AC_ARG_VAR([BLKID_LIBS_STATIC], [-l options for linking statically with blkid])
+AC_ARG_ENABLE([unshare],
+ AS_HELP_STRING([--disable-unshare], [do not build unshare]),
+ [], enable_unshare=check
+)
+build_unshare=yes
+if test "x$enable_unshare" = xcheck; then
+ if test "x$linux_os" = xno; then
+ AC_MSG_WARN([non-linux system; do not build unshare])
+ build_unshare=no
+ fi
+elif test "x$enable_unshare" = xno; then
+ build_unshare=no
+fi
+AM_CONDITIONAL(BUILD_UNSHARE, test "x$build_unshare" = xyes)
UTIL_CHECK_LIB(util, openpty)
UTIL_CHECK_LIB(termcap, tgetnum)
UTIL_CHECK_SYSCALL([fallocate])
AC_CHECK_FUNCS([fallocate])
+dnl unshare could be available as libc function or as syscall only
+UTIL_CHECK_SYSCALL([unshare])
+AC_CHECK_FUNCS([unshare])
+
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
#include <time.h>
#include <unistd.h>
--- /dev/null
+.\" Process this file with
+.\" groff -man -Tascii lscpu.1
+.\"
+.TH UNSHARE 1 "OCTOBER 2008" Linux "User Manuals"
+.SH NAME
+unshare \- run program with some namespaces unshared from parent
+.SH SYNOPSIS
+.B unshare
+.RI [ options ]
+program
+.RI [ arguments ]
+.SH DESCRIPTION
+Unshares specified namespaces from parent process and then executes specified
+program. Unshareable namespaces are:
+.TP
+.BR "mount namespace"
+mounting and unmounting filesystems will not affect rest of the system
+(\fBCLONE_NEWNS\fP flag),
+.TP
+.BR "UTS namespace"
+setting hostname, domainname will not affect rest of the system
+(\fBCLONE_NEWUTS\fP flag),
+.TP
+.BR "IPC namespace"
+process will have indpendent namespace for System V message queues, semaphore
+sets and shared memory segments (\fBCLONE_NEWIPC\fP flag),
+.TP
+.BR "network namespace"
+process will have independent IPv4 and IPv6 stacks, IP routing tables, firewall
+rules, the \fI/proc/net\fP and \fI/sys/class/net\fP directory trees, sockets
+etc. (\fBCLONE_NEWNET\fP flag).
+.TP
+See the clone(2) for exact semantics of the flags.
+.SH OPTIONS
+.TP
+.BR \-h , " \-\-help"
+Print a help message,
+.TP
+.BR \-m , " \-\-mount"
+Unshare the mount namespace,
+.TP
+.BR \-u , " \-\-uts"
+Unshare the UTC namespace,
+.TP
+.BR \-i , " \-\-ipc"
+Unshare the IPC namespace,
+.TP
+.BR \-n , " \-\-net"
+Unshare the network namespace.
+.SH SEE ALSO
+unshare(2), clone(2)
+.SH BUGS
+None known so far.
+.SH AUTHOR
+Mikhail Gusarov <dottedmag@dottedmag.net>
+.SH AVAILABILITY
+The unshare command is part of the util-linux-ng package and is available from
+ftp://ftp.kernel.org/pub/linux/utils/util-linux-ng/.
--- /dev/null
+/*
+ * unshare(1) - command-line interface for unshare(2)
+ *
+ * Copyright (C) 2009 Mikhail Gusarov <dottedmag@dottedmag.net>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <err.h>
+#include <errno.h>
+#include <getopt.h>
+#include <sched.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "nls.h"
+
+#ifndef CLONE_NEWSNS
+# define CLONE_NEWNS 0x00020000
+#endif
+#ifndef CLONE_NEWUTS
+# define CLONE_NEWUTS 0x04000000
+#endif
+#ifndef CLONE_NEWIPC
+# define CLONE_NEWIPC 0x08000000
+#endif
+#ifndef CLONE_NEWNET
+# define CLONE_NEWNET 0x40000000
+#endif
+
+#ifndef HAVE_UNSHARE
+# include <sys/syscall.h>
+
+static int unshare(int flags)
+{
+ return syscall(SYS_unshare, flags);
+}
+#endif
+
+static void usage(int status)
+{
+ FILE *out = status == EXIT_SUCCESS ? stdout : stderr;
+
+ fprintf(out, _("Usage: %s [options] <program> [args...]\n"),
+ program_invocation_short_name);
+
+ fputs(_("Run program with some namespaces unshared from parent\n\n"
+ " -h, --help usage information (this)\n"
+ " -m, --mount unshare mounts namespace\n"
+ " -u, --uts unshare UTS namespace (hostname etc)\n"
+ " -i, --ipc unshare System V IPC namespace\n"
+ " -n, --net unshare network namespace\n"), out);
+
+ fprintf(out, _("\nFor more information see unshare(1).\n"));
+ exit(status);
+}
+
+int main(int argc, char *argv[])
+{
+ struct option longopts[] = {
+ { "help", no_argument, 0, 'h' },
+ { "mount", no_argument, 0, 'm' },
+ { "uts", no_argument, 0, 'u' },
+ { "ipc", no_argument, 0, 'i' },
+ { "net", no_argument, 0, 'n' },
+ };
+
+ int unshare_flags = 0;
+
+ int c;
+
+ setlocale(LC_MESSAGES, "");
+ bindtextdomain(PACKAGE, LOCALEDIR);
+ textdomain(PACKAGE);
+
+ while((c = getopt_long(argc, argv, "hmuin", longopts, NULL)) != -1) {
+ switch(c) {
+ case 'h':
+ usage(EXIT_SUCCESS);
+ case 'm':
+ unshare_flags |= CLONE_NEWNS;
+ break;
+ case 'u':
+ unshare_flags |= CLONE_NEWUTS;
+ break;
+ case 'i':
+ unshare_flags |= CLONE_NEWIPC;
+ break;
+ case 'n':
+ unshare_flags |= CLONE_NEWNET;
+ break;
+ default:
+ usage(EXIT_FAILURE);
+ }
+ }
+
+ if(optind >= argc)
+ usage(EXIT_FAILURE);
+
+ if(-1 == unshare(unshare_flags))
+ err(EXIT_FAILURE, _("unshare failed"));
+
+ execvp(argv[optind], argv + optind);
+
+ err(EXIT_FAILURE, _("exec %s failed"), argv[optind]);
+}
projects / util-linux / commitdiff