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It was blessed by POSIX.1-2001, and GCC says that it won't go away, possibly ever. memset(3) is dangerous, as the 2nd and 3rd arguments can be accidentally swapped --who remembers what's the order of the 2nd and 3rd parameters to memset(3) without checking the manual page or some code that uses it?--. Some recent compilers may be able to catch that via some warnings, but those are not infalible. And even if compiler warnings could always catch that, the time lost in fixing or checking the docs is lost for no clear gain. Having a sane API that is unambiguous is the Right Thing (tm); and that API is bzero(3). If someone doesn't believe memset(3) is error-prone, please read the book "Unix Network Programming", Volume 1, 3rd Edition by Stevens, et al., Section 1.2. See a stackoverflow reference in the link below[1]. bzero(3) had a bad fame in the bad old days, because some ancient systems (I'm talking of many decades ago) shipped a broken version of bzero(3). We can assume that all systems in which current shadow utils can be built, have a working version of bzero(3) --if not, please fix your broken system; don't blame the programmer--. One reason that some use today to avoid bzero(3) in favor of memset(3) is that memset(3) is more often used; but that's a circular reasoning. Even if bzero(3) wasn't supported by the system, it would need to be invented. It's the right API. Another reason that some argue is that POSIX.1-2008 removed the specification of bzero(3). That's not a problem, because GCC will probably support it forever, and even if it didn't, we can redefine it like we do with memzero(). bzero(3) is just a one-liner wrapper around memset(3). Link: [1] <https://stackoverflow.com/a/17097978> Cc: Christian Göttsche <cgzones@googlemail.com> Cc: Serge Hallyn <serge@hallyn.com> Cc: Iker Pedrosa <ipedrosa@redhat.com> Signed-off-by: Alejandro Colomar <alx@kernel.org> |
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shadow-utils
Introduction
The shadow-utils package includes the necessary programs for converting UNIX password files to the shadow password format, plus programs for managing user and group accounts. The pwconv command converts passwords to the shadow password format. The pwunconv command unconverts shadow passwords and generates a passwd file (a standard UNIX password file). The pwck command checks the integrity of password and shadow files. The lastlog command prints out the last login times for all users. The useradd, userdel, and usermod commands are used for managing user accounts. The groupadd, groupdel, and groupmod commands are used for managing group accounts.
Sites
Contacts
There are several ways to contact us:
- the general discussion mailing list
- the #shadow IRC channel on libera.chat:
- irc://irc.libera.chat/shadow
Mailing archives
- the general discussion mailing list archive
- the commit mailing list archive, only used for historical purposes
Contributions
Contributions are welcome. Follow the guidelines before posting any patches.
Authors and maintainers
Authors and maintainers are listed in AUTHORS.md.