Re: No subshell ifnot root, delayed start with no internet connection

[Joerg Thuemmler <listen vordruckleitverlag de>]

Am 20.12.2016 um 11:45 schrieb Yury V. Zaytsev:
> On Tue, 20 Dec 2016, Joerg Thuemmler wrote:
>
> > thx. Do you know, how mc detects the shell?
>
> https://github.com/MidnightCommander/mc/blob/0cc22928afbc6e23eb0fa5c85fd95518d8151edc/lib/shell.c
>
>
> > It's in both cases (root and user) classical login with bash, never
> > manipulated there anything...
>
> I seriously doubt it, because otherwise it would have worked out of the
> box. A good test is to create a brand new fresh user, log in as this new
> user and start mc. If it works, then it means that you've botched your
> user profile. If it doesn't work, maybe you've botched system profile.

Hi,

don't think it's kind of this. No change for a brand new user.
I strace'd the mc running under root and user. Found a classic rights 
problem:

at users side:
===============
statfs("/dev/pts", {f_type="DEVPTS_SUPER_MAGIC", f_bsize=4096, 
f_blocks=0, f_bfree=0, f_bavail=0, f_files=0, f_ffree=0, f_fsid={0, 0},
ioctl(4, SNDCTL_TMR_TIMEBASE or SNDRV_TIMER_IOCTL_NEXT_DEVICE or TCGETS, 
{B38400 opost isig icanon echo ...}) = 0
ioctl(4, TIOCGPTN, [1])                 = 0
stat("/dev/pts/1", {st_mode=S_IFCHR|0600, st_rdev=makedev(136, 1), ...}) = 0
getuid()                                = 26
socket(PF_FILE, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0) = 5
connect(5, {sa_family=AF_FILE, sun_path="/var/run/nscd/socket"}, 110) = 
-1 ENOENT (No such file or directory)
close(5)                                = 0
socket(PF_FILE, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0) = 5
connect(5, {sa_family=AF_FILE, sun_path="/var/run/nscd/socket"}, 110) = 
-1 ENOENT (No such file or directory)
close(5)                                = 0
open("/etc/group", O_RDONLY|O_CLOEXEC)  = 5
lseek(5, 0, SEEK_CUR)                   = 0
fstat(5, {st_mode=S_IFREG|0644, st_size=669, ...}) = 0
mmap(NULL, 669, PROT_READ, MAP_SHARED, 5, 0) = 0x7f8a243b1000
lseek(5, 669, SEEK_SET)                 = 669
munmap(0x7f8a243b1000, 669)             = 0
close(5)
chown("/dev/pts/1", 26, 5)              = -1 EPERM (Operation not permitted)
close(4)                                = 0
write(2, "Cannot open master side of pty: "..., 69) = 69
write(1, "\33[?1001s\33[?1002h\33[?1006h", 24) = 24
write(1, "\33[?2004h", 8)               = 8

the last lines on root's side
=============================
open("/etc/group", O_RDONLY|O_CLOEXEC)  = 5
lseek(5, 0, SEEK_CUR)                   = 0
fstat(5, {st_mode=S_IFREG|0644, st_size=669, ...}) = 0
mmap(NULL, 669, PROT_READ, MAP_SHARED, 5, 0) = 0x7facc5f95000
lseek(5, 669, SEEK_SET)                 = 669
munmap(0x7facc5f95000, 669)             = 0
close(5)                                = 0
chown("/dev/pts/1", 0, 5)               = 0
chmod("/dev/pts/1", 0620)               = 0
ioctl(4, TIOCSPTLCK, [0])               = 0
ioctl(4, SNDCTL_TMR_TIMEBASE or SNDRV_TIMER_IOCTL_NEXT_DEVICE or TCGETS, 
{B38400 opost isig icanon echo ...}) = 0
ioctl(4, TIOCGPTN, [1])                 = 0
stat("/dev/pts/1", {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 1), ...}) = 0
open("/dev/pts/1", O_RDWR)              = 5

seems to me that's normal a user usually should not be allowed to chown 
or chmod a /dev/pts/... but I don't have a clue, why that's working on 
other people's machines.

Redirecting stderr to a file shows exactly the EPERM thats in the strace 
lines of user.

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