init: Add support for writing system property value to a file in init.rc

The write command will write a property value if the value starts with a "$'

For example:
    write /sys/class/android_usb/iSerial $ro.serialno

Use double leading '$' if you need to write a string that starts with '$':

    write /data/foo $$hello

to write "$hello" to /data/foo

Change-Id: I55431ac7715a5347bb95c3a15aee97c575444dde
This commit is contained in:
Mike Lockwood 2011-06-07 17:30:11 -07:00
parent b36f136738
commit 2c4d5dc415
1 changed files with 17 additions and 1 deletions

View File

@ -527,7 +527,23 @@ int do_sysclktz(int nargs, char **args)
int do_write(int nargs, char **args)
{
return write_file(args[1], args[2]);
char *path = args[1];
char *value = args[2];
if (value[0] == '$') {
/* Write the value of a system property if value starts with '$' */
value++;
if (value[0] != '$') {
value = property_get(value);
if (!value) {
ERROR("property %s has no value for writing to %s\n", value, path);
return -EINVAL;
}
} /* else fall through to support double '$' prefix for writing
* string literals that start with '$'
*/
}
return write_file(path, value);
}
int do_copy(int nargs, char **args)