mirror of
https://github.com/9fans/plan9port.git
synced 2025-01-15 11:20:03 +00:00
383 lines
7.9 KiB
C
383 lines
7.9 KiB
C
#ifdef PLAN9PORT /* SORRY! */
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#include <u.h>
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#include <sys/types.h>
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#include <sys/vfs.h>
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#endif
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#include "stdinc.h"
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#include <ctype.h>
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#include "dat.h"
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#include "fns.h"
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u32int maxblocksize;
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int readonly;
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static int
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strtoullsuf(char *p, char **pp, int rad, u64int *u)
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{
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u64int v;
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if(!isdigit(*p))
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return -1;
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v = strtoull(p, &p, rad);
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switch(*p){
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case 'k':
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case 'K':
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v *= 1024;
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p++;
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break;
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case 'm':
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case 'M':
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v *= 1024*1024;
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p++;
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break;
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case 'g':
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case 'G':
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v *= 1024*1024*1024;
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p++;
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break;
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case 't':
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case 'T':
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v *= 1024*1024;
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v *= 1024*1024;
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p++;
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break;
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}
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*pp = p;
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*u = v;
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return 0;
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}
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static int
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parsepart(char *name, char **file, u64int *lo, u64int *hi)
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{
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char *p;
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*file = estrdup(name);
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if((p = strrchr(*file, ':')) == nil){
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*lo = 0;
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*hi = 0;
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return 0;
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}
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*p++ = 0;
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if(*p == '-')
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*lo = 0;
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else{
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if(strtoullsuf(p, &p, 0, lo) < 0){
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free(*file);
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return -1;
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}
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}
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if(*p == '-')
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p++;
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if(*p == 0){
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*hi = 0;
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return 0;
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}
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if(strtoullsuf(p, &p, 0, hi) < 0 || *p != 0){
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free(*file);
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return -1;
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}
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return 0;
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}
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Part*
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initpart(char *name, int mode)
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{
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Part *part;
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Dir *dir;
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char *file;
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u64int lo, hi;
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if(parsepart(name, &file, &lo, &hi) < 0)
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return nil;
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trace(TraceDisk, "initpart %s file %s lo 0x%llx hi 0x%llx", name, file, lo, hi);
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part = MKZ(Part);
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part->name = estrdup(name);
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part->filename = estrdup(file);
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if(readonly){
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mode &= (OREAD|OWRITE|ORDWR);
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mode |= OREAD;
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}
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part->fd = open(file, mode);
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if(part->fd < 0){
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if((mode&(OREAD|OWRITE|ORDWR)) == ORDWR)
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part->fd = open(file, (mode&~ORDWR)|OREAD);
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if(part->fd < 0){
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freepart(part);
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fprint(2, "can't open partition='%s': %r\n", file);
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seterr(EOk, "can't open partition='%s': %r", file);
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fprint(2, "%r\n");
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free(file);
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return nil;
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}
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fprint(2, "warning: %s opened for reading only\n", name);
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}
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part->offset = lo;
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dir = dirfstat(part->fd);
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if(dir == nil){
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freepart(part);
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seterr(EOk, "can't stat partition='%s': %r", file);
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free(file);
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return nil;
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}
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if(dir->length == 0){
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free(dir);
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freepart(part);
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seterr(EOk, "can't determine size of partition %s", file);
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free(file);
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return nil;
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}
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if(dir->length < hi || dir->length < lo){
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freepart(part);
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seterr(EOk, "partition '%s': bounds out of range (max %lld)", name, dir->length);
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free(dir);
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free(file);
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return nil;
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}
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if(hi == 0)
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hi = dir->length;
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part->size = hi - part->offset;
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#ifdef _LIBC_H_
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{
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struct statfs sfs;
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if(fstatfs(part->fd, &sfs) >= 0)
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part->fsblocksize = sfs.f_bsize;
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}
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#endif
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free(dir);
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return part;
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}
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void
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freepart(Part *part)
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{
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if(part == nil)
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return;
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if(part->fd >= 0)
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close(part->fd);
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free(part->name);
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free(part);
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}
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void
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partblocksize(Part *part, u32int blocksize)
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{
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if(part->blocksize)
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sysfatal("resetting partition=%s's block size", part->name);
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part->blocksize = blocksize;
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if(blocksize > maxblocksize)
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maxblocksize = blocksize;
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}
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/*
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* Read/write some amount of data between a block device or file and a memory buffer.
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*
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* Most Unix systems require that when accessing a block device directly,
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* the buffer, offset, and count are all multiples of the device block size,
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* making this a lot more complicated than it otherwise would be.
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*
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* Most of our callers will make things easy on us, but for some callers it's best
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* if we just do the work here, with only one place to get it right (hopefully).
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*
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* If everything is aligned properly, prwb will try to do big transfers in the main
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* body of the loop: up to MaxIo bytes at a time. If everything isn't aligned properly,
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* we work one block at a time.
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*/
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#undef min
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#define min(a, b) ((a) < (b) ? (a) : (b))
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int
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prwb(char *name, int fd, int isread, u64int offset, void *vbuf, u32int count, u32int blocksize)
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{
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char *op;
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u8int *buf, *tmp, *freetmp, *dst;
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u32int c, delta, icount, opsize;
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int r;
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buf = vbuf;
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tmp = nil;
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freetmp = nil;
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icount = count;
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opsize = blocksize;
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if(count == 0){
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logerr(EStrange, "pwrb %s called to %s 0 bytes", name, isread ? "read" : "write");
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return 0;
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}
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assert(blocksize > 0);
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/* allocate blocksize-aligned temp buffer if needed */
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if((ulong)offset%blocksize || (ulong)buf%blocksize || count%blocksize){
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if((freetmp = malloc(blocksize*2)) == nil)
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return -1;
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tmp = freetmp;
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tmp += blocksize - (ulong)tmp%blocksize;
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}
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/* handle beginning fringe */
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if((delta = (ulong)offset%blocksize) != 0){
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assert(tmp != nil);
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if((r=pread(fd, tmp, blocksize, offset-delta)) != blocksize){
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dst = tmp;
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offset = offset-delta;
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op = "read";
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goto Error;
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}
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c = min(count, blocksize-delta);
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assert(c > 0 && c < blocksize);
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if(isread)
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memmove(buf, tmp+delta, c);
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else{
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memmove(tmp+delta, buf, c);
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if((r=pwrite(fd, tmp, blocksize, offset-delta)) != blocksize){
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dst = tmp;
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offset = offset-delta;
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op = "read";
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goto Error;
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}
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}
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assert(c > 0);
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offset += c;
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buf += c;
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count -= c;
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}
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/* handle full blocks */
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while(count >= blocksize){
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assert((ulong)offset%blocksize == 0);
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if((ulong)buf%blocksize){
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assert(tmp != nil);
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dst = tmp;
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opsize = blocksize;
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}else{
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dst = buf;
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opsize = count - count%blocksize;
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if(opsize > MaxIo)
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opsize = MaxIo;
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}
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if(isread){
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if((r=pread(fd, dst, opsize, offset))<=0 || r%blocksize){
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op = "read";
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goto Error;
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}
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if(dst == tmp){
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assert(r == blocksize);
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memmove(buf, tmp, blocksize);
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}
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}else{
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if(dst == tmp){
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assert(opsize == blocksize);
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memmove(dst, buf, blocksize);
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}
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if((r=pwrite(fd, dst, opsize, offset))<=0 || r%blocksize){
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op = "write";
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goto Error;
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}
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if(dst == tmp)
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assert(r == blocksize);
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}
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assert(r > 0);
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offset += r;
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buf += r;
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count -= r;
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}
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/* handle ending fringe */
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if(count > 0){
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assert((ulong)offset%blocksize == 0);
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assert(tmp != nil);
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/*
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* Complicated condition: if we're reading it's okay to get less than
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* a block as long as it's enough to satisfy the read - maybe this is
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* a normal file. (We never write to normal files, or else things would
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* be even more complicated.)
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*/
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r = pread(fd, tmp, blocksize, offset);
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if((isread && r < count) || (!isread && r != blocksize)){
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print("FAILED isread=%d r=%d count=%d blocksize=%d\n", isread, r, count, blocksize);
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dst = tmp;
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op = "read";
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goto Error;
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}
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if(isread)
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memmove(buf, tmp, count);
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else{
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memmove(tmp, buf, count);
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if(pwrite(fd, tmp, opsize, offset) != blocksize){
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dst = tmp;
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op = "write";
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goto Error;
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}
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}
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}
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if(freetmp)
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free(freetmp);
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return icount;
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Error:
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seterr(EAdmin, "%s %s offset 0x%llux count %ud buf %p returned %d: %r",
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op, name, offset, opsize, dst, r);
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if(freetmp)
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free(freetmp);
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return -1;
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}
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int
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rwpart(Part *part, int isread, u64int offset, u8int *buf, u32int count)
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{
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u32int blocksize;
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trace(TraceDisk, "%s %s %ud at 0x%llx",
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isread ? "read" : "write", part->name, count, offset);
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if(offset >= part->size || offset+count > part->size){
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seterr(EStrange, "out of bounds %s offset 0x%llux count %ud to partition %s size 0x%llux",
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isread ? "read" : "write", offset, count, part->name, part->size);
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return -1;
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}
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blocksize = part->fsblocksize;
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if(blocksize == 0)
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blocksize = part->blocksize;
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if(blocksize == 0)
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blocksize = 4096;
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return prwb(part->filename, part->fd, isread, part->offset+offset, buf, count, blocksize);
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}
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int
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readpart(Part *part, u64int offset, u8int *buf, u32int count)
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{
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return rwpart(part, 1, offset, buf, count);
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}
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int
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writepart(Part *part, u64int offset, u8int *buf, u32int count)
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{
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return rwpart(part, 0, offset, buf, count);
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}
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ZBlock*
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readfile(char *name)
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{
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Part *p;
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ZBlock *b;
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p = initpart(name, OREAD);
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if(p == nil)
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return nil;
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b = alloczblock(p->size, 0, p->blocksize);
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if(b == nil){
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seterr(EOk, "can't alloc %s: %r", name);
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freepart(p);
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return nil;
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}
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if(readpart(p, 0, b->data, p->size) < 0){
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seterr(EOk, "can't read %s: %r", name);
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freepart(p);
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freezblock(b);
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return nil;
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}
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freepart(p);
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return b;
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}
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