1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22 /* 23 * Copyright 2009 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 #pragma init(init) 28 29 #include <s10_brand.h> 30 #include <stdlib.h> 31 #include <sys/syscall.h> 32 33 /* 34 * This is a library that is LD_PRELOADed into native processes. 35 * Its primary function is to perform one brand operation, B_S10_NATIVE, 36 * which checks that this is actually a native process. If it is, then 37 * the operation changes the executable name so that it is no longer 38 * ld.sol.1. Instead it changes it to be the name of the real native 39 * executable that we're runnning. This allows things like pgrep to work 40 * as expected. Note that this brand operation only changes the process 41 * name wrt the kernel. From the process' perspective, the first 42 * argument and AT_SUN_EXECNAME are still ld.so.1. 43 * 44 * The library also unsets the LD_LIBRARY_PATH_* and LD_PRELOAD_* 45 * environment variables created by the brand's native wrapper scripts 46 * (e.g., s10_isaexec_wrapper) in order to ensure that execve(2) and its 47 * ilk, which brand the calling process, do not cause ld.so.1 to link native 48 * libraries to the resulting process. The native wrapper scripts make 49 * LD_LIBRARY_PATH_* point to library directories (e.g., /usr/lib) prefixed 50 * with "/.SUNWnative" in order to make native processes link with native 51 * libraries. However, if a native process running within a branded zone 52 * executes exec(2), then the new process becomes branded. Therefore, if this 53 * library were to not unset the LD_LIBRARY_PATH_* environment variables, then 54 * if a native process were to invoke an exec(2) function, then the resulting 55 * process would be branded and linked with native libraries. 56 * LD_PRELOAD_*, which the native wrapper scripts set to "s10_npreload.so.1" 57 * (the name of this library), must be cleared as well because 58 * s10_npreload.so.1 is only preloaded into native processes and can only be 59 * accessed via the /.SUNWnative library paths. 60 * 61 * NOTE: This trick won't work if another library that invokes an exec(2) 62 * function in its initialization function is initialized before this library. 63 * Such a problem won't happen if the brand only replaces binaries shipped with 64 * Solaris (e.g., ifconfig(1M)) with their native counterparts because most (if 65 * not all) Solaris system libraries don't exec(2) within their initialization 66 * functions. 67 */ 68 void 69 init(void) 70 { 71 sysret_t rval; 72 73 (void) __systemcall(&rval, SYS_brand, B_S10_NATIVE); 74 75 /* 76 * We can safely use unsetenv(3C) to clear LD_LIBRARY_PATH_* and 77 * LD_PRELOAD_* because ld.so.1 caches their values before this 78 * library is initialized. 79 */ 80 (void) unsetenv("LD_LIBRARY_PATH_32"); 81 (void) unsetenv("LD_LIBRARY_PATH_64"); 82 (void) unsetenv("LD_PRELOAD_32"); 83 (void) unsetenv("LD_PRELOAD_64"); 84 } 85