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