minix/lib/libc/sys-minix/brk.c
David van Moolenbroek 24ec0d73b5 Clean up interface to PM and VFS
- introduce new call numbers, names, and field aliases;
- initialize request messages to zero for all ABI calls;
- format callnr.h in the same way as com.h;
- redo call tables in both servers;
- remove param.h namespace pollution in the servers;
- make brk(2) go to VM directly, rather than through PM;
- remove obsolete BRK, UTIME, and WAIT calls;
- clean up path copying routine in VFS;
- move remaining system calls from libminlib to libc;
- correct some errno-related mistakes in libc routines.

Change-Id: I2d8ec5d061cd7e0b30c51ffd77aa72ebf84e2565
2014-03-01 09:05:01 +01:00

35 lines
904 B
C

#include <sys/cdefs.h>
#include "namespace.h"
#include <lib.h>
#include <string.h>
#include <unistd.h>
#ifdef __weak_alias
__weak_alias(brk, _brk)
#endif
extern char *_brksize;
/* Both OSF/1 and SYSVR4 man pages specify that brk(2) returns int.
* However, BSD4.3 specifies that brk() returns char*. POSIX omits
* brk() on the grounds that it imposes a memory model on an architecture.
* On the other hand, they are so crucial to correct operation of so many
* parts of the system, that we have chosen to hide the name brk using _brk,
* as with system calls. In this way, if a user inadvertently defines a
* procedure brk, MINIX may continue to work because the true call is _brk.
*/
int brk(addr)
void *addr;
{
message m;
if (addr != _brksize) {
memset(&m, 0, sizeof(m));
m.VMB_ADDR = addr;
if (_syscall(VM_PROC_NR, VM_BRK, &m) < 0) return(-1);
_brksize = addr;
}
return(0);
}