Hello. I'm writing some random access i/o software on Solaris 8 using mmap64 to memory map large files (my test file is ~25 GB).
The abbreviated code fragment is:
fd = open(cbuf,O_RDONLY|O_LARGEFILE);
struct stat statbuf;
fstat(fd,&statbuf);
off_t len =... (0 Replies)
We recently have been seeing the following type of error on our development server. Being somewhat new to HP-UX I was hoping to get some insight. Here is what I have found.
I have been doing some research.
/usr/lib/dld.sl: Call to mmap() failed - TEXT /u07/mdev/lib/libCLEND.sl... (2 Replies)
I'm using select() to monitor multiple file descriptors (inet sockets) in application. But this application must also collaborate with other applications on the same host via shared memory (mmap'ed file) due to performance reasons. How can I become notification that mmaped memory is changed or... (1 Reply)
Dear Experts,
i have a problem related to mmap(), when i run my program on sun for 64 bit which is throwing SIGBUS when it encounters mmap() function, what is the reason how to resolve this one, because it is working for 32 bit.
with regards,
vidya. (2 Replies)
Descriptions:
Develop a program that uses mmap() to map a file to memory space. Prepare such a file by yourself and do the follows.
<LI class=MsoNormal>Display the content of the file after mapping; <LI class=MsoNormal>Output how many digits included in the file; <LI class=MsoNormal>Replace... (1 Reply)
Hi
I want to lock or prevent a portion of memory which I allocated. So I tried MLOCK, MPROTECT and some like this. But all these functions works only on page border. Can I know why that so.
Is that possible to protect a portion of memory which is in middle of the page.
Example.
int A;
... (1 Reply)
I want to know whether this is possile or ever been tried out.
I want to obtain a chuck of memory using mmap()
I do it so :
n = mmap(0, 8000, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
And hold on to that memory, when a process requests for memory, some memory is... (2 Replies)
I'm new to kernels and C, and I am tinkering around trying to understand OpenBSD's secure memory management. I'm stumped on a couple points.
I've read up on malloc() which was apparently modified years ago to allocate memory using mmap. First question, that would be this here, right?
... (4 Replies)
Discussion started by: dcicc
4 Replies
LEARN ABOUT SUNOS
kmem
mem(7D) Devices mem(7D)NAME
mem, kmem, allkmem - physical or virtual memory access
SYNOPSIS
/dev/mem
/dev/kmem
/dev/allkmem
DESCRIPTION
The file /dev/mem is a special file that provides access to the physical memory of the computer.
The file /dev/kmem is a special file that provides access to the virtual address space of the operating system kernel, excluding memory
that is associated with an I/O device.
The file /dev/allkmem is a special file that provides access to the virtual address space of the operating system kernel, including memory
that is associated with an I/O device. You can use any of these devices to examine and modify the system.
Byte addresses in /dev/mem are interpreted as physical memory addresses. Byte addresses in /dev/kmem and /dev/allkmem are interpreted as
kernel virtual memory addresses. A reference to a non-existent location returns an error. See ERRORS for more information.
The file /dev/mem accesses physical memory; the size of the file is equal to the amount of physical memory in the computer. This size may
be larger than 4GB on a system running the 32-bit operating environment. In this case, you can access memory beyond 4GB using a series of
read(2) and write(2) calls, a pread64() or pwrite64() call, or a combination of llseek(2) and read(2) or write(2).
ERRORS
EFAULT Occurs when trying to write(2) a read-only location (allkmem), read(2) a write-only location (allkmem), or read(2) or
write(2) a non-existent or unimplemented location (mem, kmem, allkmem).
EIO Occurs when trying to read(2) or write(2) a memory location that is associated with an I/O device using the /dev/kmem spe-
cial file.
ENXIO Results from attempting to mmap(2) a non-existent physical (mem) or virtual (kmem, allkmem) memory address.
FILES
/dev/mem Provides access to the computer's physical memory.
/dev/kmem Provides access to the virtual address space of the operating system kernel, excluding memory that is associated with an
I/O device.
/dev/allkmem Provides access to the virtual address space of the operating system kernel, including memory that is associated with an
I/O device.
SEE ALSO llseek(2), mmap(2), read(2), write(2)WARNINGS
Using these devices to modify (that is, write to) the address space of a live running operating system or to modify the state of a
hardware device is extremely dangerous and may result in a system panic if kernel data structures are damaged or if device state is
changed.
SunOS 5.10 18 Feb 2002 mem(7D)