Import stdbuf(1) and the shared library it relies on.

This tool changes the default buffering behaviour of standard
stdio streams.

It only works on dynamic binaries.  To make it work for static
ones it would require cluttering stdio because there no single
entry point.

PR:		166660
Reviewed by:	current@, jhb
Approved by:	kib (mentor)
MFC after:	1 week

3 files changed, 229 insertions, 0 deletions

diff --git a/lib/libstdbuf/Makefile b/lib/libstdbuf/Makefile
new file mode 100644
index 0000000..cf65e4f
--- /dev/null
+++ b/lib/libstdbuf/Makefile
@@ -0,0 +1,12 @@
+# $FreeBSD$
+
+.include <bsd.own.mk>
+
+LIB=		stdbuf
+SRCS=		stdbuf.c
+SHLIB_MAJOR=	1
+MAN=		libstdbuf.3
+
+WARNS?=		6
+
+.include <bsd.lib.mk>
diff --git a/lib/libstdbuf/libstdbuf.3 b/lib/libstdbuf/libstdbuf.3
new file mode 100644
index 0000000..c60ffd7
--- /dev/null
+++ b/lib/libstdbuf/libstdbuf.3
@@ -0,0 +1,102 @@
+.\" Copyright (c) 2012 Jeremie Le Hen <jlh@FreeBSD.org>
+.\" All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code and documentation must retain the above
+.\"    copyright notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\" $FreeBSD$
+.\"
+.Dd April 28, 2012
+.Dt LIBSTDBUF 3
+.Os
+.Sh NAME
+.Nm libstdbuf
+.Nd preloaded library to change standard streams initial buffering
+.Sh DESCRIPTION
+The
+.Nm
+library is meant to be preloaded with the
+.Ev LD_PRELOAD
+environment variable to as to change the initial buffering
+of standard input, standard output and standard error streams.
+.Pp
+Although you may load and configure this library manually,
+an utility,
+.Xr stdbuf 1 ,
+can be used to run a command with the appropriate environment variables.
+.Sh ENVIRONMENT
+Each stream can be configured indepentently through the following
+environment variables (values are defined below):
+.Bl -tag -width size -offset indent
+.It Ev _STDBUF_I
+Initial buffering definition for the standard input stream
+.It Ev _STDBUF_O
+Initial buffering definition for the standard output stream
+.It Ev _STDBUF_E
+Initial buffering definition for the standard error stream
+.El
+.Pp
+Each variable may take one of the following values:
+.Bl -tag -width size -offset indent
+.It Qq 0
+unbuffered
+.It Qq L
+line buffered
+.It Qq B
+fully buffered with the default buffer size
+.It Ar size
+fully buffered with a buffer of
+.Ar size
+bytes (suffixes 'k', 'M' and 'G' are accepted)
+.El
+.Sh EXAMPLE
+In the following example, the stdout stream of the
+.Xr awk 1
+command
+will be fully buffered by default because it does not refer
+to a terminal.
+.Nm
+is used to force it to be line-buffered so
+.Xr vmstat 8 Ns 's
+output will not stall until the full buffer fills.
+.Bd -literal -offset indent
+# vmstat 1 | LD_PRELOAD=/usr/lib/libstdbuf.so \\
+    STDBUF_1=L awk '$2 > 1 || $3 > 1' | cat -n
+.Ed
+.Pp
+See also the manpage of
+.Xr stdbuf 1
+for a simpler way to do this.
+.Sh HISTORY
+The
+.Nm
+library first appeared in
+.Fx 8.4 .
+.Sh AUTHORS
+.An -nosplit
+The original idea of the
+.Nm
+command comes from
+.An Padraig Brady
+who implemented it in the GNU coreutils.
+.An Jeremie Le Hen
+implemented it on
+.Fx .
diff --git a/lib/libstdbuf/stdbuf.c b/lib/libstdbuf/stdbuf.c
new file mode 100644
index 0000000..1b5d39a
--- /dev/null
+++ b/lib/libstdbuf/stdbuf.c
@@ -0,0 +1,115 @@
+/*-
+ * Copyright (c) 2012 Jeremie Le Hen <jlh@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#include <err.h>
+#include <errno.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+static const char *
+stream_name(FILE *s)
+{
+
+	if (s == stdin)
+		return "stdin";
+	if (s == stdout)
+		return "stdout";
+	if (s == stderr)
+		return "stderr";
+	/* This should not happen. */
+	abort();
+}
+
+static void
+change_buf(FILE *s, const char *bufmode)
+{
+	char *unit;
+	size_t bufsize;
+	int mode;
+
+	bufsize = 0;
+	if (bufmode[0] == '0' && bufmode[1] == '\0')
+		mode = _IONBF;
+	else if (bufmode[0] == 'L' && bufmode[1] == '\0')
+		mode = _IOLBF;
+	else if (bufmode[0] == 'B' && bufmode[1] == '\0') {
+		mode = _IOFBF;
+		bufsize = 0;
+	} else {
+		/*
+		 * This library being preloaded, depending on libutil
+		 * would lead to excessive namespace pollution.
+		 * Thus we do not use expand_number().
+		 */
+		errno = 0;
+		bufsize = strtol(bufmode, &unit, 0);
+		if (errno == EINVAL || errno == ERANGE || unit == bufmode)
+			warn("Wrong buffer mode '%s' for %s", bufmode,
+			    stream_name(s));
+		switch (*unit) {
+		case 'G':
+			bufsize *= 1024 * 1024 * 1024;
+			break;
+		case 'M':
+			bufsize *= 1024 * 1024;
+			break;
+		case 'k':
+			bufsize *= 1024;
+			break;
+		case '\0':
+			break;
+		default:
+			warnx("Unknown suffix '%c' for %s", *unit,
+			    stream_name(s));
+			return;
+		}
+		mode = _IOFBF;
+	}
+	if (setvbuf(s, NULL, mode, bufsize) != 0)
+		warn("Cannot set buffer mode '%s' for %s", bufmode,
+		    stream_name(s));
+}
+
+__attribute__ ((constructor)) static void
+stdbuf(void)
+{
+	char *i_mode, *o_mode, *e_mode;
+
+	i_mode = getenv("_STDBUF_I");
+	o_mode = getenv("_STDBUF_O");
+	e_mode = getenv("_STDBUF_E");
+
+	if (e_mode != NULL)
+		change_buf(stderr, e_mode);
+	if (i_mode != NULL)
+		change_buf(stdin, i_mode);
+	if (o_mode != NULL)
+		change_buf(stdout, o_mode);
+}