From owner-freebsd-arch Sat Mar 9 8:26:13 2002 Delivered-To: freebsd-arch@freebsd.org Received: from iguana.icir.org (iguana.icir.org [192.150.187.36]) by hub.freebsd.org (Postfix) with ESMTP id 7184037B404 for ; Sat, 9 Mar 2002 08:26:08 -0800 (PST) Received: (from rizzo@localhost) by iguana.icir.org (8.11.6/8.11.3) id g29GQ8U24039; Sat, 9 Mar 2002 08:26:08 -0800 (PST) (envelope-from rizzo) Date: Sat, 9 Mar 2002 08:26:08 -0800 From: Luigi Rizzo To: arch@FreeBSD.ORG Subject: Re: For review: machdep.bootdev sysctl (for i386) Message-ID: <20020309082607.I21016@iguana.icir.org> References: <20020309042728.A21016@iguana.icir.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20020309042728.A21016@iguana.icir.org> User-Agent: Mutt/1.3.23i Sender: owner-freebsd-arch@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG And as a followup, attached is a patch for sysctl(8) to parse the information. Again it can be cleaned up a little bit by making machdep.bootdev opaque, but that is purely a stylistic issue -- in the end, finding the proper parsing routine always involves a string comparison. Note that this is only valid for the i386 so I will make this code conditionally compiled if it ever gets committed. cheers luigi On Sat, Mar 09, 2002 at 04:27:28AM -0800, Luigi Rizzo wrote: > Looking at a way to determine the boot device from userland, > I have come to the conclusion that the most reasonable way is to > export to userland whatever information the kernel has (and this > is machine dependent, sorry!), and let some userland program ... Index: sysctl.c =================================================================== RCS file: /home/ncvs/src/sbin/sysctl/sysctl.c,v retrieving revision 1.41 diff -u -r1.41 sysctl.c --- sysctl.c 25 Feb 2002 03:36:06 -0000 1.41 +++ sysctl.c 9 Mar 2002 15:20:52 -0000 @@ -404,6 +404,55 @@ } /* + * code to map a bootdev into a suitable string. + * Major numbers are mapped into names as in boot2.c + */ +struct _foo { + int majdev; + char *name; +} maj2name[] = { + 30, "ad", + 0, "wd", + 1, "wfd", + 2, "fd", + 4, "da", + -1, NULL /* terminator */ +}; + +#include +#include +static int +machdep_bootdev(u_long value) +{ + int majdev, unit, slice, part; + struct _foo *p; + + if (value & B_MAGICMASK != B_DEVMAGIC) { + printf("invalid (0x%08x)", value); + return 0; + } + majdev = B_TYPE(value); + unit = B_UNIT(value); + slice = B_SLICE(value); + part = B_PARTITION(value); + if (majdev == 2) { /* floppy, as known to the boot block... */ + printf("/dev/fd%d", unit); + return 0; + } + for (p = maj2name; p->name != NULL && p->majdev != majdev ; p++) ; + if (p->name != NULL) { /* found */ + if (slice == WHOLE_DISK_SLICE) + printf("/dev/%s%d%c", p->name, unit, part); + else + printf("/dev/%s%ds%d%c", + p->name, unit, slice - BASE_SLICE + 1, part + 'a'); + } else + printf("unknown (major %d unit %d slice %d part %d)", + majdev, unit, slice, part); + return 0; +} + +/* * This formats and outputs the value of one variable * * Returns zero if anything was actually output. @@ -496,6 +545,8 @@ if (!nflag) printf("%s%s", name, sep); fmt++; + if (!strcmp(name, "machdep.bootdev")) + return machdep_bootdev(*(unsigned long *)p); val = ""; while (len >= sizeof(long)) { if(*fmt == 'U') To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message