libmach

src/libmach/crackmacho.c

@@ -0,0 +1,198 @@
+#include <u.h>
+#include <libc.h>
+#include <mach.h>
+#include "macho.h"
+
+static int mapmacho(Fhdr *fp, ulong base, Map *map, Regs**);
+
+static struct
+{
+	uint etype;
+	uint mtype;
+	Mach *mach;
+	char *name;
+	int (*coreregs)(Macho*, uchar**);
+} mtab[] = 
+{
+	MachoCpuPower,	MPOWER,		&machpower, 		"powerpc",	coreregsmachopower,
+};
+
+static uchar*
+load(int fd, ulong off, int size)
+{
+	uchar *a;
+
+	a = malloc(size);
+	if(a == nil)
+		return nil;
+	if(seek(fd, off, 0) < 0 || readn(fd, a, size) != size){
+		free(a);
+		return nil;
+	}
+	return a;
+}
+
+int
+crackmacho(int fd, Fhdr *fp)
+{
+	int i;
+	Macho *m;
+
+	if((m = machoinit(fd)) == nil)
+		return -1;
+
+	fp->fd = fd;
+	fp->macho = m;
+
+	for(i=0; i<nelem(mtab); i++){
+		if(m->cputype != mtab[i].etype)
+			continue;
+		fp->mach = mtab[i].mach;
+		fp->mtype = mtab[i].mtype;
+		fp->mname = mtab[i].name;
+		m->coreregs = mtab[i].coreregs;
+		break;
+	}
+	if(i == nelem(mtab)){
+		werrstr("unsupported cpu type %ud", m->cputype);
+		goto err;
+	}
+
+	fp->atype = AMACH;
+	fp->aname = "mach";
+
+	if(mach == nil)
+		mach = fp->mach;
+
+	switch(m->filetype){
+	default:
+		werrstr("unsupported macho file type %lud", m->filetype);
+		goto err;
+	case MachoFileObject:
+		fp->ftype = FOBJ;
+		fp->fname = "object";
+		break;
+	case MachoFileExecutable:
+		fp->ftype = FEXEC;
+		fp->fname = "executable";
+		break;
+	case MachoFileFvmlib:
+		fp->ftype = FSHLIB;
+		fp->fname = "shared library";
+		break;
+	case MachoFileCore:
+		fp->ftype = FCORE;
+		fp->fname = "core";
+		break;
+	case MachoFilePreload:
+		fp->ftype = FBOOT;
+		fp->fname = "preloaded executable";
+		break;
+	}
+
+	fp->txtaddr = fp->dataddr = 0;
+	fp->txtsz = fp->datsz = 0;
+	for(i=0; i<m->ncmd; i++){
+		if(m->cmd[i].type != MachoCmdSegment)
+			continue;
+		if(strcmp(m->cmd[i].seg.name, "__TEXT") == 0){
+			fp->txtaddr = m->cmd[i].seg.vmaddr;
+			fp->txtsz = m->cmd[i].seg.vmsize;
+			fp->txtoff = m->cmd[i].seg.fileoff;
+		}
+		if(strcmp(m->cmd[i].seg.name, "__DATA") == 0){
+			fp->dataddr = m->cmd[i].seg.vmaddr;
+			fp->datsz = m->cmd[i].seg.filesz;
+			fp->datoff = m->cmd[i].seg.fileoff;
+			fp->bsssz = m->cmd[i].seg.vmsize - fp->datsz;
+		}
+	}
+
+	fp->map = mapmacho;
+	fp->syminit = symmacho;
+
+	for(i=0; i<m->ncmd; i++)
+		if(m->cmd[i].type == MachoCmdSymtab)
+			break;
+	if(i < m->ncmd){
+		fp->stabs.stabbase = load(fp->fd, m->cmd[i].sym.symoff, m->cmd[i].sym.nsyms*16);
+		fp->stabs.stabsize = m->cmd[i].sym.nsyms*16;
+		fp->stabs.strbase = load(fp->fd, m->cmd[i].sym.stroff, m->cmd[i].sym.strsize);
+		if(fp->stabs.stabbase == nil || fp->stabs.strbase == nil){
+			fp->stabs.stabbase = nil;
+			fp->stabs.strbase = nil;
+		}else{
+			fp->stabs.strsize = m->cmd[i].sym.strsize;
+			fp->stabs.e2 = (m->e4==beload4 ? beload2 : leload2);
+			fp->stabs.e4 = m->e4;
+		}
+	}
+
+	return 0;
+
+err:
+	machoclose(m);
+	return -1;
+}
+
+static int
+mapmacho(Fhdr *fp, ulong base, Map *map, Regs **rp)
+{
+	int i, n;
+	uchar *u;
+	Macho *m;
+	MachoCmd *c;
+	Seg s;
+	UregRegs *r;
+
+	m = fp->macho;
+	if(m == nil){
+		werrstr("not a macho file");
+		return -1;
+	}
+
+	for(i=0; i<m->ncmd; i++){
+		c = &m->cmd[i];
+		if(c->type != MachoCmdSegment)
+			continue;
+		if(c->seg.filesz){
+			memset(&s, 0, sizeof s);
+			s.file = fp->filename;
+			s.fd = fp->fd;
+			if(fp->ftype == FCORE)
+				s.name = "core";
+			else if(strcmp(c->seg.name, "__DATA") == 0)
+				s.name = "data";
+			else
+				s.name = "text";
+			s.base = base+c->seg.vmaddr;
+			s.size = c->seg.filesz;
+			s.offset = c->seg.fileoff;
+			if(addseg(map, s) < 0)
+				return -1;
+		}
+		if(c->seg.filesz < c->seg.vmsize){
+			memset(&s, 0, sizeof s);
+			s.name = "zero";
+			s.base = base + c->seg.vmaddr + c->seg.filesz;
+			s.size = c->seg.vmsize - c->seg.filesz;
+			if(addseg(map, s) < 0)
+				return -1;
+		}
+	}
+
+	if(fp->ftype == FCORE && m->coreregs){
+		n = m->coreregs(m, &u);
+		if(n < 0){
+			fprint(2, "mapping registers: %r\n");
+			goto noregs;
+		}
+		if((r = mallocz(sizeof *r, 1)) == nil)
+			return -1;
+		r->r.rw = _uregrw;
+		r->ureg = u;	
+		*rp = &r->r;
+	}
+noregs:
+	return 0;
+}