diff options
Diffstat (limited to 'man2/mprotect.2')
| -rw-r--r-- | man2/mprotect.2 | 32 |
1 files changed, 16 insertions, 16 deletions
diff --git a/man2/mprotect.2 b/man2/mprotect.2 index 22aa42b..91812f5 100644 --- a/man2/mprotect.2 +++ b/man2/mprotect.2 @@ -10,7 +10,7 @@ .\" 2007-06-02, mtk: Fairly substantial rewrites and additions, and .\" a much improved example program. .\" -.TH mprotect 2 2023-05-03 "Linux man-pages 6.05.01" +.TH mprotect 2 2023-10-31 "Linux man-pages 6.7" .SH NAME mprotect, pkey_mprotect \- set protection on a region of memory .SH LIBRARY @@ -19,12 +19,12 @@ Standard C library .SH SYNOPSIS .nf .B #include <sys/mman.h> -.PP +.P .BI "int mprotect(void " addr [. len "], size_t " len ", int " prot ); -.PP +.P .BR "#define _GNU_SOURCE" " /* See feature_test_macros(7) */" .B #include <sys/mman.h> -.PP +.P .BI "int pkey_mprotect(void " addr [. len "], size_t " len ", int " prot ", int " pkey ");" .fi .SH DESCRIPTION @@ -34,12 +34,12 @@ containing any part of the address range in the interval [\fIaddr\fP,\ \fIaddr\fP+\fIlen\fP\-1]. .I addr must be aligned to a page boundary. -.PP +.P If the calling process tries to access memory in a manner that violates the protections, then the kernel generates a .B SIGSEGV signal for the process. -.PP +.P .I prot is a combination of the following access flags: .B PROT_NONE @@ -74,7 +74,7 @@ This feature is specific to the PowerPC architecture (version 2.06 of the architecture specification adds the SAO CPU feature, and it is available on POWER 7 or PowerPC A2, for example). -.PP +.P Additionally (since Linux 2.6.0), .I prot can have one of the following flags set: @@ -100,7 +100,7 @@ that grows downward (which should be a stack segment or a segment mapped with the .B MAP_GROWSDOWN flag set). -.PP +.P Like .BR mprotect (), .BR pkey_mprotect () @@ -199,14 +199,14 @@ POSIX says that the behavior of is unspecified if it is applied to a region of memory that was not obtained via .BR mmap (2). -.PP +.P On Linux, it is always permissible to call .BR mprotect () on any address in a process's address space (except for the kernel vsyscall area). In particular, it can be used to change existing code mappings to be writable. -.PP +.P Whether .B PROT_EXEC has any effect different from @@ -220,12 +220,12 @@ specifying .B PROT_READ will implicitly add .BR PROT_EXEC . -.PP +.P On some hardware architectures (e.g., i386), .B PROT_WRITE implies .BR PROT_READ . -.PP +.P POSIX.1 says that an implementation may permit access other than that specified in .IR prot , @@ -234,7 +234,7 @@ but at a minimum can allow write access only if has been set, and must not allow any access if .B PROT_NONE has been set. -.PP +.P Applications should be careful when mixing use of .BR mprotect () and @@ -247,7 +247,7 @@ set to .B PROT_EXEC a pkey may be allocated and set on the memory implicitly by the kernel, but only when the pkey was 0 previously. -.PP +.P On systems that do not support protection keys in hardware, .BR pkey_mprotect () may still be used, but @@ -280,10 +280,10 @@ The program below demonstrates the use of 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. -.PP +.P An example of what we might see when running the program is the following: -.PP +.P .in +4n .EX .RB "$" " ./a.out" |