diff options
author | Lennart Poettering <lennart@poettering.net> | 2016-11-24 17:42:19 +0100 |
---|---|---|
committer | Sven Eden <yamakuzure@gmx.net> | 2017-07-17 17:58:35 +0200 |
commit | ed280b715fc427a925d418adc8ec0cfaa395f526 (patch) | |
tree | 60b6fc65e6779ece5f5dbda8d6bac18081e483a8 /src/basic/virt.c | |
parent | d3c92fb53bb92ec00914aa4b51bd21d88e887128 (diff) |
util: Fine tune running_in_chroot() a bit
Let's be a bit more careful when detecting chroot() environments, so that we
can discern them from namespaced environments.
Previously this would simply check if the root directory of PID 1 matches our
own root directory. With this commit, we also check whether the namespaces of
PID 1 and ourselves are the same. If not we assume we are running inside of a
namespaced environment instead of a chroot() environment.
This has the benefit that systemctl (which uses running_in_chroot()) will work
as usual when invoked in a namespaced service.
Diffstat (limited to 'src/basic/virt.c')
-rw-r--r-- | src/basic/virt.c | 24 |
1 files changed, 19 insertions, 5 deletions
diff --git a/src/basic/virt.c b/src/basic/virt.c index c935c534b..3957a5a8c 100644 --- a/src/basic/virt.c +++ b/src/basic/virt.c @@ -559,18 +559,32 @@ int running_in_userns(void) { #endif // 0 int running_in_chroot(void) { - int ret; + _cleanup_free_ char *self_mnt = NULL, *pid1_mnt = NULL; + int r; + + /* Try to detect whether we are running in a chroot() environment. Specifically, check whether we have a + * different root directory than PID 1, even though we live in the same mount namespace as it. */ #if 0 /// elogind does not allow to ignore chroots, we are never init! if (getenv_bool("SYSTEMD_IGNORE_CHROOT") > 0) return 0; #endif // 0 - ret = files_same("/proc/1/root", "/"); - if (ret < 0) - return ret; + r = files_same("/proc/1/root", "/"); + if (r < 0) + return r; + if (r > 0) + return 0; + + r = readlink_malloc("/proc/self/ns/mnt", &self_mnt); + if (r < 0) + return r; + + r = readlink_malloc("/proc/1/ns/mnt", &pid1_mnt); + if (r < 0) + return r; - return ret == 0; + return streq(self_mnt, pid1_mnt); /* Only if we live in the same namespace! */ } static const char *const virtualization_table[_VIRTUALIZATION_MAX] = { |