[v5] Generate NT_PROCSTAT_{AUXV,VMMAP,PS_STRINGS} in FreeBSD coredumps

Message ID h3x9R8eOcXQBRVyDqS1d2dSBbWjK755lzNGO8KjTlTMnyKZgKltVJToxgowu8o8MxqAhmiPv0FqYmc7nvcZGoM_wawX5-6dTDZFuriS9_2o=@emersion.fr
State New
Headers show
Series
  • [v5] Generate NT_PROCSTAT_{AUXV,VMMAP,PS_STRINGS} in FreeBSD coredumps
Related show

Commit Message

Simon Ser Aug. 23, 2018, 5:10 p.m.
gcore generates NT_AUXV and NT_FILE notes for Linux targets. On
FreeBSD auxv is stored in a NT_PROCSTAT_AUXV section, virtual memory
mappings are stored in a NT_PROCSTAT_VMMAP and both are prefixed with
the struct size.

2018-08-23  Simon Ser  <contact@emersion.fr>
        * target.h (enum target_object): add FreeBSD-specific
        TARGET_OBJECT_FREEBSD_VMMAP and TARGET_OBJECT_FREEBSD_PS_STRINGS
        * fbsd-nat.c (fbsd_nat_target::xfer_partial): add support for
        TARGET_OBJECT_FREEBSD_VMMAP and TARGET_OBJECT_FREEBSD_PS_STRINGS
        * fbsd-tdep.c (fbsd_make_corefile_notes): write NT_PROCSTAT_AUXV,
        NT_PROCSTAT_VMMAP and NT_PROCSTAT_PS_STRINGS notes
---

Changes from v4 to v5:
- Fixed buflen too large before sysctl

 gdb/fbsd-nat.c  | 55 +++++++++++++++++++++++++++++++++++++++++++++++++
 gdb/fbsd-tdep.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++
 gdb/target.h    |  4 ++++
 3 files changed, 113 insertions(+)

-- 
2.18.0

Comments

Simon Ser Sept. 2, 2018, 8:01 p.m. | #1
Hi John,

Did you have time to have a look at this new version ?

Thanks,
---
Simon Ser
https://emersion.fr

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On 23 August 2018 7:10 PM, Simon Ser <contact@emersion.fr> wrote:

> gcore generates NT_AUXV and NT_FILE notes for Linux targets. On

> FreeBSD auxv is stored in a NT_PROCSTAT_AUXV section, virtual memory

> mappings are stored in a NT_PROCSTAT_VMMAP and both are prefixed with

> the struct size.

>

> 2018-08-23 Simon Ser contact@emersion.fr

>

>         * target.h (enum target_object): add FreeBSD-specific

>         TARGET_OBJECT_FREEBSD_VMMAP and TARGET_OBJECT_FREEBSD_PS_STRINGS

>         * fbsd-nat.c (fbsd_nat_target::xfer_partial): add support for

>         TARGET_OBJECT_FREEBSD_VMMAP and TARGET_OBJECT_FREEBSD_PS_STRINGS

>         * fbsd-tdep.c (fbsd_make_corefile_notes): write NT_PROCSTAT_AUXV,

>         NT_PROCSTAT_VMMAP and NT_PROCSTAT_PS_STRINGS notes

>

>

> Changes from v4 to v5:

>

> -   Fixed buflen too large before sysctl

>

>     gdb/fbsd-nat.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++

>     gdb/fbsd-tdep.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++

>     gdb/target.h | 4 ++++

>     3 files changed, 113 insertions(+)

>

>     diff --git a/gdb/fbsd-nat.c b/gdb/fbsd-nat.c

>     index 115deac0..3c1904a1 100644

>     --- a/gdb/fbsd-nat.c

>     +++ b/gdb/fbsd-nat.c

>     @@ -751,6 +751,61 @@ fbsd_nat_target::xfer_partial (enum target_object object,

>     }

>     return TARGET_XFER_E_IO;

>     }

>

>

> -   case TARGET_OBJECT_FREEBSD_VMMAP:

>

> -   case TARGET_OBJECT_FREEBSD_PS_STRINGS:

>

> -        {

>

>

> -   gdb::byte_vector buf_storage;

>

> -   gdb_byte *buf;

>

> -   size_t buflen;

>

> -   int mib[4];

>

> -

> -   int proc_target;

>

> -   uint32_t struct_size;

>

> -   switch (object)

>

> -       {

>

>

> -       case TARGET_OBJECT_FREEBSD_VMMAP:

>

>

> -         proc_target = KERN_PROC_VMMAP;

>

>

> -         struct_size = sizeof (struct kinfo_vmentry);

>

>

> -         break;

>

>

> -       case TARGET_OBJECT_FREEBSD_PS_STRINGS:

>

>

> -         proc_target = KERN_PROC_PS_STRINGS;

>

>

> -         struct_size = sizeof (void *);

>

>

> -         break;

>

>

> -       }

>

>

> -

> -   if (writebuf != NULL)

>

> -       return TARGET_XFER_E_IO;

>

>

> -

> -   mib[0] = CTL_KERN;

>

> -   mib[1] = KERN_PROC;

>

> -   mib[2] = proc_target;

>

> -   mib[3] = pid;

>

> -

> -   if (sysctl (mib, 4, NULL, &buflen, NULL, 0) != 0)

>

> -       return TARGET_XFER_E_IO;

>

>

> -   buflen += sizeof (struct_size);

>

> -

> -   if (offset >= buflen)

>

> -       {

>

>

> -         *xfered_len = 0;

>

>

> -         return TARGET_XFER_EOF;

>

>

> -       }

>

>

> -

> -   buf_storage.resize (buflen);

>

> -   buf = buf_storage.data ();

>

> -

> -   memcpy (buf, &struct_size, sizeof (struct_size));

>

> -   buflen -= sizeof (struct_size);

>

> -   if (sysctl (mib, 4, buf + sizeof (struct_size), &buflen, NULL, 0) != 0)

>

> -       return TARGET_XFER_E_IO;

>

>

> -   buflen += sizeof (struct_size);

>

> -

> -   if (offset + len > buflen)

>

> -       len = buflen - offset;

>

>

> -   memcpy (readbuf, buf + offset, len);

>

> -   *xfered_len = len;

>

> -   return TARGET_XFER_OK;

>

> -        }

>

>

>     default:

>     return inf_ptrace_target::xfer_partial (object, annex,

>     readbuf, writebuf, offset,

>     diff --git a/gdb/fbsd-tdep.c b/gdb/fbsd-tdep.c

>     index 9cea0098..9242c244 100644

>     --- a/gdb/fbsd-tdep.c

>     +++ b/gdb/fbsd-tdep.c

>     @@ -512,6 +512,23 @@ fbsd_corefile_thread (struct thread_info *info,

>     args->note_size, args->stop_signal);

>

>

> }

>

> +static gdb::optionalgdb::byte_vector

> +fbsd_make_note_desc (enum target_object object, uint32_t structsize)

> +{

>

> -   gdb::optionalgdb::byte_vector buf =

>

> -   target_read_alloc (current_top_target (), object, NULL);

>

> -   if (!buf || buf->empty ())

>

> -   return {};

>

> -

> -   if (structsize == 0)

>

> -   return buf;

>

> -

> -   gdb::byte_vector desc (sizeof (structsize) + buf->size ());

>

> -   memcpy (desc.data (), &structsize, sizeof (structsize));

>

> -   memcpy (desc.data () + sizeof (structsize), buf->data (), buf->size ());

>

> -   return desc;

>     +}

>

> -

>

> /* Create appropriate note sections for a corefile, returning them in

> allocated memory. */

>

> @@ -586,6 +603,43 @@ fbsd_make_corefile_notes (struct gdbarch *gdbarch, bfd *obfd, int *note_size)

>

> note_data = thread_args.note_data;

>

> -   pid_t pid = inferior_ptid.pid ();

>

> -

> -   /* Auxiliary vector. */

>

> -   uint32_t structsize = gdbarch_ptr_bit (gdbarch) / 4; /* Elf_Auxinfo */

>

> -   gdb::optionalgdb::byte_vector note_desc =

>

> -   fbsd_make_note_desc (TARGET_OBJECT_AUXV, structsize);

>

> -   if (note_desc && !note_desc->empty ())

>

> -   {

>

> -        note_data = elfcore_write_note (obfd, note_data, note_size,

>

>

> -         		      "FreeBSD", NT_FREEBSD_PROCSTAT_AUXV,

>

>

> -         		      note_desc->data (), note_desc->size ());

>

>

> -        if (!note_data)

>

>

> -   return NULL;

>

> -   }

>

> -

> -   /* Virtual memory mappings */

>

> -   note_desc = fbsd_make_note_desc (TARGET_OBJECT_FREEBSD_VMMAP, 0);

>

> -   if (note_desc && !note_desc->empty ())

>

> -   {

>

> -        note_data = elfcore_write_note (obfd, note_data, note_size,

>

>

> -         		      "FreeBSD", NT_FREEBSD_PROCSTAT_VMMAP,

>

>

> -         		      note_desc->data (), note_desc->size ());

>

>

> -        if (!note_data)

>

>

> -   return NULL;

>

> -   }

>

> -

> -   note_desc =

>

> -   fbsd_make_note_desc (TARGET_OBJECT_FREEBSD_PS_STRINGS, 0);

>

> -   if (note_desc && !note_desc->empty ())

>

> -   {

>

> -        note_data = elfcore_write_note (obfd, note_data, note_size, "FreeBSD",

>

>

> -         		      NT_FREEBSD_PROCSTAT_PSSTRINGS,

>

>

> -         		      note_desc->data (), note_desc->size ());

>

>

> -        if (!note_data)

>

>

> -   return NULL;

>

> -   }

>

> -   return note_data;

>     }

>

>     diff --git a/gdb/target.h b/gdb/target.h

>     index 18c4a84c..c584af54 100644

>     --- a/gdb/target.h

>     +++ b/gdb/target.h

>     @@ -203,6 +203,10 @@ enum target_object

>     of the process ID of the process in question, in hexadecimal

>     format. */

>     TARGET_OBJECT_EXEC_FILE,

>

> -   /* FreeBSD virtual memory mappings */

>

> -   TARGET_OBJECT_FREEBSD_VMMAP,

>

> -   /* FreeBSD process strings */

>

> -   TARGET_OBJECT_FREEBSD_PS_STRINGS,

>     /* Possible future objects: TARGET_OBJECT_FILE, ... */

>     };

>

>     --

>     2.18.0

>
John Baldwin Sept. 6, 2018, 10:12 p.m. | #2
On 9/2/18 1:01 PM, Simon Ser wrote:
> Hi John,

> 

> Did you have time to have a look at this new version ?


Yes, sorry for the delay.  I've fixed a few small nits (updating gdb/ChangeLog,
adding a reference to a PR that this change fixes by including auxv info in
gcore output, etc.) and pushed it.
-- 
John Baldwin

Patch

diff --git a/gdb/fbsd-nat.c b/gdb/fbsd-nat.c
index 115deac0..3c1904a1 100644
--- a/gdb/fbsd-nat.c
+++ b/gdb/fbsd-nat.c
@@ -751,6 +751,61 @@  fbsd_nat_target::xfer_partial (enum target_object object,
 	  }
 	return TARGET_XFER_E_IO;
       }
+    case TARGET_OBJECT_FREEBSD_VMMAP:
+    case TARGET_OBJECT_FREEBSD_PS_STRINGS:
+      {
+	gdb::byte_vector buf_storage;
+	gdb_byte *buf;
+	size_t buflen;
+	int mib[4];
+
+	int proc_target;
+	uint32_t struct_size;
+	switch (object)
+	  {
+	  case TARGET_OBJECT_FREEBSD_VMMAP:
+	    proc_target = KERN_PROC_VMMAP;
+	    struct_size = sizeof (struct kinfo_vmentry);
+	    break;
+	  case TARGET_OBJECT_FREEBSD_PS_STRINGS:
+	    proc_target = KERN_PROC_PS_STRINGS;
+	    struct_size = sizeof (void *);
+	    break;
+	  }
+
+	if (writebuf != NULL)
+	  return TARGET_XFER_E_IO;
+
+	mib[0] = CTL_KERN;
+	mib[1] = KERN_PROC;
+	mib[2] = proc_target;
+	mib[3] = pid;
+
+	if (sysctl (mib, 4, NULL, &buflen, NULL, 0) != 0)
+	  return TARGET_XFER_E_IO;
+	buflen += sizeof (struct_size);
+
+	if (offset >= buflen)
+	  {
+	    *xfered_len = 0;
+	    return TARGET_XFER_EOF;
+	  }
+
+	buf_storage.resize (buflen);
+	buf = buf_storage.data ();
+
+	memcpy (buf, &struct_size, sizeof (struct_size));
+	buflen -= sizeof (struct_size);
+	if (sysctl (mib, 4, buf + sizeof (struct_size), &buflen, NULL, 0) != 0)
+	  return TARGET_XFER_E_IO;
+	buflen += sizeof (struct_size);
+
+	if (offset + len > buflen)
+	  len = buflen - offset;
+	memcpy (readbuf, buf + offset, len);
+	*xfered_len = len;
+	return TARGET_XFER_OK;
+      }
     default:
       return inf_ptrace_target::xfer_partial (object, annex,
 					      readbuf, writebuf, offset,
diff --git a/gdb/fbsd-tdep.c b/gdb/fbsd-tdep.c
index 9cea0098..9242c244 100644
--- a/gdb/fbsd-tdep.c
+++ b/gdb/fbsd-tdep.c
@@ -512,6 +512,23 @@  fbsd_corefile_thread (struct thread_info *info,
      args->note_size, args->stop_signal);
 }
 
+static gdb::optional<gdb::byte_vector>
+fbsd_make_note_desc (enum target_object object, uint32_t structsize)
+{
+  gdb::optional<gdb::byte_vector> buf =
+    target_read_alloc (current_top_target (), object, NULL);
+  if (!buf || buf->empty ())
+    return {};
+
+  if (structsize == 0)
+    return buf;
+
+  gdb::byte_vector desc (sizeof (structsize) + buf->size ());
+  memcpy (desc.data (), &structsize, sizeof (structsize));
+  memcpy (desc.data () + sizeof (structsize), buf->data (), buf->size ());
+  return desc;
+}
+
 /* Create appropriate note sections for a corefile, returning them in
    allocated memory.  */
 
@@ -586,6 +603,43 @@  fbsd_make_corefile_notes (struct gdbarch *gdbarch, bfd *obfd, int *note_size)
 
   note_data = thread_args.note_data;
 
+  pid_t pid = inferior_ptid.pid ();
+
+  /* Auxiliary vector.  */
+  uint32_t structsize = gdbarch_ptr_bit (gdbarch) / 4; /* Elf_Auxinfo  */
+  gdb::optional<gdb::byte_vector> note_desc =
+    fbsd_make_note_desc (TARGET_OBJECT_AUXV, structsize);
+  if (note_desc && !note_desc->empty ())
+    {
+      note_data = elfcore_write_note (obfd, note_data, note_size,
+				      "FreeBSD", NT_FREEBSD_PROCSTAT_AUXV,
+				      note_desc->data (), note_desc->size ());
+      if (!note_data)
+	return NULL;
+    }
+
+  /* Virtual memory mappings  */
+  note_desc = fbsd_make_note_desc (TARGET_OBJECT_FREEBSD_VMMAP, 0);
+  if (note_desc && !note_desc->empty ())
+    {
+      note_data = elfcore_write_note (obfd, note_data, note_size,
+				      "FreeBSD", NT_FREEBSD_PROCSTAT_VMMAP,
+				      note_desc->data (), note_desc->size ());
+      if (!note_data)
+	return NULL;
+    }
+
+  note_desc =
+    fbsd_make_note_desc (TARGET_OBJECT_FREEBSD_PS_STRINGS, 0);
+  if (note_desc && !note_desc->empty ())
+    {
+      note_data = elfcore_write_note (obfd, note_data, note_size, "FreeBSD",
+				      NT_FREEBSD_PROCSTAT_PSSTRINGS,
+				      note_desc->data (), note_desc->size ());
+      if (!note_data)
+	return NULL;
+    }
+
   return note_data;
 }
 
diff --git a/gdb/target.h b/gdb/target.h
index 18c4a84c..c584af54 100644
--- a/gdb/target.h
+++ b/gdb/target.h
@@ -203,6 +203,10 @@  enum target_object
      of the process ID of the process in question, in hexadecimal
      format.  */
   TARGET_OBJECT_EXEC_FILE,
+  /* FreeBSD virtual memory mappings  */
+  TARGET_OBJECT_FREEBSD_VMMAP,
+  /* FreeBSD process strings  */
+  TARGET_OBJECT_FREEBSD_PS_STRINGS,
   /* Possible future objects: TARGET_OBJECT_FILE, ...  */
 };