Develop Reference

Python: Reading the usb string descriptor "SerialNumber" in Windows

I'm trying to get the vendorId, the productCode and the SerialNumber of a usb device using python.
Therefore I created the following script which runs quite well in a linux environment.
import sys
import usb
devs = usb.core.find(find_all=True)
nCount=0
for dev in devs:
for cfg in dev:
intf = usb.util.find_descriptor(cfg,bInterfaceClass=0x8)
if intf is not None:
nCount += 1
try:
sys.stdout.write("USB device " + usb.util.get_string(dev,dev.iProduct,None) + '\n')
except:
sys.stdout.write("USB device " + str(nCount) + '\n')
sys.stdout.write("------" + '\n')
sys.stdout.write("VendorId = " + hex(dev.idVendor) + '\n')
sys.stdout.write("ProductId = " + hex(dev.idProduct) + '\n')
if not dev.iSerialNumber == 0:
try:
sys.stdout.write("SerialNbr = " + usb.util.get_string(dev,dev.iSerialNumber ) + '\n')
except NotImplementedError:
sys.stdout.write("Sreial-Number not readable")
else:
sys.stdout.write("SerialNbr = none" + '\n')
sys.stdout.write('\n')
As soon as a start the script in windows, the script returns an error "NotImplementedError" when calling the function usb.util.get_string(dev,dev.iSerialNumber)
I found that there is a problem with the windows drivers and the libusb.
The solution wI0m heading to, does not allow to change system drivers with Zadig first. IIt must be callable without changing drivers first.
So my question is, if it's possible to get the serial number with python on a windows system without changing the drivers first.

How to resolve BrokenPipeError when using multiprocessing in Python

I am working on learning multiproccessing, and have had no issues until I encountered this one when working with queues. Essentially, the queue gets filled up, but then something seems to go wrong and it crashes.
I am running python 3.6.8 on Windows 10. multiprocessing has seemed to work when I was not using queues (I built a similar code snippet to the below without queues to learn).
import glob, multiprocessing, os
def appendFilesThreaded(inputDirectory, outputDirectory, inputFileType=".txt", outputFileName="appended_files.txt"):
files = glob.glob(inputDirectory+'*'+inputFileType)
fileQueue = multiprocessing.Queue()
for file in files:
fileQueue.put(file)
threadsToUse = max(1, multiprocessing.cpu_count()-1)
print("Using " + str(threadsToUse) + " worker threads.")
processes = []
for i in range(threadsToUse):
p = multiprocessing.Process(target=appendFilesWorker, args=(fileQueue,outputDirectory+"temp-" + str(i) + outputFileName))
processes.append(p)
p.start()
for process in processes:
process.join()
with open(outputDirectory + outputFileName, 'w') as outputFile:
for i in range(threadsToUse):
with open(outputDirectory+"temp-" + str(i) + outputFileName) as fileToAppend:
outputFile.write(fileToAppend.read())
os.remove(outputDirectory+"temp-" + str(i) + outputFileName)
print('Done')
def appendFilesWorker(fileQueue, outputFileNamePath):
with open(outputFileNamePath, 'w') as outputFile:
while not fileQueue.empty:
with open(fileQueue.get()) as fileToAppend:
outputFile.write(fileToAppend.read())
if __name__ == '__main__':
appendFilesThreaded(inputDir,outputDir)
I would expect this to successfully append files, but it crashes. It results in BrokenPipeError: [WinError 232] The pipe is being closed

Found the issue: calling queue.empty is incorrect. You need parentheses (e.g. queue.empty())
I'll leave my embarrassing mistake up in case it helps others :)

Python crashes when using call (ntdll.dll)

I have a script that combines around 1000 files by using an external program. It does so by copying the first file to combined.sym and then combining the this file with all other files, one by one. Code is as follows:
# gets all .sym files
symfiles = []
onlyfiles = [f for f in listdir(myPath) if isfile(join(myPath, f))]
for f in onlyfiles:
if '.sym' == splitext(f)[1]:
symfiles.append(f)
# copies one initial combined file (point to start from)
combinedFileName = "combined.sym"
copyfile(myPath + symfiles[0], myPath + combinedFileName)
for sym in symfiles:
print("processing " + str(sym))
cmdString = combinedFileName + " "
cmdString += sym
cmdString += " -a " + combinedFileName
finalCmdString = r'cmd.exe /C fuseFiles.bat "' + myPath + '" "' + cmdString + '"'
call(finalCmdString)
print("done")
The batchfile I'm calling looks like this, but that is not the issue:
#set PATH=\path\to\executable\;%PATH%
#cd %1
#FusingProgram "%2"
Now, when I run this script, it runs for like 15 Minutes before it just stops and returns to the CMD.
processing onefile.sym
processing anotherfile.sym
processing evenmorefiles.sym
processing yougetit.sym
C:\Users\test\>
As you can see, it misses the "done" print, and it didn't process all files. The combined.sym is created and expanded by the other .sym files
When checking the Windows events, I can see, that it logs python as crashed and lists ntdll.dll as faulty module(sorry for german log):
Name der fehlerhaften Anwendung: python.exe, Version: 0.0.0.0, Zeitstempel: 0x53787196
Name des fehlerhaften Moduls: ntdll.dll, Version: ****, Zeitstempel: 0x5b6db230
Ausnahmecode: 0xc0000005
Fehleroffset: 0x0002e2eb
ID des fehlerhaften Prozesses: 0x6224
Startzeit der fehlerhaften Anwendung: 0x01d454e0ff20377c
Pfad der fehlerhaften Anwendung: C:\pat\to\python\python.exe
Pfad des fehlerhaften Moduls: C:\WINDOWS\SysWOW64\ntdll.dll
Berichtskennung: 8b4254f0-c0d5-11e8-9a6f-901b0e5a6206
I've done some research and it seems like I'd have to resolve this by updating the ntdll.dll file, but my system is all up to date, so there is nothing I can do about that (except for downloading another version from some untrustworthy site, which I'm not gonna do)
All this being said, have you ever encountered a similar issue or is this just a stupid mistake I made?

Fabrics put() command with hyphens

I have an issue putting files to a server that contains hyphens ("-"), and I think that it may be because of how Linux is treating the file, but I am in no way sure. The script is scanning a folder for pictures/items, puts them in a list and then transferring all items to the server.
This is a part of the script:
def _transferContent(locale):
## Transferring images to server
now = datetime.datetime.now()
localImages = '/home/bcns/Pictures/upload/'
localList = os.listdir(localImages)
print("Found local items: ")
print(localList)
fname = "/tmp/backup_images_file_list"
f = open(fname, 'r')
remoteList = f.read()
remoteImageLocation = "/var/www/bcns-site/pics/photos/backup_" + locale + "-" + `now.year` + `now.month` + `now.day` + "/"
print("Server image location: " + remoteImageLocation)
## Checking local list against remote list (from the server)
for localItem in localList:
localItem_fullpath = localImages + localItem
if os.path.exists(localItem_fullpath):
if localItem in remoteList:
print("Already exists: " + localItem)
else:
put(localItem_fullpath, remoteImageLocation)
else:
print("File not found: " + localItem)
And this is the out put:
Directory created successfully
/tmp/bcns_deploy/backup_images_file_list
[<server>] download: /tmp/backup_images_file_list <- /tmp/bcns_deploy/backup_images_file_list
Warning: Local file /tmp/backup_images_file_list already exists and is being overwritten.
Found local items:
['darth-vader-mug.jpg', 'gun-dog-leash.jpg', 'think-safety-first-sign.jpg', 'hzmp.jpg', 'cy-happ-short-arms.gif', 'Hogwarts-Crest-Pumpkin.jpg']
Server image location: /var/www/bcns-site/pics/photos/backup_fujitsu-20131031/
[<server>] put: /home/bcns/Pictures/upload/darth-vader-mug.jpg -> /var/www/bcns-site/pics/photos/backup_fujitsu-20131031/
Fatal error: put() encountered an exception while uploading '/home/bcns/Pictures/upload/darth-vader-mug.jpg'
Underlying exception:
Failure
I have tried to remove the hyphons, and then the transfer works just fine.
Server runs Ubuntu 12.04 and client runs Debian 7.1 on ext3 disks.
Irritating error, but anyone out here that has a clue on what might make this error?

Dashes in command line options in Linux matter, but dashes in the middle of filenames are file.
Check file permissions -- it's possible that in transferring one file manually, the perms are set differently than if Fabric transfers.
I suggest using put() to transfer a directory at a time. This will help to make sure all the files (and permissions) are what they should be.
Example (untested):
def _transferContent(locale):
## Transferring images to server
now = datetime.datetime.now()
localImageDir = '/home/bcns/Pictures/upload/'
remoteImageDir = "/var/www/bcns-site/pics/photos/backup_" + locale + "-" + `now.year` + `now.month` + `now.day` + "/"
print("Server image location: " + remoteImageDir)
put( localImagesDir, remoteImageDir)

trying to append a jar file in python unsuccessfully

I'm trying to append a file to a .jar file using python but i keep hitting an error which states could not find main class: jar.
def add_to_jar():
jarfile = "jarfile.jar"
skin_image= Skin_Name.text() #this stores the full path to to file to be appended
cmd = 'java jar uf ' + jarfile + " " + skin_image
proc = subprocess.Popen(cmd, shell=True)
any help appreciated

That sounds like an issue with the java interpretter's class path, which is typically defined as an environment variable. Do you need to run jar through java? Often jar is installed as a binary command by itself. Does it work if you just change it to
cmd = 'jar uf ' + jarfile + " " + skin_image