Adding upstream version 2.0.13.upstream/2.0.13upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 232 insertions, 0 deletions

diff --git a/usr/kinit/run-init/runinitlib.c b/usr/kinit/run-init/runinitlib.c
new file mode 100644
index 0000000..1c2e56a
--- /dev/null
+++ b/usr/kinit/run-init/runinitlib.c
@@ -0,0 +1,232 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2004-2006 H. Peter Anvin - All Rights Reserved
+ *
+ *   Permission is hereby granted, free of charge, to any person
+ *   obtaining a copy of this software and associated documentation
+ *   files (the "Software"), to deal in the Software without
+ *   restriction, including without limitation the rights to use,
+ *   copy, modify, merge, publish, distribute, sublicense, and/or
+ *   sell copies of the Software, and to permit persons to whom
+ *   the Software is furnished to do so, subject to the following
+ *   conditions:
+ *
+ *   The above copyright notice and this permission notice shall
+ *   be included in all copies or substantial portions of the Software.
+ *
+ *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ *   OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * run_init(realroot, consoledev, drop_caps, persist_initramfs, init, initargs)
+ *
+ * This function should be called as the last thing in kinit,
+ * from initramfs, it does the following:
+ *
+ * - Delete all files in the initramfs;
+ * - Remounts /real-root onto the root filesystem;
+ * - Chroots;
+ * - Drops comma-separated list of capabilities;
+ * - Opens /dev/console;
+ * - Spawns the specified init program (with arguments.)
+ *
+ * On failure, returns a human-readable error message.
+ */
+
+#include <assert.h>
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/mount.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/vfs.h>
+#include "run-init.h"
+#include "capabilities.h"
+
+/* Make it possible to compile on glibc by including constants that the
+   always-behind shipped glibc headers may not include.  Classic example
+   on why the lack of ABI headers screw us up. */
+#ifndef TMPFS_MAGIC
+# define TMPFS_MAGIC	0x01021994
+#endif
+#ifndef RAMFS_MAGIC
+# define RAMFS_MAGIC	0x858458f6
+#endif
+#ifndef MS_MOVE
+# define MS_MOVE	8192
+#endif
+
+static int nuke(const char *what);
+
+static int nuke_dirent(int len, const char *dir, const char *name, dev_t me)
+{
+	int bytes = len + strlen(name) + 2;
+	char path[bytes];
+	int xlen;
+	struct stat st;
+
+	xlen = snprintf(path, bytes, "%s/%s", dir, name);
+	assert(xlen < bytes);
+
+	if (lstat(path, &st))
+		return ENOENT;	/* Return 0 since already gone? */
+
+	if (st.st_dev != me)
+		return 0;	/* DO NOT recurse down mount points!!!!! */
+
+	return nuke(path);
+}
+
+/* Wipe the contents of a directory, but not the directory itself */
+static int nuke_dir(const char *what)
+{
+	int len = strlen(what);
+	DIR *dir;
+	struct dirent *d;
+	int err = 0;
+	struct stat st;
+
+	if (lstat(what, &st))
+		return errno;
+
+	if (!S_ISDIR(st.st_mode))
+		return ENOTDIR;
+
+	if (!(dir = opendir(what))) {
+		/* EACCES means we can't read it.  Might be empty and removable;
+		   if not, the rmdir() in nuke() will trigger an error. */
+		return (errno == EACCES) ? 0 : errno;
+	}
+
+	while ((d = readdir(dir))) {
+		/* Skip . and .. */
+		if (d->d_name[0] == '.' &&
+		    (d->d_name[1] == '\0' ||
+		     (d->d_name[1] == '.' && d->d_name[2] == '\0')))
+			continue;
+
+		err = nuke_dirent(len, what, d->d_name, st.st_dev);
+		if (err) {
+			closedir(dir);
+			return err;
+		}
+	}
+
+	closedir(dir);
+
+	return 0;
+}
+
+static int nuke(const char *what)
+{
+	int rv;
+	int err = 0;
+
+	rv = unlink(what);
+	if (rv < 0) {
+		if (errno == EISDIR) {
+			/* It's a directory. */
+			err = nuke_dir(what);
+			if (!err)
+				err = rmdir(what) ? errno : err;
+		} else {
+			err = errno;
+		}
+	}
+
+	if (err) {
+		errno = err;
+		return err;
+	} else {
+		return 0;
+	}
+}
+
+const char *run_init(const char *realroot, const char *console,
+		     const char *drop_caps, bool dry_run,
+		     bool persist_initramfs, const char *init, char **initargs)
+{
+	struct stat rst, cst, ist;
+	struct statfs sfs;
+	int confd;
+
+	/* First, change to the new root directory */
+	if (chdir(realroot))
+		return "chdir to new root";
+
+	/* This is a potentially highly destructive program.  Take some
+	   extra precautions. */
+
+	/* Make sure the current directory is not on the same filesystem
+	   as the root directory */
+	if (stat("/", &rst) || stat(".", &cst))
+		return "stat";
+
+	if (rst.st_dev == cst.st_dev)
+		return "current directory on the same filesystem as the root";
+
+	/* Make sure we're on a ramfs */
+	if (statfs("/", &sfs))
+		return "statfs /";
+	if (sfs.f_type != RAMFS_MAGIC && sfs.f_type != TMPFS_MAGIC)
+		return "rootfs not a ramfs or tmpfs";
+
+	/* Okay, I think we should be safe... */
+
+	if (!dry_run) {
+		if (!persist_initramfs) {
+			/* Delete rootfs contents */
+			if (nuke_dir("/"))
+				return "nuking initramfs contents";
+		}
+
+		/* Overmount the root */
+		if (mount(".", "/", NULL, MS_MOVE, NULL))
+			return "overmounting root";
+	}
+
+	/* chroot, chdir */
+	if (chroot(".") || chdir("/"))
+		return "chroot";
+
+	/* Drop capabilities */
+	if (drop_capabilities(drop_caps) < 0)
+		return "dropping capabilities";
+
+	/* Open /dev/console */
+	if ((confd = open(console, O_RDWR)) < 0)
+		return "opening console";
+	if (!dry_run) {
+		dup2(confd, 0);
+		dup2(confd, 1);
+		dup2(confd, 2);
+	}
+	close(confd);
+
+	if (!dry_run) {
+		/* Spawn init */
+		execv(init, initargs);
+		return init;		/* Failed to spawn init */
+	} else {
+		if (stat(init, &ist))
+			return init;
+		if (!S_ISREG(ist.st_mode) || !(ist.st_mode & S_IXUGO)) {
+			errno = EACCES;
+			return init;
+		}
+		return NULL;		/* Success */
+	}
+}