Date: Wed, 15 Aug 2012 17:29:05 +0000 (UTC) From: Joel Dahl <joel@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r239305 - head/share/man/man4 Message-ID: <201208151729.q7FHT51O086286@svn.freebsd.org>
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Author: joel (doc committer) Date: Wed Aug 15 17:29:05 2012 New Revision: 239305 URL: http://svn.freebsd.org/changeset/base/239305 Log: Minor mdoc fixes and language tweaks. Modified: head/share/man/man4/aout.4 Modified: head/share/man/man4/aout.4 ============================================================================== --- head/share/man/man4/aout.4 Wed Aug 15 17:12:40 2012 (r239304) +++ head/share/man/man4/aout.4 Wed Aug 15 17:29:05 2012 (r239305) @@ -35,16 +35,15 @@ kldload a.out .Sh DESCRIPTION The .Xr a.out 5 -executable format was used by -.Fx -of versions \*(Lt 3.0. -Since only i386 architecture was supported at that time, the +executable format was used before the release of +.Fx 3.0. +Since i386 was the only supported architecture at that time, .Xr a.out 5 -executables can only be activated on the platforms that support -execution of i386 code, which are i386, amd64 and (partially) ia64. +executables can only be activated on platforms that support +execution of i386 code, such as i386, amd64 and (partially) ia64. .Pp To add kernel support for old syscalls and old syscall invocation methods, -you need to place the following options in the kernel configuration file: +place the following options in the kernel configuration file: .Bd -ragged -offset indent .Cd "options COMPAT_43" .br @@ -57,14 +56,16 @@ option is only required on 64-bit CPU ar .Pp The .Va aout.ko -module must be loaded to get support for +module needs to be loaded with the +.Xr kldload 8 +utility in order to support the .Xr a.out 5 -image activator. -Use the command +image activator: .Bd -ragged -offset indent .Ic kldload aout .Ed -or put the following line in +.Pp +Alternatively, to load the module at boot time, place the following line in .Xr loader.conf 5 : .Bd -literal -offset indent aout_load="YES" @@ -72,9 +73,9 @@ aout_load="YES" .Pp The .Xr a.out 5 -format was mainstream quite long time ago. -The reasonable default settings and security requirements of the -modern OS contradict to the default environment of that time and +format was mainstream quite a long time ago. +Reasonable default settings and security requirements of +modern operating systems today contradict the default environment of that time and require adjustments of the system to mimic natural environment for old binaries. .Pp @@ -84,10 +85,10 @@ tunables are useful for this: .Bl -tag -offset indent -width "XXXXXXXXXXXXXXXXXXXXXXXXX" .It Xo Va security.bsd.map_at_zero .Xc -Set to 1 to allow the mapping of process pages at the address 0. +Set to 1 to allow mapping of process pages at address 0. Some very old .Va ZMAGIC -executable images require the text mapping at the address 0. +executable images require text mapping at address 0. .It Xo Va kern.pid_max .Xc Old versions of @@ -96,12 +97,12 @@ used 16-bit types for .Vt pid_t . Current kernels use 32-bit type for .Vt pid_t , -and allow the process id's up to 99999. +and allow process id's up to 99999. Such values cannot be represented by old .Vt pid_t , -mostly causing issues for the processes using +mostly causing issues for processes using .Xr wait 2 -syscalls, for instance, shells. +syscalls, for example shells. Set the sysctl to 30000 to work around the problem. .It Xo Va kern.elf32.read_exec .Xc @@ -109,7 +110,7 @@ Set to 1 to force any accessible memory process to allow execution, see .Xr mmap 2 . Old i386 CPUs did not have a bit in PTE which disallowed execution -from the page, so many old programs did not specified +from the page, so many old programs did not specify .Va PROT_EXEC even for mapping of executable code. The sysctl forces @@ -123,8 +124,6 @@ non-executable mappings. .Xr a.out 5 , .Xr elf 5 , .Xr sysctl 8 . -.Sh BUGS -On 64bit architectures, not all wrappers for older syscalls are implemented. .Sh HISTORY The .Xr a.out 5 @@ -132,7 +131,7 @@ executable format was used on ancient .At and served as the main executable format for .Fx -from inception up to +from the beginning up to .Fx 2.2.9 . In .Fx 3.0 @@ -143,3 +142,5 @@ The .Nm manual page was written by .An Konstantin Belousov Aq kib@FreeBSD.org . +.Sh BUGS +On 64bit architectures, not all wrappers for older syscalls are implemented.
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