[arch-general] Strange issue

[Neven Sajko]

Hello,

I used makepkg to build a package from /tmp. The package was then put
to the designated directory and a symlink to pwd. When I try to install
it with pacman -U /tmp/symlink-to-package, I get an error (permission
denied) which I don't get when invoking pacman -U directly with the
name of the file (not with the symbolic link). See, like this:


[root at lnv64 tmp]# pacman -U /tmp/lomoco-1.0-9-x86_64.pkg.tar
loading packages...
error: '/tmp/lomoco-1.0-9-x86_64.pkg.tar': permission denied
[root at lnv64 tmp]# ls -l /tmp/lomoco-1.0-9-x86_64.pkg.tar
lrwxrwxrwx 1 nsajko nsajko 55 Dec  9 17:33
/tmp/lomoco-1.0-9-x86_64.pkg.tar ->
/home/nsajko/debug-packages/lomoco-1.0-9-x86_64.pkg.tar
[root at lnv64 tmp]# pacman -U
/home/nsajko/debug-packages/lomoco-1.0-9-x86_64.pkg.tar
loading packages...
warning: lomoco-1.0-9 is up to date -- reinstalling
resolving dependencies...
looking for inter-conflicts...

Packages (1): lomoco-1.0-9

Total Installed Size:   0.19 MiB
Net Upgrade Size:       0.00 MiB

:: Proceed with installation? [Y/n] n
# I ran strace to see what really happens:
[root at lnv64 tmp]# strace pacman -U /tmp/lomoco-1.0-9-x86_64.pkg.tar
# ...
# Here comes the part that could be relevant:
write(1, "loading packages...\n", 20loading packages...
)   = 20
access("/tmp/lomoco-1.0-9-x86_64.pkg.tar.sig", R_OK) = -1 ENOENT (No
such file or directory)
access("/tmp/lomoco-1.0-9-x86_64.pkg.tar", R_OK) = -1 EACCES (Permission denied)
open("/usr/share/locale/en_US.UTF-8/LC_MESSAGES/libalpm.mo", O_RDONLY)
= -1 ENOENT (No such file or directory)
open("/usr/share/locale/en_US.utf8/LC_MESSAGES/libalpm.mo", O_RDONLY)
= -1 ENOENT (No such file or directory)
open("/usr/share/locale/en_US/LC_MESSAGES/libalpm.mo", O_RDONLY) = -1
ENOENT (No such file or directory)
open("/usr/share/locale/en.UTF-8/LC_MESSAGES/libalpm.mo", O_RDONLY) =
-1 ENOENT (No such file or directory)
open("/usr/share/locale/en.utf8/LC_MESSAGES/libalpm.mo", O_RDONLY) =
-1 ENOENT (No such file or directory)
open("/usr/share/locale/en/LC_MESSAGES/libalpm.mo", O_RDONLY) = -1
ENOENT (No such file or directory)
write(2, "\33[1;31merror: \33[0m", 18error: )  = 18
write(2, "'/tmp/lomoco-1.0-9-x86_64.pkg.ta"...,
54'/tmp/lomoco-1.0-9-x86_64.pkg.tar': permission denied
) = 54
close(4)                                = 0
munmap(0x7f6e2c980000, 4096)            = 0
unlink("/var/lib/pacman/db.lck")        = 0
close(3)                                = 0
munmap(0x7f6e2c981000, 4096)            = 0
exit_group(1)                           = ?
+++ exited with 1 +++


So from this line:
access("/tmp/lomoco-1.0-9-x86_64.pkg.tar", R_OK) = -1 EACCES (Permission denied)
we see that the kernel call access() reports that root doesn't have
read access to a 777-permissible file?!
Maybe it matters that it's on tmpfs and/or a symlink?