Kernel :: Syscall Accessing User Space?
Feb 22, 2010If the calling process passes me the virtual address of an its array for example, how can I access it without using copy_from_user?
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General :: Division Of Logical Memory Space In To User Space And Kernel Space
Jan 4, 2010Logical Memory Space of 4GB is divided in to 3GB User Space and 1GB Kernel Space. Always. Correct?
1. How can we change it? (just changing value of PAGE_OFFSET is okay?)
2. If system have only 256MB of memory (embedded system) and suppose Kernel Modules eat away all the memory during boot. User space will be left will no memory. Is this case possible?
Programming :: Passing Data Between Kernel Space To User Space In Asynchronous Way
Dec 13, 2010I am developing a I2C CDROM client driver. The CDROM firmware supports TOC information read through a I2C command. It sends the TOC information in burst ( Interrupts a GPIO pin when it is ready ) and my CPU does a I2C read to read the TOC. When the CDROM firmware finishes sending the last data burst , it informs my CPU that it is done with the TOC, by a flag in the last data burst. I would like to know, which is the most efficinet way I can send these TOC information to userspace?
View 4 Replies View RelatedGeneral :: Calling User Space Callback Function From Kernel Space?
Sep 22, 2009I am writing device driver in which i have to call callback function from kernel space, which are saving my data. But the callback functions are in userspace. While accessing them i am getting segmentation fault.
View 1 Replies View RelatedProgramming :: Function In Kernel Space Called Form User Space
Jul 7, 2009I wanna write a file in kernel space but from my searching I can to know that instead of writeing file in kernel space ,I can write data to user space by copy_to_user space.
But link is missing ...I dont know how will my user space will access kernel space means my function in kernel space which will do copy_to_user /....How my user space function will call my kernel level function ..
Can any one of you provide me with some example file which are doing this .I know every char driver is using it ...but i could not trace back how user level function is accessing it ...i m confused between user space and kernel space.
Programming :: Call Socket Prog Code Written In User Space From Kernel Space?
Jul 14, 2009How to use execv from kernel space to call a user space program writtenfor socket prog.
I tried to write code for socket in kernel but its not working.
Socket code in kernel is also needed.
Programming :: Signal From Kernel Space To User Space?
Jul 21, 2011I have the following requirement in my module. The driver gets some data from the external device. After getting 1MB of data it has to send it to the user space application. What is the best thing to implement for this in driver.? Is it ok to implement like, after getting data, the driver will send a signal to the user space application. Then the user space application sends an ioctl to read the data. Is there any alternate, that the driver directly sends the data without the user space application asks for it.?
View 4 Replies View RelatedGeneral :: Measure Kernel Space Time And User Space Time?
Nov 28, 2010measure kernel space time and user space time?
View 1 Replies View RelatedGeneral :: Kernel Module Run In It / User Space?
Oct 25, 2010I'm pretty new to this whole (micro)kernel architecture story.
Im wondering if a kernel module is running in kernel or in user space?
Is a driver running as kernel module slower than a driver build into kernel?
If so, are there some current articles, benchmarks?
General :: Difference Between User And Kernel Space?
Jul 12, 2010what difference between user and kernel space.
View 2 Replies View RelatedGeneral :: Shared Buffer Between User And Kernel Space
May 3, 2010I need a shared buffer between user and kernel space. I read that one way is to allocated buffer in kernel and then call mmap from the user space. I searched for an example but couldn't find something useful. If you know, could you please send me any links or sample code that does this..
View 1 Replies View RelatedProgramming :: Make A (user Space )process Pre Emptive / In 2.6 Kernel?
Dec 10, 2008I am writing a program which i dont want the kernel scheduler to preempt before certain time duration. I am using the system call sched_get_priority_max to set the maximum priority. However it is not producing results.
View 3 Replies View RelatedProgramming :: Accessing SPI From Kernel Level And User Level
Jan 6, 2009I want to know what are the advantages and disadvantages for accessing spi(serial peripheral inerface )from kernel level and user level. like methods of doing it, speed ,memeory utilization etc
View 1 Replies View RelatedGeneral :: Virtual Space Seen By Each New Process In User Space?
Jun 21, 2010In a 32-bit system, max memory addressable is 4GB. Now Linux kernel does memory mapping division of 1GB for kernel address space and 3GB for user address space. That means 4GB of virtual address space is divided between kernel (1GB) and user (3GB).
Q1. All virtual mapping utilizes the available physical RAM without any division? I mean to say that if RAM is 512MB then a page in kernel space can lie any where RAM (leave aside old PCI dma accesses)? (How this fits to fact that kernel memory is non-pageble)
Q2. If a process is created in user space, it has visibility 4GB address space or 3GB address space?
Ubuntu :: Accessing Free Space On Cloned Drive?
Jan 7, 2010I have an MSI Wind with Windows, Ubuntu Netbook Remix and another Ubuntu derivative installed on my 80gb drive. I recently acquired a 160gb drive, which I plan to put into the Wind. I cloned the 80gb drive, which left me with an identical configuration, plus 80gb of unallocated free space. The problem is that I already have 4 primary partitions; the last of them (adjacent to the free space) is divided up into 4 extended partitions. I tried to make the free space available in gparted, but it won't let me create a new partition because I already have 4 primaries. Is there some way I can get this into the last primary partition? I tried expanding the size of the extended partitions in the 4th primary partition, but gparted won't let me do this.
View 5 Replies View RelatedUbuntu Installation :: Accessing Liveusb Reserved Space?
May 10, 2010I am using ubuntu 9.10...now I have created an USB startup disk in my 1gb pen drive with a persistence region of 200MB. But after I have booted into the live ubuntu version using the pen drive how will I access the reserved space?.. I have tried mounting the pen drive but still couldn't access the reserved space.
NB:-I have only one FAT32 partition in my pen drive...
Software :: Write() Syscall Hangs Up
Jun 8, 2010I had a problem that my write() syscall hangs up. The write is writing data to a file descriptor which is a slave pty.
The write executed inside a loop.
Ubuntu :: Access User Account 1 Home Directory From User 2 Work Space?
Jun 16, 2011Do you think there is a way of accessing different user data from another account which I have set up.
Ie. user 1 = account has messed up
user 2 = account works fine
access user account 1 home directory from user 2 work space?
Programming :: Open() Syscall Breaks Execve()'s Work?
Jul 16, 2010here is my working code :
Code: #include <stdio.h>
#include <stdlib.h>
#include <string.h>
[code]....
Server :: See The Currently Accessing User For An Nfs Share?
Mar 2, 2011I am using Redhat EL5 ,i am having NFS server installed in my server and around 100 clients are accessing the NFS shares, i want to know the remote users with host ip and username who is currently accessing my NFS Share.and is it possible to restrict a specific share to a particular host in NFS..? if yes how
View 1 Replies View RelatedSlackware :: Accessing Public_html In User Directory?
Jun 15, 2011I cannot get apache to show the files in ~/public_html it gives me this error
Code:
Forbidden
You don't have permission to access /~george/test.txt on this server.According to the .conf file it should have read access...
Red Hat / Fedora :: Give All Set Of Permissions To An User For Accessing A Folder?
Nov 27, 2010I am new user for redhat linux.I tried to install oracle 10g on rhel 5 using vmware.every time i am getting an error message permission denied
[oracle2 localhost tmp]$ cd database_10201/
[oracle2 localhost database_10201]$ ls
doc install response runInstaller stage welcome.html
[oracle2 localhost database_10201]$ sh r
response/ runInstaller
[oracle2 localhost database_10201]$ sh runInstaller
runInstaller: line 54: /tmp/database_10201/install/.oui: Permission denied
how to give all set of permissions to an user for accessing a folder..
Security :: Restrict A User Accessing Ftp Site - Which Is Secure Ftp Or Pam
May 7, 2010I want to restrict a user accessing my ftp site.
1) i can block the user in ftp configuration file
2) i can block the user in PAM or /etc/host.deny
i heard that if pam is denying the user and ftp is allowing the user the user can get the access it means that ftp conf file is stronger than host.deny
Ubuntu Security :: Preventing User From Accessing Command Line
May 8, 2011I'm trying to set up an unprivileged user on some field systems running 11.04 with the standard Gnome shell (rather than Unity), and ideally that user would not have access to the command line. The user can log in through GDM (but not the text consoles) with no password, so I need to provide the absolute minimum of privileges; basically the user should only be able to run one program.
I've already set the /desktop/gnome/lockdown/disable_command_line key with gconf-editor for that user, which successfully disabled the "Run Command" dialog. Unfortunately, even though the description of the key in gconf-editor says "prevents the user from accessing the terminal...", the terminal emulator is still accessible from the Applications menu, and I haven't been able to find a good way of disabling the terminal or removing it from the menu. The only thing that occurs to me is an ugly hack: replace the gnome-terminal binary with another that checks to make sure the user is not the unprivileged one and then starts gnome-terminal.
Red Hat / Fedora :: Remove User's Rights From Accessing The Interactive Shell?
May 11, 2010What is it? How do I remove a user's rights from accessing the interactive shell?
View 1 Replies View RelatedProgramming :: Accessing And Performing Operations On Base Level Kernel Structure?
Jan 20, 2011We all know linux kernel base layer is made up of structures, in which every object of kernel is well defined. Structure members correspond to object properties required to define object behavior.
For example if we take case of File system.It composed of four objects , superblock objects, inode objects, file objects and dentry object.Each having well defined structure which is being operated by system call handler and by system call service routine in the kernel mode.
Now my question is even in kernel mode we do not have some mechanism by which we can get access to pointer of these structures.We have some macro.
If I want to manipulate structure on my on way, or performing some more operation defined by me.For example after the crash of Hard Disk Drive, having ext2/3 file system, If i want to know all the inode pointers, and block details.
Can I have some way out to do desired operation ??
mechanism to operate on these base label structures, even in kernel mode ..
Ubuntu :: Get The Disk Space Usage Per User?
May 27, 2009I want to get the disk space usage of each user on the machine. I Have found the command -du but how can I consultate the usage per user? The only thing I can is to consultate the usage of maps...
View 3 Replies View RelatedGeneral :: Getting Notified In User-space On Interrupts?
Jun 27, 2010I hope this is the right place to post to because I haven't found any other related forums.I'm working on an AMD opteron running Linux 2.6.28.6 I want to preload a hardware performance counter (register) with a value to have it overflow after a number of a specific event counts. As I understand, when the counter in the register overflows, an interrupt will be generated and handled by the appropriate interrupt handler. How can my user-level application get notified whenever the interrupt occurs? I want to obtain information on the instruction that caused the overflow. Is this possible? I think this is different than responding to signals with sigaction().
View 1 Replies View RelatedProgramming :: Disable Irq Line From User Space?
Jul 14, 2011I have written a device driver and I would like to disable an interrupt. In kernel space there is a function called "disable_irq(int irq)", but, is it possible to do it from user space?
View 7 Replies View RelatedGeneral :: I2C Communication From Kernel Space?
May 11, 2011How do you interface with the Linux I2C driver from kernel space? For example, if I had LEDs connected to a GPIO expander on the I2C bus, how would I blink them twice before going down for reset from machine_reset()?
Essentially, I believe I need to call the functions i2c_smbus_write_byte(), i2c_smbus_read_byte(), etc. But these functions require I2C client data that I do not understand how to supply.