I'm trying to modify UML so I'm using kernel headers
but anyway there is a problem on sigaction definition on signal.h
Jordi
linux-os wrote:
On Thu, 24 Feb 2005, Jordi Brinquez wrote:
Hi,
I think I found a possible bug on file signal.h.
The problem comes when you define a struct sigaction on a user program and then you use the function sigaction to remap a signal handler (in my case a page_fault) for my own function, this system call is compiled as __NR_sigaction system call (by default this routine is managed by sys_sigaction routine) and if the architecture defines __ARCH_WANT_SYS_RT_SIGACTION kernel uses the routine sys_rt_sigaction on the file kernel/signal.c that instead of copying the fields from one structure to the other it just uses copy_from_user and copy_to_user with the consequent mess with the fields.
You NEVER use kernel headers for user code.... EVER. If you are making something strange, like as you said a page-fault handler, then you make an in-kernel driver (module).
FYI, no page-fault handler could ever work in user-mode anyway. A page-fault occurs because the user accesses some page it doesn't own (probably because it isn't in memory). The kernel page-fault handler checks to see if the page was promised. If not, it terminates the user-mode task with a signal. If so, it finds some free page or makes one available and maps it into the user's address-space before returning control to the user. Since the user doesn't own any free pages, it can't map in any.
[SNIPPED...]
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