Import sources from 2011-03-30 iso image

1 files changed, 246 insertions, 0 deletions

diff --git a/sys/src/cmd/snap/read.c b/sys/src/cmd/snap/read.c
new file mode 100755
index 000000000..961781807
--- /dev/null
+++ b/sys/src/cmd/snap/read.c
@@ -0,0 +1,246 @@
+#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;
+}