diff options
author | Niklas Hallqvist <niklas@cvs.openbsd.org> | 1996-03-19 23:15:57 +0000 |
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committer | Niklas Hallqvist <niklas@cvs.openbsd.org> | 1996-03-19 23:15:57 +0000 |
commit | e46701f3ba417eb809e480d2383217567bd8a0d3 (patch) | |
tree | 6418b00c595e11941ebeb3d312e0136cfb1621b8 /lib/libkvm.old/kvm_open.3 | |
parent | 169c29d1b708c51bbae3f546e0adfe0d433b5b7b (diff) |
From NetBSD: merge of 960317
Diffstat (limited to 'lib/libkvm.old/kvm_open.3')
-rw-r--r-- | lib/libkvm.old/kvm_open.3 | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/lib/libkvm.old/kvm_open.3 b/lib/libkvm.old/kvm_open.3 new file mode 100644 index 00000000000..e0465058fde --- /dev/null +++ b/lib/libkvm.old/kvm_open.3 @@ -0,0 +1,188 @@ +.\" $OpenBSD: kvm_open.3,v 1.1 1996/03/19 23:15:38 niklas Exp $ +.\" +.\" Copyright (c) 1992, 1993 +.\" The Regents of the University of California. All rights reserved. +.\" +.\" This code is derived from software developed by the Computer Systems +.\" Engineering group at Lawrence Berkeley Laboratory under DARPA contract +.\" BG 91-66 and contributed to Berkeley. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" 3. All advertising materials mentioning features or use of this software +.\" must display the following acknowledgement: +.\" This product includes software developed by the University of +.\" California, Berkeley and its contributors. +.\" 4. Neither the name of the University nor the names of its contributors +.\" may be used to endorse or promote products derived from this software +.\" without specific prior written permission. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" @(#)kvm_open.3 8.3 (Berkeley) 4/19/94 +.\" +.Dd April 19, 1994 +.Dt KVM_OPEN 3 +.Os +.Sh NAME +.Nm kvm_open , +.Nm kvm_openfiles , +.Nm kvm_close +.Nd initialize kernel virtual memory access +.Sh SYNOPSIS +.Fd #include <fcntl.h> +.Fd #include <kvm.h> +.br +.Ft kvm_t * +.Fn kvm_open "const char *execfile" "const char *corefile" "char *swapfile" "int flags" "const char *errstr" +.Ft kvm_t * +.Fn kvm_openfiles "const char *execfile" "const char *corefile" "char *swapfile" "int flags" "char *errbuf" +.Ft int +.Fn kvm_close "kvm_t *kd" +.Sh DESCRIPTION +The functions +.Fn kvm_open +and +.Fn kvm_openfiles +return a descriptor used to access kernel virtual memory +via the +.Xr kvm 3 +library routines. Both active kernels and crash dumps are accessible +through this interface. +.Pp +.Fa execfile +is the executable image of the kernel being examined. +This file must contain a symbol table. +If this argument is +.Dv NULL , +the currently running system is assumed, +which is indicated by +.Dv _PATH_UNIX +in <paths.h>. +.Pp +.Fa corefile +is the kernel memory device file. It can be either /dev/mem +or a crash dump core generated by +.Xr savecore 8 . +If +.Fa corefile +is +.Dv NULL , +the default indicated by +.Dv _PATH_MEM +from <paths.h> is used. +.Pp +.Fa swapfile +should indicate the swap device. If +.Dv NULL , +.Dv _PATH_DRUM +from <paths.h> is used. +.Pp +The +.Fa flags +argument indicates read/write access as in +.Xr open 2 +and applies only to the core file. +Only +.Dv O_RDONLY , +.Dv O_WRONLY , +and +.Dv O_RDWR +are permitted. +.Pp +There are two open routines which differ only with respect to +the error mechanism. +One provides backward compatibility with the SunOS kvm library, while the +other provides an improved error reporting framework. +.Pp +The +.Fn kvm_open +function is the Sun kvm compatible open call. Here, the +.Fa errstr +argument indicates how errors should be handled. If it is +.Dv NULL , +no errors are reported and the application cannot know the +specific nature of the failed kvm call. +If it is not +.Dv NULL , +errors are printed to stderr with +.Fa errstr +prepended to the message, as in +.Xr perror 3 . +Normally, the name of the program is used here. +The string is assumed to persist at least until the corresponding +.Fn kvm_close +call. +.Pp +The +.Fn kvm_openfiles +function provides BSD style error reporting. +Here, error messages are not printed out by the library. +Instead, the application obtains the error message +corresponding to the most recent kvm library call using +.Fn kvm_geterr +(see +.Xr kvm_geterr 3 ). +The results are undefined if the most recent kvm call did not produce +an error. +Since +.Fn kvm_geterr +requires a kvm descriptor, but the open routines return +.Dv NULL +on failure, +.Fn kvm_geterr +cannot be used to get the error message if open fails. +Thus, +.Fn kvm_openfiles +will place any error message in the +.Fa errbuf +argument. This buffer should be _POSIX2_LINE_MAX characters large (from +<limits.h>). +.Sh RETURN VALUES +The +.Fn kvm_open +and +.Fn kvm_openfiles +functions both return a descriptor to be used +in all subsequent kvm library calls. +The library is fully re-entrant. +On failure, +.Dv NULL +is returned, in which case +.Fn kvm_openfiles +writes the error message into +.Fa errbuf . +.Pp +The +.Fn kvm_close +function returns 0 on success and -1 on failure. +.Sh BUGS +There should not be two open calls. The ill-defined error semantics +of the Sun library and the desire to have a backward-compatible library +for BSD left little choice. +.Sh SEE ALSO +.Xr open 2 , +.Xr kvm 3 , +.Xr kvm_getargv 3 , +.Xr kvm_getenvv 3 , +.Xr kvm_geterr 3 , +.Xr kvm_getprocs 3 , +.Xr kvm_nlist 3 , +.Xr kvm_read 3 , +.Xr kvm_write 3 |