add alignment check of virtual address to exec()

67a7f959 · MikeCAT · Frans Kaashoek · a7c03bd9 · 67a7f959
--- a/exec.c
+++ b/exec.c
@@ -46,6 +46,8 @@ exec(char *path, char **argv)
      goto bad;
    if((sz = allocuvm(pgdir, sz, ph.vaddr + ph.memsz)) == 0)
      goto bad;
+    if(ph.vaddr % PGSIZE != 0)
+      goto bad;
    if(loaduvm(pgdir, (char*)ph.vaddr, ip, ph.off, ph.filesz) < 0)
      goto bad;
  }