Rom Lemarchand | 113bd47 | 2013-01-10 15:21:18 -0800 | [diff] [blame^] | 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 | #include <libgen.h> |
| 26 | |
| 27 | #include <logwrap/logwrap.h> |
| 28 | #include "private/android_filesystem_config.h" |
| 29 | #include "cutils/log.h" |
| 30 | |
| 31 | static int fatal(const char *msg) { |
| 32 | fprintf(stderr, "%s", msg); |
| 33 | ALOG(LOG_ERROR, "logwrapper", "%s", msg); |
| 34 | return -1; |
| 35 | } |
| 36 | |
| 37 | void parent(const char *tag, int parent_read, int *chld_sts) { |
| 38 | int status; |
| 39 | char buffer[4096]; |
| 40 | |
| 41 | int a = 0; // start index of unprocessed data |
| 42 | int b = 0; // end index of unprocessed data |
| 43 | int sz; |
| 44 | |
| 45 | char *btag = basename(tag); |
| 46 | if (!btag) btag = (char*) tag; |
| 47 | |
| 48 | while ((sz = read(parent_read, &buffer[b], sizeof(buffer) - 1 - b)) > 0) { |
| 49 | |
| 50 | sz += b; |
| 51 | // Log one line at a time |
| 52 | for (b = 0; b < sz; b++) { |
| 53 | if (buffer[b] == '\r') { |
| 54 | buffer[b] = '\0'; |
| 55 | } else if (buffer[b] == '\n') { |
| 56 | buffer[b] = '\0'; |
| 57 | ALOG(LOG_INFO, btag, "%s", &buffer[a]); |
| 58 | a = b + 1; |
| 59 | } |
| 60 | } |
| 61 | |
| 62 | if (a == 0 && b == sizeof(buffer) - 1) { |
| 63 | // buffer is full, flush |
| 64 | buffer[b] = '\0'; |
| 65 | ALOG(LOG_INFO, btag, "%s", &buffer[a]); |
| 66 | b = 0; |
| 67 | } else if (a != b) { |
| 68 | // Keep left-overs |
| 69 | b -= a; |
| 70 | memmove(buffer, &buffer[a], b); |
| 71 | a = 0; |
| 72 | } else { |
| 73 | a = 0; |
| 74 | b = 0; |
| 75 | } |
| 76 | |
| 77 | } |
| 78 | // Flush remaining data |
| 79 | if (a != b) { |
| 80 | buffer[b] = '\0'; |
| 81 | ALOG(LOG_INFO, btag, "%s", &buffer[a]); |
| 82 | } |
| 83 | |
| 84 | if (wait(&status) != -1) { // Wait for child |
| 85 | if (WIFEXITED(status) && WEXITSTATUS(status)) |
| 86 | ALOG(LOG_INFO, "logwrapper", "%s terminated by exit(%d)", tag, |
| 87 | WEXITSTATUS(status)); |
| 88 | else if (WIFSIGNALED(status)) |
| 89 | ALOG(LOG_INFO, "logwrapper", "%s terminated by signal %d", tag, |
| 90 | WTERMSIG(status)); |
| 91 | else if (WIFSTOPPED(status)) |
| 92 | ALOG(LOG_INFO, "logwrapper", "%s stopped by signal %d", tag, |
| 93 | WSTOPSIG(status)); |
| 94 | if (chld_sts != NULL) |
| 95 | *chld_sts = status; |
| 96 | } else |
| 97 | ALOG(LOG_INFO, "logwrapper", "%s wait() failed: %s (%d)", tag, |
| 98 | strerror(errno), errno); |
| 99 | } |
| 100 | |
| 101 | void child(int argc, char* argv[]) { |
| 102 | // create null terminated argv_child array |
| 103 | char* argv_child[argc + 1]; |
| 104 | memcpy(argv_child, argv, argc * sizeof(char *)); |
| 105 | argv_child[argc] = NULL; |
| 106 | |
| 107 | if (execvp(argv_child[0], argv_child)) { |
| 108 | ALOG(LOG_ERROR, "logwrapper", |
| 109 | "executing %s failed: %s\n", argv_child[0], strerror(errno)); |
| 110 | exit(-1); |
| 111 | } |
| 112 | } |
| 113 | |
| 114 | int logwrap(int argc, char* argv[], int *chld_sts) { |
| 115 | pid_t pid; |
| 116 | |
| 117 | int parent_ptty; |
| 118 | int child_ptty; |
| 119 | char *child_devname = NULL; |
| 120 | |
| 121 | /* Use ptty instead of socketpair so that STDOUT is not buffered */ |
| 122 | parent_ptty = open("/dev/ptmx", O_RDWR); |
| 123 | if (parent_ptty < 0) { |
| 124 | return fatal("Cannot create parent ptty\n"); |
| 125 | } |
| 126 | |
| 127 | if (grantpt(parent_ptty) || unlockpt(parent_ptty) || |
| 128 | ((child_devname = (char*)ptsname(parent_ptty)) == 0)) { |
| 129 | return fatal("Problem with /dev/ptmx\n"); |
| 130 | } |
| 131 | |
| 132 | pid = fork(); |
| 133 | if (pid < 0) { |
| 134 | close(parent_ptty); |
| 135 | return fatal("Failed to fork\n"); |
| 136 | } else if (pid == 0) { |
| 137 | child_ptty = open(child_devname, O_RDWR); |
| 138 | close(parent_ptty); |
| 139 | if (child_ptty < 0) { |
| 140 | return fatal("Problem with child ptty\n"); |
| 141 | } |
| 142 | |
| 143 | // redirect stdout and stderr |
| 144 | dup2(child_ptty, 1); |
| 145 | dup2(child_ptty, 2); |
| 146 | close(child_ptty); |
| 147 | |
| 148 | child(argc - 1, &argv[1]); |
| 149 | |
| 150 | } else { |
| 151 | // switch user and group to "log" |
| 152 | // this may fail if we are not root, |
| 153 | // but in that case switching user/group is unnecessary |
| 154 | setgid(AID_LOG); |
| 155 | setuid(AID_LOG); |
| 156 | |
| 157 | parent(argv[1], parent_ptty, chld_sts); |
| 158 | } |
| 159 | |
| 160 | return 0; |
| 161 | } |