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#include <u.h>
#include <libc.h>
#include <bio.h>
#include "snap.h"
void
panic(char *s)
{
fprint(2, "%s\n", s);
abort();
exits(s);
}
static Proc*
findpid(Proc *plist, long pid)
{
while(plist) {
if(plist->pid == pid)
break;
plist = plist->link;
}
return plist;
}
Page*
findpage(Proc *plist, long pid, int type, uvlong off)
{
Seg *s;
int i;
plist = findpid(plist, pid);
if(plist == nil)
panic("can't find referenced pid");
if(type == 't') {
if(off%Pagesize)
panic("bad text offset alignment");
s = plist->text;
if(off >= s->len)
return nil;
return s->pg[off/Pagesize];
}
s = nil;
for(i=0; i<plist->nseg; i++) {
s = plist->seg[i];
if(s && s->offset <= off && off < s->offset+s->len)
break;
s = nil;
}
if(s == nil)
return nil;
off -= s->offset;
if(off%Pagesize)
panic("bad mem offset alignment");
return s->pg[off/Pagesize];
}
static int
Breadnumber(Biobuf *b, char *buf)
{
int i;
int c;
int havedigits;
havedigits = 0;
for(i=0; i<22; i++){
if((c = Bgetc(b)) == Beof)
return -1;
if('0' <= c && c <= '9'){
*buf++ = c;
havedigits = 1;
}else if(c == ' '){
if(havedigits){
while((c = Bgetc(b)) == ' ')
;
if(c != Beof)
Bungetc(b);
break;
}
}else{
werrstr("bad character %.2ux", c);
return -1;
}
}
*buf = 0;
return 0;
}
static int
Breadulong(Biobuf *b, ulong *x)
{
char buf[32];
if(Breadnumber(b, buf) < 0)
return -1;
*x = strtoul(buf, 0, 0);
return 0;
}
static int
Breaduvlong(Biobuf *b, uvlong *x)
{
char buf[32];
if(Breadnumber(b, buf) < 0)
return -1;
*x = strtoull(buf, 0, 0);
return 0;
}
static Data*
readdata(Biobuf *b)
{
Data *d;
char str[32];
long len;
if(Bread(b, str, 12) != 12)
panic("can't read data hdr\n");
len = atoi(str);
d = emalloc(sizeof(*d) + len);
if(Bread(b, d->data, len) != len)
panic("can't read data body\n");
d->len = len;
return d;
}
static Seg*
readseg(Seg **ps, Biobuf *b, Proc *plist)
{
Seg *s;
Page **pp;
int i, npg;
int t;
int n, len;
ulong pid;
uvlong off;
char buf[Pagesize];
static char zero[Pagesize];
s = emalloc(sizeof *s);
if(Breaduvlong(b, &s->offset) < 0
|| Breaduvlong(b, &s->len) < 0)
panic("error reading segment");
npg = (s->len + Pagesize-1)/Pagesize;
s->npg = npg;
if(s->npg == 0)
return s;
pp = emalloc(sizeof(*pp)*npg);
s->pg = pp;
*ps = s;
len = Pagesize;
for(i=0; i<npg; i++) {
if(i == npg-1)
len = s->len - i*Pagesize;
switch(t = Bgetc(b)) {
case 'z':
pp[i] = datapage(zero, len);
if(debug)
fprint(2, "0x%.8llux all zeros\n", s->offset+i*Pagesize);
break;
case 'm':
case 't':
if(Breadulong(b, &pid) < 0
|| Breaduvlong(b, &off) < 0)
panic("error reading segment x");
pp[i] = findpage(plist, pid, t, off);
if(pp[i] == nil)
panic("bad page reference in snapshot");
if(debug)
fprint(2, "0x%.8llux same as %s pid %lud 0x%.8llux\n", s->offset+i*Pagesize, t=='m'?"mem":"text", pid, off);
break;
case 'r':
if((n=Bread(b, buf, len)) != len)
sysfatal("short read of segment %d/%d at %llx: %r", n, len, Boffset(b));
pp[i] = datapage(buf, len);
if(debug)
fprint(2, "0x%.8llux is raw data\n", s->offset+i*Pagesize);
break;
default:
fprint(2, "bad type char %#.2ux\n", t);
panic("error reading segment");
}
}
return s;
}
Proc*
readsnap(Biobuf *b)
{
char *q;
char buf[12];
long pid;
Proc *p, *plist;
int i, n;
if((q = Brdline(b, '\n')) == nil)
panic("error reading snapshot file");
if(strncmp(q, "process snapshot", strlen("process snapshot")) != 0)
panic("bad snapshot file format");
plist = nil;
while(q = Brdline(b, '\n')) {
q[Blinelen(b)-1] = 0;
pid = atol(q);
q += 12;
p = findpid(plist, pid);
if(p == nil) {
p = emalloc(sizeof(*p));
p->link = plist;
p->pid = pid;
plist = p;
}
for(i=0; i<Npfile; i++) {
if(strcmp(pfile[i], q) == 0) {
p->d[i] = readdata(b);
break;
}
}
if(i != Npfile)
continue;
if(strcmp(q, "mem") == 0) {
if(Bread(b, buf, 12) != 12)
panic("can't read memory section");
n = atoi(buf);
p->nseg = n;
p->seg = emalloc(n*sizeof(*p->seg));
for(i=0; i<n; i++)
readseg(&p->seg[i], b, plist);
} else if(strcmp(q, "text") == 0)
readseg(&p->text, b, plist);
else
panic("unknown section");
}
return plist;
}
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