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Viewing changes to sam/disk.c

  • Committer: Bazaar Package Importer
  • Author(s): Daniel Baumann
  • Date: 2010-06-04 17:22:03 UTC
  • mfrom: (1.1.6 upstream)
  • Revision ID: james.westby@ubuntu.com-20100604172203-ei85j0da495sr8ut
Tags: 1:6-1
* Adding Kai as co-maintainer.
* Merging upstream version 6.

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sam/disk.c
 
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#include "sam.h"
 
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static  Block   *blist;
 
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#if 0
 
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static int
 
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tempdisk(void)
 
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{
 
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        char buf[128];
 
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        int i, fd;
 
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        snprint(buf, sizeof buf, "/tmp/X%d.%.4ssam", getpid(), getuser());
 
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        for(i='A'; i<='Z'; i++){
 
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                buf[5] = i;
 
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                if(access(buf, AEXIST) == 0)
 
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                        continue;
 
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                fd = create(buf, ORDWR|ORCLOSE|OCEXEC, 0600);
 
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                if(fd >= 0)
 
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                        return fd;
 
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        }
 
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        return -1;
 
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}
 
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#else
 
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extern int tempdisk(void);
 
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#endif
 
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Disk*
 
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diskinit(void)
 
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{
 
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        Disk *d;
 
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        d = emalloc(sizeof(Disk));
 
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        d->fd = tempdisk();
 
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        if(d->fd < 0){
 
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                fprint(2, "sam: can't create temp file: %r\n");
 
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                exits("diskinit");
 
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        }
 
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        return d;
 
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}
 
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static
 
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uint
 
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ntosize(uint n, uint *ip)
 
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{
 
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        uint size;
 
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        if(n > Maxblock)
 
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                panic("internal error: ntosize");
 
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        size = n;
 
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        if(size & (Blockincr-1))
 
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                size += Blockincr - (size & (Blockincr-1));
 
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        /* last bucket holds blocks of exactly Maxblock */
 
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        if(ip)
 
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                *ip = size/Blockincr;
 
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        return size * sizeof(Rune);
 
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}
 
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Block*
 
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disknewblock(Disk *d, uint n)
 
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{
 
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        uint i, j, size;
 
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        Block *b;
 
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        size = ntosize(n, &i);
 
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        b = d->free[i];
 
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        if(b)
 
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                d->free[i] = b->u.next;
 
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        else{
 
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                /* allocate in chunks to reduce malloc overhead */
 
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                if(blist == nil){
 
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                        blist = emalloc(100*sizeof(Block));
 
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                        for(j=0; j<100-1; j++)
 
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                                blist[j].u.next = &blist[j+1];
 
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                }
 
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                b = blist;
 
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                blist = b->u.next;
 
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                b->addr = d->addr;
 
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                d->addr += size;
 
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        }
 
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        b->u.n = n;
 
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        return b;
 
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}
 
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void
 
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diskrelease(Disk *d, Block *b)
 
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{
 
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        uint i;
 
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        ntosize(b->u.n, &i);
 
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        b->u.next = d->free[i];
 
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        d->free[i] = b;
 
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}
 
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void
 
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diskwrite(Disk *d, Block **bp, Rune *r, uint n)
 
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{
 
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        int size, nsize;
 
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        Block *b;
 
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        b = *bp;
 
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        size = ntosize(b->u.n, nil);
 
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        nsize = ntosize(n, nil);
 
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        if(size != nsize){
 
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                diskrelease(d, b);
 
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                b = disknewblock(d, n);
 
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                *bp = b;
 
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        }
 
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        if(pwrite(d->fd, r, n*sizeof(Rune), b->addr) != n*sizeof(Rune))
 
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                panic("write error to temp file");
 
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        b->u.n = n;
 
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}
 
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void
 
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diskread(Disk *d, Block *b, Rune *r, uint n)
 
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{
 
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        if(n > b->u.n)
 
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                panic("internal error: diskread");
 
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        ntosize(b->u.n, nil);   /* called only for sanity check on Maxblock */
 
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        if(pread(d->fd, r, n*sizeof(Rune), b->addr) != n*sizeof(Rune))
 
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                panic("read error from temp file");
 
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}