From cb8010bbffaa680968ed0301a5da5b55ed399a56 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Torsten=20B=C3=B6gershausen?= Date: Fri, 9 Nov 2018 18:41:10 +0100 Subject: remote-curl.c: xcurl_off_t is not portable (on 32 bit platfoms) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When setting DEVELOPER = 1 DEVOPTS = extra-all "gcc (Raspbian 6.3.0-18+rpi1+deb9u1) 6.3.0 20170516" errors out with "comparison is always false due to limited range of data type" "[-Werror=type-limits]" It turns out that the function xcurl_off_t() has 2 flavours: - It gives a warning 32 bit systems, like Linux - It takes the signed ssize_t as a paramter, but the only caller is using a size_t (which is typically unsigned these days) The original motivation of this function is to make sure that sizes > 2GiB are handled correctly. The curl documentation says: "For any given platform/compiler curl_off_t must be typedef'ed to a 64-bit wide signed integral data type" On a 32 bit system "size_t" can be promoted into a 64 bit signed value without loss of data, and therefore we may see the "comparison is always false" warning. On a 64 bit system it may happen, at least in theory, that size_t is > 2^63, and then the promotion from an unsigned "size_t" into a signed "curl_off_t" may be a problem. One solution to suppress a possible compiler warning could be to remove the function xcurl_off_t(). However, to be on the very safe side, we keep it and improve it: - The len parameter is changed from ssize_t to size_t - A temporally variable "size" is used, promoted int uintmax_t and the compared with "maximum_signed_value_of_type(curl_off_t)". Thanks to Junio C Hamano for this hint. Signed-off-by: Torsten Bögershausen Signed-off-by: Junio C Hamano diff --git a/remote-curl.c b/remote-curl.c index 762a55a..1220dff 100644 --- a/remote-curl.c +++ b/remote-curl.c @@ -617,10 +617,11 @@ static int probe_rpc(struct rpc_state *rpc, struct slot_results *results) return err; } -static curl_off_t xcurl_off_t(ssize_t len) { - if (len > maximum_signed_value_of_type(curl_off_t)) +static curl_off_t xcurl_off_t(size_t len) { + uintmax_t size = len; + if (size > maximum_signed_value_of_type(curl_off_t)) die("cannot handle pushes this big"); - return (curl_off_t) len; + return (curl_off_t)size; } static int post_rpc(struct rpc_state *rpc) -- cgit v0.10.2-6-g49f6