@@ -3,6 +3,11 @@
# ifndef _ISOMAC
+# ifndef PR_SET_VMA
+# define PR_SET_VMA 0x53564d41
+# define PR_SET_VMA_ANON_NAME 0
+# endif
+
extern int __prctl (int __option, ...);
libc_hidden_proto (__prctl)
new file mode 100644
@@ -0,0 +1,27 @@
+/* Utilities functions to name memory mappings.
+ 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/>. */
+
+#ifndef __SETVMANAME_H
+#define __SETVMANAME_H
+
+static inline
+void __set_vma_name (void *start, size_t len, const char *name)
+{
+}
+
+#endif
@@ -97,6 +97,7 @@ sysdep_routines += \
readahead \
setfsgid \
setfsuid \
+ setvmaname \
signalfd \
splice \
sysctl \
new file mode 100644
@@ -0,0 +1,44 @@
+/* Utilities functions to name memory mappings.
+ 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 <ldsodefs.h>
+#include <setvmaname.h>
+#include <sys/prctl.h>
+#include <sysdep.h>
+
+/* If PR_SET_VMA_ANON_NAME is not supported by the kernel, prctl returns
+ EINVAL. However, it also returns the same error for invalid argument.
+ Since it is an internal-only API, it assumes well formatted input:
+ aligned START, with (START, START+LEN) being a valid memory range,
+ and NAME with a limit of 80 characters without invalid one ("\\`$[]"). */
+
+void
+__set_vma_name (void *start, size_t len, const char *name)
+{
+ static int prctl_supported = 1;
+ if (atomic_load_relaxed (&prctl_supported) == 0)
+ return;
+
+ int r = INTERNAL_SYSCALL_CALL (prctl, PR_SET_VMA, PR_SET_VMA_ANON_NAME,
+ start, len, name);
+ if (r == 0 || r != -EINVAL)
+ return;
+
+ atomic_store_relaxed (&prctl_supported, 0);
+ return;
+}
new file mode 100644
@@ -0,0 +1,36 @@
+/* Utilities functions to name memory mappings.
+ 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/>. */
+
+#ifndef __SETVMANAME_H
+#define __SETVMANAME_H
+
+/* Set the NAME to the anonymous memory map START with size of LEN.
+ It assumes well-formatted input. */
+#if IS_IN(libc) || IS_IN(rtld)
+void __set_vma_name (void *start, size_t len, const char *name)
+ attribute_hidden;
+#else
+#include <sys/prctl.h>
+
+static inline void __set_vma_name (void *start, size_t len, const char *name)
+{
+ prctl (PR_SET_VMA, PR_SET_VMA_ANON_NAME, start, len, name);
+}
+#endif
+
+#endif
Linux 5.17 added support to naming anonymous virtual memory areas through the prctl syscall. The __set_vma_name is a wrapper to avoid optimizing the prctl call if the kernel does not support it. If the kernel does not support PR_SET_VMA_ANON_NAME, prctl returns EINVAL. And it also returns the same error for an invalid argument. Since it is an internal-only API, it assumes well-formatted input: aligned START, with (START, START+LEN) being a valid memory range, and NAME with a limit of 80 characters without an invalid one ("\\`$[]"). Reviewed-by: DJ Delorie <dj@redhat.com> --- include/sys/prctl.h | 5 ++++ sysdeps/generic/setvmaname.h | 27 +++++++++++++++++ sysdeps/unix/sysv/linux/Makefile | 1 + sysdeps/unix/sysv/linux/setvmaname.c | 44 ++++++++++++++++++++++++++++ sysdeps/unix/sysv/linux/setvmaname.h | 36 +++++++++++++++++++++++ 5 files changed, 113 insertions(+) create mode 100644 sysdeps/generic/setvmaname.h create mode 100644 sysdeps/unix/sysv/linux/setvmaname.c create mode 100644 sysdeps/unix/sysv/linux/setvmaname.h