diff mbox

[nfsometer,2/2] trace.py: Add some more error handling to probe_mounts()

Message ID 1456174931-61514-2-git-send-email-smayhew@redhat.com (mailing list archive)
State New, archived
Headers show

Commit Message

Scott Mayhew Feb. 22, 2016, 9:02 p.m. UTC
An nfsometer run can fail very early into the process due to things like
directory permissions, kerberos creds, and root squashing.  Try to give
the user some idea why the failure occurred instead of dumping a
backtrace.

Signed-off-by: Scott Mayhew <smayhew@redhat.com>
---
 nfsometerlib/trace.py | 85 ++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 84 insertions(+), 1 deletion(-)

Comments

Weston Andros Adamson March 2, 2016, 6:40 p.m. UTC | #1
These look good, thanks!

I’ll merge and cut a new release soon.

-dros



> On Feb 22, 2016, at 4:02 PM, Scott Mayhew <smayhew@redhat.com> wrote:
> 
> An nfsometer run can fail very early into the process due to things like
> directory permissions, kerberos creds, and root squashing.  Try to give
> the user some idea why the failure occurred instead of dumping a
> backtrace.
> 
> Signed-off-by: Scott Mayhew <smayhew@redhat.com>
> ---
> nfsometerlib/trace.py | 85 ++++++++++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 84 insertions(+), 1 deletion(-)
> 
> diff --git a/nfsometerlib/trace.py b/nfsometerlib/trace.py
> index cd1d3c3..0ab9f85 100644
> --- a/nfsometerlib/trace.py
> +++ b/nfsometerlib/trace.py
> @@ -20,6 +20,7 @@ import multiprocessing
> import signal
> import random
> import atexit
> +import pwd
> 
> from cmd import *
> from config import *
> @@ -517,6 +518,77 @@ def probe_detect(probe_trace_dir, mountopt):
> 
>     return detect
> 
> +def _is_auth_gss():
> +    lines = [ x.strip() for x in file('/proc/self/mountstats') ]
> +    mounted_on = ' mounted on %s with ' % MOUNTDIR
> +    start = -1
> +    end = -1
> +
> +    for i, line in enumerate(lines):
> +        if line.find(mounted_on) >= 0:
> +            assert start == -1
> +            start = i
> +        elif start >= 0 and line.startswith('device '):
> +            assert end == -1
> +            end = i
> +
> +    if end < 0:
> +        end = len(lines)
> +
> +    if start >= 0:
> +        lines = lines[start:end]
> +    else:
> +        return False
> +
> +    for line in lines:
> +        if line.startswith('sec:'):
> +            label, data = line.split(':')
> +            data = data.strip()
> +            if data.startswith('flavor=6'):
> +                return True
> +    return False
> +
> +def _has_creds():
> +    return os.stat(os.path.join(RUNNING_TRACE_DIR,
> +                                'klist_user.start')).st_size != 1
> +
> +def _has_tkt(server):
> +    princ = re.compile('nfs/' + server + '\S+$')
> +    lines = [ x.strip() for x in file(os.path.join(RUNNING_TRACE_DIR,
> +                                                   'klist_user.start')) ]
> +    for i, line in enumerate(lines):
> +        if re.search(princ, line):
> +            return True
> +    return False
> +
> +def _eperm_helper(opts):
> +    server, path = opts.serverpath.split(':')
> +    if _is_auth_gss():
> +        if _has_creds():
> +            if _has_tkt(server):
> +                info = str.format(
> +                    ' Check {:s} on {:s} and ensure user {:s} has the correct'
> +                    ' permission.', path, server,
> +                    pwd.getpwuid(os.getuid())[0])
> +            else:
> +                info = str.format(
> +                    ' No nfs service ticket for {:s} in user {:s}\'s'
> +                    ' credential cache.', server,
> +                    pwd.getpwuid(os.getuid())[0])
> +        else:
> +            info = str.format(
> +                ' User {:s} has no kerberos credentials.',
> +                pwd.getpwuid(os.getuid())[0])
> +    elif os.getuid() == 0:
> +        info = str.format(
> +            ' Check for root squashing in the export options for {:s} on'
> +            ' {:s}.', path, server)
> +    else:
> +       info = str.format(
> +            ' Check {:s} on {:s} and ensure user {:s} has the correct'
> +            ' permission.', path, server, pwd.getpwuid(os.getuid())[0])
> +    return info
> +
> #
> # public api commands
> #
> @@ -746,7 +818,18 @@ def probe_mounts(opts):
>         start(m, opts.serverpath, '__nfsometer-probe', [], [], is_probe=True)
>         fpath = os.path.join(RUNROOT, '__nfsometer-probe')
> 
> -        cmd('mkdir -p "%s"' % RUNROOT)
> +        try:
> +            cmd('mkdir -p "%s"' % RUNROOT)
> +        except CmdErrorCode, e:
> +            msg = str.format('"mkdir -p {:s}" failed.', RUNROOT)
> +            # try to hint why it failed
> +            if e.code == errno.EPERM:
> +                msg += _eperm_helper(opts)
> +            else:
> +                msg += e.errstr
> +            warn(msg)
> +            # and bail out right now
> +            sys.exit(1)
> 
>         f = file(fpath, 'w+')
>         f.write('nfsometer probe to determine server features: %s' % m)
> -- 
> 2.4.3
> 
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diff mbox

Patch

diff --git a/nfsometerlib/trace.py b/nfsometerlib/trace.py
index cd1d3c3..0ab9f85 100644
--- a/nfsometerlib/trace.py
+++ b/nfsometerlib/trace.py
@@ -20,6 +20,7 @@  import multiprocessing
 import signal
 import random
 import atexit
+import pwd
 
 from cmd import *
 from config import *
@@ -517,6 +518,77 @@  def probe_detect(probe_trace_dir, mountopt):
 
     return detect
 
+def _is_auth_gss():
+    lines = [ x.strip() for x in file('/proc/self/mountstats') ]
+    mounted_on = ' mounted on %s with ' % MOUNTDIR
+    start = -1
+    end = -1
+
+    for i, line in enumerate(lines):
+        if line.find(mounted_on) >= 0:
+            assert start == -1
+            start = i
+        elif start >= 0 and line.startswith('device '):
+            assert end == -1
+            end = i
+
+    if end < 0:
+        end = len(lines)
+
+    if start >= 0:
+        lines = lines[start:end]
+    else:
+        return False
+
+    for line in lines:
+        if line.startswith('sec:'):
+            label, data = line.split(':')
+            data = data.strip()
+            if data.startswith('flavor=6'):
+                return True
+    return False
+
+def _has_creds():
+    return os.stat(os.path.join(RUNNING_TRACE_DIR,
+                                'klist_user.start')).st_size != 1
+
+def _has_tkt(server):
+    princ = re.compile('nfs/' + server + '\S+$')
+    lines = [ x.strip() for x in file(os.path.join(RUNNING_TRACE_DIR,
+                                                   'klist_user.start')) ]
+    for i, line in enumerate(lines):
+        if re.search(princ, line):
+            return True
+    return False
+
+def _eperm_helper(opts):
+    server, path = opts.serverpath.split(':')
+    if _is_auth_gss():
+        if _has_creds():
+            if _has_tkt(server):
+                info = str.format(
+                    ' Check {:s} on {:s} and ensure user {:s} has the correct'
+                    ' permission.', path, server,
+                    pwd.getpwuid(os.getuid())[0])
+            else:
+                info = str.format(
+                    ' No nfs service ticket for {:s} in user {:s}\'s'
+                    ' credential cache.', server,
+                    pwd.getpwuid(os.getuid())[0])
+        else:
+            info = str.format(
+                ' User {:s} has no kerberos credentials.',
+                pwd.getpwuid(os.getuid())[0])
+    elif os.getuid() == 0:
+        info = str.format(
+            ' Check for root squashing in the export options for {:s} on'
+            ' {:s}.', path, server)
+    else:
+       info = str.format(
+            ' Check {:s} on {:s} and ensure user {:s} has the correct'
+            ' permission.', path, server, pwd.getpwuid(os.getuid())[0])
+    return info
+
 #
 # public api commands
 #
@@ -746,7 +818,18 @@  def probe_mounts(opts):
         start(m, opts.serverpath, '__nfsometer-probe', [], [], is_probe=True)
         fpath = os.path.join(RUNROOT, '__nfsometer-probe')
 
-        cmd('mkdir -p "%s"' % RUNROOT)
+        try:
+            cmd('mkdir -p "%s"' % RUNROOT)
+        except CmdErrorCode, e:
+            msg = str.format('"mkdir -p {:s}" failed.', RUNROOT)
+            # try to hint why it failed
+            if e.code == errno.EPERM:
+                msg += _eperm_helper(opts)
+            else:
+                msg += e.errstr
+            warn(msg)
+            # and bail out right now
+            sys.exit(1)
 
         f = file(fpath, 'w+')
         f.write('nfsometer probe to determine server features: %s' % m)