From 5f8354f3585dd1fb852a097253e38cb91ee909d2 Mon Sep 17 00:00:00 2001 From: Niels Martin Hansen Date: Mon, 28 Jan 2019 11:10:59 +0100 Subject: Change: Make a shortened network revision string for use in server queries --- src/network/network.cpp | 57 ++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 56 insertions(+), 1 deletion(-) (limited to 'src/network/network.cpp') diff --git a/src/network/network.cpp b/src/network/network.cpp index 0bbdd0d06..d70d800f9 100644 --- a/src/network/network.cpp +++ b/src/network/network.cpp @@ -1100,13 +1100,68 @@ void NetworkShutDown() NetworkCoreShutdown(); } +/** + * How many hex digits of the git hash to include in network revision string. + * Determined as 10 hex digits + 2 characters for -g/-u/-m prefix. + */ +static const uint GITHASH_SUFFIX_LEN = 12; + +/** + * Get the network version string used by this build. + * The returned string is guaranteed to be at most NETWORK_REVISON_LENGTH bytes. + */ +const char * GetNetworkRevisionString() +{ + /* This will be allocated on heap and never free'd, but only once so not a "real" leak. */ + static char *network_revision = nullptr; + + if (!network_revision) { + /* Start by taking a chance on the full revision string. */ + network_revision = stredup(_openttd_revision); + /* Ensure it's not longer than the packet buffer length. */ + if (strlen(network_revision) >= NETWORK_REVISION_LENGTH) network_revision[NETWORK_REVISION_LENGTH - 1] = '\0'; + + /* Release version names are not mangled further. */ + if (IsReleasedVersion()) return network_revision; + + /* Prepare a prefix of the git hash. + * Size is length + 1 for terminator, +2 for -g prefix. */ + assert(_openttd_revision_modified < 3); + char githash_suffix[GITHASH_SUFFIX_LEN + 1] = "-"; + githash_suffix[1] = "gum"[_openttd_revision_modified]; + for (uint i = 2; i < GITHASH_SUFFIX_LEN; i++) { + githash_suffix[i] = _openttd_revision_hash[i-2]; + } + + /* Where did the hash start in the original string? + * Overwrite from that position, unless that would go past end of packet buffer length. */ + ptrdiff_t hashofs = strrchr(_openttd_revision, '-') - _openttd_revision; + if (hashofs + strlen(githash_suffix) + 1 > NETWORK_REVISION_LENGTH) hashofs = strlen(network_revision) - strlen(githash_suffix); + /* Replace the git hash in revision string. */ + strecpy(network_revision + hashofs, githash_suffix, network_revision + NETWORK_REVISION_LENGTH); + assert(strlen(network_revision) < NETWORK_REVISION_LENGTH); // strlen does not include terminator, constant does, hence strictly less than + } + + return network_revision; +} + +static const char *ExtractNetworkRevisionHash(const char *revstr) +{ + return strrchr(revstr, '-'); +} + /** * Checks whether the given version string is compatible with our version. + * First tries to match the full string, if that fails, attempts to compare just git hashes. * @param other the version string to compare to */ bool IsNetworkCompatibleVersion(const char *other) { - return strncmp(_openttd_revision, other, NETWORK_REVISION_LENGTH - 1) == 0; + if (strncmp(GetNetworkRevisionString(), other, NETWORK_REVISION_LENGTH - 1) == 0) return true; + + const char *hash1 = ExtractNetworkRevisionHash(GetNetworkRevisionString()); + const char *hash2 = ExtractNetworkRevisionHash(other); + return hash1 && hash2 && (strncmp(hash1, hash2, GITHASH_SUFFIX_LEN) == 0); } #endif /* ENABLE_NETWORK */ -- cgit v1.2.3-54-g00ecf