/ # /var/lib/snapd/hostfs/usr/bin/strace /var/lib/snapd/hostfs/sbin/ip netns list
execve("/var/lib/snapd/hostfs/sbin/ip", ["/var/lib/snapd/hostfs/sbin/ip", "netns", "list"], [/* 27 vars */]) = 0
brk(NULL) = 0x2418000
access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fd65623f000
access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=31854, ...}) = 0
mmap(NULL, 31854, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7fd656237000
close(3) = 0
access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libdl.so.2", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\240\r\0\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0644, st_size=14608, ...}) = 0
mmap(NULL, 2109680, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fd655e18000
mprotect(0x7fd655e1b000, 2093056, PROT_NONE) = 0
mmap(0x7fd65601a000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x2000) = 0x7fd65601a000
close(3) = 0
access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1864888, ...}) = 0
mmap(NULL, 3967488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fd655a4f000
mprotect(0x7fd655c0f000, 2093056, PROT_NONE) = 0
mmap(0x7fd655e0e000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1bf000) = 0x7fd655e0e000
mmap(0x7fd655e14000, 14848, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7fd655e14000
close(3) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fd656236000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fd656235000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fd656234000
arch_prctl(ARCH_SET_FS, 0x7fd656235700) = 0
mprotect(0x7fd655e0e000, 16384, PROT_READ) = 0
mprotect(0x7fd65601a000, 4096, PROT_READ) = 0
mprotect(0x656000, 4096, PROT_READ) = 0
mprotect(0x7fd656241000, 4096, PROT_READ) = 0
munmap(0x7fd656237000, 31854) = 0
socket(PF_NETLINK, SOCK_RAW|SOCK_CLOEXEC, NETLINK_ROUTE) = 3
setsockopt(3, SOL_SOCKET, SO_SNDBUF, [32768], 4) = 0
setsockopt(3, SOL_SOCKET, SO_RCVBUF, [1048576], 4) = 0
bind(3, {sa_family=AF_NETLINK, pid=0, groups=00000000}, 12) = 0
getsockname(3, {sa_family=AF_NETLINK, pid=8121, groups=00000000}, [12]) = 0
open("/proc/self/ns/net", O_RDONLY) = -1 EACCES (Permission denied)
dup(2) = 4
fcntl(4, F_GETFL) = 0x8002 (flags O_RDWR|O_LARGEFILE)
brk(NULL) = 0x2418000
brk(0x2439000) = 0x2439000
fstat(4, 0x7fff7fe39650) = -1 EACCES (Permission denied)
write(4, "open(\"/proc/self/ns/net\"): Permi"..., 45open("/proc/self/ns/net"): Permission denied
) = 45
close(4) = 0
exit_group(1) = ?
+++ exited with 1 +++
/ #
/ # python3
Python 3.5.2 (default, Jul 5 2016, 12:43:10)
[GCC 5.4.0 20160609] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import os
>>> os.open("/proc/self/ns/net", os.O_RDONLY)
3
>>>