Allow ro. properties to have arbitrary lengths

Android now allows ro. properties to have arbitrary lengths.  Two
changes need to happen to support this:

1) The length check in setprop.c before attempting to set a property
   needs to be removed for ro. properties
2) __system_property_read_callback() must be used in place of
   __system_property_get() in getprop.c as only the former is capable
   of reading properties with size > 92 characters.

Bug: 23102347
Bug: 34954705
Change-Id: Ib8565a3e6d987dd5e6a5fe790e804ecf8ad1e020

2 files changed, 13 insertions, 4 deletions

diff --git a/toys/android/getprop.c b/toys/android/getprop.c
index 04a9b282..51ef7f6b 100644
--- a/toys/android/getprop.c
+++ b/toys/android/getprop.c
@@ -57,6 +57,12 @@ static void add_property(const prop_info *pi, void *unused)
   __system_property_read_callback(pi, read_callback, NULL);
 }
 
+static void print_callback(void *unused, const char *unused_name, const char *value,
+                           unsigned unused_serial)
+{
+  puts(value);
+}
+
 // Needed to supress extraneous "Loaded property_contexts from" message
 static int selinux_log_callback_local(int type, const char *fmt, ...)
 {
@@ -87,9 +93,12 @@ void getprop_main(void)
       puts(context);
       if (CFG_TOYBOX_FREE) free(context);
     } else {
-      if (__system_property_get(*toys.optargs, toybuf) <= 0)
-        strcpy(toybuf, toys.optargs[1] ? toys.optargs[1] : "");
-      puts(toybuf);
+      const prop_info* pi = __system_property_find(*toys.optargs);
+      if (pi == NULL) {
+        puts(toys.optargs[1] ? toys.optargs[1] : "");
+      } else {
+        __system_property_read_callback(pi, print_callback, NULL);
+      }
     }
   } else {
     size_t i;
diff --git a/toys/android/setprop.c b/toys/android/setprop.c
index ec411f41..14c24d9f 100644
--- a/toys/android/setprop.c
+++ b/toys/android/setprop.c
@@ -29,7 +29,7 @@ void setprop_main(void)
   // recognize most failures (because it doesn't wait for init), so
   // we duplicate all of init's checks here to help the user.
 
-  if (value_len >= PROP_VALUE_MAX)
+  if (value_len >= PROP_VALUE_MAX && !strncmp(value, "ro.", 3))
     error_exit("value '%s' too long; try '%.*s'",
                value, PROP_VALUE_MAX - 1, value);