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
parent(const char * tag,int parent_read)29 int 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 LOG(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 LOG(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 LOG(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 LOG(LOG_INFO, "logwrapper", "%s terminated by exit(%d)", tag,
77 WEXITSTATUS(status));
78 }
79 return WEXITSTATUS(status);
80 } else if (WIFSIGNALED(status))
81 LOG(LOG_INFO, "logwrapper", "%s terminated by signal %d", tag,
82 WTERMSIG(status));
83 else if (WIFSTOPPED(status))
84 LOG(LOG_INFO, "logwrapper", "%s stopped by signal %d", tag,
85 WSTOPSIG(status));
86 } else
87 LOG(LOG_INFO, "logwrapper", "%s wait() failed: %s (%d)", tag,
88 strerror(errno), errno);
89 return -EAGAIN;
90 }
91
child(int argc,const char ** argv)92 void 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 LOG(LOG_ERROR, "logwrapper",
101 "executing %s failed: %s", argv_child[0], strerror(errno));
102 exit(-1);
103 }
104 }
105
logwrap(int argc,const char * argv[],int background)106 int logwrap(int argc, const char* argv[], int background)
107 {
108 pid_t pid;
109
110 int parent_ptty;
111 int child_ptty;
112 char *child_devname = NULL;
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 LOG(LOG_ERROR, "logwrapper", "Cannot create parent ptty");
118 return -errno;
119 }
120
121 if (grantpt(parent_ptty) || unlockpt(parent_ptty) ||
122 ((child_devname = (char*)ptsname(parent_ptty)) == 0)) {
123 close(parent_ptty);
124 LOG(LOG_ERROR, "logwrapper", "Problem with /dev/ptmx");
125 return -1;
126 }
127
128 pid = fork();
129 if (pid < 0) {
130 close(parent_ptty);
131 LOG(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 LOG(LOG_ERROR, "logwrapper", "Problem with child ptty");
141 return -errno;
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 if (background) {
151 int fd = open("/dev/cpuctl/bg_non_interactive/tasks", O_WRONLY);
152 if (fd >= 0) {
153 char text[64];
154 sprintf(text, "%d", getpid());
155 if (write(fd, text, strlen(text)) < 0) {
156 LOG(LOG_WARN, "logwrapper",
157 "Unable to background process (%s)", strerror(errno));
158 close(fd);
159 }
160 close(fd);
161 } else {
162 LOG(LOG_WARN, "logwrapper",
163 "Unable to background process (%s)", strerror(errno));
164 }
165 }
166
167 child(argc, argv);
168 } else {
169 /*
170 * Parent
171 */
172 int rc = parent(argv[0], parent_ptty);
173 close(parent_ptty);
174 return rc;
175 }
176
177 return 0;
178 }
179