libbsd —
utility
functions from BSD systems
The
libbsd library provides a set of compatibility
macros and functions commonly found on BSD-based systems. Its purpose is to
make those available 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-processor 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 mandatory 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.
The following are the headers provided by
libbsd,
that extend the standard 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>
-
Some functions have different prototypes depending on the BSD where they
originated from, and these various implementations provided are selectable 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.
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
implementation 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
implementation 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 functions being available.
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
implementations 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)
functions.
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).
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.