common/vmalloc/vmmopen.c

/***********************************************************************
*                                                                      *
*               This software is part of the ast package               *
*          Copyright (c) 1985-2010 AT&T Intellectual Property          *
*                      and is licensed under the                       *
*                  Common Public License, Version 1.0                  *
*                    by AT&T Intellectual Property                     *
*                                                                      *
*                A copy of the License is available at                 *
*            http://www.opensource.org/licenses/cpl1.0.txt             *
*         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
*                                                                      *
*              Information and Software Systems Research               *
*                            AT&T Research                             *
*                           Florham Park NJ                            *
*                                                                      *
*                 Glenn Fowler <gsf@research.att.com>                  *
*                  David Korn <dgk@research.att.com>                   *
*                   Phong Vo <kpv@research.att.com>                    *
*                                                                      *
***********************************************************************/
#if defined(_UWIN) && defined(_BLD_ast)

void _STUB_vmmopen(){}

#else

#include    "vmhdr.h"

#if _sys_stat
#include    <sys/stat.h>
#endif
#include    <fcntl.h>

#ifdef S_IRUSR
#define CREAT_MODE  (S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH)
#else
#define CREAT_MODE  0644
#endif

#if _lib_mmap
#include    <sys/mman.h>
#else
#define mmap(a,b,c,d,e,f)   MAP_FAILED
#define munmap(a,b)     MAP_FAILED
#endif

/* Create a region to allocate based on mmap()
**
** Written by Kiem-Phong Vo (kpv@research.att.com)
*/

#ifndef MAP_FAILED
#define MAP_FAILED  (void*)(-1)
#endif

#define MM_MAGIC    (('V'<<24) | ('M'<<16) | ('A'<<8) | ('P'))
#define MM_ROUND    (64*1024)
#define MM_START    ROUND(sizeof(Mmvm_t),ALIGN)

typedef struct _user_s
{   struct _user_s* next;   /* link list        */
    int     key;    /* identifying key  */
    Void_t*     data;   /* data to be returned  */
} User_t;

typedef struct _mmvm_s
{
    Vmulong_t   magic;  /* magic bytes      */
    Void_t*     base;   /* base of the map  */
    size_t      size;   /* current size     */
    size_t      busy;   /* amount in use    */
    size_t      round;  /* amount to round to   */
    User_t*     user;   /* some user data   */
} Mmvm_t;

typedef struct _mmvmdisc_s
{
    Vmdisc_t    disc;   /* Vmalloc discipline   */
    int     fd; /* file descriptor  */
    Mmvm_t*     mm; /* mmap data        */
} Mmvmdisc_t;

#if __STD_C
static int mmvminit(char* file, Void_t* addr, size_t round, Mmvm_t* mm)
#else
static int mmvminit(file, addr, round, mm)
char*   file;   /* file to map data from    */
Void_t* addr;   /* desired starting address */
size_t  round;  /* amount to round requests     */
Mmvm_t* mm; /* to return some mapped info   */
#endif
{
    int     fd;
    off_t       size;
    Void_t      *base;
    Mmvm_t      *hdr;

    base = NIL(Void_t*);
    if((fd = open(file, O_RDWR, CREAT_MODE)) >= 0)
    {   if((size = lseek(fd, (off_t)0, 2)) < 0)
            goto done;
        else if(size == 0)
            goto new_f;

        /* read the header */
        if(lseek(fd, (off_t)0, 0) != (off_t)0)
            goto done;
        if(read(fd, mm, sizeof(Mmvm_t)) != sizeof(Mmvm_t))
            goto done;
        if(mm->magic != MM_MAGIC || !mm->base ||
           (off_t)mm->size != size || mm->busy > mm->size )
            goto done;
        base = (Void_t*)mmap(mm->base, mm->size, PROT_READ|PROT_WRITE,
                     MAP_FIXED|MAP_SHARED, fd, (off_t)0 );
        if(base == (Void_t*)MAP_FAILED)
            base = NIL(Void_t*);
    }
    else
    {   if((fd = open(file, O_RDWR|O_CREAT, CREAT_MODE)) < 0)
            goto done;

    new_f:  /* create an initial set of data */
        size = round;
        if(lseek(fd, size-1, 0) != (size-1) || write(fd, "", 1) != 1 )
            goto done;

        base = (Void_t*)mmap(addr, (size_t)size, PROT_READ|PROT_WRITE,
                     (addr ? MAP_FIXED : 0)|MAP_SHARED, fd, (off_t)0 );
        if(base == (Void_t*)MAP_FAILED)
            base = NIL(Void_t*);
        if(!base)
            goto done;

        /* write magic number */
        hdr = (Mmvm_t*)base;
        hdr->magic = MM_MAGIC;
        hdr->base  = base;
        hdr->size  = size;
        hdr->busy  = MM_START;
        hdr->round = round;
        hdr->user  = NIL(User_t*);
        memcpy(mm, hdr, sizeof(Mmvm_t));
    }

done:
    if(!base)
    {   if(fd >= 0)
            close(fd);
        fd = -1;
    }

    return fd;
}


#if __STD_C
static Void_t* mmvmmemory(Vmalloc_t* vm, Void_t* caddr,
            size_t csize, size_t nsize, Vmdisc_t* disc)
#else
static Void_t* mmvmmemory(vm, caddr, csize, nsize, disc)
Vmalloc_t*  vm;
Void_t*     caddr;
size_t      csize;
size_t      nsize;
Vmdisc_t*   disc;
#endif
{
    Mmvmdisc_t  *mmdc = (Mmvmdisc_t*)disc;

    if(mmdc->fd < 0 || !mmdc->mm)
        return NIL(Void_t*);

#define MMADDR(b)   ((Void_t*)(((Vmuchar_t*)b) + MM_START) )
    if(caddr && caddr != MMADDR(mmdc->mm->base) )
        return NIL(Void_t*);
    if(nsize < csize)
        return NIL(Void_t*);

    if(nsize > mmdc->mm->size-MM_START)
    {   /* base and size of new map */
        caddr = mmdc->mm->base;
        csize = MM_START + nsize +
            ((nsize % disc->round) < (disc->round/2) ? disc->round/2 : 0);
        csize = ROUND(csize, disc->round);

        /* make room for new space */
        if(lseek(mmdc->fd, (off_t)(csize-1), 0) != (off_t)(csize-1) ||
           write(mmdc->fd, "", 1) != 1 )
            return NIL(Void_t*);

        /* remap the space */
        (void)munmap(caddr, mmdc->mm->size);
        caddr = (Void_t*)mmap(caddr, csize, PROT_READ|PROT_WRITE,
                     MAP_FIXED|MAP_SHARED, mmdc->fd, (off_t)0 );
        if(caddr == (Void_t*)MAP_FAILED)
            caddr = NIL(Void_t*);
        if(caddr)
            mmdc->mm->size = csize;
        else    /* bad problem */
        {   close(mmdc->fd);
            mmdc->fd = -1;
            mmdc->mm = NIL(Mmvm_t*);
            return NIL(Void_t*);
        }
    }

    mmdc->mm->busy = nsize+MM_START;
    return (Void_t*)(((Vmuchar_t*)mmdc->mm->base) + MM_START);
}


#if __STD_C
static int mmvmexcept(Vmalloc_t* vm, int type, Void_t* data, Vmdisc_t* disc)
#else
static int mmvmexcept(vm, type, data, disc)
Vmalloc_t*  vm;
int     type;
Void_t*     data;
Vmdisc_t*   disc;
#endif
{
    Mmvmdisc_t  *mmdc = (Mmvmdisc_t*)disc;
    Vmuchar_t   *base;

    if(type == VM_OPEN)
    {   if(mmdc->mm->busy > MM_START)
        {   base = ((Vmuchar_t*)mmdc->mm->base) + MM_START;
            *((Void_t**)data) = (Void_t*)base;
            return 1;
        }
        else    return 0;
    }
    else if(type == VM_CLOSE)
    {   (void)munmap(mmdc->mm->base, mmdc->mm->size);
        (void)close(mmdc->fd);
        vmfree(Vmheap, mmdc);
        return 1; /* freeing of mapped data is already done */
    }
    else    return 0;
}


#if __STD_C
Vmalloc_t* vmmopen(char* file, Void_t* base, size_t round)
#else
Vmalloc_t* vmmopen(file, base, round)
char*       file;   /* file mapping data from   */
Void_t*     base;   /* desired starting address */
size_t      round;  /* amount to round requests */
#endif
{
    Vmalloc_t   *vm;
    Mmvmdisc_t  *mmdc;
    Mmvm_t      mm;
    int     fd;

    if(!file)
        return NIL(Vmalloc_t*);

    /* set the amount to round up to on each memory request */
    GETPAGESIZE(_Vmpagesize);
    if(round < MM_ROUND)
        round = MM_ROUND;
    round = ROUND(round, _Vmpagesize);

    if((fd = mmvminit(file, base, round, &mm)) < 0)
        return NIL(Vmalloc_t*);

    if(!(mmdc = (Mmvmdisc_t*)vmalloc(Vmheap, sizeof(Mmvmdisc_t))) )
    {   close(fd);
        return NIL(Vmalloc_t*);
    }

    mmdc->disc.memoryf = mmvmmemory;
    mmdc->disc.exceptf = mmvmexcept;
    mmdc->disc.round   = mm.round;
    mmdc->fd = fd;
    mmdc->mm = (Mmvm_t*)mm.base;

    if(!(vm = vmopen(&mmdc->disc, Vmbest, VM_TRUST)) )
    {   mmvmexcept(NIL(Vmalloc_t*), VM_CLOSE, NIL(Void_t*), &mmdc->disc);
        return NIL(Vmalloc_t*);
    }

    return vm;
}


#if __STD_C
Void_t* vmmset(Vmalloc_t* vm, int key, Void_t* data, int set)
#else
Void_t* vmmset(vm, data, key, set)
Vmalloc_t*  vm; /* a region based on vmmmopen   */
int     key;    /* key of data to be set    */
Void_t*     data;   /* data to be set       */
int     set;    /* 1 for setting, 0 for getting */
#endif
{
    User_t  *u;
    Mmvm_t  *mmvm = ((Mmvmdisc_t*)vm->disc)->mm;

    for(u = mmvm->user; u; u = u->next)
        if(u->key == key)
            break;
    if(!set)
        return u ? u->data : NIL(Void_t*);
    else if(u)
    {   Void_t* old = u->data;
        u->data = data;
        return old;
    }
    else if(!(u = (User_t*)vmalloc(vm, sizeof(User_t))) )
        return NIL(Void_t*);
    else
    {   u->data = data;
        u->key  = key;
        u->next = mmvm->user;
        mmvm->user = u;
        return data;
    }
}

#endif