1 /* 2 * Copyright (C) 2017 The Android Open Source Project 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in 12 * the documentation and/or other materials provided with the 13 * distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <errno.h> 30 #include <string.h> 31 #include <sys/cdefs.h> 32 #include <unistd.h> 33 34 #define VENDOR_PREFIX "/vendor/" 35 36 static const char* init_sh_path() { 37 /* If the device is not treble enabled, return the path to the system shell. 38 * Vendor code, on non-treble enabled devices could use system() / popen() 39 * with relative paths for executables on /system. Since /system will not be 40 * in $PATH for the vendor shell, simply return the system shell. 41 */ 42 43 #ifdef TREBLE_LINKER_NAMESPACES 44 /* look for /system or /vendor prefix */ 45 char exe_path[strlen(VENDOR_PREFIX)]; 46 ssize_t len = readlink("/proc/self/exe", exe_path, sizeof(exe_path)); 47 if (len != -1 && !strncmp(exe_path, VENDOR_PREFIX, strlen(VENDOR_PREFIX))) { 48 return "/vendor/bin/sh"; 49 } 50 #endif 51 return "/system/bin/sh"; 52 } 53 54 __LIBC_HIDDEN__ extern "C" const char* __bionic_get_shell_path() { 55 static const char* sh_path = init_sh_path(); 56 return sh_path; 57 } 58
