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From: Alexander Sosedkin <>
Subject: [musl] $ORIGIN rpath expansion without /proc: code looks wrong
Date: Wed, 17 Nov 2021 15:04:15 +0100	[thread overview]
Message-ID: <> (raw)

Hello, I've encountered a case of a binary with an rpath of
not starting up due to not finding /some/meaningful/lib/
ldd'ing said it's there though.
And the library was found alright when I patchelf'd rpath to just

I dug into musl code and came across that bit that checks /proc.
Sure enough, when I tried mounting /proc, it started working fine.
Yet the error handling from accessing /proc puzzles me:

ldso/dynlink.c, fixup_rpath():
                 l = readlink("/proc/self/exe", buf, buf_size);
                 if (l == -1) switch (errno) {
                 case ENOENT:
                 case ENOTDIR:
                 case EACCES:
                         return -1;
                 if (l >= buf_size)
                         return 0;
                 buf[l] = 0;
                 origin = buf;

hitting that break like I had means zeroing buf[-1], right?
Could somebody take a look at this and double-check that
this codepath makes sense?
My attempts at comprehending it fail irrecoverably at this line.

(CC me on replies, please.
  No nice context to provide, building my own toolchain at

             reply	other threads:[~2021-11-17 14:33 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-17 14:04 Alexander Sosedkin [this message]
2021-11-17 17:00 ` Érico Nogueira
2021-11-17 19:25   ` Alexander Sosedkin
2021-11-18 19:15     ` Érico Nogueira
2021-11-17 20:01   ` Jeffrey Walton
2021-11-18 19:21     ` Érico Nogueira
2021-11-18 19:41       ` Alexander Sosedkin
2021-11-18 19:42       ` Jeffrey Walton
2021-11-18 20:30         ` Rich Felker

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