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 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
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 ALOG(LOG_ERROR, "logwrapper",
101 "executing %s failed: %s", argv_child[0], strerror(errno));
102 }
103 _exit(1);
104 }
105
logwrap(int argc,const char * argv[])106 int 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 int fork_and_execve(const char*, char*[]);
164
165 /*
166 * The following is based off of bionic/libc/unistd/system.c with
167 * modifications to avoid calling /system/bin/sh -c
168 */
system_nosh(const char * command)169 int system_nosh(const char *command)
170 {
171 char buffer[255];
172 char *argp[32];
173 char *next = buffer;
174 char *tmp;
175 int i = 0;
176
177 if (!command) /* just checking... */
178 return(1);
179
180 /*
181 * The command to argp splitting is from code that was
182 * reverted in Change: 11b4e9b2
183 */
184 if (strnlen(command, sizeof(buffer) - 1) == sizeof(buffer) - 1) {
185 ALOGE("command line too long while processing: %s", command);
186 errno = E2BIG;
187 return -1;
188 }
189 strcpy(buffer, command); // Command len is already checked.
190 while ((tmp = strsep(&next, " "))) {
191 argp[i++] = tmp;
192 if (i == 32) {
193 ALOGE("argument overflow while processing: %s", command);
194 errno = E2BIG;
195 return -1;
196 }
197 }
198 argp[i] = NULL;
199
200 return fork_and_execve(argp[0], argp);
201 }
202
203 extern char **environ;
fork_and_execve(const char * filename,char * argv[])204 int fork_and_execve(const char* filename, char* argv[]) {
205 pid_t pid;
206 sig_t intsave, quitsave;
207 sigset_t mask, omask;
208 int pstat;
209
210 sigemptyset(&mask);
211 sigaddset(&mask, SIGCHLD);
212 sigprocmask(SIG_BLOCK, &mask, &omask);
213 switch (pid = vfork()) {
214 case -1: /* error */
215 sigprocmask(SIG_SETMASK, &omask, NULL);
216 return(-1);
217 case 0: /* child */
218 sigprocmask(SIG_SETMASK, &omask, NULL);
219 execve(filename, argv, environ);
220 _exit(127);
221 }
222
223 intsave = (sig_t) bsd_signal(SIGINT, SIG_IGN);
224 quitsave = (sig_t) bsd_signal(SIGQUIT, SIG_IGN);
225 pid = waitpid(pid, (int *)&pstat, 0);
226 sigprocmask(SIG_SETMASK, &omask, NULL);
227 (void)bsd_signal(SIGINT, intsave);
228 (void)bsd_signal(SIGQUIT, quitsave);
229 return (pid == -1 ? -1 : pstat);
230 }
231