On 2021-09-07 22:22:34 +0000, David wrote: > On Tue, Sep 07, 2021 at 12:23:38PM +0200, Axel Beckert wrote: > > ... > > David wrote: > > > ... > > > > Sorry for the trouble. I (and the tests) admittedly only test the > > non-static zsh. And except for some special lookups known to be not > > possible with static compiled binaries, I also don't expect any > > difference in functionality with zsh-static. > > Thank you both so much for looking into it! And Vincent noticing that > /lib/x86_64-linux-gnu/libc.so.6 is being opened and mapped into memory is > very eye opening, for a static binary! > > Please forgive my ignorange in the automated test suites, but perhaps for a > future test, would verifying the expected exit status of these commands help > intercept this (and any other) weird problem? :-) > > zsh-static -f -c "exit 0" > zsh-static -f -c "exit 1"
No, this wouldn't help, because the libc6 version zsh-static has been compiled against would be the same as the one for the test. Here, the issue is that zsh-static is built against some libc6 version (at this time, zsh-static would work as expected), then libc6 is upgraded to some newer version, and zsh-static no longer works. I'd say that it would be difficult to design a test framework for up-to-date Debian/unstable that would be useful in practice (since as soon as a new version of some package gets in unstable, all the other packages would need to be tested), except for non-regression tests about particular bugs like this one. > Now for a more thorough test: Is it possible (or even desireable?) to test > the binary to verify it really is statically linked? Perhaps grep strace > output looking for potential evidence of .so files getting opened in some > lib directory? > > > strace zsh-static -f -c "exit 0" 2>&1 | grep > > '^open[a-zA-Z0-9_]*(.*"[^"]*lib.*\.so\>[^"]*"' > openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libnss_compat.so.2", > O_RDONLY|O_CLOEXEC) = 11 > openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 11 > openat(AT_FDCWD, "/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2", > O_RDONLY|O_CLOEXEC) = 11 > > echo $? > 0 Perhaps. > For comparison, busybox is statically linked: > > > strace /bin/busybox -f -c "exit 0" 2>&1 | grep > > '^open[a-zA-Z0-9_]*(.*"[^"]*lib.*\.so\>[^"]*"' echo $? > 1 busybox is dynamically linked: $ file /bin/busybox /bin/busybox: ELF 64-bit LSB pie executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, BuildID[sha1]=280a5ddfb6379abacc1a6c7a6024876f653cd6bf, for GNU/Linux 3.2.0, stripped > (And I also just tested a couple small C programs invoking printf and > compiled with and without "-static".) I confirm that no shared libraries are read with -static on simple programs. -- Vincent Lefèvre <[email protected]> - Web: <https://www.vinc17.net/> 100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/> Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)
