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Diffstat (limited to '')
| -rw-r--r-- | man/dpkg-buildflags.pod | 72 |
1 files changed, 62 insertions, 10 deletions
diff --git a/man/dpkg-buildflags.pod b/man/dpkg-buildflags.pod index 6673a65..7b31238 100644 --- a/man/dpkg-buildflags.pod +++ b/man/dpkg-buildflags.pod @@ -239,10 +239,8 @@ Print the features enabled for a given area (since dpkg 1.16.2). If the feature is handled (even if only on some architectures) as a builtin default by the compiler, then a B<Builtin> field is printed (since dpkg 1.21.14). -The only currently recognized -areas on Debian and derivatives are B<future>, B<qa>, B<reproducible>, -B<sanitize> and B<hardening>, see the B<FEATURE AREAS> -section for more details. +See the L</FEATURE AREAS> section for more details about the currently +recognized areas. Exits with 0 if the area is known otherwise exits with 1. The output is in RFC822 format, with one section per feature. @@ -401,20 +399,51 @@ to support other languages). =head1 FEATURE AREAS +Feature areas are currently vendor specific, +and the ones described below are only recognized on Debian and derivatives. + Each area feature can be enabled and disabled in the B<DEB_BUILD_OPTIONS> and B<DEB_BUILD_MAINT_OPTIONS> environment variable's area value with the ‘B<+>’ and ‘B<->’ modifier. +Following the general syntax of these variables +(described in L<dpkg-buildpackage(1)>), +multiple feature areas can be specified separated by spaces, +where each get feature specifiers as mandatory parameters after an +equal sign (‘B<=>’). +The feature specifiers are comma-separated and parsed from left to right, +where the settings within the same feature specifier override previous ones, +even if the feature specifiers are split across multiple space-separated +feature area settings for the same area. + For example, to enable the B<hardening> “pie” feature and disable the “fortify” feature you can do this in B<debian/rules>: - export DEB_BUILD_MAINT_OPTIONS=hardening=+pie,-fortify + export DEB_BUILD_MAINT_OPTIONS = hardening=+pie,-fortify The special feature B<all> (valid in any area) can be used to enable or disable all area features at the same time. Thus disabling everything in the B<hardening> area and enabling only “format” and “fortify” can be achieved with: - export DEB_BUILD_MAINT_OPTIONS=hardening=-all,+format,+fortify + export DEB_BUILD_MAINT_OPTIONS = hardening=-all,+format,+fortify + +Multiple feature areas can be set: + + export DEB_BUILD_MAINT_OPTIONS = hardening=+pie abi=+lfs + +The override behavior applies as much to the B<all> special feature, +as to specific features, +which should allow for composition. +Thus to enable “lfs” in the B<abi> area, and only “pie” and “fortify” +in the B<hardening> area, but “format” only when CONDITION is defined, +this could be done with: + + export DEB_BUILD_MAINT_OPTIONS = hardening=-all,+pie,+format abi=+lfs + … + DEB_BUILD_MAINT_OPTIONS += hardening=+fortify + ifdef CONDITION + DEB_BUILD_MAINT_OPTIONS += hardening=-format + endif =head2 abi @@ -436,10 +465,33 @@ feature in the B<future> feature area. =item B<time64> -This setting (since dpkg 1.22.0; disabled by default) enables 64-bit time_t -support on 32-bit architectures where their ABI does not include it by -default, by adding B<-D_TIME_BITS=64> to B<CPPFLAGS>. -This setting automatically enables the B<lfs> feature as it requires it. +This setting (since dpkg 1.22.0; enabled by default except for i386, +hurd-i386 and kfreebsd-i386 since dpkg 1.22.5) enables 64-bit time_t support +on 32-bit architectures where their ABI does not include it by default, +by adding B<-D_TIME_BITS=64> to B<CPPFLAGS>. +This setting automatically enables the B<lfs> feature from the B<abi> +feature area, +and the B<bug-implicit-func> feature from the B<qa> feature area +as it requires them. + +If the setting is enabled explicitly then it gets enabled on all +architectures including i386 but not hurd-i386 nor kfreebsd-i386 +(where the kernel does not have time64 interfaces), +ignoring the binary backwards compatibility default. + +It is also enabled by default by gcc on the +armel, +armhf, +hppa, +m68k, +mips, +mipsel, +powerpc +and +sh4 +Debian architectures, +where disabling the feature will add instead +B<-U_LARGEFILE_SOURCE -U_FILE_OFFSET_BITS -U_TIME_BITS> to B<CPPFLAGS>. =back |