From ef6acdb81c3610ccf4da25db5728277b5a162e78 Mon Sep 17 00:00:00 2001
From: Karel Zak
Date: Thu, 17 Jan 2013 13:00:44 +0100
Subject: Revert "unshare: support the switching of namespaces"

The functionality will be replaced with nsenter from Eric W.
Biederman.

This reverts commit 4bbe8099390d528018890efa914e268de3c4b44b.
---
 sys-utils/unshare.c | 75 ++++++++++++-----------------------------------------
 1 file changed, 17 insertions(+), 58 deletions(-)

(limited to 'sys-utils/unshare.c')

diff --git a/sys-utils/unshare.c b/sys-utils/unshare.c
index 64ea3766f..9de997bdc 100644
--- a/sys-utils/unshare.c
+++ b/sys-utils/unshare.c
@@ -24,12 +24,10 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
-#include <getopt.h>
 
 #include "nls.h"
 #include "c.h"
 #include "closestream.h"
-#include "strutils.h"
 
 #ifndef CLONE_NEWSNS
 # define CLONE_NEWNS 0x00020000
@@ -62,10 +60,10 @@ static void usage(int status)
 	      _(" %s [options] <program> [args...]\n"),	program_invocation_short_name);
 
 	fputs(USAGE_OPTIONS, out);
-	fputs(_(" -m, --mount [=<pid>]   unshare or migrate mounts namespace\n"
-		" -u, --uts [=<pid>]     unshare or migrate UTS namespace (hostname etc)\n"
-		" -i, --ipc [=<pid>]     unshare or migrate System V IPC namespace\n"
-		" -n, --net [=<pid>]     unshare or migrate network namespace\n"), out);
+	fputs(_(" -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);
 
 	fputs(USAGE_SEPARATOR, out);
 	fputs(USAGE_HELP, out);
@@ -78,18 +76,17 @@ static void usage(int status)
 int main(int argc, char *argv[])
 {
 	static const struct option longopts[] = {
-		{ "help",    no_argument, 0, 'h' },
+		{ "help", no_argument, 0, 'h' },
 		{ "version", no_argument, 0, 'V'},
-		{ "mount",   optional_argument, 0, 'm' },
-		{ "uts",     optional_argument, 0, 'u' },
-		{ "ipc",     optional_argument, 0, 'i' },
-		{ "net",     optional_argument, 0, 'n' },
+		{ "mount", no_argument, 0, 'm' },
+		{ "uts", no_argument, 0, 'u' },
+		{ "ipc", no_argument, 0, 'i' },
+		{ "net", no_argument, 0, 'n' },
 		{ NULL, 0, 0, 0 }
 	};
 
-	int namespaces[128];		/* /proc/#/ns/<name> file descriptors */
-	size_t i, nscount = 0;		/* number of used namespaces[] */
 	int unshare_flags = 0;
+
 	int c;
 
 	setlocale(LC_MESSAGES, "");
@@ -97,13 +94,7 @@ int main(int argc, char *argv[])
 	textdomain(PACKAGE);
 	atexit(close_stdout);
 
-	memset(namespaces, 0, sizeof(namespaces));
-
-	while((c = getopt_long(argc, argv,
-			"hVm::u::i::n::", longopts, NULL)) != -1) {
-
-		const char *ns = NULL;
-
+	while((c = getopt_long(argc, argv, "hVmuin", longopts, NULL)) != -1) {
 		switch(c) {
 		case 'h':
 			usage(EXIT_SUCCESS);
@@ -111,58 +102,26 @@ int main(int argc, char *argv[])
 			printf(UTIL_LINUX_VERSION);
 			return EXIT_SUCCESS;
 		case 'm':
-			ns = "mnt";
-			if (!optarg)
-				unshare_flags |= CLONE_NEWNS;
+			unshare_flags |= CLONE_NEWNS;
 			break;
 		case 'u':
-			ns = "uts";
-			if (!optarg)
-				unshare_flags |= CLONE_NEWUTS;
+			unshare_flags |= CLONE_NEWUTS;
 			break;
 		case 'i':
-			ns = "ipc";
-			if (!optarg)
-				unshare_flags |= CLONE_NEWIPC;
+			unshare_flags |= CLONE_NEWIPC;
 			break;
 		case 'n':
-			ns = "net";
-			if (!optarg)
-				unshare_flags |= CLONE_NEWNET;
+			unshare_flags |= CLONE_NEWNET;
 			break;
 		default:
 			usage(EXIT_FAILURE);
 		}
-
-		if (ns && optarg) {
-			pid_t pid;
-			char path[512];
-
-			if (nscount >= ARRAY_SIZE(namespaces))
-				err(EXIT_FAILURE, _("too many new namespaces specified"));
-
-			if (*optarg == '=')
-				optarg++;
-
-			pid = strtoul_or_err(optarg, _("failed to parse pid argument"));
-
-			sprintf(path, "/proc/%lu/ns/%s", (unsigned long) pid, ns);
-			namespaces[nscount] = open(path, O_RDONLY | O_CLOEXEC);
-			if (namespaces[nscount] < 0)
-				err(EXIT_FAILURE, _("cannot open %s"), path);
-			nscount++;
-		}
 	}
 
-	if (optind >= argc)
+	if(optind >= argc)
 		usage(EXIT_FAILURE);
 
-	for (i = 0; i < nscount; i++) {
-		if (setns(namespaces[i], 0) != 0)
-			err(EXIT_FAILURE, _("setns failed"));
-	}
-
-	if (unshare_flags && unshare(unshare_flags) != 0)
+	if(-1 == unshare(unshare_flags))
 		err(EXIT_FAILURE, _("unshare failed"));
 
 	/* drop potential root euid/egid if we had been setuid'd */
-- 
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