I developed a python file copyer in a Docker using smbclient library.
I’m trying to read a csv file existing on my TrueNas to hash a md5 from it :
with smbclient.open_file(fullname_csv, mode="rb") as remote_file:
remote_content = remote_file.read()
samba_md5 = utils.sign_md5_base64_from_file(remote_content)
Thing is, my read() gets stuck or has concurrent access issues :
ERROR:file_sender:Failed sending to Samba Server : \\my-server.org\D\poub\MV\Quids. Erreur : [Error 1] [NtStatus 0xc0000043] The process cannot access the file because it is being used by another process: '\\my-nas.org\nfs_smb\my-smb.org\D\poub\MV\Quids\test_NH.csv'
ERROR:main:Une erreur est survenue lors du traitement de la requête.
Traceback (most recent call last):
File "/app/file_sender.py", line 61, in send_file
with smbclient.open_file(fullname_csv, mode="rb") as remote_file:
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/smbclient/_os.py", line 533, in open_file
raw_fd.open()
File "/usr/local/lib/python3.12/site-packages/smbclient/_io.py", line 463, in open
transaction.commit()
File "/usr/local/lib/python3.12/site-packages/smbclient/_io.py", line 349, in commit
raise failures[0]
smbprotocol.exceptions.SMBOSError: [Error 1] [NtStatus 0xc0000043] The process cannot access the file because it is being used by another process: '\\my-nas.org\nfs_smb\my-samba-server\D\poub\MV\Quids\test_NH.csv'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/app/main.py", line 132, in download_file
file_sender.send_file(value)
File "/app/file_sender.py", line 99, in send_file
raise RuntimeError(f"Erreur d'envoi Samba : {str(e)}")
RuntimeError: Erreur d'envoi Samba : [Error 1] [NtStatus 0xc0000043] The process cannot access the file because it is being used by another process: '\\my-nas-server.org\nfs_smb\my-samba-server\D\poub\MV\Quids\test_NH.csv'
My NAS has no issues receiving my write / stat / makedirs requests from smbclient.
I did many tests and am frying my brain over this.
Some causes i’m exploring :
trying to hash and read in the same with : tested without the hashing, as the example from the library github repo, doesn’t work
NAS server configuration is incorrectly sending SMB close requests : i don’t want to tcpdump smb server requests…please, mercy.
my smbclient is not using the right SMB protocol : i think the library is intelligent enough to do what’s right.
i’m trying to read a CSV file and it does not have an EOF character : untested - i would have to manually put EOF in a csv to see what happens, or copy a txt file
This is a bit weird, the read calls are sending SMB2 READ requests [1] with a newer offset. With the read call it is meant to continue to do this until the whole file is read. I have no idea why your example is hanging but you should look into the requests sent to see what offset/length it is on and whether it is exceeding the length of the file or not. This sounds more like a server implementation detail where it is not sending the READ response once the end of the file is reached.
It’s a common problem with pipes as a pipe won’t have an EOF until the server end is closed but the EOF for a file is simply once the file has no more data.
I personally use the python SMB client distributed by the samba project (which is a wrapper around libsmbclient the Samba userspace SMB client library used by many other projects).
/*
Template code to use this library:
-------------------------
from samba.samba3 import libsmb_samba_internal as libsmb
from samba.samba3 import param as s3param
from samba import (credentials,NTSTATUSError)
lp = s3param.get_context()
lp.load("/etc/samba/smb.conf");
creds = credentials.Credentials()
creds.guess(lp)
creds.set_username("administrator")
creds.set_password("1234")
c = libsmb.Conn("127.0.0.1",
"tmp",
lp,
creds,
multi_threaded=True)
-------------------------
*/
For upstream Samba python SMB client.
Another trivial example:
from samba.samba3 import libsmb_samba_internal as libsmb
from samba.dcerpc import security
from samba.samba3 import param as s3param
from samba import credentials
from samba import NTSTATUSError
LP_CTX = s3param.get_context()
LP_CTX.load_default()
cred = credentials.Credentials()
cred.guess(LP_CTX)
cred.set_username('smbuser')
cred.set_password('Cats')
HOST = '127.0.0.1'
SHARE = 'SHARE'
FILE_NAME = 'canary'
conn = libsmb.Conn(HOST, SHARE, LP_CTX, cred, force_smb1=False)
fhdl = conn.create(
FILE_NAME,
CreateDisposition=1,
DesiredAccess=security.SEC_GENERIC_READ,
)
print(conn.read(fhdl, 0, 2000))
