Date: Tue, 19 Oct 2021 13:11:48 +0000
From: bugzilla-noreply@freebsd.org
To: bugs@FreeBSD.org
Subject: [Bug 248184] readlink("/proc/curproc/file") returns arbitrary correct name for programs with more than one link (name)
Message-ID: <bug-248184-227-v8jz8IEuHJ@https.bugs.freebsd.org/bugzilla/>
In-Reply-To: <bug-248184-227@https.bugs.freebsd.org/bugzilla/>
References: <bug-248184-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D248184 Tobias Kortkamp <tobik@freebsd.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |tobik@freebsd.org --- Comment #6 from Tobias Kortkamp <tobik@freebsd.org> --- (In reply to Conrad Meyer from comment #1) The problem is also present with AT_EXECPATH. AT_EXECPATH doesn't really make a difference if the wrong name is copied to userspace in the first place. $ freebsd-version 13.0-RELEASE-p4 $ cat execpath.c #include <sys/auxv.h> #include <limits.h> #include <stdio.h> int main(int argc, char *argv[]) { char pathname[PATH_MAX]; elf_aux_info(AT_EXECPATH, pathname, PATH_MAX); puts(pathname); return 0; } $ make execpath $ ln -f execpath tmp/execpath $ ./execpath /home/tobias/execpath $ ./tmp/execpath /home/tobias/tmp/execpath $ ./execpath # I'd expect this to return /home/tobias/execpath again but: /home/tobias/tmp/execpath Now I'm coming back to this because lang/rust uses hardlinks in the build by default. We have disabled this since it caused intermittent build failur= es because env::current_exe (uses kern.proc.pathname.-1 sysctl internally) mig= ht returns the wrong pathname (one of the hardlinks) sometimes and rustc fails to find the right std crate. This is my working theory anyway. It's diffic= ult to trigger the problem on my package builder. I was going to experiment with switching it over to AT_EXECPATH but I guess that will make no difference because of the current behavior of it. If getexecname() would be just a wrapper for elf_aux_info(AT_EXECPATH) then it wouldn't solve the problem either. Any suggestions what we should use instead of kern.proc.pathname, AT_EXECPA= TH, or /proc/curproc/file? --=20 You are receiving this mail because: You are the assignee for the bug.=
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