(split) LDP: Update original to LDP v3.65

[linuxjm/LDP_man-pages.git] / original / man2 / prctl.2

diff --git a/original/man2/prctl.2 b/original/man2/prctl.2
index bb455fa..bab8d59 100644 (file)
--- a/original/man2/prctl.2
+++ b/original/man2/prctl.2
@@ -1,9 +1,8 @@
-.\" Hey Emacs! This file is -*- nroff -*- source.
-.\"

 .\" Copyright (C) 1998 Andries Brouwer (aeb@cwi.nl)
 .\" Copyright (C) 1998 Andries Brouwer (aeb@cwi.nl)

-.\" and Copyright (C) 2002 Michael Kerrisk <mtk.manpages@gmail.com>
+.\" and Copyright (C) 2002, 2006, 2008, 2012, 2013 Michael Kerrisk <mtk.manpages@gmail.com>

 .\" and Copyright Guillem Jover <guillem@hadrons.org>
 .\"
 .\" and Copyright Guillem Jover <guillem@hadrons.org>
 .\"

+.\" %%%LICENSE_START(VERBATIM)

 .\" Permission is granted to make and distribute verbatim copies of this
 .\" manual provided the copyright notice and this permission notice are
 .\" preserved on all copies.
 .\" Permission is granted to make and distribute verbatim copies of this
 .\" manual provided the copyright notice and this permission notice are
 .\" preserved on all copies.


@@ -23,6 +22,7 @@
 .\"
 .\" Formatted or processed versions of this manual, if unaccompanied by
 .\" the source, must acknowledge the copyright and authors of this work.
 .\"
 .\" Formatted or processed versions of this manual, if unaccompanied by
 .\" the source, must acknowledge the copyright and authors of this work.

+.\" %%%LICENSE_END

 .\"
 .\" Modified Thu Nov 11 04:19:42 MET 1999, aeb: added PR_GET_PDEATHSIG
 .\" Modified 27 Jun 02, Michael Kerrisk
 .\"
 .\" Modified Thu Nov 11 04:19:42 MET 1999, aeb: added PR_GET_PDEATHSIG
 .\" Modified 27 Jun 02, Michael Kerrisk


@@ -37,13 +37,19 @@
 .\" 2008-06-13 Erik Bosman, <ejbosman@cs.vu.nl>
 .\"     Document PR_GET_TSC and PR_SET_TSC.
 .\" 2008-06-15 mtk, Document PR_SET_SECCOMP, PR_GET_SECCOMP
 .\" 2008-06-13 Erik Bosman, <ejbosman@cs.vu.nl>
 .\"     Document PR_GET_TSC and PR_SET_TSC.
 .\" 2008-06-15 mtk, Document PR_SET_SECCOMP, PR_GET_SECCOMP

-.\" 2009-10-03 Andi Kleen, document PR_MCE_KILL_*
+.\" 2009-10-03 Andi Kleen, document PR_MCE_KILL
+.\" 2012-04 Cyrill Gorcunov, Document PR_SET_MM
+.\" 2012-04-25 Michael Kerrisk, Document PR_TASK_PERF_EVENTS_DISABLE and
+.\"                            PR_TASK_PERF_EVENTS_ENABLE
+.\" 2012-09-20 Kees Cook, update PR_SET_SECCOMP for mode 2
+.\" 2012-09-20 Kees Cook, document PR_SET_NO_NEW_PRIVS, PR_GET_NO_NEW_PRIVS
+.\" 2012-10-25 Michael Kerrisk, Document PR_SET_TIMERSLACK and
+.\"                             PR_GET_TIMERSLACK
+.\" 2013-01-10 Kees Cook, document PR_SET_PTRACER
+.\" 2012-02-04 Michael kerrisk, document PR_{SET,GET}_CHILD_SUBREAPER

 .\"
 .\"

-.\" FIXME: Document PR_SET_TIMERSLACK and PR_GET_TIMERSLACK (new in 2.6.28)
-.\" FIXME: Document PR_TASK_PERF_EVENTS_DISABLE and
-.\"        PR_TASK_PERF_EVENTS_ENABLE (new in 2.6.32)

 .\"
 .\"

-.TH PRCTL 2 2010-05-13 "Linux" "Linux Programmer's Manual"
+.TH PRCTL 2 2014-04-14 "Linux" "Linux Programmer's Manual"

 .SH NAME
 prctl \- operations on a process
 .SH SYNOPSIS
 .SH NAME
 prctl \- operations on a process
 .SH SYNOPSIS


@@ -60,7 +66,7 @@ is called with a first argument describing what to do
 arguments with a significance depending on the first one.
 The first argument can be:
 .TP
 arguments with a significance depending on the first one.
 The first argument can be:
 .TP

-.BR PR_CAPBSET_READ " (since Linux 2.6.25)
+.BR PR_CAPBSET_READ " (since Linux 2.6.25)"

 Return (as the function result) 1 if the capability specified in
 .I arg2
 is in the calling thread's capability bounding set,
 Return (as the function result) 1 if the capability specified in
 .I arg2
 is in the calling thread's capability bounding set,


@@ -98,11 +104,41 @@ does not represent a valid capability; or
 if file capabilities are not enabled in the kernel,
 in which case bounding sets are not supported.
 .TP
 if file capabilities are not enabled in the kernel,
 in which case bounding sets are not supported.
 .TP

+.BR PR_SET_CHILD_SUBREAPER " (since Linux 3.4)"
+.\" commit ebec18a6d3aa1e7d84aab16225e87fd25170ec2b
+If
+.I arg2
+is nonzero,
+set the "child subreaper" attribute of the calling process;
+if
+.I arg2
+is zero, unset the attribute.
+When a process is marked as a child subreaper,
+all of the children that it creates, and their descendants,
+will be marked as having a subreaper.
+In effect, a subreaper fulfills the role of
+.BR init (1)
+for its descendant processes.
+Upon termination of a process
+that is orphaned (i.e., its immediate parent has already terminated)
+and marked as having a subreaper,
+the nearest still living ancestor subreaper
+will receive a
+.BR SIGCHLD
+signal and be able to
+.BR wait (2)
+on the process to discover its termination status.
+.TP
+.BR PR_GET_CHILD_SUBREAPER " (since Linux 3.4)"
+Return the "child subreaper" setting of the caller,
+in the location pointed to by
+.IR "(int\ *) arg2" .
+.TP

 .BR PR_SET_DUMPABLE " (since Linux 2.3.20)"
 Set the state of the flag determining whether core dumps are produced
 .BR PR_SET_DUMPABLE " (since Linux 2.3.20)"
 Set the state of the flag determining whether core dumps are produced

-for this process upon delivery of a signal whose default behavior is
+for the calling process upon delivery of a signal whose default behavior is

 to produce a core dump.
 to produce a core dump.

-(Normally this flag is set for a process by default, but it is cleared
+(Normally, this flag is set for a process by default, but it is cleared

 when a set-user-ID or set-group-ID program is executed and also by
 various system calls that manipulate process UIDs and GIDs).
 In kernels up to and including 2.6.12,
 when a set-user-ID or set-group-ID program is executed and also by
 various system calls that manipulate process UIDs and GIDs).
 In kernels up to and including 2.6.12,


@@ -120,6 +156,9 @@ for security reasons, this feature has been removed.
 .I /proc/sys/fs/suid_dumpable
 in
 .BR proc (5).)
 .I /proc/sys/fs/suid_dumpable
 in
 .BR proc (5).)

+Processes that are not dumpable can not be attached via
+.BR ptrace (2)
+.BR PTRACE_ATTACH .

 .TP
 .BR PR_GET_DUMPABLE " (since Linux 2.3.20)"
 Return (as the function result) the current state of the calling
 .TP
 .BR PR_GET_DUMPABLE " (since Linux 2.3.20)"
 Return (as the function result) the current state of the calling


@@ -196,20 +235,66 @@ Return (as the function result) the current state of the calling threads's
 "keep capabilities" flag.
 .TP
 .BR PR_SET_NAME " (since Linux 2.6.9)"
 "keep capabilities" flag.
 .TP
 .BR PR_SET_NAME " (since Linux 2.6.9)"

-Set the process name for the calling process,
+Set the name of the calling thread,

 using the value in the location pointed to by
 .IR "(char\ *) arg2" .
 The name can be up to 16 bytes long,
 .\" TASK_COMM_LEN in include/linux/sched.h
 and should be null-terminated if it contains fewer bytes.
 using the value in the location pointed to by
 .IR "(char\ *) arg2" .
 The name can be up to 16 bytes long,
 .\" TASK_COMM_LEN in include/linux/sched.h
 and should be null-terminated if it contains fewer bytes.

+This is the same attribute that can be set via
+.BR pthread_setname_np (3)
+and retrieved using
+.BR pthread_getname_np (3).
+The attribute is likewise accessible via
+.IR /proc/self/task/[tid]/comm ,
+where
+.I tid
+is the name of the calling thread.

 .TP
 .BR PR_GET_NAME " (since Linux 2.6.11)"
 .TP
 .BR PR_GET_NAME " (since Linux 2.6.11)"

-Return the process name for the calling process,
+Return the name of the calling thread,

 in the buffer pointed to by
 .IR "(char\ *) arg2" .
 The buffer should allow space for up to 16 bytes;
 the returned string will be null-terminated if it is shorter than that.
 .TP
 in the buffer pointed to by
 .IR "(char\ *) arg2" .
 The buffer should allow space for up to 16 bytes;
 the returned string will be null-terminated if it is shorter than that.
 .TP

+.BR PR_SET_NO_NEW_PRIVS " (since Linux 3.5)"
+Set the calling process's
+.I no_new_privs
+bit to the value in
+.IR arg2 .
+With
+.I no_new_privs
+set to 1,
+.BR execve (2)
+promises not to grant privileges to do anything
+that could not have been done without the
+.BR execve (2)
+call (for example,
+rendering the set-user-ID and set-group-ID permission bits,
+and file capabilities non-functional).
+Once set, this bit cannot be unset.
+The setting of this bit is inherited by children created by
+.BR fork (2)
+and
+.BR clone (2),
+and preserved across
+.BR execve (2).
+
+For more information, see the kernel source file
+.IR Documentation/prctl/no_new_privs.txt .
+.TP
+.BR PR_GET_NO_NEW_PRIVS " (since Linux 3.5)"
+Return (as the function result) the value of the
+.I no_new_privs
+bit for the current process.
+A value of 0 indicates the regular
+.BR execve (2)
+behavior.
+A value of 1 indicates
+.BR execve (2)
+will operate in the privilege-restricting mode described above.
+.TP

 .BR PR_SET_PDEATHSIG " (since Linux 2.1.57)"
 Set the parent process death signal
 of the calling process to \fIarg2\fP (either a signal value
 .BR PR_SET_PDEATHSIG " (since Linux 2.1.57)"
 Set the parent process death signal
 of the calling process to \fIarg2\fP (either a signal value


@@ -217,22 +302,60 @@ in the range 1..maxsig, or 0 to clear).
 This is the signal that the calling process will get when its
 parent dies.
 This value is cleared for the child of a
 This is the signal that the calling process will get when its
 parent dies.
 This value is cleared for the child of a

-.BR fork (2).
+.BR fork (2)
+and (since Linux 2.4.36 / 2.6.23)
+when executing a set-user-ID or set-group-ID binary.
+This value is preserved across
+.BR execve (2).

 .TP
 .BR PR_GET_PDEATHSIG " (since Linux 2.3.15)"
 Return the current value of the parent process death signal,
 in the location pointed to by
 .IR "(int\ *) arg2" .
 .TP
 .TP
 .BR PR_GET_PDEATHSIG " (since Linux 2.3.15)"
 Return the current value of the parent process death signal,
 in the location pointed to by
 .IR "(int\ *) arg2" .
 .TP

+.BR PR_SET_PTRACER " (since Linux 3.4)"
+.\" commit 2d514487faf188938a4ee4fb3464eeecfbdcf8eb
+.\" commit bf06189e4d14641c0148bea16e9dd24943862215
+This is meaningful only when the Yama LSM is enabled and in mode 1
+("restricted ptrace", visible via
+.IR /proc/sys/kernel/yama/ptrace_scope ).
+When a "ptracer process ID" is passed in \fIarg2\fP,
+the caller is declaring that the ptracer process can
+.BR ptrace (2)
+the calling process as if it were a direct process ancestor.
+Each
+.B PR_SET_PTRACER
+operation replaces the previous "ptracer process ID".
+Employing
+.B PR_SET_PTRACER
+with
+.I arg2
+set to 0 clears the caller's "ptracer process ID".
+If
+.I arg2
+is
+.BR PR_SET_PTRACER_ANY ,
+the ptrace restrictions introduced by Yama are effectively disabled for the
+calling process.
+
+For further information, see the kernel source file
+.IR Documentation/security/Yama.txt .
+.TP

 .BR PR_SET_SECCOMP " (since Linux 2.6.23)"
 .\" See http://thread.gmane.org/gmane.linux.kernel/542632
 .\" [PATCH 0 of 2] seccomp updates
 .\" andrea@cpushare.com
 .BR PR_SET_SECCOMP " (since Linux 2.6.23)"
 .\" See http://thread.gmane.org/gmane.linux.kernel/542632
 .\" [PATCH 0 of 2] seccomp updates
 .\" andrea@cpushare.com

-Set the secure computing mode for the calling thread.
-In the current implementation,
+Set the secure computing (seccomp) mode for the calling thread, to limit
+the available system calls.
+The seccomp mode is selected via
+.IR arg2 .
+(The seccomp constants are defined in
+.IR <linux/seccomp.h> .)
+
+With

 .IR arg2
 .IR arg2

-must be 1.
-After the secure computing mode has been set to 1,
+set to
+.BR SECCOMP_MODE_STRICT

 the only system calls that the thread is permitted to make are
 .BR read (2),
 .BR write (2),
 the only system calls that the thread is permitted to make are
 .BR read (2),
 .BR write (2),


@@ -242,24 +365,62 @@ and
 Other system calls result in the delivery of a
 .BR SIGKILL
 signal.
 Other system calls result in the delivery of a
 .BR SIGKILL
 signal.

-Secure computing mode is useful for number-crunching applications
+Strict secure computing mode is useful for number-crunching applications

 that may need to execute untrusted byte code,
 perhaps obtained by reading from a pipe or socket.
 that may need to execute untrusted byte code,
 perhaps obtained by reading from a pipe or socket.

-This operation is only available
-if the kernel is configured with CONFIG_SECCOMP enabled.
+This operation is available only
+if the kernel is configured with
+.B CONFIG_SECCOMP
+enabled.
+
+With
+.IR arg2
+set to
+.BR SECCOMP_MODE_FILTER " (since Linux 3.5)"
+the system calls allowed are defined by a pointer
+to a Berkeley Packet Filter passed in
+.IR arg3 .
+This argument is a pointer to
+.IR "struct sock_fprog" ;
+it can be designed to filter
+arbitrary system calls and system call arguments.
+This mode is available only if the kernel is configured with
+.B CONFIG_SECCOMP_FILTER
+enabled.
+
+If
+.BR SECCOMP_MODE_FILTER
+filters permit
+.BR fork (2),
+then the seccomp mode is inherited by children created by
+.BR fork (2);
+if
+.BR execve (2)
+is permitted, then the seccomp mode is preserved across
+.BR execve (2).
+If the filters permit
+.BR prctl ()
+calls, then additional filters can be added;
+they are run in order until the first non-allow result is seen.
+
+For further information, see the kernel source file
+.IR Documentation/prctl/seccomp_filter.txt .

 .TP
 .BR PR_GET_SECCOMP " (since Linux 2.6.23)"
 .TP
 .BR PR_GET_SECCOMP " (since Linux 2.6.23)"

-Return the secure computing mode of the calling thread.
-Not very useful for the current implementation (mode equals 1),
-but may be useful for other possible future modes:
-if the caller is not in secure computing mode, this operation returns 0;
-if the caller is in secure computing mode, then the
+Return (as the function result)
+the secure computing mode of the calling thread.
+If the caller is not in secure computing mode, this operation returns 0;
+if the caller is in strict secure computing mode, then the

 .BR prctl ()
 call will cause a
 .B SIGKILL
 signal to be sent to the process.
 .BR prctl ()
 call will cause a
 .B SIGKILL
 signal to be sent to the process.

-This operation is only available
-if the kernel is configured with CONFIG_SECCOMP enabled.
+If the caller is in filter mode, and this system call is allowed by the
+seccomp filters, it returns 2.
+This operation is available only
+if the kernel is configured with
+.B CONFIG_SECCOMP
+enabled.

 .TP
 .BR PR_SET_SECUREBITS " (since Linux 2.6.26)"
 Set the "securebits" flags of the calling thread to the value supplied in
 .TP
 .BR PR_SET_SECUREBITS " (since Linux 2.6.26)"
 Set the "securebits" flags of the calling thread to the value supplied in


@@ -273,6 +434,106 @@ the "securebits" flags of the calling thread.
 See
 .BR capabilities (7).
 .TP
 See
 .BR capabilities (7).
 .TP

+.BR PR_SET_THP_DISABLE " (since Linux 3.15)"
+.\" commit a0715cc22601e8830ace98366c0c2bd8da52af52
+Set the state of the "THP disable" flag for the calling thread.
+If
+.I arg2
+has a nonzero value, the flag is set, otherwise it is cleared.
+Setting this flag provides a method
+for disabling transparent huge pages
+for jobs where the code cannot be modified, and using a malloc hook with
+.BR madvise (2)
+is not an option (i.e., statically allocated data).
+The setting of the "THP disable" flag is inherited by a child created via
+.BR fork (2)
+and is preserved across
+.BR execve (2).
+.TP
+.BR PR_GET_THP_DISABLE " (since Linux 3.15)"
+Return (via the function result) the current setting of the "THP disable"
+flag for the calling thread:
+either 1, if the flag is set, or 0, if it is not.
+.TP
+.BR PR_GET_TID_ADDRESS " (since Linux 3.5)"
+.\" commit 300f786b2683f8bb1ec0afb6e1851183a479c86d
+Retrieve the
+.I clear_child_tid
+address set by
+.BR set_tid_address (2)
+and the
+.BR clone (2)
+.B CLONE_CHILD_CLEARTID
+flag, in the location pointed to by
+.IR "(int\ **)\ arg2" .
+This feature is available only if the kernel is built with the
+.BR CONFIG_CHECKPOINT_RESTORE
+option enabled.
+.TP
+.BR PR_SET_TIMERSLACK " (since Linux 2.6.28)"
+.\" See https://lwn.net/Articles/369549/
+.\" commit 6976675d94042fbd446231d1bd8b7de71a980ada
+Set the current timer slack for the calling thread to the nanosecond value
+supplied in
+.IR arg2 .
+If
+.I arg2
+is less than or equal to zero,
+.\" It seems that it's not possible to set the timer slack to zero;
+.\" The minimum value is 1? Seems a little strange.
+reset the current timer slack to the thread's default timer slack value.
+The timer slack is used by the kernel to group timer expirations
+for the calling thread that are close to one another;
+as a consequence, timer expirations for the thread may be
+up to the specified number of nanoseconds late (but will never expire early).
+Grouping timer expirations can help reduce system power consumption
+by minimizing CPU wake-ups.
+
+The timer expirations affected by timer slack are those set by
+.BR select (2),
+.BR pselect (2),
+.BR poll (2),
+.BR ppoll (2),
+.BR epoll_wait (2),
+.BR epoll_pwait (2),
+.BR clock_nanosleep (2),
+.BR nanosleep (2),
+and
+.BR futex (2)
+(and thus the library functions implemented via futexes, including
+.\" List obtained by grepping for futex usage in glibc source
+.BR pthread_cond_timedwait (3),
+.BR pthread_mutex_timedlock (3),
+.BR pthread_rwlock_timedrdlock (3),
+.BR pthread_rwlock_timedwrlock (3),
+and
+.BR sem_timedwait (3)).
+
+Timer slack is not applied to threads that are scheduled under
+a real-time scheduling policy (see
+.BR sched_setscheduler (2)).
+
+Each thread has two associated timer slack values:
+a "default" value, and a "current" value.
+The current value is the one that governs grouping
+of timer expirations.
+When a new thread is created,
+the two timer slack values are made the same as the current value
+of the creating thread.
+Thereafter, a thread can adjust its current timer slack value via
+.BR PR_SET_TIMERSLACK
+(the default value can't be changed).
+The timer slack values of
+.IR init
+(PID 1), the ancestor of all processes,
+are 50,000 nanoseconds (50 microseconds).
+The timer slack values are preserved across
+.BR execve (2).
+.TP
+.BR PR_GET_TIMERSLACK " (since Linux 2.6.28)"
+Return (as the function result)
+the current timer slack value of the calling thread.
+.TP

 .BR PR_SET_TIMING " (since Linux 2.6.0-test4)"
 Set whether to use (normal, traditional) statistical process timing or
 accurate timestamp-based process timing, by passing
 .BR PR_SET_TIMING " (since Linux 2.6.0-test4)"
 Set whether to use (normal, traditional) statistical process timing or
 accurate timestamp-based process timing, by passing


@@ -294,6 +555,33 @@ is not currently implemented
 Return (as the function result) which process timing method is currently
 in use.
 .TP
 Return (as the function result) which process timing method is currently
 in use.
 .TP

+.BR PR_TASK_PERF_EVENTS_DISABLE " (since Linux 2.6.31)"
+Disable all performance counters attached to the calling process,
+regardless of whether the counters were created by
+this process or another process.
+Performance counters created by the calling process for other
+processes are unaffected.
+For more information on performance counters, see the Linux kernel source file
+.IR tools/perf/design.txt .
+.IP
+Originally called
+.BR PR_TASK_PERF_COUNTERS_DISABLE ;
+.\" commit 1d1c7ddbfab358445a542715551301b7fc363e28
+renamed (with same numerical value)
+in Linux 2.6.32.
+.TP
+.BR PR_TASK_PERF_EVENTS_ENABLE " (since Linux 2.6.31)"
+The converse of
+.BR PR_TASK_PERF_EVENTS_DISABLE ;
+enable performance counters attached to the calling process.
+.IP
+Originally called
+.BR PR_TASK_PERF_COUNTERS_ENABLE ;
+.\" commit 1d1c7ddbfab358445a542715551301b7fc363e28
+renamed
+.\" commit cdd6c482c9ff9c55475ee7392ec8f672eddb7be6
+in Linux 2.6.32.
+.TP

 .BR PR_SET_TSC " (since Linux 2.6.26, x86 only)"
 Set the state of the flag determining whether the timestamp counter
 can be read by the process.
 .BR PR_SET_TSC " (since Linux 2.6.26, x86 only)"
 Set the state of the flag determining whether the timestamp counter
 can be read by the process.


@@ -355,13 +643,13 @@ defines whether the policy is
 .RB ( PR_MCE_KILL_LATE ),
 or the system-wide default
 .RB ( PR_MCE_KILL_DEFAULT ).
 .RB ( PR_MCE_KILL_LATE ),
 or the system-wide default
 .RB ( PR_MCE_KILL_DEFAULT ).

-Early kill means that the task receives a
+Early kill means that the thread receives a

 .B SIGBUS
 signal as soon as hardware memory corruption is detected inside
 its address space.
 .B SIGBUS
 signal as soon as hardware memory corruption is detected inside
 its address space.

-In late kill mode, the process is only killed when it accesses a corrupted page.
+In late kill mode, the process is killed only when it accesses a corrupted page.

 See
 See

-.I sigaction(2)
+.BR sigaction (2)

 for more information on the
 .BR SIGBUS
 signal.
 for more information on the
 .BR SIGBUS
 signal.


@@ -375,12 +663,151 @@ Return the current per-process machine check kill policy.
 All unused
 .BR prctl ()
 arguments must be zero.
 All unused
 .BR prctl ()
 arguments must be zero.

-.SH "RETURN VALUE"
+.TP
+.BR PR_SET_MM " (since Linux 3.3)"
+.\" commit 028ee4be34a09a6d48bdf30ab991ae933a7bc036
+Modify certain kernel memory map descriptor fields
+of the calling process.
+Usually these fields are set by the kernel and dynamic loader (see
+.BR ld.so (8)
+for more information) and a regular application should not use this feature.
+However, there are cases, such as self-modifying programs,
+where a program might find it useful to change its own memory map.
+This feature is available only if the kernel is built with the
+.BR CONFIG_CHECKPOINT_RESTORE
+option enabled.
+The calling process must have the
+.BR CAP_SYS_RESOURCE
+capability.
+The value in
+.I arg2
+is one of the options below, while
+.I arg3
+provides a new value for the option.
+.RS
+.TP
+.BR PR_SET_MM_START_CODE
+Set the address above which the program text can run.
+The corresponding memory area must be readable and executable,
+but not writable or sharable (see
+.BR mprotect (2)
+and
+.BR mmap (2)
+for more information).
+.TP
+.BR PR_SET_MM_END_CODE
+Set the address below which the program text can run.
+The corresponding memory area must be readable and executable,
+but not writable or sharable.
+.TP
+.BR PR_SET_MM_START_DATA
+Set the address above which initialized and
+uninitialized (bss) data are placed.
+The corresponding memory area must be readable and writable,
+but not executable or sharable.
+.TP
+.B PR_SET_MM_END_DATA
+Set the address below which initialized and
+uninitialized (bss) data are placed.
+The corresponding memory area must be readable and writable,
+but not executable or sharable.
+.TP
+.BR PR_SET_MM_START_STACK
+Set the start address of the stack.
+The corresponding memory area must be readable and writable.
+.TP
+.BR PR_SET_MM_START_BRK
+Set the address above which the program heap can be expanded with
+.BR brk (2)
+call.
+The address must be greater than the ending address of
+the current program data segment.
+In addition, the combined size of the resulting heap and
+the size of the data segment can't exceed the
+.BR RLIMIT_DATA
+resource limit (see
+.BR setrlimit (2)).
+.TP
+.BR PR_SET_MM_BRK
+Set the current
+.BR brk (2)
+value.
+The requirements for the address are the same as for the
+.BR PR_SET_MM_START_BRK
+option.
+.P
+The following options are available since Linux 3.5.
+.\" commit fe8c7f5cbf91124987106faa3bdf0c8b955c4cf7
+.TP
+.BR PR_SET_MM_ARG_START
+Set the address above which the program command line is placed.
+.TP
+.BR PR_SET_MM_ARG_END
+Set the address below which the program command line is placed.
+.TP
+.BR PR_SET_MM_ENV_START
+Set the address above which the program environment is placed.
+.TP
+.BR PR_SET_MM_ENV_END
+Set the address below which the program environment is placed.
+.IP
+The address passed with
+.BR PR_SET_MM_ARG_START ,
+.BR PR_SET_MM_ARG_END ,
+.BR PR_SET_MM_ENV_START ,
+and
+.BR PR_SET_MM_ENV_END
+should belong to a process stack area.
+Thus, the corresponding memory area must be readable, writable, and
+(depending on the kernel configuration) have the
+.BR MAP_GROWSDOWN
+attribute set (see
+.BR mmap (2)).
+.TP
+.BR PR_SET_MM_AUXV
+Set a new auxiliary vector.
+The
+.I arg3
+argument should provide the address of the vector.
+The
+.I arg4
+is the size of the vector.
+.TP
+.BR PR_SET_MM_EXE_FILE
+.\" commit b32dfe377102ce668775f8b6b1461f7ad428f8b6
+Supersede the
+.IR /proc/pid/exe
+symbolic link with a new one pointing to a new executable file
+identified by the file descriptor provided in
+.I arg3
+argument.
+The file descriptor should be obtained with a regular
+.BR open (2)
+call.
+.IP
+To change the symbolic link, one needs to unmap all existing
+executable memory areas, including those created by the kernel itself
+(for example the kernel usually creates at least one executable
+memory area for the ELF
+.IR \.text
+section).
+.IP
+The second limitation is that such transitions can be done only once
+in a process life time.
+Any further attempts will be rejected.
+This should help system administrators monitor unusual
+symbolic-link transitions over all processes running on a system.
+.RE
+.\"
+.SH RETURN VALUE

 On success,
 .BR PR_GET_DUMPABLE ,
 .BR PR_GET_KEEPCAPS ,
 On success,
 .BR PR_GET_DUMPABLE ,
 .BR PR_GET_KEEPCAPS ,

+.BR PR_GET_NO_NEW_PRIVS ,
+.BR PR_GET_THP_DISABLE ,

 .BR PR_CAPBSET_READ ,
 .BR PR_GET_TIMING ,
 .BR PR_CAPBSET_READ ,
 .BR PR_GET_TIMING ,

+.BR PR_GET_TIMERSLACK ,

 .BR PR_GET_SECUREBITS ,
 .BR PR_MCE_KILL_GET ,
 and (if it returns)
 .BR PR_GET_SECUREBITS ,
 .BR PR_MCE_KILL_GET ,
 and (if it returns)


@@ -408,7 +835,9 @@ is not recognized.
 is
 .BR PR_MCE_KILL
 or
 is
 .BR PR_MCE_KILL
 or

-.BR PR_MCE_KILL_GET ,
+.BR PR_MCE_KILL_GET
+or
+.BR PR_SET_MM ,

 and unused
 .BR prctl ()
 arguments were not specified as zero.
 and unused
 .BR prctl ()
 arguments were not specified as zero.


@@ -423,10 +852,135 @@ is not valid value for this
 is
 .BR PR_SET_SECCOMP
 or
 is
 .BR PR_SET_SECCOMP
 or

-.BR PR_SET_SECCOMP ,
+.BR PR_GET_SECCOMP ,

 and the kernel was not configured with
 .BR CONFIG_SECCOMP .
 .TP
 and the kernel was not configured with
 .BR CONFIG_SECCOMP .
 .TP

+.B EINVAL
+.I option
+is
+.BR PR_SET_MM ,
+and one of the following is true
+.RS
+.IP * 3
+.I arg4
+or
+.I arg5
+is nonzero;
+.IP *
+.I arg3
+is greater than
+.B TASK_SIZE
+(the limit on the size of the user address space for this architecture);
+.IP *
+.I arg2
+is
+.BR PR_SET_MM_START_CODE ,
+.BR PR_SET_MM_END_CODE ,
+.BR PR_SET_MM_START_DATA ,
+.BR PR_SET_MM_END_DATA ,
+or
+.BR PR_SET_MM_START_STACK ,
+and the permissions of the corresponding memory area are not as required;
+.IP *
+.I arg2
+is
+.BR PR_SET_MM_START_BRK
+or
+.BR PR_SET_MM_BRK ,
+and
+.I arg3
+is less than or equal to the end of the data segment
+or specifies a value that would cause the
+.B RLIMIT_DATA
+resource limit to be exceeded.
+.RE
+.TP
+.B EINVAL
+.I option
+is
+.BR PR_SET_PTRACER
+and
+.I arg2
+is not 0,
+.BR PR_SET_PTRACER_ANY ,
+or the PID of an existing process.
+.TP
+.B EINVAL
+.I option
+is
+.B PR_SET_PDEATHSIG
+and
+.I arg2
+is not a valid signal number.
+.TP
+.B EINVAL
+.I option
+is
+.BR PR_SET_DUMPABLE
+and
+.I arg2
+is neither
+.B SUID_DUMP_DISABLE
+nor
+.BR SUID_DUMP_USER .
+.TP
+.B EINVAL
+.I option
+is
+.BR PR_SET_TIMING
+and
+.I arg2
+is not
+.BR PR_TIMING_STATISTICAL .
+.TP
+.B EINVAL
+.I option
+is
+.BR PR_SET_NO_NEW_PRIVS
+and
+.I arg2
+is not equal to 1
+or
+.IR arg3 ,
+.IR arg4 ,
+or
+.IR arg5
+is nonzero.
+.TP
+.B EINVAL
+.I option
+is
+.BR PR_GET_NO_NEW_PRIVS
+and
+.IR arg2 ,
+.IR arg3 ,
+.IR arg4 ,
+or
+.IR arg5
+is nonzero.
+.TP
+.B EINVAL
+.I option
+is PR_SET_THP_DISABLE
+and
+.IR arg3 ,
+.IR arg4 ,
+or
+.IR arg5
+is nonzero.
+.TP
+.B EINVAL
+.I option
+is PR_GET_THP_DISABLE
+and
+.IR arg2 ,
+.IR arg3 ,
+.IR arg4 ,
+or
+.IR arg5
+is nonzero.
+.TP

 .B EPERM
 .I option
 is
 .B EPERM
 .I option
 is


@@ -456,6 +1010,46 @@ is
 and the caller does not have the
 .B CAP_SETPCAP
 capability.
 and the caller does not have the
 .B CAP_SETPCAP
 capability.

+.TP
+.B EPERM
+.I option
+is
+.BR PR_SET_MM ,
+and the caller does not have the
+.B CAP_SYS_RESOURCE
+capability.
+.TP
+.B EACCES
+.I option
+is
+.BR PR_SET_MM ,
+and
+.I arg3
+is
+.BR PR_SET_MM_EXE_FILE ,
+the file is not executable.
+.TP
+.B EBUSY
+.I option
+is
+.BR PR_SET_MM ,
+.I arg3
+is
+.BR PR_SET_MM_EXE_FILE ,
+and this the second attempt to change the
+.I /proc/pid/exe
+symbolic link, which is prohibited.
+.TP
+.B EBADF
+.I option
+is
+.BR PR_SET_MM ,
+.I arg3
+is
+.BR PR_SET_MM_EXE_FILE ,
+and the file descriptor passed in
+.I arg4
+is not valid.

 .\" The following can't actually happen, because prctl() in
 .\" seccomp mode will cause SIGKILL.
 .\" .TP
 .\" The following can't actually happen, because prctl() in
 .\" seccomp mode will cause SIGKILL.
 .\" .TP


@@ -469,7 +1063,7 @@ The
 .BR prctl ()
 system call was introduced in Linux 2.1.57.
 .\" The library interface was added in glibc 2.0.6
 .BR prctl ()
 system call was introduced in Linux 2.1.57.
 .\" The library interface was added in glibc 2.0.6

-.SH "CONFORMING TO"
+.SH CONFORMING TO

 This call is Linux-specific.
 IRIX has a
 .BR prctl ()
 This call is Linux-specific.
 IRIX has a
 .BR prctl ()


@@ -482,7 +1076,15 @@ with prototype
 and options to get the maximum number of processes per user,
 get the maximum number of processors the calling process can use,
 find out whether a specified process is currently blocked,
 and options to get the maximum number of processes per user,
 get the maximum number of processors the calling process can use,
 find out whether a specified process is currently blocked,

-get or set the maximum stack size, etc.
-.SH "SEE ALSO"
+get or set the maximum stack size, and so on.
+.SH SEE ALSO

 .BR signal (2),
 .BR core (5)
 .BR signal (2),
 .BR core (5)

+.SH COLOPHON
+This page is part of release 3.65 of the Linux
+.I man-pages
+project.
+A description of the project,
+and information about reporting bugs,
+can be found at
+\%http://www.kernel.org/doc/man\-pages/.