[src/trunk]: src/sys/kern Add debugging.

[christos <christos%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/f688c8e46412
branches:  trunk
changeset: 347759:f688c8e46412
user:      christos <christos%NetBSD.org@localhost>
date:      Thu Sep 15 17:45:44 2016 +0000

description:
Add debugging.

diffstat:

 sys/kern/exec_elf.c |  50 +++++++++++++++++++++++++++++++++++++++++---------
 1 files changed, 41 insertions(+), 9 deletions(-)

diffs (165 lines):

diff -r 95fc4be3f992 -r f688c8e46412 sys/kern/exec_elf.c
--- a/sys/kern/exec_elf.c       Thu Sep 15 17:44:16 2016 +0000
+++ b/sys/kern/exec_elf.c       Thu Sep 15 17:45:44 2016 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: exec_elf.c,v 1.85 2016/05/25 17:25:32 christos Exp $   */
+/*     $NetBSD: exec_elf.c,v 1.86 2016/09/15 17:45:44 christos Exp $   */
 
 /*-
  * Copyright (c) 1994, 2000, 2005, 2015 The NetBSD Foundation, Inc.
@@ -57,7 +57,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(1, "$NetBSD: exec_elf.c,v 1.85 2016/05/25 17:25:32 christos Exp $");
+__KERNEL_RCSID(1, "$NetBSD: exec_elf.c,v 1.86 2016/09/15 17:45:44 christos Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_pax.h"
@@ -110,6 +110,11 @@
 
 static void    elf_free_emul_arg(void *);
 
+#ifdef DEBUG_ELF
+#define DPRINTF(a, ...)        printf("%s: " a "\n", __func__, ##__VA_ARGS__)
+#else
+#define DPRINTF(a, ...)
+
 /* round up and down to page boundaries. */
 #define        ELF_ROUND(a, b)         (((a) + (b) - 1) & ~((b) - 1))
 #define        ELF_TRUNC(a, b)         ((a) & ~((b) - 1))
@@ -259,22 +264,30 @@
 {
 
        if (memcmp(eh->e_ident, ELFMAG, SELFMAG) != 0 ||
-           eh->e_ident[EI_CLASS] != ELFCLASS)
+           eh->e_ident[EI_CLASS] != ELFCLASS) {
+               DPRINTF("bad magic %#x%x%x", eh->e_ident[0], eh->e_ident[1],
+                   eh->e_ident[2]);
                return ENOEXEC;
+       }
 
        switch (eh->e_machine) {
 
        ELFDEFNNAME(MACHDEP_ID_CASES)
 
        default:
+               DPRINTF("bad machine %#x", eh->e_machine);
                return ENOEXEC;
        }
 
-       if (ELF_EHDR_FLAGS_OK(eh) == 0)
+       if (ELF_EHDR_FLAGS_OK(eh) == 0) {
+               DPRINTF("bad flags %#x", eh->e_flags);
                return ENOEXEC;
+       }
 
-       if (eh->e_shnum > ELF_MAXSHNUM || eh->e_phnum > ELF_MAXPHNUM)
+       if (eh->e_shnum > ELF_MAXSHNUM || eh->e_phnum > ELF_MAXPHNUM) {
+               DPRINTF("bad shnum/phnum %#x/%#x", eh->e_shnum, eh->e_phnum);
                return ENOEXEC;
+       }
 
        return 0;
 }
@@ -451,6 +464,7 @@
        if ((error = elf_check_header(&eh)) != 0)
                goto bad;
        if (eh.e_type != ET_DYN || eh.e_phnum == 0) {
+               DPRINTF("bad interpreter type %#x", eh.e_type);
                error = ENOEXEC;
                goto bad;
        }
@@ -495,6 +509,7 @@
                }
 
                if (base_ph == NULL) {
+                       DPRINTF("no interpreter loadable sections");
                        error = ENOEXEC;
                        goto bad;
                }
@@ -616,19 +631,25 @@
        struct elf_args *ap;
        bool is_dyn = false;
 
-       if (epp->ep_hdrvalid < sizeof(Elf_Ehdr))
+       if (epp->ep_hdrvalid < sizeof(Elf_Ehdr)) {
+               DPRINTF("small header %#x", epp->ep_hdrvalid);
                return ENOEXEC;
+       }
        if ((error = elf_check_header(eh)) != 0)
                return error;
 
        if (eh->e_type == ET_DYN)
                /* PIE, and some libs have an entry point */
                is_dyn = true;
-       else if (eh->e_type != ET_EXEC)
+       else if (eh->e_type != ET_EXEC) {
+               DPRINTF("bad type %#x", eh->e_type);
                return ENOEXEC;
+       }
 
-       if (eh->e_phnum == 0)
+       if (eh->e_phnum == 0) {
+               DPRINTF("no program headers");
                return ENOEXEC;
+       }
 
        error = vn_marktext(epp->ep_vp);
        if (error)
@@ -652,6 +673,8 @@
                pp = &ph[i];
                if (pp->p_type == PT_INTERP) {
                        if (pp->p_filesz < 2 || pp->p_filesz > MAXPATHLEN) {
+                               DPRINTF("bad interpreter namelen %#jx",
+                                   (uintmax_t)pp->p_filesz);
                                error = ENOEXEC;
                                goto bad;
                        }
@@ -661,6 +684,7 @@
                                goto bad;
                        /* Ensure interp is NUL-terminated and of the expected length */
                        if (strnlen(interp, pp->p_filesz) != pp->p_filesz - 1) {
+                               DPRINTF("bad interpreter name");
                                error = ENOEXEC;
                                goto bad;
                        }
@@ -746,6 +770,7 @@
        if (epp->ep_vmcmds.evs_used == 0) {
                /* No VMCMD; there was no PT_LOAD section, or those
                 * sections were empty */
+               DPRINTF("no vmcommands");
                error = ENOEXEC;
                goto bad;
        }
@@ -769,6 +794,7 @@
                }
                if (epp->ep_vmcmds.evs_used == nused) {
                        /* elf_load_interp() has not set up any new VMCMD */
+                       DPRINTF("no vmcommands for interpreter");
                        error = ENOEXEC;
                        goto bad;
                }
@@ -839,8 +865,10 @@
 #endif
 
        epp->ep_pax_flags = 0;
-       if (eh->e_shnum > ELF_MAXSHNUM || eh->e_shnum == 0)
+       if (eh->e_shnum > ELF_MAXSHNUM || eh->e_shnum == 0) {
+               DPRINTF("no signature %#x", eh->e_shnum);
                return ENOEXEC;
+       }
 
        shsize = eh->e_shnum * sizeof(Elf_Shdr);
        sh = kmem_alloc(shsize, KM_SLEEP);
@@ -1004,6 +1032,10 @@
        kmem_free(np, ELF_MAXNOTESIZE);
 
        error = isnetbsd ? 0 : ENOEXEC;
+#ifdef DEBUG_ELF
+       if (error)
+               DPRINTF("not netbsd");
+#endif
 out:
        kmem_free(sh, shsize);
        return error;