[PATCH 0/5] Linux: lchmod and AT_SYMLINK_NOFOLLOW support for fchmodat

[Andreas Schwab]

On Jan 22 2020, Florian Weimer wrote:

> These patches use the O_PATH hack to implement a fairly close
> approximation of fchmodat in AT_SYMLINK_NOFOLLOW mode.

This means that cp -a now fails when /proc is not mounted.

<https://build.opensuse.org/package/live_build_log/home:Andreas_Schwab:glibc:rebuild/installation-images:openSUSE/f/x86_64>

running "cp -a /var/lib/ca-certificates var/lib"
cp: setting permissions for 'var/lib/ca-certificates/pem': Operation not supported
cp: setting permissions for 'var/lib/ca-certificates/openssl': Operation not supported

newfstatat(AT_FDCWD, "/var/lib/ca-certificates/pem", {st_mode=S_IFDIR|0500, st_size=4096, ...}, AT_SYMLINK_NOFOLLOW) = 0
mkdir("var/lib/ca-certificates/pem", 0500) = 0
lstat("var/lib/ca-certificates/pem", {st_mode=S_IFDIR|0500, st_size=4096, ...}) = 0
openat(AT_FDCWD, "var/lib/ca-certificates/pem", O_RDONLY|O_NOFOLLOW|O_CLOEXEC|O_PATH) = 3
newfstatat(3, "", {st_mode=S_IFDIR|0500, st_size=4096, ...}, AT_EMPTY_PATH) = 0
chmod("/proc/self/fd/3", 040700)        = -1 ENOENT (No such file or directory)
close(3)                                = 0
write(2, "cp: ", 4)                     = 4
write(2, "setting permissions for 'var/lib"..., 53) = 53
write(2, ": Operation not supported", 25) = 25
write(2, "\n", 1)                       = 1

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
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