libshadow.a -lcrypt -lsystemd -lpam -lpam_misc -lbsd
/usr/lib/gcc/x86_64-pc-linux-gnu/13/../../../../x86_64-pc-linux-gnu/bin/ld: ../lib/.libs/libshadow.a(libshadow_la-nss.o): undefined reference to symbol 'dlclose@@GLIBC_2.2.5'
/usr/lib/gcc/x86_64-pc-linux-gnu/13/../../../../x86_64-pc-linux-gnu/bin/ld: /lib64/libdl.so.2: error adding symbols: DSO missing from command line
collect2: error: ld returned 1 exit status
```
In Debian, the needed macro from libtool seems to be in libltdl-dev.
Signed-off-by: Sam James <sam@gentoo.org>
Cc: Iker Pedrosa <ikerpedrosam@gmail.com>
Cherry-picked-from: 0f4e59fd00 ("Link correctly with libdl")
Link: <https://github.com/shadow-maint/shadow/pull/917>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
getline(3) is much more readable than manually looping. It has some
overhead due to the allocation of a buffer, but that shouldn't be a
problem here. If that was a problem, we could reuse the buffer (thus
making the function non-reentrant), but I don't think that's worth the
extra complexity.
Using rpmatch(3) instead of a simple y/n test provides i18n to the
response checking. We have a fall-back minimalistic implementation for
systems that lack this function (e.g., musl libc).
While we're at it, apply some other minor improvements to this file:
- Remove comment saying which files use this function. That's likely
to get outdated. And anyway, it's just a grep(1) away, so it doesn't
really add any value.
- Remove unnecessary casts to (void) that were used to verbosely ignore
errors from stdio calls. They add clutter without really adding much
value to the code (or I don't see it).
- Remove comments from the function body. They make the function less
readable. Instead, centralize the description of the function into a
man-page-like comment before the function definition. This keeps the
function body short and sweet.
- Add '#include <stdbool.h>', which was missing.
- Minor whitespace style changes (it doesn't hurt the diff at this
point, since most of the affected lines were already touched by other
changes, so I applied my preferred style :).
Acked-by: Samanta Navarro <ferivoz@riseup.net>
Cc: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
strncat(3), strlcpy(3), and many other functions are often misused for
catenating strings, when they should never be used for that. strlcat(3)
is good. However, there's no equivalent to strlcat(3) similar to
snprintf(3). Let's add stpecpy(), which is similar to strlcat(3), but
it is also the only function compatible with stpeprintf(), which makes
it more useful than strlcat(3).
Signed-off-by: Alejandro Colomar <alx@kernel.org>
[v]stpeprintf() are similar to [v]snprintf(3), but they allow chaining.
[v]snprintf(3) are very dangerous for catenating strings, since the
obvious ways to do it invoke Undefined Behavior, and the ways that avoid
UB are very error-prone.
Cc: Iker Pedrosa <ipedrosa@redhat.com>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
Recently, we removed support for 'struct utmpx'. We did it because utmp
and utmpx are identical, and while POSIX specifies utmpx (and not utmp),
GNU/Linux documentation seems to favor utmp. Also, this project
defaulted to utmp, so changing to utmpx would be more dangerous than
keeping old defaults, even if it's supposed to be the same.
Now, I just found more code that didn't make much sense: lib/utent.c
provides definitions for getutent(3) and friends in case the system
doesn't provide them, but we don't provide prototypes for those
definitions, so code using the functions would have never compiled.
Let's just remove these definitions as dead code.
Fixes: 3be7b9d75a ("Remove traces of utmpx")
Fixes: 170b76cdd1 ("Disable utmpx permanently")
Cc: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
memset_s() has a different signature than memset(3) or explicit_bzero(),
thus the current code would not compile. Also memset_s()
implementations are quite rare.
Use the C23 standardized version memset_explicit(3).
Fixes: 7a799ebb ("Ensure memory cleaning")
- USER_NAME_MAX_LENGTH was being calculated in terms of utmpx. Do it
in terms of utmp.
- Remove utmpx support from the whishlist.
- Remove unused tests about utmpx members.
Signed-off-by: Alejandro Colomar <alx@kernel.org>
On Linux, utmpx and utmp are identical. However, documentation (manual
pages) covers utmp, and just says about utmpx that it's identical to
utmp. It seems that it's preferred to use utmp, at least by reading the
manual pages.
Moreover, we were defaulting to utmp (utmpx had to be explicitly enabled
at configuration time). So, it seems safer to just make it permanent,
which should not affect default builds.
Signed-off-by: Alejandro Colomar <alx@kernel.org>
We already made that assumption in commit b47aa1e9aa. While the
header is not required by POSIX (it is an XSI extension), it is defined
in systems that are of interest to this project (GNU/Linux).
Fixes: b47aa1e9aa ("Assume <utmpx.h> exists")
Cc: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
