From 577a0c8192c18d5a65aae98aebffe903dd82fd70 Mon Sep 17 00:00:00 2001 From: Bryce Kwon Date: Thu, 1 Oct 2026 14:52:59 -1000 Subject: Keep the builder's home directory out of the binary Git's Makefile defaults `prefix` to `$HOME` and compiles it into `exec-cmd.o` as the fallback runtime prefix, so each build embedded the path of whoever ran it and no two builders could produce the same bytes. The release script also maps the build directory out of the debug info, which otherwise differs between checkouts. --- Makefile | 7 +++++-- tools/release-build.sh | 6 ++++++ 2 files changed, 11 insertions(+), 2 deletions(-) diff --git a/Makefile b/Makefile index 53580f3..fe65cba 100644 --- a/Makefile +++ b/Makefile @@ -65,8 +65,11 @@ all: cgit # be WITH_RUST, so Rust is now compiled in unless it is turned off, and leaving # this out would quietly make Cargo a build requirement. Git 3.0 drops the # choice entirely, at which point this stops working and Rust becomes -# mandatory. -GIT_BUILD_FLAGS = NO_CURL=1 NO_OPENSSL=1 NO_RUST=1 +# mandatory. Git's own build defaults prefix to $HOME and compiles it in as +# its fallback runtime prefix, so without the last flag every binary carries +# the home directory of whoever built it and no two builders get the same +# bytes. +GIT_BUILD_FLAGS = NO_CURL=1 NO_OPENSSL=1 NO_RUST=1 prefix='$(prefix)' # Apple's linker otherwise stamps each object's mtime into the debug map, so # two builds of the same sources would differ. diff --git a/tools/release-build.sh b/tools/release-build.sh index c5ca6e9..a6d10dc 100755 --- a/tools/release-build.sh +++ b/tools/release-build.sh @@ -62,6 +62,12 @@ if supports "-fstack-clash-protection"; then CFLAGS="$CFLAGS -fstack-clash-protection" fi +# The debug info otherwise records the absolute build directory, so the same +# sources built in two checkouts would differ. +if supports "-ffile-prefix-map=/x=."; then + CFLAGS="$CFLAGS -ffile-prefix-map=$PWD=." +fi + LDFLAGS="-pie -Wl,-z,relro,-z,now -Wl,-z,noexecstack" # These reach only the cgit objects, so git's own sources are not held to them. -- cgit v2.8.0