libbsd(7) BSD Miscellaneous Information Manual libbsd(7)
NAME
libbsd — utility functions from BSD systems
DESCRIPTION
The libbsd library provides a set of compatibility macros and functions
commonly found on BSD-based systems. Its purpose is to make those avail-
able on non-BSD based systems to ease portability.
The library can be used in an overlay mode, which is the preferred way,
so that the code is portable and requires no modification to the original
BSD code. This can be done easily with the pkgconf(1) library named
libbsd-overlay. Or by adding the system-specific include directory with
the bsd/ suffix to the list of system include paths. With gcc this could
be -isystem ${includedir}/bsd. In addition the LIBBSD_OVERLAY pre-pro-
cessor variable needs to be defined. The includes in this case should be
the usual system ones, such as <unistd.h>.
The other way to use the library is to use the namespaced headers, which
is a discouraged way, being less portable as it makes using libbsd manda-
tory and it will not work on BSD-based systems, and requires modifying
original BSD code. This can be done with the pkgconf(1) library named
libbsd. The includes in this case should be namespaced with bsd/, such
as <bsd/unistd.h>.
The package also provides a libbsd-ctor static library that can be used
to inject automatic constructors into a program so that the
setproctitle_init(3) function gets invoked automatically at startup time.
This can be done with the pkgconf(1) library named libbsd-ctor.
HEADERS
The following are the headers provided by libbsd, that extend the stan-
dard system headers. They can work in normal or overlay modes, for the
former they need to be prefixed with bsd/.
<bitstring.h>
<err.h>
<getopt.h>
<grp.h>
<inttypes.h>
<libutil.h>
<md5.h>
<netinet/ip_icmp.h>
<nlist.h>
<pwd.h>
<readpassphrase.h>
<stdio.h>
<stdlib.h>
<string.h>
<stringlist.h>
<sys/bitstring.h>
<sys/cdefs.h>
<sys/endian.h>
<sys/param.h>
<sys/poll.h>
<sys/queue.h>
<sys/time.h>
<sys/tree.h>
<timeconv.h>
<unistd.h>
<vis.h>
<wchar.h>
The following is a libbsd specific convenience header, that includes some
of the extended headers. It only works in non-overlay mode.
<bsd/bsd.h>
ALTERNATIVES
Some functions have different prototypes depending on the BSD where they
originated from, and these various implementations provided are se-
lectable at build-time.
This is the list of functions that provide multiple implementations:
strnvis(3)
strnunvis(3)
NetBSD added strnvis(3) and strnunvis(3) but unfortunately made it
incompatible with the existing one in OpenBSD and Freedesktop's
libbsd (the former having existed for over ten years). Despite
this incompatibility being reported during development (see
http://gnats.netbsd.org/44977) they still shipped it. Even more
unfortunately FreeBSD and later MacOS picked up this incompatible
implementation.
Provide both implementations and default for now to the historical
one to avoid breakage, but we will switch to the NetBSD one in a
later release, which is internally consistent with the other vis(3)
functions and is now more widespread. Define LIBBSD_NETBSD_VIS to
switch to the NetBSD one now. Define LIBBSD_OPENBSD_VIS to keep
using the OpenBSD one.
DEPRECATED
Some functions have been deprecated, they will emit warnings at compile
time and possibly while being linked at run-time. This might be due to
the functions not being portable at all to other systems, making the
package not buildable there; not portable in a correct or non-buggy way;
or because there are better more portable replacements now.
This is the list of currently deprecated macros and functions:
fgetln(3)
Unportable, requires assistance from the stdio layer. An implemen-
tation has to choose between leaking buffers or being reentrant for
a limited amount of streams (this implementation chose the latter
with a limit of 32). Use getline(3) instead, which is available in
many systems and required by IEEE Std 1003.1-2008 (“POSIX.1”).
fgetwln(3)
Unportable, requires assistance from the stdio layer. An implemen-
tation has to choose between leaking buffers or being reentrant for
a limited amount of streams (this implementation chose the latter
with a limit of 32). Use fgetwc(3) instead, which is available in
many systems and required by ISO/IEC 9899:1999 (“ISO C99”) and IEEE
Std 1003.1-2001 (“POSIX.1”).
funopen(3)
Unportable, requires assistance from the stdio layer or some hook
framework. On GNU systems the fopencookie(3) function can be used.
Otherwise the code needs to be prepared for neither of these func-
tions being available.
SUPERSEDED
Some functions have been superseded by implementations in other system
libraries, and might disappear on the next SONAME bump, assuming those
other implementation have widespread deployment, or the implementations
are present in all major libc for example.
MD5Init(3)
MD5Update(3)
MD5Pad(3)
MD5Final(3)
MD5Transform(3)
MD5End(3)
MD5File(3)
MD5FileChunk(3)
MD5Data(3)
The set of MD5 digest functions are now proxies for the implementa-
tions provided by the libmd companion library, so it is advised to
switch to use that directly instead.
explicit_bzero(3)
This function is provided by glibc 2.25, and musl 1.1.20.
reallocarray(3)
This function is provided by glibc 2.26, and musl 1.2.2.
arc4random(3)
arc4random_buf(3)
arc4random_uniform(3)
These functions are provided by glibc 2.36. Note that it does not
provide the arc4random_stir(3) and arc4random_addrandom(3) func-
tions.
SEE ALSO
arc4random(3bsd), bitstring(3bsd), byteorder(3bsd), closefrom(3bsd),
errc(3bsd), expand_number(3bsd), explicit_bzero(3bsd), fgetln(3bsd),
fgetwln(3bsd), flopen(3bsd), fmtcheck(3bsd), fparseln(3bsd),
fpurge(3bsd), funopen(3bsd), getbsize(3bsd), getpeereid(3bsd),
getprogname(3bsd), heapsort(3bsd), humanize_number(3bsd), md5(3bsd),
nlist(3bsd), pidfile(3bsd), pwcache(3bsd), queue(3bsd), radixsort(3bsd),
readpassphrase(3bsd), reallocarray(3bsd), reallocf(3bsd), setmode(3bsd),
setproctitle(3bsd), stringlist(3bsd), strlcpy(3bsd), strmode(3bsd),
strnstr(3bsd), strtoi(3bsd), strtonum(3bsd), strtou(3bsd),
timeradd(3bsd), timeval(3bsd), tree(3bsd), unvis(3bsd), vis(3bsd),
wcslcpy(3bsd).
HISTORY
The libbsd project started in the Debian GNU/kFreeBSD port as a way to
ease porting code from FreeBSD to the GNU-based system. Pretty early on
it was generalized and a project created on FreeDesktop.org for other
distributions and projects to use.
It is now distributed as part of most non-BSD distributions.
BSD August 3, 2022 BSD
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