logwrapper.c revision c4bbfa247dbe4dda17e28694d49afd3ec0b06bad
1/* 2 * Copyright (C) 2008 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#include <string.h> 18#include <sys/types.h> 19#include <sys/wait.h> 20#include <stdio.h> 21#include <stdlib.h> 22#include <unistd.h> 23#include <errno.h> 24#include <fcntl.h> 25 26#include "private/android_filesystem_config.h" 27#include "cutils/log.h" 28 29int parent(const char *tag, int parent_read) { 30 int status; 31 char buffer[4096]; 32 33 int a = 0; // start index of unprocessed data 34 int b = 0; // end index of unprocessed data 35 int sz; 36 while ((sz = read(parent_read, &buffer[b], sizeof(buffer) - 1 - b)) > 0) { 37 38 sz += b; 39 // Log one line at a time 40 for (b = 0; b < sz; b++) { 41 if (buffer[b] == '\r') { 42 buffer[b] = '\0'; 43 } else if (buffer[b] == '\n') { 44 buffer[b] = '\0'; 45 46 ALOG(LOG_INFO, tag, "%s", &buffer[a]); 47 a = b + 1; 48 } 49 } 50 51 if (a == 0 && b == sizeof(buffer) - 1) { 52 // buffer is full, flush 53 buffer[b] = '\0'; 54 ALOG(LOG_INFO, tag, "%s", &buffer[a]); 55 b = 0; 56 } else if (a != b) { 57 // Keep left-overs 58 b -= a; 59 memmove(buffer, &buffer[a], b); 60 a = 0; 61 } else { 62 a = 0; 63 b = 0; 64 } 65 66 } 67 // Flush remaining data 68 if (a != b) { 69 buffer[b] = '\0'; 70 ALOG(LOG_INFO, tag, "%s", &buffer[a]); 71 } 72 status = 0xAAAA; 73 if (wait(&status) != -1) { // Wait for child 74 if (WIFEXITED(status)) { 75 if (WEXITSTATUS(status) != 0) { 76 ALOG(LOG_INFO, "logwrapper", "%s terminated by exit(%d)", tag, 77 WEXITSTATUS(status)); 78 } 79 return WEXITSTATUS(status); 80 } else if (WIFSIGNALED(status)) 81 ALOG(LOG_INFO, "logwrapper", "%s terminated by signal %d", tag, 82 WTERMSIG(status)); 83 else if (WIFSTOPPED(status)) 84 ALOG(LOG_INFO, "logwrapper", "%s stopped by signal %d", tag, 85 WSTOPSIG(status)); 86 } else 87 ALOG(LOG_INFO, "logwrapper", "%s wait() failed: %s (%d)", tag, 88 strerror(errno), errno); 89 return -EAGAIN; 90} 91 92void child(int argc, const char**argv) { 93 // create null terminated argv_child array 94 char* argv_child[argc + 1]; 95 memcpy(argv_child, argv, argc * sizeof(char *)); 96 argv_child[argc] = NULL; 97 98 // XXX: PROTECT FROM VIKING KILLER 99 if (execv(argv_child[0], argv_child)) { 100 ALOG(LOG_ERROR, "logwrapper", 101 "executing %s failed: %s", argv_child[0], strerror(errno)); 102 } 103 _exit(1); 104} 105 106int logwrap(int argc, const char* argv[]) 107{ 108 pid_t pid; 109 110 int parent_ptty; 111 int child_ptty; 112 char child_devname[64]; // same size as libc/unistd/ptsname_r.c 113 114 /* Use ptty instead of socketpair so that STDOUT is not buffered */ 115 parent_ptty = open("/dev/ptmx", O_RDWR); 116 if (parent_ptty < 0) { 117 ALOG(LOG_ERROR, "logwrapper", "Cannot create parent ptty"); 118 return -errno; 119 } 120 121 if (grantpt(parent_ptty) || unlockpt(parent_ptty) || 122 ptsname_r(parent_ptty, child_devname, sizeof(child_devname))) { 123 close(parent_ptty); 124 ALOG(LOG_ERROR, "logwrapper", "Problem with /dev/ptmx"); 125 return -1; 126 } 127 128 pid = fork(); 129 if (pid < 0) { 130 close(parent_ptty); 131 ALOG(LOG_ERROR, "logwrapper", "Failed to fork"); 132 return -errno; 133 } else if (pid == 0) { 134 /* 135 * Child 136 */ 137 child_ptty = open(child_devname, O_RDWR); 138 if (child_ptty < 0) { 139 close(parent_ptty); 140 ALOG(LOG_ERROR, "logwrapper", "Problem with child ptty"); 141 _exit(errno < 128 ? errno : 1); // XXX lame 142 } 143 144 // redirect stdout and stderr 145 close(parent_ptty); 146 dup2(child_ptty, 1); 147 dup2(child_ptty, 2); 148 close(child_ptty); 149 150 child(argc, argv); 151 } else { 152 /* 153 * Parent 154 */ 155 int rc = parent(argv[0], parent_ptty); 156 close(parent_ptty); 157 return rc; 158 } 159 160 return 0; 161} 162 163/* 164 * The following is based off of bionic/libc/unistd/system.c with 165 * modifications to avoid calling /system/bin/sh -c 166 */ 167extern char **environ; 168int system_nosh(const char *command) 169{ 170 pid_t pid; 171 sig_t intsave, quitsave; 172 sigset_t mask, omask; 173 int pstat; 174 char buffer[255]; 175 char *argp[32]; 176 char *next = buffer; 177 char *tmp; 178 int i = 0; 179 180 if (!command) /* just checking... */ 181 return(1); 182 183 /* 184 * The command to argp splitting is from code that was 185 * reverted in Change: 11b4e9b2 186 */ 187 if (strnlen(buffer, sizeof(buffer) - 1) == sizeof(buffer) - 1) { 188 ALOGE("command line too long while processing: %s", command); 189 errno = E2BIG; 190 return -1; 191 } 192 strcpy(buffer, command); // Command len is already checked. 193 while ((tmp = strsep(&next, " "))) { 194 argp[i++] = tmp; 195 if (i == 32) { 196 ALOGE("argument overflow while processing: %s", command); 197 errno = E2BIG; 198 return -1; 199 } 200 } 201 argp[i] = NULL; 202 203 204 sigemptyset(&mask); 205 sigaddset(&mask, SIGCHLD); 206 sigprocmask(SIG_BLOCK, &mask, &omask); 207 switch (pid = vfork()) { 208 case -1: /* error */ 209 sigprocmask(SIG_SETMASK, &omask, NULL); 210 return(-1); 211 case 0: /* child */ 212 sigprocmask(SIG_SETMASK, &omask, NULL); 213 execve(argp[0], argp, environ); 214 _exit(127); 215 } 216 217 intsave = (sig_t) bsd_signal(SIGINT, SIG_IGN); 218 quitsave = (sig_t) bsd_signal(SIGQUIT, SIG_IGN); 219 pid = waitpid(pid, (int *)&pstat, 0); 220 sigprocmask(SIG_SETMASK, &omask, NULL); 221 (void)bsd_signal(SIGINT, intsave); 222 (void)bsd_signal(SIGQUIT, quitsave); 223 return (pid == -1 ? -1 : pstat); 224} 225