/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
*/
#include <stdio.h>
#include <strings.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/mount.h>
#include <sys/mntent.h>
#include <unistd.h>
/*
* This program aids the Solaris 10 patch tools (specifically
* /usr/lib/patch/patch_common_lib) in DAP patching.
*
* Whenever the patch tools replace a critical system component (e.g.,
* /lib/libc.so.1), they move the old component to a temporary location,
* move the new component to where the old component was, and establish
* an overlay mount of the old component on top of the new component.
* The patch tools do this with a shell script; consequently, the three
* operations occur in three processes.
*
* This doesn't work inside Solaris 10 Containers (S10Cs). Suppose the
* patch tools need to replace /lib/libc.so.1. The tools will move the old
* libc.so.1 to a temporary location. But when they try to move the new
* libc.so.1, they fork a mv(1) process, which loads the solaris10 brand's
* emulation library. The emulation library will try to load the zone's
* libc.so.1, but the library no longer exists; consequently, the emulation
* library aborts and the zone's users won't be able to start any processes.
*
* This program solves the problem by combining the move and mount operations
* into a single process. The emulation library will already have loaded
* libc.so.1 for the process by the time the process starts to replace
* libc.so.1.
*
* This program takes six parameters that correspond to six variables within
* /usr/lib/patch/patch_common_lib:InstallSafemodeObject():
*
* argv[1] - dstActual (the path to the file that will be replaced)
* argv[2] - tmp_file (the temporary location to which the file will be
* moved)
* argv[3] - tmpDst (the path to the replacement file)
* argv[4] - tmpFile (the path to a temporary copy of the running system's
* version of the file being replaced; the source [special] of
* the overlay mount)
* argv[5] - cksumTmpDst (checksum of the file represented by tmpDst)
* argv[6] - cksumTmpFile (checksum of the file represented by tmpFile)
*
* NOTE: This program will only establish an overlay mount if argv[4] or argv[5]
* is emtpy or if argv[4] and argv[5] differ.
*
* This program returns zero when it succeeds. Non-negative values indicate
* failure.
*/
int
main(int argc, char **argv)
{
struct stat statbuf;
char mntoptions[MAX_MNTOPT_STR];
/*
* Check the number of arguments that were passed to s10_replacefile.
*/
if (argc != 7) {
(void) fprintf(stderr, "Usage: %s dstActual tmp_file tmpDst "
"tmpFile cksumTmpDst cksumTmpFile\n", argv[0]);
return (1);
}
/*
* Move the destination file (dstActual) out of the way and move the
* new file (tmpDst) into its place.
*
* NOTE: s10_replacefile won't print error messages here because
* the Solaris 10 patch tools will.
*/
if (rename(argv[1], argv[2]) != 0)
return (2);
if (rename(argv[3], argv[1]) != 0)
return (3);
/*
* If there was a lofs mount on dstActual (which we just moved), then
* s10_replacefile should reestablish the lofs mount. A lofs mount
* existed if tmpFile exists.
*/
if (stat(argv[4], &statbuf) == 0 && (statbuf.st_mode & S_IFREG)) {
/*
* Create a lofs overlay mount only if the checksums of the
* old file at dstActual and the new file at dstActual differ.
*/
if (argv[5][0] == '\0' || argv[6][0] == '\0' ||
strcmp(argv[5], argv[6]) != 0) {
mntoptions[0] = '\0';
if (mount(argv[4], argv[1], MS_OVERLAY | MS_OPTIONSTR,
MNTTYPE_LOFS, NULL, 0, mntoptions,
sizeof (mntoptions)) != 0) {
/*
* Although the patch tools will print error
* messages, the tools won't know that
* s10_replacefile failed to establish an
* overlay mount. Printing an error message
* here clarifies the problem for the user.
*/
(void) fprintf(stderr, "ERROR: Failed to "
"overlay mount %s onto %s\n", argv[4],
argv[1]);
return (4);
}
} else {
/*
* dstActual does not need an overlay mount. Delete
* tmpFile.
*/
(void) unlink(argv[4]);
}
}
return (0);
}