51f4f46ae0
The calculation of the last block size is wrong and we can only shrink the size of the last data block, not extend it.
517 lines
8.3 KiB
C
517 lines
8.3 KiB
C
#include <u.h>
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#include <libc.h>
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#include <auth.h>
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#include <fcall.h>
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#include <thread.h>
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#include <9p.h>
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#include <pool.h>
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char Ebadoff[] = "bad file offset or count";
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char Eexist[] = "file already exists";
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char Enomem[] = "no memory";
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char Eperm[] = "permission denied";
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char Enotowner[] = "not owner";
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char Elocked[] = "file is locked";
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enum {
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Tdat = 0xbabababa,
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Tind = 0xdadadada,
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ESIZE = 64*1024,
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};
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#define MAXFSIZE ((0x7fffffffll/sizeof(Ram*))*ESIZE)
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typedef struct Ram Ram;
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struct Ram
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{
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int type;
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int size;
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Ram **link;
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Ram *ent[];
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};
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int private;
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void*
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ramalloc(ulong size)
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{
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void *v;
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v = sbrk(size);
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if(v == (void*)-1)
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return nil;
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return v;
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}
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void
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rammoved(void*, void *to)
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{
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Ram **link, **elink, *x = to;
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*x->link = x;
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if(x->type != Tind)
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return;
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link = x->ent;
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for(elink = link + (x->size / sizeof(Ram*)); link < elink; link++)
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if((x = *link) != nil)
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x->link = link;
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}
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void
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ramnolock(Pool*)
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{
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}
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Pool rampool = {
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.name= "ram",
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.maxsize= 800*1024*1024,
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.minarena= 4*1024,
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.quantum= 32,
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.alloc= ramalloc,
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.move= rammoved,
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.lock= ramnolock,
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.unlock= ramnolock,
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.flags= 0,
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};
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void
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accessfile(File *f, int a)
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{
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f->atime = time(0);
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if(a & AWRITE){
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f->mtime = f->atime;
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f->qid.vers++;
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}
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}
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void
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fsread(Req *r)
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{
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int o, n, i, count;
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vlong top, off;
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File *f;
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Ram *x;
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char *p;
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f = r->fid->file;
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off = r->ifcall.offset;
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count = r->ifcall.count;
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if(count == 0 || off >= f->length || f->aux == nil){
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r->ofcall.count = 0;
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respond(r, nil);
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return;
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}
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top = off + count;
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if(top > MAXFSIZE){
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respond(r, Ebadoff);
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return;
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}
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if(top > f->length){
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top = f->length;
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count = top - off;
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}
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p = (char*)r->ofcall.data;
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while(count > 0){
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i = off / ESIZE;
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o = off % ESIZE;
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x = (Ram*)f->aux;
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if(i < (x->size / sizeof(Ram*)))
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x = x->ent[i];
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else
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x = nil;
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if(x != nil && o < x->size){
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n = x->size - o;
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if(n > count)
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n = count;
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memmove(p, (char*)&x[1] + o, n);
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} else {
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n = ESIZE - o;
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if(n > count)
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n = count;
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memset(p, 0, n);
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}
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p += n;
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off += n;
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count -= n;
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}
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accessfile(f, AREAD);
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r->ofcall.count = p - (char*)r->ofcall.data;
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respond(r, nil);
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}
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void
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fswrite(Req *r)
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{
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int o, n, i, count;
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Ram *x, **link;
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vlong top, off;
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File *f;
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char *p;
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f = r->fid->file;
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off = r->ifcall.offset;
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count = r->ifcall.count;
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if(f->mode & DMAPPEND)
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off = f->length;
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if(count == 0){
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r->ofcall.count = 0;
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respond(r, nil);
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return;
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}
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top = off + count;
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if(top > MAXFSIZE){
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respond(r, Ebadoff);
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return;
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}
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n = ((top + ESIZE-1)/ESIZE) * sizeof(Ram*);
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x = (Ram*)f->aux;
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if(x == nil || x->size < n){
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x = poolrealloc(&rampool, x, sizeof(Ram) + n);
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if(x == nil){
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respond(r, Enomem);
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return;
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}
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link = (Ram**)&f->aux;
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if(*link == nil){
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memset(x, 0, sizeof(Ram));
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x->type = Tind;
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x->link = link;
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*link = x;
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} else if(x != *link)
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rammoved(*link, x);
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memset((char*)&x[1] + x->size, 0, n - x->size);
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x->size = n;
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}
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p = (char*)r->ifcall.data;
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while(count > 0){
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i = off / ESIZE;
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o = off % ESIZE;
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n = ESIZE - o;
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if(n > count)
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n = count;
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x = ((Ram*)f->aux)->ent[i];
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if(x == nil || x->size < o+n){
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x = poolrealloc(&rampool, x, sizeof(Ram) + o+n);
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if(x == nil){
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respond(r, Enomem);
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return;
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}
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link = &((Ram*)f->aux)->ent[i];
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if(*link == nil){
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memset(x, 0, sizeof(Ram));
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x->type = Tdat;
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}
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if(o > x->size)
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memset((char*)&x[1] + x->size, 0, o - x->size);
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x->size = o + n;
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x->link = link;
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*link = x;
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}
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memmove((char*)&x[1] + o, p, n);
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p += n;
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off += n;
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count -= n;
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}
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if(top > f->length)
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f->length = top;
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accessfile(f, AWRITE);
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r->ofcall.count = p - (char*)r->ifcall.data;
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respond(r, nil);
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}
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void
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truncfile(File *f, vlong l)
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{
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int i, o, n;
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Ram *x;
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x = (Ram*)f->aux;
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if(x != nil){
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n = x->size / sizeof(Ram*);
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i = l / ESIZE;
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if(i < n){
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o = l % ESIZE;
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if(o != 0 && x->ent[i] != nil){
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if(o < x->ent[i]->size)
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x->ent[i]->size = o;
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i++;
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}
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while(i < n){
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if(x->ent[i] != nil){
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poolfree(&rampool, x->ent[i]);
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x->ent[i] = nil;
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}
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i++;
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}
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}
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if(l == 0){
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poolfree(&rampool, (Ram*)f->aux);
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f->aux = nil;
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}
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}
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f->length = l;
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}
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void
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fswstat(Req *r)
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{
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File *f, *w;
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char *u;
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f = r->fid->file;
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u = r->fid->uid;
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/*
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* To change length, must have write permission on file.
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*/
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if(r->d.length != ~0 && r->d.length != f->length){
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if(r->d.length > MAXFSIZE){
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respond(r, Ebadoff);
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return;
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}
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if(!hasperm(f, u, AWRITE) || (f->mode & DMDIR) != 0)
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goto Perm;
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}
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/*
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* To change name, must have write permission in parent.
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*/
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if(r->d.name[0] != '\0' && strcmp(r->d.name, f->name) != 0){
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if((w = f->parent) == nil)
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goto Perm;
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incref(w);
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if(!hasperm(w, u, AWRITE)){
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closefile(w);
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goto Perm;
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}
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if((w = walkfile(w, r->d.name)) != nil){
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closefile(w);
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respond(r, Eexist);
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return;
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}
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}
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/*
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* To change mode, must be owner or group leader.
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* Because of lack of users file, leader=>group itself.
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*/
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if(r->d.mode != ~0 && f->mode != r->d.mode){
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if(strcmp(u, f->uid) != 0)
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if(strcmp(u, f->gid) != 0){
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respond(r, Enotowner);
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return;
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}
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}
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/*
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* To change group, must be owner and member of new group,
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* or leader of current group and leader of new group.
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* Second case cannot happen, but we check anyway.
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*/
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while(r->d.gid[0] != '\0' && strcmp(f->gid, r->d.gid) != 0){
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if(strcmp(u, f->uid) == 0)
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break;
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if(strcmp(u, f->gid) == 0)
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if(strcmp(u, r->d.gid) == 0)
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break;
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respond(r, Enotowner);
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return;
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}
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if(r->d.mode != ~0){
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f->mode = r->d.mode;
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f->qid.type = f->mode >> 24;
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}
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if(r->d.name[0] != '\0'){
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free(f->name);
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f->name = estrdup9p(r->d.name);
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}
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if(r->d.length != ~0 && r->d.length != f->length)
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truncfile(f, r->d.length);
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accessfile(f, AWRITE);
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if(r->d.mtime != ~0){
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f->mtime = r->d.mtime;
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}
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respond(r, nil);
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return;
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Perm:
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respond(r, Eperm);
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}
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void
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fscreate(Req *r)
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{
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File *f;
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int p;
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f = r->fid->file;
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p = r->ifcall.perm;
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if((p & DMDIR) != 0)
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p = (p & ~0777) | ((p & f->mode) & 0777);
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else
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p = (p & ~0666) | ((p & f->mode) & 0666);
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if((f = createfile(f, r->ifcall.name, r->fid->uid, p, nil)) == nil){
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responderror(r);
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return;
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}
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f->atime = f->mtime = time(0);
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f->aux = nil;
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r->fid->file = f;
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r->ofcall.qid = f->qid;
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respond(r, nil);
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}
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void
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fsopen(Req *r)
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{
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File *f;
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f = r->fid->file;
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if((f->mode & DMEXCL) != 0){
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if(f->ref > 2 && (long)((ulong)time(0)-(ulong)f->atime) < 300){
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respond(r, Elocked);
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return;
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}
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}
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if((f->mode & DMAPPEND) == 0 && (r->ifcall.mode & OTRUNC) != 0){
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truncfile(f, 0);
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accessfile(f, AWRITE);
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}
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respond(r, nil);
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}
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void
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fsdestroyfid(Fid *fid)
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{
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File *f;
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f = fid->file;
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if(fid->omode != -1 && (fid->omode & ORCLOSE) != 0 && f != nil && f->parent != nil)
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removefile(f);
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}
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void
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fsdestroyfile(File *f)
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{
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truncfile(f, 0);
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}
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void
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fsstart(Srv *)
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{
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char buf[40];
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int ctl;
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if(private){
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snprint(buf, sizeof buf, "/proc/%d/ctl", getpid());
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if((ctl = open(buf, OWRITE)) < 0)
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sysfatal("can't protect memory: %r");
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fprint(ctl, "noswap\n");
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fprint(ctl, "private\n");
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close(ctl);
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}
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}
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Srv fs = {
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.open= fsopen,
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.read= fsread,
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.write= fswrite,
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.wstat= fswstat,
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.create= fscreate,
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.destroyfid= fsdestroyfid,
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.start= fsstart,
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};
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void
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usage(void)
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{
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fprint(2, "usage: %s [-Dipsubac] [-m mountpoint] [-S srvname]\n", argv0);
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exits("usage");
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}
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void
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main(int argc, char **argv)
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{
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char *srvname = nil;
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char *mtpt = "/tmp";
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int mountflags, stdio;
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fs.tree = alloctree(nil, nil, DMDIR|0777, fsdestroyfile);
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mountflags = stdio = 0;
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ARGBEGIN{
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case 'D':
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chatty9p++;
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break;
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case 's':
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srvname = "ramfs";
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mtpt = nil;
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break;
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case 'S':
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srvname = EARGF(usage());
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mtpt = nil;
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break;
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case 'm':
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mtpt = EARGF(usage());
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break;
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case 'i':
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stdio = 1;
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break;
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case 'p':
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private = 1;
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break;
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case 'u':
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rampool.maxsize = (uintptr)~0;
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break;
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case 'b':
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mountflags |= MBEFORE;
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break;
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case 'c':
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mountflags |= MCREATE;
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break;
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case 'a':
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mountflags |= MAFTER;
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break;
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default:
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usage();
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}ARGEND;
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if(argc > 0)
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usage();
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if(stdio){
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fs.infd = 0;
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fs.outfd = 1;
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srv(&fs);
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exits(0);
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}
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if(srvname == nil && mtpt == nil)
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sysfatal("must specify -S, or -m option");
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if(mountflags == 0)
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mountflags = MREPL | MCREATE;
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postmountsrv(&fs, srvname, mtpt, mountflags);
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exits(0);
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}
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