diff mbox series

[13/14] dlfcn: Eliminate GLIBC_PRIVATE dependency from tststatic2

Message ID 55b77553739d573de35d0b558e9c5fa453cc84dd.1621953727.git.fweimer@redhat.com
State Superseded
Headers
Series Move libdl into libc |

Checks

Context Check Description
dj/TryBot-apply_patch success Patch applied to master at the time it was sent

Commit Message

Florian Weimer May 25, 2021, 2:46 p.m. UTC 
  The test appears to use _dlfcn_hook@@GLIBC_PRIVATE as a way to
test dlvsym without having to know the appropriate symbol version.
With <first-versions.h>, we can use a public symbol and the symbol
version at which it was defined first.
---
 dlfcn/modstatic2.c | 3 ++-
 dlfcn/tststatic2.c | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

Comments

Andreas Schwab May 25, 2021, 3:38 p.m. UTC | #1 
On Mai 25 2021, Florian Weimer via Libc-alpha wrote:

> diff --git a/dlfcn/modstatic2.c b/dlfcn/modstatic2.c
> index 9b5aae8b9f..34568d4e6e 100644
> --- a/dlfcn/modstatic2.c
> +++ b/dlfcn/modstatic2.c
> @@ -4,6 +4,7 @@
>  #include <stdlib.h>
>  #include <string.h>
>  #include <gnu/lib-names.h>
> +#include <first-versions.h>
>  
>  int test (FILE *out, int a);
>  
> @@ -117,7 +118,7 @@ test (FILE *out, int a)
>        exit (1);
>      }
>  
> -  if (dlvsym (handle2, "_dlfcn_hook", "GLIBC_PRIVATE") == NULL)
> +  if (dlvsym (handle2, "malloc", FIRST_VERSION_libc_malloc_STRING) == NULL)

Shouldn't that use a public symbol from libdl?

Andreas.
Florian Weimer May 25, 2021, 3:42 p.m. UTC | #2 
* Andreas Schwab:

> On Mai 25 2021, Florian Weimer via Libc-alpha wrote:
>
>> diff --git a/dlfcn/modstatic2.c b/dlfcn/modstatic2.c
>> index 9b5aae8b9f..34568d4e6e 100644
>> --- a/dlfcn/modstatic2.c
>> +++ b/dlfcn/modstatic2.c
>> @@ -4,6 +4,7 @@
>>  #include <stdlib.h>
>>  #include <string.h>
>>  #include <gnu/lib-names.h>
>> +#include <first-versions.h>
>>  
>>  int test (FILE *out, int a);
>>  
>> @@ -117,7 +118,7 @@ test (FILE *out, int a)
>>        exit (1);
>>      }
>>  
>> -  if (dlvsym (handle2, "_dlfcn_hook", "GLIBC_PRIVATE") == NULL)
>> +  if (dlvsym (handle2, "malloc", FIRST_VERSION_libc_malloc_STRING) == NULL)
>
> Shouldn't that use a public symbol from libdl?

libdl is empty at this point, and there are no
FIRST_VERSION_libdl_*_STRING macros left.  I could use
FIRST_VERSION_libc_dlopen_STRING, I assume.  But malloc has the
advantage that it's unlikely that there are going to be multiple symbol
versions for it.

Thanks,
Florian
Andreas Schwab May 25, 2021, 3:54 p.m. UTC | #3 
On Mai 25 2021, Florian Weimer wrote:

> But malloc has the advantage that it's unlikely that there are going
> to be multiple symbol versions for it.

What would happen if it did?

Andreas.
Florian Weimer May 25, 2021, 3:56 p.m. UTC | #4 
* Andreas Schwab:

> On Mai 25 2021, Florian Weimer wrote:
>
>> But malloc has the advantage that it's unlikely that there are going
>> to be multiple symbol versions for it.
>
> What would happen if it did?

The test will still work, I think, but anyone reading it will wonder if
the intent is to test multiple symbol versions at the same symbol.

Thanks,
Florian
Andreas Schwab May 25, 2021, 4:45 p.m. UTC | #5 
On Mai 25 2021, Florian Weimer wrote:

> The test will still work, I think, but anyone reading it will wonder if
> the intent is to test multiple symbol versions at the same symbol.

Then I think a comment is needed.

Andreas.
diff mbox series

Patch

diff --git a/dlfcn/modstatic2.c b/dlfcn/modstatic2.c
index 9b5aae8b9f..34568d4e6e 100644
--- a/dlfcn/modstatic2.c
+++ b/dlfcn/modstatic2.c
@@ -4,6 +4,7 @@ 
 #include <stdlib.h>
 #include <string.h>
 #include <gnu/lib-names.h>
+#include <first-versions.h>
 
 int test (FILE *out, int a);
 
@@ -117,7 +118,7 @@  test (FILE *out, int a)
       exit (1);
     }
 
-  if (dlvsym (handle2, "_dlfcn_hook", "GLIBC_PRIVATE") == NULL)
+  if (dlvsym (handle2, "malloc", FIRST_VERSION_libc_malloc_STRING) == NULL)
     {
       fprintf (out, "dlvsym: %s\n", dlerror ());
       exit (1);
diff --git a/dlfcn/tststatic2.c b/dlfcn/tststatic2.c
index f8cd5a964b..ba4648e521 100644
--- a/dlfcn/tststatic2.c
+++ b/dlfcn/tststatic2.c
@@ -4,6 +4,7 @@ 
 #include <stdlib.h>
 #include <string.h>
 #include <gnu/lib-names.h>
+#include <first-versions.h>
 
 static int
 do_test (void)
@@ -115,7 +116,7 @@  do_test (void)
       exit (1);
     }
 
-  if (dlvsym (handle2, "_dlfcn_hook", "GLIBC_PRIVATE") == NULL)
+  if (dlvsym (handle2, "malloc", FIRST_VERSION_libc_malloc_STRING) == NULL)
     {
       printf ("dlvsym: %s\n", dlerror ());
       exit (1);