[src/trunk]: src/sys Support PIOD_READ_AUXV so that gdb can handle PIE binari...

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

details:   https://anonhg.NetBSD.org/src/rev/87b2cbbf7180
branches:  trunk
changeset: 339178:87b2cbbf7180
user:      christos <christos%NetBSD.org@localhost>
date:      Thu Jul 02 03:47:54 2015 +0000

description:
Support PIOD_READ_AUXV so that gdb can handle PIE binaries. From OpenBSD.

diffstat:

 sys/kern/sys_process.c |  63 +++++++++++++++++++++++++++++++++++++++++++------
 sys/sys/ptrace.h       |   3 +-
 2 files changed, 57 insertions(+), 9 deletions(-)

diffs (133 lines):

diff -r 734fbd53594e -r 87b2cbbf7180 sys/kern/sys_process.c
--- a/sys/kern/sys_process.c    Wed Jul 01 18:18:00 2015 +0000
+++ b/sys/kern/sys_process.c    Thu Jul 02 03:47:54 2015 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: sys_process.c,v 1.165 2014/11/24 02:34:04 christos Exp $       */
+/*     $NetBSD: sys_process.c,v 1.166 2015/07/02 03:47:54 christos Exp $       */
 
 /*-
  * Copyright (c) 2008, 2009 The NetBSD Foundation, Inc.
@@ -118,7 +118,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: sys_process.c,v 1.165 2014/11/24 02:34:04 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: sys_process.c,v 1.166 2015/07/02 03:47:54 christos Exp $");
 
 #include "opt_ptrace.h"
 #include "opt_ktrace.h"
@@ -127,6 +127,7 @@
 #include <sys/systm.h>
 #include <sys/proc.h>
 #include <sys/errno.h>
+#include <sys/exec.h>
 #include <sys/ptrace.h>
 #include <sys/uio.h>
 #include <sys/ras.h>
@@ -148,6 +149,9 @@
 # endif
 
 static kauth_listener_t ptrace_listener;
+#ifdef PTRACE
+static int process_auxv_offset(struct proc *, struct uio *);
+#endif
 
 static int
 ptrace_listener_cb(kauth_cred_t cred, kauth_action_t action, void *cookie,
@@ -531,6 +535,14 @@
                error = copyin(SCARG(uap, addr), &piod, sizeof(piod));
                if (error)
                        break;
+
+               iov.iov_base = piod.piod_addr;
+               iov.iov_len = piod.piod_len;
+               uio.uio_iov = &iov;
+               uio.uio_iovcnt = 1;
+               uio.uio_offset = (off_t)(unsigned long)piod.piod_offs;
+               uio.uio_resid = piod.piod_len;
+
                switch (piod.piod_op) {
                case PIOD_READ_D:
                case PIOD_READ_I:
@@ -546,6 +558,19 @@
                        }
                        uio.uio_rw = UIO_WRITE;
                        break;
+               case PIOD_READ_AUXV:
+                       req = PT_READ_D;
+                       uio.uio_rw = UIO_READ;
+                       tmp = t->p_execsw->es_arglen * sizeof(char *);
+                       if (uio.uio_offset > tmp)
+                               return EIO;
+                       if (uio.uio_resid > tmp - uio.uio_offset)
+                               uio.uio_resid = tmp - uio.uio_offset;
+                       piod.piod_len = iov.iov_len = uio.uio_resid;
+                       error = process_auxv_offset(t, &uio);
+                       if (error)
+                               return error;
+                       break;
                default:
                        error = EINVAL;
                        break;
@@ -555,12 +580,6 @@
                error = proc_vmspace_getref(l->l_proc, &vm);
                if (error)
                        break;
-               iov.iov_base = piod.piod_addr;
-               iov.iov_len = piod.piod_len;
-               uio.uio_iov = &iov;
-               uio.uio_iovcnt = 1;
-               uio.uio_offset = (off_t)(unsigned long)piod.piod_offs;
-               uio.uio_resid = piod.piod_len;
                uio.uio_vmspace = vm;
 
                error = process_domem(l, lt, &uio);
@@ -1138,3 +1157,31 @@
        mutex_exit(p->p_lock);
 }
 #endif /* KTRACE || PTRACE */
+
+#ifdef PTRACE
+static int
+process_auxv_offset(struct proc *p, struct uio *uio)
+{
+       struct ps_strings pss;
+       int error;
+       off_t off = (off_t)p->p_psstrp;
+
+       if ((error = copyin_psstrings(p, &pss)) != 0)
+               return error;
+
+       if (pss.ps_envstr == NULL)
+               return EIO;
+
+       uio->uio_offset += (off_t)(vaddr_t)(pss.ps_envstr + pss.ps_nenvstr + 1);
+#ifdef __MACHINE_STACK_GROWS_UP
+       if (uio->uio_offset < off)
+               return EIO;
+#else
+       if (uio->uio_offset > off)
+               return EIO;
+       if ((uio->uio_offset + uio->uio_resid) > off)
+               uio->uio_resid = off - uio->uio_offset;
+#endif
+       return 0;
+}
+#endif
diff -r 734fbd53594e -r 87b2cbbf7180 sys/sys/ptrace.h
--- a/sys/sys/ptrace.h  Wed Jul 01 18:18:00 2015 +0000
+++ b/sys/sys/ptrace.h  Thu Jul 02 03:47:54 2015 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ptrace.h,v 1.45 2014/01/04 00:10:03 dsl Exp $  */
+/*     $NetBSD: ptrace.h,v 1.46 2015/07/02 03:47:54 christos Exp $     */
 
 /*-
  * Copyright (c) 1984, 1993
@@ -104,6 +104,7 @@
 #define        PIOD_WRITE_D    2       /* write to D spcae */
 #define        PIOD_READ_I     3       /* read from I space */
 #define        PIOD_WRITE_I    4       /* write to I space */
+#define PIOD_READ_AUXV 5       /* Read from aux array */
 
 /*
  * Argument structure for PT_LWPINFO.