Question

All

Here i want to run .sh file via system call in android NDK.

I able to run cp,rm command via system call. but sh command is not working via system call.

I also installed busy-box on android.I am using below code.I set all permission on test.sh.

Code :

#include <stdlib.h>
#include <stdio.h>
#include <android/log.h>
#include <jni.h>

#define LOG_TAG "Demo"

#define LOGD(...)  __android_log_print(ANDROID_LOG_DEBUG,LOG_TAG,__VA_ARGS__)


void Java_com_ndkdemo_NDKdemoActivity_systemcall(JNIEnv * env, jobject obj) {

    int result;

    result = system("cp /mnt/sdcard/test /Download");

    LOGD("result is cp %d", result);

    result = system("sh ./test.sh");

    LOGD("result of test.sh is %d", result);

}

Output :

 result is cp 0.
 result of test.sh is 0.

Here i am getting 0 in system("sh ./test.sh"); but not started the test.sh script.

cant get output "Hi" on console.

test.sh contains

#!/system/bin/
echo "Hi"

If i am executing direct command on prompt than its working fine and its given output "Hi" on console.

Please Help me to figure out this issue.

Thanks

Answer 1

Where are you expecting to see the “echo”? By default, android sends stdout to /dev/null.

According to the documentation you can redirect stdout and stderr to the log (so it will show up in logcat) using the following commands:

$ adb shell stop
$ adb shell setprop log.redirect-stdio true
$ adb shell start

Now you may see your echo in adb logcat.