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?
For the life of me, I can't track down source code for mmap(). I know that this is a kernel system call, but where is that source? In particular, I'm interested to see how mmap() now returns a randomized location in memory.
Last edited by Scott; 09-30-2013 at 05:26 PM..
Reason: Code tags
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)
Discussion started by: xerox
2 Replies
LEARN ABOUT MOJAVE
memory
MEMORY(3) BSD Library Functions Manual MEMORY(3)NAME
alloca, calloc, free, malloc, mmap, realloc -- general memory allocation operations
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <stdlib.h>
void *
alloca(size_t size);
void *
calloc(size_t nelem, size_t elsize);
void
free(void *ptr);
void *
malloc(size_t size);
void *
realloc(void *ptr, size_t size);
#include <sys/mman.h>
void *
mmap(void * addr, size_t len, int prot, int flags, int fildes, off_t off);
DESCRIPTION
These functions allocate and free memory for the calling process. They are described in the individual manual pages.
LEGACY SYNOPSIS
#include <sys/types.h>
#include <sys/mman.h>
void *
mmap(void * addr, size_t len, int prot, int flags, int fildes, off_t off);
The include file <sys/types.h> is needed for this function.
COMPATIBILITY
mmap() now returns with errno set to EINVAL in places that historically succeeded. The rules have changed as follows:
o The flags parameter must specify either MAP_PRIVATE or MAP_SHARED.
o The size parameter must not be 0.
o The off parameter must be a multiple of pagesize, as returned by sysconf().
SEE ALSO mmap(2), alloca(3), calloc(3), free(3), malloc(3), realloc(3), compat(5)STANDARDS
These functions, with the exception of alloca() and mmap() conform to ISO/IEC 9899:1990 (``ISO C90'').
BSD June 4, 1993 BSD