diff mbox series

powerpc: Use FLAG_ELF_LIBC6 for 32-bit known libraries

Message ID 20211104181039.97106-1-lamm@linux.ibm.com
State Superseded
Headers show
Series powerpc: Use FLAG_ELF_LIBC6 for 32-bit known libraries | expand

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

Lucas A. M. Magalhaes Nov. 4, 2021, 6:10 p.m. UTC
In systems with more versions of the known libraries, i.e. on IBM
Advance Toolchain, ldconfig will order them incorrectly on ld.cache.

The issue only occurs with 32-bit libraries that don't depend on libc or
libm. That's because process_elf32_file check if the elf depends on one
of the libraries at known_libs to select the elf flag. For example, as
libc.so.6 don't depend on itself or on libm it will be flagged as
FLAG_ELF instead of FLAG_ELF_LIBC6 as expected.

This commit fixes this by checking if a appropriate flag was set by
process_elf32_file. If not it will search on known_libs and use the flag
in there.
---
 sysdeps/unix/sysv/linux/powerpc/readelflib.c | 21 +++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

Comments

Lucas A. M. Magalhaes Dec. 3, 2021, 12:40 p.m. UTC | #1
Ping.

Quoting Lucas A. M. Magalhaes via Libc-alpha (2021-11-04 15:10:39)
> In systems with more versions of the known libraries, i.e. on IBM
> Advance Toolchain, ldconfig will order them incorrectly on ld.cache.
> 
> The issue only occurs with 32-bit libraries that don't depend on libc or
> libm. That's because process_elf32_file check if the elf depends on one
> of the libraries at known_libs to select the elf flag. For example, as
> libc.so.6 don't depend on itself or on libm it will be flagged as
> FLAG_ELF instead of FLAG_ELF_LIBC6 as expected.
> 
> This commit fixes this by checking if a appropriate flag was set by
> process_elf32_file. If not it will search on known_libs and use the flag
> in there.
> ---
>  sysdeps/unix/sysv/linux/powerpc/readelflib.c | 21 +++++++++++++++++---
>  1 file changed, 18 insertions(+), 3 deletions(-)
> 
> diff --git a/sysdeps/unix/sysv/linux/powerpc/readelflib.c b/sysdeps/unix/sysv/linux/powerpc/readelflib.c
> index 51f8a9496a..94da21c407 100644
> --- a/sysdeps/unix/sysv/linux/powerpc/readelflib.c
> +++ b/sysdeps/unix/sysv/linux/powerpc/readelflib.c
> @@ -33,11 +33,26 @@ process_elf_file (const char *file_name, const char *lib, int *flag,
>                   char **soname, void *file_contents, size_t file_length)
>  {
>    ElfW(Ehdr) *elf_header = (ElfW(Ehdr) *) file_contents;
> -  int ret;
> +  int ret, j;
>  
>    if (elf_header->e_ident [EI_CLASS] == ELFCLASS32)
> -    return process_elf32_file (file_name, lib, flag, osversion, isa_level,
> -                              soname, file_contents, file_length);
> +    {
> +      ret = process_elf32_file (file_name, lib, flag, osversion, isa_level,
> +                                soname, file_contents, file_length);
> +      /* Use the apropriate flag for known_libs instead of FLAG_ELF.  */
> +      if (*flag == FLAG_ELF)
> +        {
> +          for (j = 0;
> +               j < sizeof (known_libs) / sizeof (known_libs [0]);
> +               ++j)
> +            if (strcmp (lib, known_libs [j].soname) == 0)
> +              {
> +                *flag = known_libs [j].flag;
> +                break;
> +              }
> +        }
> +      return ret;
> +    }
>    else
>      {
>        ret = process_elf64_file (file_name, lib, flag, osversion, isa_level,
> -- 
> 2.31.1
>
Florian Weimer Dec. 3, 2021, 2:17 p.m. UTC | #2
* Lucas A. M. Magalhaes:

> In systems with more versions of the known libraries, i.e. on IBM
> Advance Toolchain, ldconfig will order them incorrectly on ld.cache.
>
> The issue only occurs with 32-bit libraries that don't depend on libc or
> libm. That's because process_elf32_file check if the elf depends on one
> of the libraries at known_libs to select the elf flag. For example, as
> libc.so.6 don't depend on itself or on libm it will be flagged as
> FLAG_ELF instead of FLAG_ELF_LIBC6 as expected.
>
> This commit fixes this by checking if a appropriate flag was set by
> process_elf32_file. If not it will search on known_libs and use the flag
> in there.

I would like to defer review of this patch to the POWER maintainers, sorry.
(I just spotted a typo in the first version.)

Thanks,
Florian
Adhemerval Zanella Dec. 3, 2021, 2:51 p.m. UTC | #3
On 04/11/2021 15:10, Lucas A. M. Magalhaes via Libc-alpha wrote:
> In systems with more versions of the known libraries, i.e. on IBM
> Advance Toolchain, ldconfig will order them incorrectly on ld.cache.
> 
> The issue only occurs with 32-bit libraries that don't depend on libc or
> libm. That's because process_elf32_file check if the elf depends on one
> of the libraries at known_libs to select the elf flag. For example, as
> libc.so.6 don't depend on itself or on libm it will be flagged as
> FLAG_ELF instead of FLAG_ELF_LIBC6 as expected.

Wouldn't be simpler to check if the DT_SONAME matches any on 'known_libs' after
dynamic section parsing and set the appropriated flag on generic 'process_file'? 

(also powerpc SYSDEP_KNOWN_LIBRARY_NAMES seems redundant).

> 
> This commit fixes this by checking if a appropriate flag was set by
> process_elf32_file. If not it will search on known_libs and use the flag
> in there.
> ---
>  sysdeps/unix/sysv/linux/powerpc/readelflib.c | 21 +++++++++++++++++---
>  1 file changed, 18 insertions(+), 3 deletions(-)
> 
> diff --git a/sysdeps/unix/sysv/linux/powerpc/readelflib.c b/sysdeps/unix/sysv/linux/powerpc/readelflib.c
> index 51f8a9496a..94da21c407 100644
> --- a/sysdeps/unix/sysv/linux/powerpc/readelflib.c
> +++ b/sysdeps/unix/sysv/linux/powerpc/readelflib.c
> @@ -33,11 +33,26 @@ process_elf_file (const char *file_name, const char *lib, int *flag,
>  		  char **soname, void *file_contents, size_t file_length)
>  {
>    ElfW(Ehdr) *elf_header = (ElfW(Ehdr) *) file_contents;
> -  int ret;
> +  int ret, j;
>  
>    if (elf_header->e_ident [EI_CLASS] == ELFCLASS32)
> -    return process_elf32_file (file_name, lib, flag, osversion, isa_level,
> -			       soname, file_contents, file_length);
> +    {
> +      ret = process_elf32_file (file_name, lib, flag, osversion, isa_level,
> +                                soname, file_contents, file_length);
> +      /* Use the apropriate flag for known_libs instead of FLAG_ELF.  */
> +      if (*flag == FLAG_ELF)
> +        {
> +          for (j = 0;
> +               j < sizeof (known_libs) / sizeof (known_libs [0]);
> +               ++j)
> +            if (strcmp (lib, known_libs [j].soname) == 0)
> +              {
> +                *flag = known_libs [j].flag;
> +                break;
> +              }
> +        }
> +      return ret;
> +    }
>    else
>      {
>        ret = process_elf64_file (file_name, lib, flag, osversion, isa_level,
>
diff mbox series

Patch

diff --git a/sysdeps/unix/sysv/linux/powerpc/readelflib.c b/sysdeps/unix/sysv/linux/powerpc/readelflib.c
index 51f8a9496a..94da21c407 100644
--- a/sysdeps/unix/sysv/linux/powerpc/readelflib.c
+++ b/sysdeps/unix/sysv/linux/powerpc/readelflib.c
@@ -33,11 +33,26 @@  process_elf_file (const char *file_name, const char *lib, int *flag,
 		  char **soname, void *file_contents, size_t file_length)
 {
   ElfW(Ehdr) *elf_header = (ElfW(Ehdr) *) file_contents;
-  int ret;
+  int ret, j;
 
   if (elf_header->e_ident [EI_CLASS] == ELFCLASS32)
-    return process_elf32_file (file_name, lib, flag, osversion, isa_level,
-			       soname, file_contents, file_length);
+    {
+      ret = process_elf32_file (file_name, lib, flag, osversion, isa_level,
+                                soname, file_contents, file_length);
+      /* Use the apropriate flag for known_libs instead of FLAG_ELF.  */
+      if (*flag == FLAG_ELF)
+        {
+          for (j = 0;
+               j < sizeof (known_libs) / sizeof (known_libs [0]);
+               ++j)
+            if (strcmp (lib, known_libs [j].soname) == 0)
+              {
+                *flag = known_libs [j].flag;
+                break;
+              }
+        }
+      return ret;
+    }
   else
     {
       ret = process_elf64_file (file_name, lib, flag, osversion, isa_level,