diff mbox series

mips: pldd: support DT_MIPS_RLD_MAP and DT_MIPS_RLD_MAP_REL

Message ID 046da3ae8fc57687b5a9480381904d3f53b1010f.camel@mengyan1223.wang
State Superseded
Headers
Series mips: pldd: support DT_MIPS_RLD_MAP and DT_MIPS_RLD_MAP_REL |

Checks

Context Check Description
dj/TryBot-apply_patch success Patch applied to master at the time it was sent
dj/TryBot-32bit success Build for i686

Commit Message

Xi Ruoyao Jan. 28, 2022, 6:56 p.m. UTC 
  MIPS uses DT_MIPS_RLD_MAP and DT_MIPS_RLD_MAP_REL for accessing r_debug,
instead of DT_DEBUG.
---
 elf/pldd-xx.c | 67 ++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 53 insertions(+), 14 deletions(-)

Comments

H.J. Lu Jan. 28, 2022, 8:45 p.m. UTC | #1 
On Fri, Jan 28, 2022 at 10:57 AM Xi Ruoyao via Libc-alpha
<libc-alpha@sourceware.org> wrote:
>
> MIPS uses DT_MIPS_RLD_MAP and DT_MIPS_RLD_MAP_REL for accessing r_debug,
> instead of DT_DEBUG.
> ---
>  elf/pldd-xx.c | 67 ++++++++++++++++++++++++++++++++++++++++-----------
>  1 file changed, 53 insertions(+), 14 deletions(-)
>
> diff --git a/elf/pldd-xx.c b/elf/pldd-xx.c
> index 1cdfb49c53..ec397f00e5 100644
> --- a/elf/pldd-xx.c
> +++ b/elf/pldd-xx.c
> @@ -22,6 +22,12 @@
>  #define EW_(e, w, t) EW__(e, w, _##t)
>  #define EW__(e, w, t) e##w##t
>
> +#if CLASS == 32
> +typedef Elf32_Word E(val_type);
> +#else
> +typedef Elf64_Xword E(val_type);
> +#endif
> +
>  struct E(link_map)
>  {
>    EW(Addr) l_addr;
> @@ -70,6 +76,35 @@ _Static_assert (offsetof (struct r_debug, r_map)
>                 == offsetof (struct E(r_debug), r_map), "r_map");
>  #endif
>
> +static EW(Addr)
> +E(r_debug_offset) (EW(Dyn) *d, int memfd, EW(Addr) d_addr)
> +{
> +#ifdef __mips__
> +  EW(Addr) ptr;
> +
> +  switch (d->d_tag)
> +    {
> +    case DT_MIPS_RLD_MAP_REL:
> +      ptr = d_addr + d->d_un.d_val;
> +      break;
> +    case DT_MIPS_RLD_MAP:
> +      ptr = d->d_un.d_ptr;
> +      break;
> +    default:
> +      return 0;
> +    }
> +
> +    if (pread (memfd, &ptr, sizeof (ptr), ptr) != sizeof (ptr))
> +      return 0;
> +
> +    return ptr;
> +#else
> +  if (d->d_tag == DT_DEBUG)
> +    return (off_t) d->d_un.d_ptr;
> +
> +  return 0;
> +#endif
> +}
>
>  static int
>
> @@ -126,21 +161,25 @@ E(find_maps) (const char *exe, int memfd, pid_t pid, void *auxv,
>             != p[i].p_filesz)
>           error (EXIT_FAILURE, 0, gettext ("cannot read dynamic section"));
>
> -       /* Search for the DT_DEBUG entry.  */
> +       /* Search for the r_debug struct.  */
>         for (unsigned int j = 0; j < p[i].p_filesz / sizeof (EW(Dyn)); ++j)
> -         if (dyn[j].d_tag == DT_DEBUG && dyn[j].d_un.d_ptr != 0)
> -           {
> -             struct E(r_debug) r;
> -             if (pread (memfd, &r, sizeof (r), dyn[j].d_un.d_ptr)
> -                 != sizeof (r))
> -               error (EXIT_FAILURE, 0, gettext ("cannot read r_debug"));
> -
> -             if (r.r_map != 0)
> -               {
> -                 list = r.r_map;
> -                 break;
> -               }
> -           }
> +         {
> +           EW(Addr) d_addr = offset + p[i].p_vaddr + sizeof (EW(Dyn)) * j;
> +           EW(Addr) off = E(r_debug_offset)(&dyn[j], memfd, d_addr);
> +           if (off != 0)
> +             {
> +               struct E(r_debug) r;
> +               if (pread (memfd, &r, sizeof (r), off)
> +                   != sizeof (r))
> +                 error (EXIT_FAILURE, 0, gettext ("cannot read r_debug"));
> +
> +               if (r.r_map != 0)
> +                 {
> +                   list = r.r_map;
> +                   break;
> +                 }
> +             }
> +         }
>
>         free (dyn);
>         break;
> --
> 2.35.0
>
>

I think a header file to access r_debug works better.  MIPS can provide
one to override the generic header file.
Adhemerval Zanella Jan. 28, 2022, 8:48 p.m. UTC | #2 
On 28/01/2022 17:45, H.J. Lu via Libc-alpha wrote:
> On Fri, Jan 28, 2022 at 10:57 AM Xi Ruoyao via Libc-alpha
> <libc-alpha@sourceware.org> wrote:
>>
>> MIPS uses DT_MIPS_RLD_MAP and DT_MIPS_RLD_MAP_REL for accessing r_debug,
>> instead of DT_DEBUG.
>> ---
>>  elf/pldd-xx.c | 67 ++++++++++++++++++++++++++++++++++++++++-----------
>>  1 file changed, 53 insertions(+), 14 deletions(-)
>>
>> diff --git a/elf/pldd-xx.c b/elf/pldd-xx.c
>> index 1cdfb49c53..ec397f00e5 100644
>> --- a/elf/pldd-xx.c
>> +++ b/elf/pldd-xx.c
>> @@ -22,6 +22,12 @@
>>  #define EW_(e, w, t) EW__(e, w, _##t)
>>  #define EW__(e, w, t) e##w##t
>>
>> +#if CLASS == 32
>> +typedef Elf32_Word E(val_type);
>> +#else
>> +typedef Elf64_Xword E(val_type);
>> +#endif
>> +
>>  struct E(link_map)
>>  {
>>    EW(Addr) l_addr;
>> @@ -70,6 +76,35 @@ _Static_assert (offsetof (struct r_debug, r_map)
>>                 == offsetof (struct E(r_debug), r_map), "r_map");
>>  #endif
>>
>> +static EW(Addr)
>> +E(r_debug_offset) (EW(Dyn) *d, int memfd, EW(Addr) d_addr)
>> +{
>> +#ifdef __mips__
>> +  EW(Addr) ptr;
>> +
>> +  switch (d->d_tag)
>> +    {
>> +    case DT_MIPS_RLD_MAP_REL:
>> +      ptr = d_addr + d->d_un.d_val;
>> +      break;
>> +    case DT_MIPS_RLD_MAP:
>> +      ptr = d->d_un.d_ptr;
>> +      break;
>> +    default:
>> +      return 0;
>> +    }
>> +
>> +    if (pread (memfd, &ptr, sizeof (ptr), ptr) != sizeof (ptr))
>> +      return 0;
>> +
>> +    return ptr;
>> +#else
>> +  if (d->d_tag == DT_DEBUG)
>> +    return (off_t) d->d_un.d_ptr;
>> +
>> +  return 0;
>> +#endif
>> +}
>>
>>  static int
>>
>> @@ -126,21 +161,25 @@ E(find_maps) (const char *exe, int memfd, pid_t pid, void *auxv,
>>             != p[i].p_filesz)
>>           error (EXIT_FAILURE, 0, gettext ("cannot read dynamic section"));
>>
>> -       /* Search for the DT_DEBUG entry.  */
>> +       /* Search for the r_debug struct.  */
>>         for (unsigned int j = 0; j < p[i].p_filesz / sizeof (EW(Dyn)); ++j)
>> -         if (dyn[j].d_tag == DT_DEBUG && dyn[j].d_un.d_ptr != 0)
>> -           {
>> -             struct E(r_debug) r;
>> -             if (pread (memfd, &r, sizeof (r), dyn[j].d_un.d_ptr)
>> -                 != sizeof (r))
>> -               error (EXIT_FAILURE, 0, gettext ("cannot read r_debug"));
>> -
>> -             if (r.r_map != 0)
>> -               {
>> -                 list = r.r_map;
>> -                 break;
>> -               }
>> -           }
>> +         {
>> +           EW(Addr) d_addr = offset + p[i].p_vaddr + sizeof (EW(Dyn)) * j;
>> +           EW(Addr) off = E(r_debug_offset)(&dyn[j], memfd, d_addr);
>> +           if (off != 0)
>> +             {
>> +               struct E(r_debug) r;
>> +               if (pread (memfd, &r, sizeof (r), off)
>> +                   != sizeof (r))
>> +                 error (EXIT_FAILURE, 0, gettext ("cannot read r_debug"));
>> +
>> +               if (r.r_map != 0)
>> +                 {
>> +                   list = r.r_map;
>> +                   break;
>> +                 }
>> +             }
>> +         }
>>
>>         free (dyn);
>>         break;
>> --
>> 2.35.0
>>
>>
> 
> I think a header file to access r_debug works better.  MIPS can provide
> one to override the generic header file.
> 

Agreed, I think we should avoid arch specific defines (__mips__) on generic
code.
Carlos O'Donell Jan. 28, 2022, 8:50 p.m. UTC | #3 
On 1/28/22 15:48, Adhemerval Zanella via Libc-alpha wrote:
> 
> 
> On 28/01/2022 17:45, H.J. Lu via Libc-alpha wrote:
>> On Fri, Jan 28, 2022 at 10:57 AM Xi Ruoyao via Libc-alpha
>> <libc-alpha@sourceware.org> wrote:
>>>
>>> MIPS uses DT_MIPS_RLD_MAP and DT_MIPS_RLD_MAP_REL for accessing r_debug,
>>> instead of DT_DEBUG.
>>> ---
>>>  elf/pldd-xx.c | 67 ++++++++++++++++++++++++++++++++++++++++-----------
>>>  1 file changed, 53 insertions(+), 14 deletions(-)
>>>
>>> diff --git a/elf/pldd-xx.c b/elf/pldd-xx.c
>>> index 1cdfb49c53..ec397f00e5 100644
>>> --- a/elf/pldd-xx.c
>>> +++ b/elf/pldd-xx.c
>>> @@ -22,6 +22,12 @@
>>>  #define EW_(e, w, t) EW__(e, w, _##t)
>>>  #define EW__(e, w, t) e##w##t
>>>
>>> +#if CLASS == 32
>>> +typedef Elf32_Word E(val_type);
>>> +#else
>>> +typedef Elf64_Xword E(val_type);
>>> +#endif
>>> +
>>>  struct E(link_map)
>>>  {
>>>    EW(Addr) l_addr;
>>> @@ -70,6 +76,35 @@ _Static_assert (offsetof (struct r_debug, r_map)
>>>                 == offsetof (struct E(r_debug), r_map), "r_map");
>>>  #endif
>>>
>>> +static EW(Addr)
>>> +E(r_debug_offset) (EW(Dyn) *d, int memfd, EW(Addr) d_addr)
>>> +{
>>> +#ifdef __mips__
>>> +  EW(Addr) ptr;
>>> +
>>> +  switch (d->d_tag)
>>> +    {
>>> +    case DT_MIPS_RLD_MAP_REL:
>>> +      ptr = d_addr + d->d_un.d_val;
>>> +      break;
>>> +    case DT_MIPS_RLD_MAP:
>>> +      ptr = d->d_un.d_ptr;
>>> +      break;
>>> +    default:
>>> +      return 0;
>>> +    }
>>> +
>>> +    if (pread (memfd, &ptr, sizeof (ptr), ptr) != sizeof (ptr))
>>> +      return 0;
>>> +
>>> +    return ptr;
>>> +#else
>>> +  if (d->d_tag == DT_DEBUG)
>>> +    return (off_t) d->d_un.d_ptr;
>>> +
>>> +  return 0;
>>> +#endif
>>> +}
>>>
>>>  static int
>>>
>>> @@ -126,21 +161,25 @@ E(find_maps) (const char *exe, int memfd, pid_t pid, void *auxv,
>>>             != p[i].p_filesz)
>>>           error (EXIT_FAILURE, 0, gettext ("cannot read dynamic section"));
>>>
>>> -       /* Search for the DT_DEBUG entry.  */
>>> +       /* Search for the r_debug struct.  */
>>>         for (unsigned int j = 0; j < p[i].p_filesz / sizeof (EW(Dyn)); ++j)
>>> -         if (dyn[j].d_tag == DT_DEBUG && dyn[j].d_un.d_ptr != 0)
>>> -           {
>>> -             struct E(r_debug) r;
>>> -             if (pread (memfd, &r, sizeof (r), dyn[j].d_un.d_ptr)
>>> -                 != sizeof (r))
>>> -               error (EXIT_FAILURE, 0, gettext ("cannot read r_debug"));
>>> -
>>> -             if (r.r_map != 0)
>>> -               {
>>> -                 list = r.r_map;
>>> -                 break;
>>> -               }
>>> -           }
>>> +         {
>>> +           EW(Addr) d_addr = offset + p[i].p_vaddr + sizeof (EW(Dyn)) * j;
>>> +           EW(Addr) off = E(r_debug_offset)(&dyn[j], memfd, d_addr);
>>> +           if (off != 0)
>>> +             {
>>> +               struct E(r_debug) r;
>>> +               if (pread (memfd, &r, sizeof (r), off)
>>> +                   != sizeof (r))
>>> +                 error (EXIT_FAILURE, 0, gettext ("cannot read r_debug"));
>>> +
>>> +               if (r.r_map != 0)
>>> +                 {
>>> +                   list = r.r_map;
>>> +                   break;
>>> +                 }
>>> +             }
>>> +         }
>>>
>>>         free (dyn);
>>>         break;
>>> --
>>> 2.35.0
>>>
>>>
>>
>> I think a header file to access r_debug works better.  MIPS can provide
>> one to override the generic header file.
>>
> 
> Agreed, I think we should avoid arch specific defines (__mips__) on generic
> code.
 
Ah! I see, the objection if about arch-defines in tests. Yes, lets clean that up.
diff mbox series

Patch

diff --git a/elf/pldd-xx.c b/elf/pldd-xx.c
index 1cdfb49c53..ec397f00e5 100644
--- a/elf/pldd-xx.c
+++ b/elf/pldd-xx.c
@@ -22,6 +22,12 @@ 
 #define EW_(e, w, t) EW__(e, w, _##t)
 #define EW__(e, w, t) e##w##t
 
+#if CLASS == 32
+typedef Elf32_Word E(val_type);
+#else
+typedef Elf64_Xword E(val_type);
+#endif
+
 struct E(link_map)
 {
   EW(Addr) l_addr;
@@ -70,6 +76,35 @@  _Static_assert (offsetof (struct r_debug, r_map)
 		== offsetof (struct E(r_debug), r_map), "r_map");
 #endif
 
+static EW(Addr)
+E(r_debug_offset) (EW(Dyn) *d, int memfd, EW(Addr) d_addr)
+{
+#ifdef __mips__
+  EW(Addr) ptr;
+
+  switch (d->d_tag)
+    {
+    case DT_MIPS_RLD_MAP_REL:
+      ptr = d_addr + d->d_un.d_val;
+      break;
+    case DT_MIPS_RLD_MAP:
+      ptr = d->d_un.d_ptr;
+      break;
+    default:
+      return 0;
+    }
+
+    if (pread (memfd, &ptr, sizeof (ptr), ptr) != sizeof (ptr))
+      return 0;
+
+    return ptr;
+#else
+  if (d->d_tag == DT_DEBUG)
+    return (off_t) d->d_un.d_ptr;
+
+  return 0;
+#endif
+}
 
 static int
 
@@ -126,21 +161,25 @@  E(find_maps) (const char *exe, int memfd, pid_t pid, void *auxv,
 	    != p[i].p_filesz)
 	  error (EXIT_FAILURE, 0, gettext ("cannot read dynamic section"));
 
-	/* Search for the DT_DEBUG entry.  */
+	/* Search for the r_debug struct.  */
 	for (unsigned int j = 0; j < p[i].p_filesz / sizeof (EW(Dyn)); ++j)
-	  if (dyn[j].d_tag == DT_DEBUG && dyn[j].d_un.d_ptr != 0)
-	    {
-	      struct E(r_debug) r;
-	      if (pread (memfd, &r, sizeof (r), dyn[j].d_un.d_ptr)
-		  != sizeof (r))
-		error (EXIT_FAILURE, 0, gettext ("cannot read r_debug"));
-
-	      if (r.r_map != 0)
-		{
-		  list = r.r_map;
-		  break;
-		}
-	    }
+	  {
+	    EW(Addr) d_addr = offset + p[i].p_vaddr + sizeof (EW(Dyn)) * j;
+	    EW(Addr) off = E(r_debug_offset)(&dyn[j], memfd, d_addr);
+	    if (off != 0)
+	      {
+		struct E(r_debug) r;
+		if (pread (memfd, &r, sizeof (r), off)
+		    != sizeof (r))
+		  error (EXIT_FAILURE, 0, gettext ("cannot read r_debug"));
+
+		if (r.r_map != 0)
+		  {
+		    list = r.r_map;
+		    break;
+		  }
+	      }
+	  }
 
 	free (dyn);
 	break;