1/* 2** 3** Copyright 2008, The Android Open Source Project 4** 5** Licensed under the Apache License, Version 2.0 (the "License"); 6** you may not use this file except in compliance with the License. 7** You may obtain a copy of the License at 8** 9** http://www.apache.org/licenses/LICENSE-2.0 10** 11** Unless required by applicable law or agreed to in writing, software 12** distributed under the License is distributed on an "AS IS" BASIS, 13** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14** See the License for the specific language governing permissions and 15** limitations under the License. 16*/ 17 18#define LOG_TAG "su" 19 20#include <stdio.h> 21#include <stdlib.h> 22#include <string.h> 23#include <sys/types.h> 24#include <dirent.h> 25#include <errno.h> 26 27#include <unistd.h> 28#include <time.h> 29 30#include <pwd.h> 31 32#include <private/android_filesystem_config.h> 33 34/* 35 * SU can be given a specific command to exec. UID _must_ be 36 * specified for this (ie argc => 3). 37 * 38 * Usage: 39 * su 1000 40 * su 1000 ls -l 41 */ 42int main(int argc, char **argv) 43{ 44 struct passwd *pw; 45 int uid, gid, myuid; 46 47 if(argc < 2) { 48 uid = gid = 0; 49 } else { 50 pw = getpwnam(argv[1]); 51 52 if(pw == 0) { 53 uid = gid = atoi(argv[1]); 54 } else { 55 uid = pw->pw_uid; 56 gid = pw->pw_gid; 57 } 58 } 59 60 /* Until we have something better, only root and the shell can use su. */ 61 myuid = getuid(); 62 if (myuid != AID_ROOT && myuid != AID_SHELL) { 63 fprintf(stderr,"su: uid %d not allowed to su\n", myuid); 64 return 1; 65 } 66 67 if(setgid(gid) || setuid(uid)) { 68 fprintf(stderr,"su: permission denied\n"); 69 return 1; 70 } 71 72 /* User specified command for exec. */ 73 if (argc == 3 ) { 74 if (execlp(argv[2], argv[2], NULL) < 0) { 75 fprintf(stderr, "su: exec failed for %s Error:%s\n", argv[2], 76 strerror(errno)); 77 return -errno; 78 } 79 } else if (argc > 3) { 80 /* Copy the rest of the args from main. */ 81 char *exec_args[argc - 1]; 82 memset(exec_args, 0, sizeof(exec_args)); 83 memcpy(exec_args, &argv[2], sizeof(exec_args)); 84 if (execvp(argv[2], exec_args) < 0) { 85 fprintf(stderr, "su: exec failed for %s Error:%s\n", argv[2], 86 strerror(errno)); 87 return -errno; 88 } 89 } 90 91 /* Default exec shell. */ 92 execlp("/system/bin/sh", "sh", NULL); 93 94 fprintf(stderr, "su: exec failed\n"); 95 return 1; 96} 97