snap: check for overflows, cleanup error handling
This commit is contained in:
cinap_lenrek
parent
3363693205
commit
9d471caaae
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@ -3,14 +3,6 @@
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#include <bio.h>
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#include "snap.h"
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void
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panic(char *s)
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{
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fprint(2, "%s\n", s);
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abort();
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exits(s);
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}
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static Proc*
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findpid(Proc *plist, long pid)
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{
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@ -30,11 +22,11 @@ findpage(Proc *plist, long pid, int type, uvlong off)
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plist = findpid(plist, pid);
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if(plist == nil)
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panic("can't find referenced pid");
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sysfatal("can't find referenced pid");
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if(type == 't') {
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if(off%Pagesize)
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panic("bad text offset alignment");
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sysfatal("bad text offset alignment");
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s = plist->text;
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if(off >= s->len)
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return nil;
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@ -53,7 +45,7 @@ findpage(Proc *plist, long pid, int type, uvlong off)
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off -= s->offset;
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if(off%Pagesize)
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panic("bad mem offset alignment");
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sysfatal("bad mem offset alignment");
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return s->pg[off/Pagesize];
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}
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@ -116,15 +108,17 @@ readdata(Biobuf *b)
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{
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Data *d;
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char str[32];
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long len;
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ulong len;
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if(Bread(b, str, 12) != 12)
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panic("can't read data hdr\n");
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len = atoi(str);
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sysfatal("can't read data hdr: %r");
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str[12] = 0;
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len = strtoul(str, 0, 0);
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if(len + sizeof(*d) < sizeof(*d))
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sysfatal("data len too large");
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d = emalloc(sizeof(*d) + len);
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if(Bread(b, d->data, len) != len)
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panic("can't read data body\n");
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if(len && Bread(b, d->data, len) != len)
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sysfatal("can't read data body");
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d->len = len;
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return d;
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}
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@ -140,12 +134,12 @@ readseg(Seg **ps, Biobuf *b, Proc *plist)
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ulong pid;
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uvlong off;
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char buf[Pagesize];
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static char zero[Pagesize];
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extern char zeros[];
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s = emalloc(sizeof *s);
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if(Breaduvlong(b, &s->offset) < 0
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|| Breaduvlong(b, &s->len) < 0)
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panic("error reading segment");
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sysfatal("error reading segment: %r");
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npg = (s->len + Pagesize-1)/Pagesize;
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s->npg = npg;
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@ -164,7 +158,7 @@ readseg(Seg **ps, Biobuf *b, Proc *plist)
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switch(t = Bgetc(b)) {
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case 'z':
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pp[i] = datapage(zero, len);
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pp[i] = datapage(zeros, len);
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if(debug)
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fprint(2, "0x%.8llux all zeros\n", s->offset+(uvlong)i*Pagesize);
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break;
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@ -172,10 +166,10 @@ readseg(Seg **ps, Biobuf *b, Proc *plist)
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case 't':
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if(Breadulong(b, &pid) < 0
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|| Breaduvlong(b, &off) < 0)
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panic("error reading segment x");
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sysfatal("error reading segment x: %r");
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pp[i] = findpage(plist, pid, t, off);
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if(pp[i] == nil)
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panic("bad page reference in snapshot");
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sysfatal("bad page reference in snapshot");
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if(debug)
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fprint(2, "0x%.8llux same as %s pid %lud 0x%.8llux\n",
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s->offset+(uvlong)i*Pagesize, t=='m'?"mem":"text", pid, off);
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@ -189,7 +183,7 @@ readseg(Seg **ps, Biobuf *b, Proc *plist)
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break;
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default:
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fprint(2, "bad type char %#.2ux\n", t);
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panic("error reading segment");
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sysfatal("error reading segment");
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}
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}
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return s;
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@ -205,9 +199,9 @@ readsnap(Biobuf *b)
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int i, n;
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if((q = Brdline(b, '\n')) == nil)
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panic("error reading snapshot file");
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sysfatal("error reading snapshot file");
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if(strncmp(q, "process snapshot", strlen("process snapshot")) != 0)
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panic("bad snapshot file format");
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sysfatal("bad snapshot file format");
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plist = nil;
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while(q = Brdline(b, '\n')) {
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@ -232,8 +226,11 @@ readsnap(Biobuf *b)
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continue;
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if(strcmp(q, "mem") == 0) {
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if(Bread(b, buf, 12) != 12)
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panic("can't read memory section");
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sysfatal("can't read memory section: %r");
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buf[12] = 0;
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n = atoi(buf);
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if(n <= 0 || n > 16)
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sysfatal("bad segment count: %d", n);
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p->nseg = n;
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p->seg = emalloc(n*sizeof(*p->seg));
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for(i=0; i<n; i++)
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@ -241,7 +238,7 @@ readsnap(Biobuf *b)
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} else if(strcmp(q, "text") == 0)
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readseg(&p->text, b, plist);
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else
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panic("unknown section");
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sysfatal("unknown section");
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}
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return plist;
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}
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@ -33,15 +33,11 @@ main(int argc, char **argv)
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usage();
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/* get kernel compilation time */
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if((d = dirstat("#/")) == nil) {
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fprint(2, "cannot stat #/ ???\n");
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exits("stat");
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}
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if((d = dirstat("#/")) == nil)
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sysfatal("cannot stat #/: %r");
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if((b = Bopen(ofile, OWRITE)) == nil) {
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fprint(2, "cannot write to \"%s\"\n", ofile);
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exits("Bopen");
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}
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if((b = Bopen(ofile, OWRITE)) == nil)
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sysfatal("cannot write to \"%s\": %r", ofile);
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if((user = getuser()) == nil)
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user = "gre";
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@ -154,16 +154,11 @@ main(int argc, char **argv)
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if(argc != 1)
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usage();
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b = Bopen(argv[0], OREAD);
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if(b == nil) {
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fprint(2, "cannot open \"%s\": %r\n", argv[0]);
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exits("Bopen");
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}
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if((b = Bopen(argv[0], OREAD)) == nil)
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sysfatal("cannot open \"%s\": %r", argv[0]);
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if((plist = readsnap(b)) == nil) {
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fprint(2, "readsnap fails\n");
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exits("readsnap");
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}
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if((plist = readsnap(b)) == nil)
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sysfatal("readsnap fails");
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tree = alloctree(nil, nil, DMDIR|0555, nil);
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fs.tree = tree;
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@ -20,6 +20,7 @@ sumr(ulong sum, void *buf, int n)
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return sum;
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}
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char zeros[Pagesize];
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static ulong npage;
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static Page *pgtab[1<<10];
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@ -27,43 +28,27 @@ Page*
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datapage(char *p, long len)
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{
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Page *pg;
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char *q, *ep;
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long sum;
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int iszero;
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ulong sum;
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if(len > Pagesize) {
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fprint(2, "datapage cannot handle pages > %d\n", Pagesize);
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exits("datapage");
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}
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if(len > Pagesize)
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sysfatal("datapage cannot handle pages > %d", Pagesize);
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sum = sumr(0, p, len) & (nelem(pgtab)-1);
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if(sum == 0) {
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iszero = 1;
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for(q=p, ep=p+len; q<ep; q++)
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if(*q != 0) {
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iszero = 0;
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break;
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}
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} else
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iszero = 0;
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for(pg = pgtab[sum]; pg; pg=pg->link)
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for(pg = pgtab[sum]; pg != nil; pg=pg->link)
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if(pg->len == len && memcmp(pg->data, p, len) == 0)
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break;
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if(pg)
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return pg;
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return pg;
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pg = emalloc(sizeof(*pg)+len);
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pg->data = (char*)&pg[1];
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pg->type = 0;
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pg->len = len;
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memmove(pg->data, p, len);
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pg->link = pgtab[sum];
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pgtab[sum] = pg;
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if(iszero) {
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if(sum == 0 && memcmp(zeros, p, len) == 0) {
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pg->type = 'z';
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pg->written = 1;
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}
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pg->link = pgtab[sum];
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pgtab[sum] = pg;
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++npage;
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return pg;
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@ -148,7 +133,7 @@ stackptr(Proc *proc, int fd)
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char *q;
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Fhdr f;
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Reglist *r;
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long textoff;
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vlong textoff;
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int i;
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Data *dreg;
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@ -160,7 +145,9 @@ stackptr(Proc *proc, int fd)
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if(textoff == -1)
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return 0;
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seek(fd, textoff, 0);
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if(seek(fd, textoff, 0) < 0)
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return 0;
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if(crackhdr(fd, &f) == 0)
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return 0;
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@ -8,10 +8,8 @@ emalloc(ulong n)
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{
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void *v;
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v = malloc(n);
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if(v == nil){
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fprint(2, "out of memory\n");
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exits("memory");
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}
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if(v == nil)
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sysfatal("out of memory");
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memset(v, 0, n);
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return v;
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}
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@ -20,10 +18,8 @@ void*
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erealloc(void *v, ulong n)
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{
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v = realloc(v, n);
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if(v == nil) {
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fprint(2, "out of memory\n");
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exits("memory");
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}
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if(v == nil && n != 0)
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sysfatal("out of memory");
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return v;
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}
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@ -31,9 +27,7 @@ char*
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estrdup(char *s)
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{
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s = strdup(s);
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if(s == nil) {
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fprint(2, "out of memory\n");
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exits("memory");
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}
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if(s == nil)
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sysfatal("out of memory");
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return s;
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}
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