rsCppUtils.cpp revision 2a61168a777ee434ce2c28945aa74f6a6bcf2820 
1/*
2 * Copyright (C) 2013 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 "rsUtils.h"
18#include "rsCppUtils.h"
19
20#include <string>
21#include <unistd.h>
22
23#include <sys/system_properties.h>
24
25#ifndef RS_COMPATIBILITY_LIB
26#include <sys/wait.h>
27#endif
28
29
30namespace android {
31namespace renderscript {
32
33const char * rsuCopyString(const char *name) {
34    return rsuCopyString(name, strlen(name));
35}
36
37const char * rsuCopyString(const char *name, size_t len) {
38    char *n = new char[len+1];
39    memcpy(n, name, len);
40    n[len] = 0;
41    return n;
42}
43
44const char* rsuJoinStrings(int n, const char* const* strs) {
45    std::string tmp;
46    for (int i = 0; i < n; i++) {
47        if (i > 0) {
48            tmp.append(" ");
49        }
50        tmp.append(strs[i]);
51    }
52    return strndup(tmp.c_str(), tmp.size());
53}
54
55#ifndef RS_COMPATIBILITY_LIB
56bool rsuExecuteCommand(const char *exe, int nArgs, const char * const *args) {
57    std::unique_ptr<const char> joined(rsuJoinStrings(nArgs, args));
58    ALOGV("Invoking %s with args '%s'", exe, joined.get());
59
60    pid_t pid = fork();
61
62    switch (pid) {
63    case -1: {  // Error occurred (we attempt no recovery)
64        ALOGE("Fork of \"%s\" failed with error %s", exe, strerror(errno));
65        return false;
66    }
67    case 0: {  // Child process
68        // No (direct or indirect) call to malloc between fork and exec.  It is
69        // possible that a different thread holds the heap lock before the fork.
70
71        // ProcessManager in libcore can reap unclaimed SIGCHLDs in its process
72        // group.  To ensure that the exit signal is not caught by
73        // ProcessManager and instead sent to libRS, set the child's PGID to its
74        // PID.
75        setpgid(0, 0);
76
77        execv(exe, (char * const *)args);
78
79        ALOGE("execv() failed: %s", strerror(errno));
80        abort();
81        return false;
82    }
83    default: {  // Parent process (actual driver)
84        // Wait on child process to finish execution.
85        int status = 0;
86        pid_t w = TEMP_FAILURE_RETRY(waitpid(pid, &status, 0));
87        if (w == -1) {
88            ALOGE("Waitpid of \"%s\" failed with error %s", exe,
89                  strerror(errno));
90            return false;
91        }
92
93        if (WIFEXITED(status) && WEXITSTATUS(status) == 0) {
94            return true;
95        }
96
97        ALOGE("Child process \"%s\" terminated with status %d", exe, status);
98        return false;
99    }
100    }
101}
102#endif // RS_COMPATIBILITY_LIB
103
104// Implementation of property_get from libcutils
105int property_get(const char *key, char *value, const char *default_value) {
106    int len;
107    len = __system_property_get(key, value);
108    if (len > 0) {
109        return len;
110    }
111
112    if (default_value) {
113        len = strlen(default_value);
114        memcpy(value, default_value, len + 1);
115    }
116    return len;
117}
118
119} // namespace renderscript
120} // namespace android
121