13483 2019-08-14 20:46:04 +0000 pseudo prevents using /dev/fd/* 2019-08-15 15:44:20 +0000 1 1 6 Yocto Project Subprojects Pseudo pseudo master x86 x86_64 RESOLVED DUPLICATE 13288 Medium+ major 2.8 M4 1 sam seebs randy.macleod yp.pseudo.watcher yp.watcher --- --- No (bug/feature does not impact docs) oldest_to_newest 84667 0 sam 2019-08-14 20:46:04 +0000 pseudo insists on dereferencing /proc/*/fd/* filenames which means that /dev/fd/62 or /proc/$$/fd/62 or /proc/self/fd/62 don't work. This means the pseudo environment can break any program or script that depends on /dev/fd/* working I think the easiest fix is to attempt to open the last symlink where lstat worked, not the one where it doesn't work. This example works under normal system or with fakeroot, but fails under pseudo: bash -c 'cat <( echo hello )' strace shows what is going on: bash -c 'strace -f cat <( echo hello )' without pseudo (or even just using fakeroot), it's as simple as: openat(AT_FDCWD, "/dev/fd/63", O_RDONLY) = 3 but with pseudo we get this link de-referencing and failure: lstat("/dev", {st_mode=S_IFDIR|0755, st_size=4040, ...}) = 0 lstat("/dev/fd", {st_mode=S_IFLNK|0777, st_size=13, ...}) = 0 rt_sigprocmask(SIG_BLOCK, [HUP USR1 USR2 ALRM TERM CHLD], [HUP USR1 USR2 ALRM TERM CHLD], 8) = 0 readlink("/dev/fd", "/proc/self/fd", 4096) = 13 rt_sigprocmask(SIG_SETMASK, [HUP USR1 USR2 ALRM TERM CHLD], NULL, 8) = 0 lstat("/proc", {st_mode=S_IFDIR|0555, st_size=0, ...}) = 0 lstat("/proc/self", {st_mode=S_IFLNK|0777, st_size=0, ...}) = 0 rt_sigprocmask(SIG_BLOCK, [HUP USR1 USR2 ALRM TERM CHLD], [HUP USR1 USR2 ALRM TERM CHLD], 8) = 0 readlink("/proc/self", "6724", 4096) = 4 rt_sigprocmask(SIG_SETMASK, [HUP USR1 USR2 ALRM TERM CHLD], NULL, 8) = 0 lstat("/proc/6724", {st_mode=S_IFDIR|0555, st_size=0, ...}) = 0 lstat("/proc/6724/fd", {st_mode=S_IFDIR|0500, st_size=0, ...}) = 0 lstat("/proc/6724/fd/63", {st_mode=S_IFLNK|0500, st_size=64, ...}) = 0 rt_sigprocmask(SIG_BLOCK, [HUP USR1 USR2 ALRM TERM CHLD], [HUP USR1 USR2 ALRM TERM CHLD], 8) = 0 readlink("/proc/6724/fd/63", "pipe:[21346885]", 4096) = 15 rt_sigprocmask(SIG_SETMASK, [HUP USR1 USR2 ALRM TERM CHLD], NULL, 8) = 0 lstat("/proc/6724/fd/pipe:[21346885]", 0x7ffe0f16e040) = -1 ENOENT (No such file or directory) newfstatat(AT_FDCWD, "/proc/6724/fd/pipe:[21346885]", 0x7ffe0f16e080, 0) = -1 ENOENT (No such file or directory) openat(AT_FDCWD, "/proc/6724/fd/pipe:[21346885]", O_RDONLY) = -1 ENOENT (No such file or directory) 84668 1 sam 2019-08-15 05:28:10 +0000 NOTE: it is pipe and socket fd's that fail to open under linux because they appear to be dangling symlinks, but the kernel successfully opens them anyway 84672 2 randy.macleod 2019-08-15 14:49:28 +0000 Seebs, should this work under pseudo? 84687 3 seebs 2019-08-15 15:44:20 +0000 This looks to be the same underlying issue as 13288. *** This bug has been marked as a duplicate of bug 13288 ***