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| author | Michael Kerrisk <mtk.manpages@gmail.com> | 2016-10-13 12:44:52 +0200 |
|---|---|---|
| committer | Michael Kerrisk <mtk.manpages@gmail.com> | 2016-10-17 14:04:17 +0200 |
| commit | 9e7d6be1f5d3b4a97f1e9f892e8180b82f6e2ccd (patch) | |
| tree | 9881a87cbe8504bb027c7ea660410934543d2453 | |
| parent | f74aed0e620fd948756e856efe6d6f4c908e844c (diff) | |
| download | man-pages-9e7d6be1f5d3b4a97f1e9f892e8180b82f6e2ccd.tar.gz | |
mprotect.2: Various tweaks to the text
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
| -rw-r--r-- | man2/mprotect.2 | 35 |
1 files changed, 25 insertions, 10 deletions
diff --git a/man2/mprotect.2 b/man2/mprotect.2 index 9cc3753643..05efc27285 100644 --- a/man2/mprotect.2 +++ b/man2/mprotect.2 @@ -48,9 +48,7 @@ mprotect, pkey_mprotect \- set protection on a region of memory .fi .SH DESCRIPTION .BR mprotect () -and -.BR pkey_mprotect () -change protection for the calling process's memory page(s) +changes protection for the calling process's memory page(s) containing any part of the address range in the interval [\fIaddr\fP,\ \fIaddr\fP+\fIlen\fP\-1]. .I addr @@ -78,19 +76,31 @@ The memory can be modified. .B PROT_EXEC The memory can be executed. .PP +Like +.BR mprotect (), +.BR pkey_mprotect () +changes the protection on the pages specified by +.IR addr +and +.IR len . +The .I pkey -is the protection key to assign to the memory. -A pkey must be allocated with +argument specifies the protection key (see +.BR pkey (7)) +to assign to the memory. +The protection key must be allocated with .BR pkey_alloc (2) before it is passed to .BR pkey_mprotect (). +For an example of the use of this system call, see +.BR pkey (7). .SH RETURN VALUE On success, .BR mprotect () and .BR pkey_mprotect () return zero. -On error, \-1 is returned, and +On error, these system calls return \-1, and .I errno is set appropriately. .SH ERRORS @@ -107,7 +117,10 @@ to mark it .B EINVAL \fIaddr\fP is not a valid pointer, or not a multiple of the system page size. -Or: \fIpkey\fP has not been allocated with +.TP +.BR EINVAL +.RB ( pkey_mprotect ()) +\fIpkey\fP has not been allocated with .BR pkey_alloc (2) .\" Or: both PROT_GROWSUP and PROT_GROWSDOWN were specified in 'prot'. .TP @@ -191,7 +204,7 @@ has been set. Applications should be careful when mixing use of .BR mprotect () and -.BR pkey_mprotect () . +.BR pkey_mprotect (). On x86, when .BR mprotect () is used with @@ -213,7 +226,9 @@ is equivalent to .SH EXAMPLE .\" sigaction.2 refers to this example .PP -The program below allocates four pages of memory, makes the third +The program below demonstrates the use of +.BR mprotect () +The program allocates four pages of memory, makes the third of these pages read-only, and then executes a loop that walks upward through the allocated region modifying bytes. @@ -290,5 +305,5 @@ main(int argc, char *argv[]) .fi .SH SEE ALSO .BR mmap (2), -.BR sysconf (3) +.BR sysconf (3), .BR pkey (7) |