robseb / linuxbootimagefilegenerator

Python Script to automatically generate a bootable Image (.img) file with a specifiable partition table and Linux files (e.g. zImage, u-boot,...) for embedded Linux distributions

Robin Sebastian (rsyocto GmbH & Co. KG)

linuxbootimagefilegenerator's Issues

losetup failed to set up loop device: Resource temporarily unavailable

I though I'll share a problem which I ran into while using the LinuxBootImageFileGenerator.py. The workaround I implemented is attached in the code below.

Problem description and workaround

In function __createLoopbackDevice the error "losetup failed to set up loop device: Resource temporarily unavailable" gets thrown, resulting in Exception("Failed to get a loopback device")
I changed the __createLoopbackDevice to retry if it's fails to create dev loop, as the attached code below displays.

def __createLoopbackDevice(self, diagnosticOutput = True,size =0, offset_bytes = 0):
    self.__print(diagnosticOutput,'--> Create loopback device')
    # Calculate offset from sectors to byte
    retries = 0
    success = False
    while (not success):
        try:
            if offset_bytes != 0:
                loop_dev = self.__runCmdInShell(diagnosticOutput,
                    ["sudo","losetup", "--show", "-f", "-o "+str(offset_bytes),
                    "--sizelimit",str(size), self.__imageFilepath])
                success = True
            else:
                os.system('sudo losetup --show -f --sizelimit '+str(size)+' '+\
                            self.__imageFilepath)
                loop_dev = self.__runCmdInShell(diagnosticOutput,
                            ["sudo","losetup","--show", "-f",
                            "--sizelimit", str(size), self.__imageFilepath])
                success = True            
        except subprocess.CalledProcessError:
            retries += 1
            time.sleep(0.001)
            if retries > 1000:
                self.__unmountDeleteLoopbacks(diagnosticOutput)
                raise Exception("Failed to get a loopback device")
    # convert the loop device name as string
    loop_dev_str = str(loop_dev) 

Running on Ubuntu 18.04.5 LTS.