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You're reading from  Mastering Embedded Linux Programming - Third Edition

Product typeBook
Published inMay 2021
PublisherPackt
ISBN-139781789530384
Edition3rd Edition
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Authors (2):
Frank Vasquez
Frank Vasquez
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Frank Vasquez

Frank Vasquez is an independent software consultant specializing in consumer electronics. He has over a decade of experience designing and building embedded Linux systems. During that time, he has shipped numerous devices including a rackmount DSP audio server, a diver-held sonar camcorder, and a consumer IoT hotspot. Before his career as an embedded Linux engineer, Frank was a database kernel developer at IBM where he worked on DB2. He lives in Silicon Valley.
Read more about Frank Vasquez

Chris Simmonds
Chris Simmonds
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Chris Simmonds

Chris Simmonds is a software consultant and trainer living in southern England. He has almost two decades of experience in designing and building open-source embedded systems. He is the founder and chief consultant at 2net Ltd, which provides professional training and mentoring services in embedded Linux, Linux device drivers, and Android platform development. He has trained engineers at many of the biggest companies in the embedded world, including ARM, Qualcomm, Intel, Ericsson, and General Dynamics. He is a frequent presenter at open source and embedded conferences, including the Embedded Linux Conference and Embedded World.
Read more about Chris Simmonds

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A better way of managing device nodes

Creating device nodes statically with mknod is quite hard work and inflexible. There are other ways to create device nodes automatically on demand:

  • devtmpfs: This is a pseudo filesystem that you mount over /dev at boot time.
    The kernel populates it with device nodes for all the devices that the kernel currently knows about, and it creates nodes for new devices as they are detected at runtime. The nodes are owned by root and have default permissions of 0600. Some well-known device nodes, such as /dev/null and /dev/random, override the default to 0666. To see exactly how this is done, take a look at the Linux source file drivers/char/mem.c and see how struct memdev is initialized.
  • mdev: This is a BusyBox applet that is used to populate a directory with device nodes and to create new nodes as needed. There is a configuration file, /etc/mdev.conf, which contains rules for ownership and the mode of the nodes.
  • udev: This is the mainstream...
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Mastering Embedded Linux Programming - Third Edition
Published in: May 2021Publisher: PacktISBN-13: 9781789530384

Authors (2)

author image
Frank Vasquez

Frank Vasquez is an independent software consultant specializing in consumer electronics. He has over a decade of experience designing and building embedded Linux systems. During that time, he has shipped numerous devices including a rackmount DSP audio server, a diver-held sonar camcorder, and a consumer IoT hotspot. Before his career as an embedded Linux engineer, Frank was a database kernel developer at IBM where he worked on DB2. He lives in Silicon Valley.
Read more about Frank Vasquez

author image
Chris Simmonds

Chris Simmonds is a software consultant and trainer living in southern England. He has almost two decades of experience in designing and building open-source embedded systems. He is the founder and chief consultant at 2net Ltd, which provides professional training and mentoring services in embedded Linux, Linux device drivers, and Android platform development. He has trained engineers at many of the biggest companies in the embedded world, including ARM, Qualcomm, Intel, Ericsson, and General Dynamics. He is a frequent presenter at open source and embedded conferences, including the Embedded Linux Conference and Embedded World.
Read more about Chris Simmonds