common/os/modsysfile.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident	"@(#)modsysfile.c	1.109	07/11/29 SMI"

#include <sys/types.h>
#include <sys/inttypes.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/user.h>
#include <sys/disp.h>
#include <sys/conf.h>
#include <sys/bootconf.h>
#include <sys/sysconf.h>
#include <sys/sunddi.h>
#include <sys/esunddi.h>
#include <sys/ddi_impldefs.h>
#include <sys/kmem.h>
#include <sys/vmem.h>
#include <sys/fs/ufs_fsdir.h>
#include <sys/hwconf.h>
#include <sys/modctl.h>
#include <sys/cmn_err.h>
#include <sys/kobj.h>
#include <sys/kobj_lex.h>
#include <sys/errno.h>
#include <sys/debug.h>
#include <sys/autoconf.h>
#include <sys/callb.h>
#include <sys/sysmacros.h>
#include <sys/dacf.h>
#include <vm/seg_kmem.h>

struct hwc_class *hcl_head;	/* head of list of classes */
static kmutex_t hcl_lock;	/* for accessing list of classes */

#define	DAFILE		"/etc/driver_aliases"
#define	CLASSFILE	"/etc/driver_classes"
#define	DACFFILE	"/etc/dacf.conf"

static char class_file[] = CLASSFILE;
static char dafile[] = DAFILE;
static char dacffile[] = DACFFILE;

char *systemfile = "/etc/system";	/* name of ascii system file */

static struct sysparam *sysparam_hd;	/* head of parameters list */
static struct sysparam *sysparam_tl;	/* tail of parameters list */
static vmem_t *mod_sysfile_arena;	/* parser memory */

char obp_bootpath[BO_MAXOBJNAME];	/* bootpath from obp */
char svm_bootpath[BO_MAXOBJNAME];	/* bootpath redirected via rootdev */

#if defined(_PSM_MODULES)

struct psm_mach {
	struct psm_mach *m_next;
	char		*m_machname;
};

static struct psm_mach *pmach_head;	/* head of list of classes */

#define	MACHFILE	"/etc/mach"
static char mach_file[] = MACHFILE;

#endif	/* _PSM_MODULES */

#if defined(_RTC_CONFIG)
static char rtc_config_file[] = "/etc/rtc_config";
#endif

static void sys_set_var(int, struct sysparam *, void *);

static void setparams(void);

/*
 * driver.conf parse thread control structure
 */
struct hwc_parse_mt {
	ksema_t		sema;
	char		*name;		/* name of .conf files */
	struct par_list	**pl;		/* parsed parent list */
	ddi_prop_t	**props;	/* parsed properties */
	int		rv;		/* return value */
};

static int hwc_parse_now(char *, struct par_list **, ddi_prop_t **);
static void hwc_parse_thread(struct hwc_parse_mt *);
static struct hwc_parse_mt *hwc_parse_mtalloc(char *, struct par_list **,
	ddi_prop_t **);
static void hwc_parse_mtfree(struct hwc_parse_mt *);
static void add_spec(struct hwc_spec *, struct par_list **);
static void add_props(struct hwc_spec *, ddi_prop_t **);

static void check_system_file(void);
static int sysparam_compare_entry(struct sysparam *, struct sysparam *);
static char *sysparam_type_to_str(int);
static void sysparam_count_entry(struct sysparam *, int *, u_longlong_t *);
static void sysparam_print_warning(struct sysparam *, u_longlong_t);

#ifdef DEBUG
static int parse_debug_on = 0;

/*VARARGS1*/
static void
parse_debug(struct _buf *file, char *fmt, ...)
{
	va_list adx;

	if (parse_debug_on) {
		va_start(adx, fmt);
		vprintf(fmt, adx);
		if (file)
			printf(" on line %d of %s\n", kobj_linenum(file),
			    kobj_filename(file));
		va_end(adx);
	}
}
#endif /* DEBUG */

#define	FE_BUFLEN 256

/*PRINTFLIKE3*/
void
kobj_file_err(int type,  struct _buf *file, char *fmt, ...)
{
	va_list ap;
	/*
	 * If we're in trouble, we might be short on stack... be paranoid
	 */
	char *buf = kmem_alloc(FE_BUFLEN, KM_SLEEP);
	char *trailer = kmem_alloc(FE_BUFLEN, KM_SLEEP);
	char *fmt_str = kmem_alloc(FE_BUFLEN, KM_SLEEP);
	char prefix = '\0';

	va_start(ap, fmt);
	if (strchr("^!?", fmt[0]) != NULL) {
		prefix = fmt[0];
		fmt++;
	}
	(void) vsnprintf(buf, FE_BUFLEN, fmt, ap);
	va_end(ap);
	(void) snprintf(trailer, FE_BUFLEN, " on line %d of %s",
	    kobj_linenum(file), kobj_filename(file));

	/*
	 * If prefixed with !^?, prepend that character
	 */
	if (prefix != '\0') {
		(void) snprintf(fmt_str, FE_BUFLEN, "%c%%s%%s", prefix);
	} else {
		(void) strncpy(fmt_str, "%s%s", FE_BUFLEN);
	}

	cmn_err(type, fmt_str, buf, trailer);
	kmem_free(buf, FE_BUFLEN);
	kmem_free(trailer, FE_BUFLEN);
	kmem_free(fmt_str, FE_BUFLEN);
}

#ifdef DEBUG
char *tokennames[] = {
	"UNEXPECTED",
	"EQUALS",
	"AMPERSAND",
	"BIT_OR",
	"STAR",
	"POUND",
	"COLON",
	"SEMICOLON",
	"COMMA",
	"SLASH",
	"WHITE_SPACE",
	"NEWLINE",
	"EOF",
	"STRING",
	"HEXVAL",
	"DECVAL",
	"NAME"
};
#endif /* DEBUG */

token_t
kobj_lex(struct _buf *file, char *val, size_t size)
{
	char	*cp;
	int	ch, oval, badquote;
	size_t	remain;
	token_t token = UNEXPECTED;

	if (size < 2)
		return (token);	/* this token is UNEXPECTED */

	cp = val;
	while ((ch = kobj_getc(file)) == ' ' || ch == '\t')
		;

	remain = size - 1;
	*cp++ = (char)ch;
	switch (ch) {
	case '=':
		token = EQUALS;
		break;
	case '&':
		token = AMPERSAND;
		break;
	case '|':
		token = BIT_OR;
		break;
	case '*':
		token = STAR;
		break;
	case '#':
		token = POUND;
		break;
	case ':':
		token = COLON;
		break;
	case ';':
		token = SEMICOLON;
		break;
	case ',':
		token = COMMA;
		break;
	case '/':
		token = SLASH;
		break;
	case ' ':
	case '\t':
	case '\f':
		while ((ch = kobj_getc(file)) == ' ' ||
		    ch == '\t' || ch == '\f') {
			if (--remain == 0) {
				token = UNEXPECTED;
				goto out;
			}
			*cp++ = (char)ch;
		}
		(void) kobj_ungetc(file);
		token = WHITE_SPACE;
		break;
	case '\n':
	case '\r':
		token = NEWLINE;
		break;
	case '"':
		remain++;
		cp--;
		badquote = 0;
		while (!badquote && (ch  = kobj_getc(file)) != '"') {
			switch (ch) {
			case '\n':
			case -1:
				kobj_file_err(CE_WARN, file, "Missing \"");
				remain = size - 1;
				cp = val;
				*cp++ = '\n';
				badquote = 1;
				/* since we consumed the newline/EOF */
				(void) kobj_ungetc(file);
				break;

			case '\\':
				if (--remain == 0) {
					token = UNEXPECTED;
					goto out;
				}
				ch = (char)kobj_getc(file);
				if (!isdigit(ch)) {
					/* escape the character */
					*cp++ = (char)ch;
					break;
				}
				oval = 0;
				while (ch >= '0' && ch <= '7') {
					ch -= '0';
					oval = (oval << 3) + ch;
					ch = (char)kobj_getc(file);
				}
				(void) kobj_ungetc(file);
				/* check for character overflow? */
				if (oval > 127) {
					cmn_err(CE_WARN,
					    "Character "
					    "overflow detected.");
				}
				*cp++ = (char)oval;
				break;
			default:
				if (--remain == 0) {
					token = UNEXPECTED;
					goto out;
				}
				*cp++ = (char)ch;
				break;
			}
		}
		token = STRING;
		break;

	case -1:
		token = EOF;
		break;

	default:
		/*
		 * detect a lone '-' (including at the end of a line), and
		 * identify it as a 'name'
		 */
		if (ch == '-') {
			if (--remain == 0) {
				token = UNEXPECTED;
				goto out;
			}
			*cp++ = (char)(ch = kobj_getc(file));
			if (iswhite(ch) || (ch == '\n')) {
				(void) kobj_ungetc(file);
				remain++;
				cp--;
				token = NAME;
				break;
			}
		} else if (isunary(ch)) {
			if (--remain == 0) {
				token = UNEXPECTED;
				goto out;
			}
			*cp++ = (char)(ch = kobj_getc(file));
		}


		if (isdigit(ch)) {
			if (ch == '0') {
				if ((ch = kobj_getc(file)) == 'x') {
					if (--remain == 0) {
						token = UNEXPECTED;
						goto out;
					}
					*cp++ = (char)ch;
					ch = kobj_getc(file);
					while (isxdigit(ch)) {
						if (--remain == 0) {
							token = UNEXPECTED;
							goto out;
						}
						*cp++ = (char)ch;
						ch = kobj_getc(file);
					}
					(void) kobj_ungetc(file);
					token = HEXVAL;
				} else {
					goto digit;
				}
			} else {
				ch = kobj_getc(file);
digit:
				while (isdigit(ch)) {
					if (--remain == 0) {
						token = UNEXPECTED;
						goto out;
					}
					*cp++ = (char)ch;
					ch = kobj_getc(file);
				}
				(void) kobj_ungetc(file);
				token = DECVAL;
			}
		} else if (isalpha(ch) || ch == '\\' || ch == '_') {
			if (ch != '\\') {
				ch = kobj_getc(file);
			} else {
				/*
				 * if the character was a backslash,
				 * back up so we can overwrite it with
				 * the next (i.e. escaped) character.
				 */
				remain++;
				cp--;
			}
			while (isnamechar(ch) || ch == '\\') {
				if (ch == '\\')
					ch = kobj_getc(file);
				if (--remain == 0) {
					token = UNEXPECTED;
					goto out;
				}
				*cp++ = (char)ch;
				ch = kobj_getc(file);
			}
			(void) kobj_ungetc(file);
			token = NAME;
		} else {
			token = UNEXPECTED;
		}
		break;
	}
out:
	*cp = '\0';

#ifdef DEBUG
	/*
	 * The UNEXPECTED token is the first element of the tokennames array,
	 * but its token value is -1.  Adjust the value by adding one to it
	 * to change it to an index of the array.
	 */
	parse_debug(NULL, "kobj_lex: token %s value '%s'\n",
	    tokennames[token+1], val);
#endif
	return (token);
}

/*
 * Leave NEWLINE as the next character.
 */

void
kobj_find_eol(struct _buf *file)
{
	int ch;

	while ((ch = kobj_getc(file)) != -1) {
		if (isnewline(ch)) {
			(void) kobj_ungetc(file);
			break;
		}
	}
}

/*
 * The ascii system file is read and processed.
 *
 * The syntax of commands is as follows:
 *
 * '*' in column 1 is a comment line.
 * <command> : <value>
 *
 * command is EXCLUDE, INCLUDE, FORCELOAD, ROOTDEV, ROOTFS,
 *	SWAPDEV, SWAPFS, MODDIR, SET
 *
 * value is an ascii string meaningful for the command.
 */

/*
 * Table of commands
 */
static struct modcmd modcmd[] = {
	{ "EXCLUDE",	MOD_EXCLUDE	},
	{ "exclude",	MOD_EXCLUDE	},
	{ "INCLUDE",	MOD_INCLUDE	},
	{ "include",	MOD_INCLUDE	},
	{ "FORCELOAD",	MOD_FORCELOAD	},
	{ "forceload",	MOD_FORCELOAD	},
	{ "ROOTDEV",	MOD_ROOTDEV	},
	{ "rootdev",	MOD_ROOTDEV	},
	{ "ROOTFS",	MOD_ROOTFS	},
	{ "rootfs",	MOD_ROOTFS	},
	{ "SWAPDEV",	MOD_SWAPDEV	},
	{ "swapdev",	MOD_SWAPDEV	},
	{ "SWAPFS",	MOD_SWAPFS	},
	{ "swapfs",	MOD_SWAPFS	},
	{ "MODDIR",	MOD_MODDIR	},
	{ "moddir",	MOD_MODDIR	},
	{ "SET",	MOD_SET		},
	{ "set",	MOD_SET		},
	{ "SET32",	MOD_SET32	},
	{ "set32",	MOD_SET32	},
	{ "SET64",	MOD_SET64	},
	{ "set64",	MOD_SET64	},
	{ NULL,		MOD_UNKNOWN	}
};


static char bad_op[] = "illegal operator '%s' used on a string";
static char colon_err[] = "A colon (:) must follow the '%s' command";
static char tok_err[] = "Unexpected token '%s'";
static char extra_err[] = "extraneous input ignored starting at '%s'";
static char oversize_err[] = "value too long";

static struct sysparam *
do_sysfile_cmd(struct _buf *file, const char *cmd)
{
	struct sysparam *sysp;
	struct modcmd *mcp;
	token_t token, op;
	char *cp;
	int ch;
	char tok1[MOD_MAXPATH + 1]; /* used to read the path set by 'moddir' */
	char tok2[64];

	for (mcp = modcmd; mcp->mc_cmdname != NULL; mcp++) {
		if (strcmp(mcp->mc_cmdname, cmd) == 0)
			break;
	}
	sysp = vmem_alloc(mod_sysfile_arena, sizeof (struct sysparam),
	    VM_SLEEP);
	bzero(sysp, sizeof (struct sysparam));
	sysp->sys_op = SETOP_NONE; /* set op to noop initially */

	switch (sysp->sys_type = mcp->mc_type) {
	case MOD_INCLUDE:
	case MOD_EXCLUDE:
	case MOD_FORCELOAD:
		/*
		 * Are followed by colon.
		 */
	case MOD_ROOTFS:
	case MOD_SWAPFS:
		if ((token = kobj_lex(file, tok1, sizeof (tok1))) == COLON) {
			token = kobj_lex(file, tok1, sizeof (tok1));
		} else {
			kobj_file_err(CE_WARN, file, colon_err, cmd);
		}
		if (token != NAME) {
			kobj_file_err(CE_WARN, file, "value expected");
			goto bad;
		}

		cp = tok1 + strlen(tok1);
		while ((ch = kobj_getc(file)) != -1 && !iswhite(ch) &&
		    !isnewline(ch)) {
			if (cp - tok1 >= sizeof (tok1) - 1) {
				kobj_file_err(CE_WARN, file, oversize_err);
				goto bad;
			}
			*cp++ = (char)ch;
		}
		*cp = '\0';

		if (ch != -1)
			(void) kobj_ungetc(file);
		if (sysp->sys_type == MOD_INCLUDE)
			return (NULL);
		sysp->sys_ptr = vmem_alloc(mod_sysfile_arena, strlen(tok1) + 1,
		    VM_SLEEP);
		(void) strcpy(sysp->sys_ptr, tok1);
		break;
	case MOD_SET:
	case MOD_SET64:
	case MOD_SET32:
	{
		char *var;
		token_t tok3;

		if (kobj_lex(file, tok1, sizeof (tok1)) != NAME) {
			kobj_file_err(CE_WARN, file, "value expected");
			goto bad;
		}

		/*
		 * If the next token is a colon (:),
		 * we have the <modname>:<variable> construct.
		 */
		if ((token = kobj_lex(file, tok2, sizeof (tok2))) == COLON) {
			if ((token = kobj_lex(file, tok2,
			    sizeof (tok2))) == NAME) {
				var = tok2;
				/*
				 * Save the module name.
				 */
				sysp->sys_modnam = vmem_alloc(mod_sysfile_arena,
				    strlen(tok1) + 1, VM_SLEEP);
				(void) strcpy(sysp->sys_modnam, tok1);
				op = kobj_lex(file, tok1, sizeof (tok1));
			} else {
				kobj_file_err(CE_WARN, file, "value expected");
				goto bad;
			}
		} else {
			/* otherwise, it was the op */
			var = tok1;
			op = token;
		}
		/*
		 * kernel param - place variable name in sys_ptr.
		 */
		sysp->sys_ptr = vmem_alloc(mod_sysfile_arena, strlen(var) + 1,
		    VM_SLEEP);
		(void) strcpy(sysp->sys_ptr, var);
		/* set operation */
		switch (op) {
		case EQUALS:
			/* simple assignment */
			sysp->sys_op = SETOP_ASSIGN;
			break;
		case AMPERSAND:
			/* bitwise AND */
			sysp->sys_op = SETOP_AND;
			break;
		case BIT_OR:
			/* bitwise OR */
			sysp->sys_op = SETOP_OR;
			break;
		default:
			/* unsupported operation */
			kobj_file_err(CE_WARN, file,
			    "unsupported operator %s", tok2);
			goto bad;
		}

		switch ((tok3 = kobj_lex(file, tok1, sizeof (tok1)))) {
		case STRING:
			/* string variable */
			if (sysp->sys_op != SETOP_ASSIGN) {
				kobj_file_err(CE_WARN, file, bad_op, tok1);
				goto bad;
			}
			if (kobj_get_string(&sysp->sys_info, tok1) == 0) {
				kobj_file_err(CE_WARN, file, "string garbled");
				goto bad;
			}
			/*
			 * Set SYSPARAM_STR_TOKEN in sys_flags to notify
			 * sysparam_print_warning() that this is a string
			 * token.
			 */
			sysp->sys_flags |= SYSPARAM_STR_TOKEN;
			break;
		case HEXVAL:
		case DECVAL:
			if (kobj_getvalue(tok1, &sysp->sys_info) == -1) {
				kobj_file_err(CE_WARN, file,
				    "invalid number '%s'", tok1);
				goto bad;
			}

			/*
			 * Set the appropriate flag (hexadecimal or decimal)
			 * in sys_flags for sysparam_print_warning() to be
			 * able to print the number with the correct format.
			 */
			if (tok3 == HEXVAL) {
				sysp->sys_flags |= SYSPARAM_HEX_TOKEN;
			} else {
				sysp->sys_flags |= SYSPARAM_DEC_TOKEN;
			}
			break;
		default:
			kobj_file_err(CE_WARN, file, "bad rvalue '%s'", tok1);
			goto bad;
		} /* end switch */

		/*
		 * Now that we've parsed it to check the syntax, consider
		 * discarding it (because it -doesn't- apply to this flavor
		 * of the kernel)
		 */
#ifdef _LP64
		if (sysp->sys_type == MOD_SET32)
			return (NULL);
#else
		if (sysp->sys_type == MOD_SET64)
			return (NULL);
#endif
		sysp->sys_type = MOD_SET;
		break;
	}
	case MOD_MODDIR:
		if ((token = kobj_lex(file, tok1, sizeof (tok1))) != COLON) {
			kobj_file_err(CE_WARN, file, colon_err, cmd);
			goto bad;
		}

		cp = tok1;
		while ((token = kobj_lex(file, cp,
		    sizeof (tok1) - (cp - tok1))) != NEWLINE && token != EOF) {
			if (token == -1) {
				kobj_file_err(CE_WARN, file, oversize_err);
				goto bad;
			}
			cp += strlen(cp);
			while ((ch = kobj_getc(file)) != -1 && !iswhite(ch) &&
			    !isnewline(ch) && ch != ':') {
				if (cp - tok1 >= sizeof (tok1) - 1) {
					kobj_file_err(CE_WARN, file,
					    oversize_err);
					goto bad;
				}
				*cp++ = (char)ch;
			}
			*cp++ = ':';
			if (isnewline(ch)) {
				cp--;
				(void) kobj_ungetc(file);
			}
		}
		(void) kobj_ungetc(file);
		*cp  = '\0';
		sysp->sys_ptr = vmem_alloc(mod_sysfile_arena, strlen(tok1) + 1,
		    VM_SLEEP);
		(void) strcpy(sysp->sys_ptr, tok1);
		break;

	case MOD_SWAPDEV:
	case MOD_ROOTDEV:
		if ((token = kobj_lex(file, tok1, sizeof (tok1))) != COLON) {
			kobj_file_err(CE_WARN, file, colon_err, cmd);
			goto bad;
		}
		while ((ch = kobj_getc(file)) == ' ' || ch == '\t')
			;
		cp = tok1;
		while (!iswhite(ch) && !isnewline(ch) && ch != -1) {
			if (cp - tok1 >= sizeof (tok1) - 1) {
				kobj_file_err(CE_WARN, file, oversize_err);
				goto bad;
			}

			*cp++ = (char)ch;
			ch = kobj_getc(file);
		}
		if (ch != -1)
			(void) kobj_ungetc(file);
		*cp = '\0';

		sysp->sys_ptr = vmem_alloc(mod_sysfile_arena, strlen(tok1) + 1,
		    VM_SLEEP);
		(void) strcpy(sysp->sys_ptr, tok1);
		break;

	case MOD_UNKNOWN:
	default:
		kobj_file_err(CE_WARN, file, "unknown command '%s'", cmd);
		goto bad;
	}

	return (sysp);

bad:
	kobj_find_eol(file);
	return (NULL);
}

void
mod_read_system_file(int ask)
{
	register struct sysparam *sp;
	register struct _buf *file;
	register token_t token, last_tok;
	char tokval[MAXLINESIZE];

	mod_sysfile_arena = vmem_create("mod_sysfile", NULL, 0, 8,
	    segkmem_alloc, segkmem_free, heap_arena, 0, VM_SLEEP);

	if (ask)
		mod_askparams();

	if (systemfile != NULL) {

		if ((file = kobj_open_file(systemfile)) ==
		    (struct _buf *)-1) {
			cmn_err(CE_WARN, "cannot open system file: %s",
			    systemfile);
		} else {
			sysparam_tl = (struct sysparam *)&sysparam_hd;

			last_tok = NEWLINE;
			while ((token = kobj_lex(file, tokval,
			    sizeof (tokval))) != EOF) {
				switch (token) {
				case STAR:
				case POUND:
					/*
					 * Skip comments.
					 */
					kobj_find_eol(file);
					break;
				case NEWLINE:
					kobj_newline(file);
					last_tok = NEWLINE;
					break;
				case NAME:
					if (last_tok != NEWLINE) {
						kobj_file_err(CE_WARN, file,
						    extra_err, tokval);
						kobj_find_eol(file);
					} else if ((sp = do_sysfile_cmd(file,
					    tokval)) != NULL) {
						sp->sys_next = NULL;
						sysparam_tl->sys_next = sp;
						sysparam_tl = sp;
					}
					last_tok = NAME;
					break;
				default:
					kobj_file_err(CE_WARN,
					    file, tok_err, tokval);
					kobj_find_eol(file);
					break;
				}
			}
			kobj_close_file(file);
		}
	}

	/*
	 * Sanity check of /etc/system.
	 */
	check_system_file();

	param_preset();
	(void) mod_sysctl(SYS_SET_KVAR, NULL);
	param_check();

	if (ask == 0)
		setparams();
}

/*
 * Search for a specific module variable assignment in /etc/system.  If
 * successful, 1 is returned and the value is stored in '*value'.
 * Otherwise 0 is returned and '*value' isn't modified.  If 'module' is
 * NULL we look for global definitions.
 *
 * This is useful if the value of an assignment is needed before a
 * module is loaded (e.g. to obtain a default privileged rctl limit).
 */
int
mod_sysvar(const char *module, const char *name, u_longlong_t *value)
{
	struct sysparam	*sysp;
	int cnt = 0; /* dummy */

	ASSERT(name != NULL);
	ASSERT(value != NULL);
	for (sysp = sysparam_hd; sysp != NULL; sysp = sysp->sys_next) {

		if ((sysp->sys_type == MOD_SET) &&
		    (((module == NULL) && (sysp->sys_modnam == NULL)) ||
		    ((module != NULL) && (sysp->sys_modnam != NULL) &&
		    (strcmp(module, sysp->sys_modnam) == 0)))) {

			ASSERT(sysp->sys_ptr != NULL);

			if (strcmp(name, sysp->sys_ptr) == 0) {
				sysparam_count_entry(sysp, &cnt, value);
				if ((sysp->sys_flags & SYSPARAM_TERM) != 0)
					return (1);
				continue;
			}
		}
	}
	ASSERT(cnt == 0);
	return (0);
}

/*
 * This function scans sysparam records, which are created from the
 * contents of /etc/system, for entries which are logical duplicates,
 * and prints warning messages as appropriate.  When multiple "set"
 * commands are encountered, the pileup of values with "&", "|"
 * and "=" operators results in the final value.
 */
static void
check_system_file(void)
{
	struct sysparam	*sysp;

	for (sysp = sysparam_hd; sysp != NULL; sysp = sysp->sys_next) {
		struct sysparam *entry, *final;
		u_longlong_t value = 0;
		int cnt = 1;
		/*
		 * If the entry is already checked, skip it.
		 */
		if ((sysp->sys_flags & SYSPARAM_DUP) != 0)
			continue;
		/*
		 * Check if there is a duplicate entry by doing a linear
		 * search.
		 */
		final = sysp;
		for (entry = sysp->sys_next; entry != NULL;
		    entry = entry->sys_next) {
			/*
			 * Check the entry. if it's different, skip this.
			 */
			if (sysparam_compare_entry(sysp, entry) != 0)
				continue;
			/*
			 * Count the entry and put the mark.
			 */
			sysparam_count_entry(entry, &cnt, &value);
			entry->sys_flags |= SYSPARAM_DUP;
			final = entry;
		}
		final->sys_flags |= SYSPARAM_TERM;
		/*
		 * Print the warning if it's duplicated.
		 */
		if (cnt >= 2)
			sysparam_print_warning(final, value);
	}
}

/*
 * Compare the sysparam records.
 * Return 0 if they are the same, return 1 if not.
 */
static int
sysparam_compare_entry(struct sysparam *sysp, struct sysparam *entry)
{
	ASSERT(sysp->sys_ptr != NULL && entry->sys_ptr != NULL);

	/*
	 * If the command is rootdev, rootfs, swapdev, swapfs or moddir,
	 * the record with the same type is treated as a duplicate record.
	 * In other cases, the record is treated as a duplicate record when
	 * its type, its module name (if it exists), and its variable name
	 * are the same.
	 */
	switch (sysp->sys_type) {
	case MOD_ROOTDEV:
	case MOD_ROOTFS:
	case MOD_SWAPDEV:
	case MOD_SWAPFS:
	case MOD_MODDIR:
		return (sysp->sys_type == entry->sys_type ? 0 : 1);
	default: /* In other cases, just go through it. */
		break;
	}

	if (sysp->sys_type != entry->sys_type)
		return (1);

	if (sysp->sys_modnam != NULL && entry->sys_modnam == NULL)
		return (1);

	if (sysp->sys_modnam == NULL && entry->sys_modnam != NULL)
		return (1);

	if (sysp->sys_modnam != NULL && entry->sys_modnam != NULL &&
	    strcmp(sysp->sys_modnam, entry->sys_modnam) != 0)
		return (1);

	return (strcmp(sysp->sys_ptr, entry->sys_ptr));
}

/*
 * Translate a sysparam type value to a string.
 */
static char *
sysparam_type_to_str(int type)
{
	struct modcmd *mcp;

	for (mcp = modcmd; mcp->mc_cmdname != NULL; mcp++) {
		if (mcp->mc_type == type)
			break;
	}
	ASSERT(mcp->mc_type == type);

	if (type != MOD_UNKNOWN)
		return ((++mcp)->mc_cmdname); /* lower case */
	else
		return ("");	/* MOD_UNKNOWN */
}

/*
 * Check the entry and accumulate the number of entries.
 */
static void
sysparam_count_entry(struct sysparam *sysp, int *cnt, u_longlong_t *value)
{
	u_longlong_t ul = sysp->sys_info;

	switch (sysp->sys_op) {
	case SETOP_ASSIGN:
		*value = ul;
		(*cnt)++;
		return;
	case SETOP_AND:
		*value &= ul;
		return;
	case SETOP_OR:
		*value |= ul;
		return;
	default: /* Not MOD_SET */
		(*cnt)++;
		return;
	}
}

/*
 * Print out the warning if multiple entries are found in the system file.
 */
static void
sysparam_print_warning(struct sysparam *sysp, u_longlong_t value)
{
	char *modnam = sysp->sys_modnam;
	char *varnam = sysp->sys_ptr;
	int type = sysp->sys_type;
	char *typenam = sysparam_type_to_str(type);
	boolean_t str_token = ((sysp->sys_flags & SYSPARAM_STR_TOKEN) != 0);
	boolean_t hex_number = ((sysp->sys_flags & SYSPARAM_HEX_TOKEN) != 0);
#define	warn_format1 " is set more than once in /%s. "
#define	warn_format2 " applied as the current setting.\n"

	ASSERT(varnam != NULL);

	if (type == MOD_SET) {
		/*
		 * If a string token is set, print out the string
		 * instead of its pointer value. In other cases,
		 * print out the value with the appropriate format
		 * for a hexadecimal number or a decimal number.
		 */
		if (modnam == NULL) {
			if (str_token == B_TRUE) {
				cmn_err(CE_WARN, "%s" warn_format1
				    "\"%s %s = %s\"" warn_format2,
				    varnam, systemfile, typenam,
				    varnam, (char *)(uintptr_t)value);
			} else if (hex_number == B_TRUE) {
				cmn_err(CE_WARN, "%s" warn_format1
				    "\"%s %s = 0x%llx\"" warn_format2,
				    varnam, systemfile, typenam,
				    varnam, value);
			} else {
				cmn_err(CE_WARN, "%s" warn_format1
				    "\"%s %s = %lld\"" warn_format2,
				    varnam, systemfile, typenam,
				    varnam, value);
			}
		} else {
			if (str_token == B_TRUE) {
				cmn_err(CE_WARN, "%s:%s" warn_format1
				    "\"%s %s:%s = %s\"" warn_format2,
				    modnam, varnam, systemfile,
				    typenam, modnam, varnam,
				    (char *)(uintptr_t)value);
			} else if (hex_number == B_TRUE) {
				cmn_err(CE_WARN, "%s:%s" warn_format1
				    "\"%s %s:%s = 0x%llx\"" warn_format2,
				    modnam, varnam, systemfile,
				    typenam, modnam, varnam, value);
			} else {
				cmn_err(CE_WARN, "%s:%s" warn_format1
				    "\"%s %s:%s = %lld\"" warn_format2,
				    modnam, varnam, systemfile,
				    typenam, modnam, varnam, value);
			}
		}
	} else {
		/*
		 * If the type is MOD_ROOTDEV, MOD_ROOTFS, MOD_SWAPDEV,
		 * MOD_SWAPFS or MOD_MODDIR, the entry is treated as
		 * a duplicate one if it has the same type regardless
		 * of its variable name.
		 */
		switch (type) {
		case MOD_ROOTDEV:
		case MOD_ROOTFS:
		case MOD_SWAPDEV:
		case MOD_SWAPFS:
		case MOD_MODDIR:
			cmn_err(CE_WARN, "\"%s\" appears more than once "
			    "in /%s.", typenam, systemfile);
			break;
		default:
			cmn_err(CE_NOTE, "\"%s: %s\" appears more than once "
			    "in /%s.", typenam, varnam, systemfile);
			break;
		}
	}
}

/*
 * Process the system file commands.
 */
int
mod_sysctl(int fcn, void *p)
{
	static char wmesg[] = "forceload of %s failed";
	struct sysparam *sysp;
	char *name;
	struct modctl *modp;

	if (sysparam_hd == NULL)
		return (0);

	for (sysp = sysparam_hd; sysp != NULL; sysp = sysp->sys_next) {

		switch (fcn) {

		case SYS_FORCELOAD:
		if (sysp->sys_type == MOD_FORCELOAD) {
			name = sysp->sys_ptr;
			if (modload(NULL, name) == -1)
				cmn_err(CE_WARN, wmesg, name);
			/*
			 * The following works because it
			 * runs before autounloading is started!!
			 */
			modp = mod_find_by_filename(NULL, name);
			if (modp != NULL)
				modp->mod_loadflags |= MOD_NOAUTOUNLOAD;
			/*
			 * For drivers, attempt to install it.
			 */
			if (strncmp(sysp->sys_ptr, "drv", 3) == 0) {
				(