Re: static pie: confusion between _DYNAMIC, crt1.o, Scrt1.o

[Samuel Thibault <sthibault@debian.org>]

Hello,

Xi Ruoyao, le sam. 22 oct. 2022 22:25:42 +0800, a ecrit:
> On Sat, 2022-10-22 at 16:06 +0200, Samuel Thibault wrote:
> > https://buildd.debian.org/status/fetch.php?pkg=gnupg2&arch=hurd-i386&ver=2.2.40-1&stamp=1666261690&raw=0
> > 
> > which is leaving me completely confused.
> > 
> > 
> > gcc -I/usr/include  -I/usr/include  -Wall -Wno-format-zero-length -
> > Wno-pointer-sign -Wpointer-arith -g -O2 -ffile-prefix-
> > map=/<<PKGBUILDDIR>>=. -fstack-protector-strong -Wformat -
> > Werror=format-security  -Wl,-z,relro -Wl,-z,now -pie -static -o gpgv
> > gpgv.o build-packet.o compress.o  free-packet.o getkey.o keydb.o
> > keyring.o seskey.o kbnode.o mainproc.o armor.o mdfilter.o textfilter.o
> > progress.o misc.o rmd160.o openfile.o keyid.o parse-packet.o cpr.o
> > plaintext.o sig-check.o keylist.o pkglue.o ecdh.o verify.o
> > ../kbx/libkeybox.a ../common/libcommon.a ../regexp/libregexp.a
> > ../common/libgpgrl.a -lz   -L/usr/lib/i386-gnu -lgcrypt -
> > L/usr/lib/i386-gnu -lgpg-error
> > 
> > So this is static pie (-pie -static)
> 
> No it's not.  The GCC option for static PIE is -static-pie (no
> whitespace between -static and -pie), not -pie -static.

Oh.

Is it not possible to make -static -pie get the same behavior? That'd be
way more orthogonal for people to understand.

As the gnupg example shows, people seem to be expecting it to be
static-pie, and I don't think documentation will manage to fix that.

> > So this is using Scrt1.o
> 
> A static PIE should use rcrt1.o.  If you pass the correct -static-pie
> option to GCC, GCC will use it.

Ok.

$ gcc test.o -o test -static-pie -v
[...]
 /usr/lib/gcc/i686-gnu/12/collect2 -plugin /usr/lib/gcc/i686-gnu/12/liblto_plugin.so -plugin-opt=/usr/lib/gcc/i686-gnu/12/lto-wrapper -plugin-opt=-fresolution=/tmp/cclPHnby.res -plugin-opt=-pass-through=-lgcc -plugin-opt=-pass-through=-lgcc_eh -plugin-opt=-pass-through=-lc --build-id --eh-frame-hdr -m elf_i386 --hash-style=gnu --as-needed -static -pie --no-dynamic-linker -z text -pie -o test /usr/lib/gcc/i686-gnu/12/../../../i386-gnu/crt1.o /usr/lib/gcc/i686-gnu/12/../../../i386-gnu/crti.o /usr/lib/gcc/i686-gnu/12/crtbegin.o -L/usr/lib/gcc/i686-gnu/12 -L/usr/lib/gcc/i686-gnu/12/../../../i386-gnu -L/usr/lib/gcc/i686-gnu/12/../../.. -L/lib/i386-gnu -L/usr/lib/i386-gnu test.o --start-group -lgcc -lgcc_eh -lc --end-group /usr/lib/gcc/i686-gnu/12/crtendS.o /usr/lib/gcc/i686-gnu/12/../../../i386-gnu/crtn.o

That doesn't seem to have been fixed for the hurd case, I will have
a look (and that will most probably point me to the piece that makes
-static -pie use crt1.o on Linux).

Samuel