Implement setprop for toybox.
Because bionic/libcutils doesn't wait for init, I've duplicated a lot
of the input validation that init does so we can give good error messages.
Change-Id: I175421f7409f88813b88109f58825ce5649f1550
diff --git a/toys/android/setprop.c b/toys/android/setprop.c
new file mode 100644
index 0000000..ef24c9a
--- /dev/null
+++ b/toys/android/setprop.c
@@ -0,0 +1,52 @@
+/* setprop.c - Set an Android system property
+ *
+ * Copyright 2015 The Android Open Source Project
+
+USE_SETPROP(NEWTOY(setprop, "<2>2", TOYFLAG_USR|TOYFLAG_SBIN))
+
+config SETPROP
+ bool "setprop"
+ default y
+ help
+ usage: setprop NAME VALUE
+
+ Sets an Android system property.
+*/
+
+#define FOR_setprop
+#include "toys.h"
+
+#if defined(__ANDROID__)
+#include <cutils/properties.h>
+#endif
+
+void setprop_main(void)
+{
+#if defined(__ANDROID__)
+ char *name = toys.optargs[0], *value = toys.optargs[1];
+ char *p;
+ size_t name_len = strlen(name), value_len = strlen(value);
+
+ // property_set doesn't tell us why it failed, and actually can't
+ // recognize most failures (because it doesn't wait for init), so
+ // we duplicate all of init's checks here to help the user.
+
+ if (name_len >= PROP_NAME_MAX)
+ error_exit("name '%s' too long; try '%.*s'",
+ name, PROP_NAME_MAX - 1, name);
+ if (value_len >= PROP_VALUE_MAX)
+ error_exit("value '%s' too long; try '%.*s'",
+ value, PROP_VALUE_MAX - 1, value);
+
+ if (*name == '.' || name[name_len - 1] == '.')
+ error_exit("property names must not start or end with '.'");
+ if (strstr(name, ".."))
+ error_exit("'..' is not allowed in a property name");
+ for (p = name; *p; ++p)
+ if (!isalnum(*p) && !strchr("_.-", *p))
+ error_exit("invalid character '%c' in name '%s'", *p, name);
+
+ if (property_set(name, value))
+ error_msg("failed to set property '%s' to '%s'", name, value);
+#endif
+}
