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Questions tagged [userspace]

109 questions
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Maintaing some sort of object between kernel and userspace program. And synchronizing data from both userspace and kernel in that object

I am looking for a mechanism to implement shared objects between kernel and userspace. Useless to say the type but it may probably be char * or char obj[array_size] or void *. The functionality should enable both the userspace program and kernel to…
user786
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can kernel identify which userapp got killed/closed, among few apps it is serving

I'm writing a linux kernel driver, which creates a char device file "/dev/my_file". Multiple userspace applications do open() of this file and use the ioctl cmd provided to register app specific data. IOCTL also provides for deregister cmd, which…
Sheetal T
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Making Kernel Module and registering it as pci device driver and network device driver and accessing the module's buffer using ioctl. Possible?

I like to make a kernel module. And inside it I like to register it as pci and network device driver. And using ioctle from user space to access the module's buffer(in pci and network driver) and getting buffer. The buffer contains packets received…
user786
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Is it possible to mmap the network-adapter's DMA region into userspace?

How do you find the DMA address of the network-adapter, then is it possible to mmap that address and then read and write to it?
Tyler Curtis Jowers
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Why is 64-bit Linux user space between the virtual addresses 55Fxxxxxxxxx and 7FFxxxxxxxxx? (only 45 bits)

(Tested on Linux 64 bits) If you watch the content of /proc//maps (being the process identifier of any process running in that moment in your system) you will see that the virtual space assigned to the process is between 555xxxxxxxxx and…
isma
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Why applications cannot access a hardware device directly ? Why we need to switch to kernel space in order to do this?

I wondered why we need to switch to kernel space when we want to access a hardware device. I understand that sometimes, for specific actions such as memory allocation, we need to make system calls in order to switch from user space to kernel space…
Andrei Deatcu
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php snippets user profile edit in wordpress

I created a snippet in WordPress with this shortcode post found here https://wabeo.fr/espace-membre-wordpress/. I was constrained to add the edit_user_form() to show form, but when I post some user profile modification with it, they are not…
delepelaire charles
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Is it possible to create a userspace networking stack with python?

Looking to create a project which implements a user-space networking stack, so that a user space application has access to the network cards, I've never done this before and I was wondering if it would possible to get this close to the hardware…
datasplice
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Little/big endian integer types in user space

I'm going to use struct solaris_x86_slice from linux kernel header in user space. Struct is defined as: struct solaris_x86_slice { __le16 s_tag; /* ID tag of partition */ __le16 s_flag; /* permission flags */ __le32 s_start; …
pevik
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write hard-codded to RAM at specific physical-address

I want write something in userspace program, for example: write the value 3 in the physical address 0xF7F4900(260MB) from the start address 0x0, while all kernel sits in the range 0-240MB. How can I do it? any idea please? Best regards. I thought to…
ninja
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How do I compile a userspace application for a particular Linux kernel?

I have a Linux kernel source. I am building Linux kernel image from that source. Now, I have a userspace application. How do I compile the userspace application for that particular Linux kernel source?
sal_guy
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Fatal error: net/sock.h: No such file or directory (Kernel - Userspace application communication) [C]

I am trying to develop a module to communicate between Kernel and Userspace application. I tried the answer provided in https://stackoverflow.com/a/25071310/4190159 The issue is I have the following code: #include #include…
Somdip Dey
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copy_to_user does not return expected data

I have a ioctl in my kernel driver and that needs to return some data upon read. When I read it back in userspace, it's not showing expected results. Userspace snippet: typedef struct abc_T { int size; int addr; int data[32]; }…
oak1208
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vfs_write kernel to user space file

I am trying to write a file in user space from keyboard interrupt module I am using vfs_write to write to file. static char *key_names_caps[] = { "-", "", "1", "2", "3", "4", "5", "6", "7", "8", "9", "0", "-", "=", "",…
anmol sandhu
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Calling default signal handler directly from new one

I have signal handler for a timer signal. This is part of a library, and I'd like to not make any assumptions about any other timer handlers the calling program already has enabled, so I'd like my handler to trigger only on my events, and call the…
HardcoreHenry
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