diff mbox series

[v2,2/7] support: Add support_set_vma_name

Message ID 20231028195559.390407-3-adhemerval.zanella@linaro.org
State Superseded
Headers show
Series Add a tunable to decorate anonymous memory maps | expand

Commit Message

Adhemerval Zanella Oct. 28, 2023, 7:55 p.m. UTC
Check if kernel supports prctl (PR_SET_VMA, PR_SET_VMA_ANON_NAME, ...).
---
 support/Makefile               |  1 +
 support/support.h              |  4 +++
 support/support_set_vma_name.c | 49 ++++++++++++++++++++++++++++++++++
 3 files changed, 54 insertions(+)
 create mode 100644 support/support_set_vma_name.c

Comments

DJ Delorie Oct. 31, 2023, 9:34 p.m. UTC | #1
Adhemerval Zanella <adhemerval.zanella@linaro.org> writes:
> diff --git a/support/support.h b/support/support.h
> index b7f76bf080..659ef25b06 100644
> --- a/support/support.h
> +++ b/support/support.h
> @@ -235,6 +235,10 @@ void support_stack_free (struct support_stack *stack);
>     The returned value is the lowest file descriptor number.  */
>  int support_open_dev_null_range (int num, int flags, mode_t mode);
>  
> +
> +/* Check if kernel supports set VMA range name.  */
> +extern bool support_set_vma_name (void);
> +
>  __END_DECLS
>  
>  #endif /* SUPPORT_H */

This doesn't match the idiom the rest of the support_*() functions use;
I would expect this to mean "support's version of set_vma_name()" and
would expect it to set the vma name.

Something like "support_set_vma_name_supported ()" would (sadly) be more
appropriate.

> diff --git a/support/support_set_vma_name.c b/support/support_set_vma_name.c
> new file mode 100644
> index 0000000000..41f5dea409
> --- /dev/null
> +++ b/support/support_set_vma_name.c
> @@ -0,0 +1,49 @@
> +/* Check if kernel supports set VMA range name.
> +   Copyright (C) 2023 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#include <support/check.h>
> +#include <support/support.h>
> +#include <support/xunistd.h>
> +#include <sys/mman.h>
> +#ifdef __linux__
> +# include <sys/prctl.h>
> +#endif
> +
> +bool
> +support_set_vma_name (void)
> +{
> +#ifdef __linux__
> +  size_t size = sysconf (_SC_PAGESIZE);
> +  if (size == -1)
> +    FAIL_EXIT1 ("sysconf (_SC_PAGESIZE): %m\n");
> +
> +  void *vma = xmmap (0,
> +		     size,
> +		     PROT_NONE,
> +		     MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
> +		     -1);
> +
> +  int r = prctl (PR_SET_VMA, PR_SET_VMA_ANON_NAME, vma, size, "vmaname");
> +
> +  xmunmap (vma, size);
> +
> +  return r == 0;
> +#else
> +  return false;
> +#endif
> +}

Ok.
Adhemerval Zanella Nov. 1, 2023, 11:58 a.m. UTC | #2
On 31/10/23 18:34, DJ Delorie wrote:
> 
> Adhemerval Zanella <adhemerval.zanella@linaro.org> writes:
>> diff --git a/support/support.h b/support/support.h
>> index b7f76bf080..659ef25b06 100644
>> --- a/support/support.h
>> +++ b/support/support.h
>> @@ -235,6 +235,10 @@ void support_stack_free (struct support_stack *stack);
>>     The returned value is the lowest file descriptor number.  */
>>  int support_open_dev_null_range (int num, int flags, mode_t mode);
>>  
>> +
>> +/* Check if kernel supports set VMA range name.  */
>> +extern bool support_set_vma_name (void);
>> +
>>  __END_DECLS
>>  
>>  #endif /* SUPPORT_H */
> 
> This doesn't match the idiom the rest of the support_*() functions use;
> I would expect this to mean "support's version of set_vma_name()" and
> would expect it to set the vma name.
> 
> Something like "support_set_vma_name_supported ()" would (sadly) be more
> appropriate.

Ack, I will change it.

> 
>> diff --git a/support/support_set_vma_name.c b/support/support_set_vma_name.c
>> new file mode 100644
>> index 0000000000..41f5dea409
>> --- /dev/null
>> +++ b/support/support_set_vma_name.c
>> @@ -0,0 +1,49 @@
>> +/* Check if kernel supports set VMA range name.
>> +   Copyright (C) 2023 Free Software Foundation, Inc.
>> +   This file is part of the GNU C Library.
>> +
>> +   The GNU C Library is free software; you can redistribute it and/or
>> +   modify it under the terms of the GNU Lesser General Public
>> +   License as published by the Free Software Foundation; either
>> +   version 2.1 of the License, or (at your option) any later version.
>> +
>> +   The GNU C Library is distributed in the hope that it will be useful,
>> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
>> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
>> +   Lesser General Public License for more details.
>> +
>> +   You should have received a copy of the GNU Lesser General Public
>> +   License along with the GNU C Library; if not, see
>> +   <https://www.gnu.org/licenses/>.  */
>> +
>> +#include <support/check.h>
>> +#include <support/support.h>
>> +#include <support/xunistd.h>
>> +#include <sys/mman.h>
>> +#ifdef __linux__
>> +# include <sys/prctl.h>
>> +#endif
>> +
>> +bool
>> +support_set_vma_name (void)
>> +{
>> +#ifdef __linux__
>> +  size_t size = sysconf (_SC_PAGESIZE);
>> +  if (size == -1)
>> +    FAIL_EXIT1 ("sysconf (_SC_PAGESIZE): %m\n");
>> +
>> +  void *vma = xmmap (0,
>> +		     size,
>> +		     PROT_NONE,
>> +		     MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
>> +		     -1);
>> +
>> +  int r = prctl (PR_SET_VMA, PR_SET_VMA_ANON_NAME, vma, size, "vmaname");
>> +
>> +  xmunmap (vma, size);
>> +
>> +  return r == 0;
>> +#else
>> +  return false;
>> +#endif
>> +}
> 
> Ok.
>
diff mbox series

Patch

diff --git a/support/Makefile b/support/Makefile
index 917a858bd1..54a8cc30ac 100644
--- a/support/Makefile
+++ b/support/Makefile
@@ -80,6 +80,7 @@  libsupport-routines = \
   support_select_modifies_timeout \
   support_select_normalizes_timeout \
   support_set_small_thread_stack_size \
+  support_set_vma_name \
   support_shared_allocate \
   support_small_stack_thread_attribute \
   support_socket_so_timestamp_time64 \
diff --git a/support/support.h b/support/support.h
index b7f76bf080..659ef25b06 100644
--- a/support/support.h
+++ b/support/support.h
@@ -235,6 +235,10 @@  void support_stack_free (struct support_stack *stack);
    The returned value is the lowest file descriptor number.  */
 int support_open_dev_null_range (int num, int flags, mode_t mode);
 
+
+/* Check if kernel supports set VMA range name.  */
+extern bool support_set_vma_name (void);
+
 __END_DECLS
 
 #endif /* SUPPORT_H */
diff --git a/support/support_set_vma_name.c b/support/support_set_vma_name.c
new file mode 100644
index 0000000000..41f5dea409
--- /dev/null
+++ b/support/support_set_vma_name.c
@@ -0,0 +1,49 @@ 
+/* Check if kernel supports set VMA range name.
+   Copyright (C) 2023 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <support/check.h>
+#include <support/support.h>
+#include <support/xunistd.h>
+#include <sys/mman.h>
+#ifdef __linux__
+# include <sys/prctl.h>
+#endif
+
+bool
+support_set_vma_name (void)
+{
+#ifdef __linux__
+  size_t size = sysconf (_SC_PAGESIZE);
+  if (size == -1)
+    FAIL_EXIT1 ("sysconf (_SC_PAGESIZE): %m\n");
+
+  void *vma = xmmap (0,
+		     size,
+		     PROT_NONE,
+		     MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
+		     -1);
+
+  int r = prctl (PR_SET_VMA, PR_SET_VMA_ANON_NAME, vma, size, "vmaname");
+
+  xmunmap (vma, size);
+
+  return r == 0;
+#else
+  return false;
+#endif
+}