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      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 <errno.h>
     21 #include <string.h>
     22 #include <unistd.h>
     23 
     24 #include <string>
     25 
     26 #ifndef RS_COMPATIBILITY_LIB
     27 #include <sys/wait.h>
     28 #endif
     29 
     30 
     31 namespace android {
     32 namespace renderscript {
     33 
     34 const char * rsuCopyString(const char *name) {
     35     return rsuCopyString(name, strlen(name));
     36 }
     37 
     38 const char * rsuCopyString(const char *name, size_t len) {
     39     char *n = new char[len+1];
     40     memcpy(n, name, len);
     41     n[len] = 0;
     42     return n;
     43 }
     44 
     45 const char* rsuJoinStrings(int n, const char* const* strs) {
     46     std::string tmp;
     47     for (int i = 0; i < n; i++) {
     48         if (i > 0) {
     49             tmp.append(" ");
     50         }
     51         tmp.append(strs[i]);
     52     }
     53     return strndup(tmp.c_str(), tmp.size());
     54 }
     55 
     56 #ifndef RS_COMPATIBILITY_LIB
     57 bool rsuExecuteCommand(const char *exe, int nArgs, const char * const *args) {
     58     std::unique_ptr<const char> joined(rsuJoinStrings(nArgs, args));
     59     ALOGV("Invoking %s with args '%s'", exe, joined.get());
     60 
     61     pid_t pid = fork();
     62 
     63     switch (pid) {
     64     case -1: {  // Error occurred (we attempt no recovery)
     65         ALOGE("Fork of \"%s\" failed with error %s", exe, strerror(errno));
     66         return false;
     67     }
     68     case 0: {  // Child process
     69         // No (direct or indirect) call to malloc between fork and exec.  It is
     70         // possible that a different thread holds the heap lock before the fork.
     71 
     72         // ProcessManager in libcore can reap unclaimed SIGCHLDs in its process
     73         // group.  To ensure that the exit signal is not caught by
     74         // ProcessManager and instead sent to libRS, set the child's PGID to its
     75         // PID.
     76         setpgid(0, 0);
     77 
     78         execv(exe, (char * const *)args);
     79 
     80         ALOGE("execv() failed: %s", strerror(errno));
     81         abort();
     82         return false;
     83     }
     84     default: {  // Parent process (actual driver)
     85         // Wait on child process to finish execution.
     86         int status = 0;
     87         pid_t w = TEMP_FAILURE_RETRY(waitpid(pid, &status, 0));
     88         if (w == -1) {
     89             ALOGE("Waitpid of \"%s\" failed with error %s", exe,
     90                   strerror(errno));
     91             return false;
     92         }
     93 
     94         if (WIFEXITED(status) && WEXITSTATUS(status) == 0) {
     95             return true;
     96         }
     97 
     98         ALOGE("Child process \"%s\" terminated with status %d", exe, status);
     99         return false;
    100     }
    101     }
    102 }
    103 #endif // RS_COMPATIBILITY_LIB
    104 
    105 // Implementation of property_get from libcutils
    106 int property_get(const char *key, char *value, const char *default_value) {
    107     int len;
    108     len = __system_property_get(key, value);
    109     if (len > 0) {
    110         return len;
    111     }
    112 
    113     if (default_value) {
    114         len = strlen(default_value);
    115         memcpy(value, default_value, len + 1);
    116     }
    117     return len;
    118 }
    119 
    120 } // namespace renderscript
    121 } // namespace android
    122