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2010-01-12Merge branch 'jv/binary_to_term-opts' into ccase/r13b04_devErlang/OTP
* jv/binary_to_term-opts: document ErtsExternalDist flags and CON_ID mask add options to binary_to_term OTP-8367 There is new erlang:binary_to_binary/2 BIF that takes an option list. The option safe can be used to prevent creation of resources that are not garbage collected (such as atoms). (Thanks to Jayson Vantuyl.)
2010-01-08document ErtsExternalDist flags and CON_ID maskJayson Vantuyl
In the ErtsExternalDist structure, the flags field holds a combination of flags (tagged into the high bits) and the connection ID (in the low bits). This wasn't clearing indicated anywhere. This patch adds a comment before the flags and mask that indicates their use and relation to each other. This will help guide people through the code and reduce the likelihood that someone will add a flag without adjusting the mask.
2010-01-08add options to binary_to_termJayson Vantuyl
term_to_binary and binary_to_term are powerful tools that can be used easily in lieu of a custom binary network protocol. Unfortunately, carefully crafted data can be used to exhaust the memory in an Erlang node by merely attempting to decode binaries. This makes it unsafe to receive data from untrusted sources. This is possible because binary_to_term/1 will allocate new atoms and new external function references. These data structures are not garbage collected. This patch implements the new form of binary_to_term that takes a list of options, and a simple option called 'safe'. If specified, this option will cause decoding to fail with a badarg error if an atom or external function reference would be allocated. In the general case, it will happily decode any Erlang term other than those containing new atoms or new external function references. However, fun, pid, and ref data types can embed atoms. They might fail to decode if one of these embedded atoms is new to the node. This may be an issue if encoded binaries are transferred between nodes or persisted between invocations of Erlang.
2009-11-20The R13B03 release.OTP_R13B03Erlang/OTP