gopack: allow ELF/Mach-O objects in .a files without clearing allobj

R=iant
CC=golang-dev
https://golang.org/cl/3503041

diff --git a/src/cmd/gopack/ar.c b/src/cmd/gopack/ar.c
index 5c8cd75efd1fe2652ebd720eb58b39bd58ef440a..063967bd70bc80fb69f138b02405a0acb2caeead 100644 (file)
--- a/src/cmd/gopack/ar.c
+++ b/src/cmd/gopack/ar.c
@@ -593,12 +593,26 @@ scanobj(Biobuf *b, Arfile *ap, long size)
        vlong offset;
        Dir *d;
        static int lastobj = -1;
+       uchar buf[4];
 
        if (!allobj)                    /* non-object file encountered */
                return;
        offset = Boffset(b);
        obj = objtype(b, 0);
        if (obj < 0) {                  /* not an object file */
+               /* maybe a foreign object file */
+               Bseek(b, offset, 0);
+               memset(buf, 0, sizeof buf);
+               Bread(b, buf, 4);
+               
+               /* maybe a foreign object file?  that's okay */
+               if((buf[0] == 0x7F && buf[1] == 'E' && buf[2] == 'L' && buf[3] == 'F') ||   // ELF
+                  (buf[0] == 0xFE && buf[1] == 0xED && buf[2] == 0xFA && (buf[3]&~1) == 0xCE) ||  // Mach-O big-endian
+                  (buf[3] == 0xFE && buf[2] == 0xED && buf[1] == 0xFA && (buf[0]&~1) == 0xCE)) {  // Mach-O little-endian
+                       Bseek(b, offset, 0);
+                       return;
+               }
+               
                if (!gflag || strcmp(file, pkgdef) != 0) {  /* don't clear allobj if it's pkg defs */
                        fprint(2, "gopack: non-object file %s\n", file);
                        errors++;