xref: /illumos-gate/usr/src/lib/libc/i386/crt/_rtld.c (revision e86c3f00)
17c478bd9Sstevel@tonic-gate /*
27c478bd9Sstevel@tonic-gate  * CDDL HEADER START
37c478bd9Sstevel@tonic-gate  *
47c478bd9Sstevel@tonic-gate  * The contents of this file are subject to the terms of the
58fd04b83SRoger A. Faulkner  * Common Development and Distribution License (the "License").
68fd04b83SRoger A. Faulkner  * You may not use this file except in compliance with the License.
77c478bd9Sstevel@tonic-gate  *
87c478bd9Sstevel@tonic-gate  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
97c478bd9Sstevel@tonic-gate  * or http://www.opensolaris.org/os/licensing.
107c478bd9Sstevel@tonic-gate  * See the License for the specific language governing permissions
117c478bd9Sstevel@tonic-gate  * and limitations under the License.
127c478bd9Sstevel@tonic-gate  *
137c478bd9Sstevel@tonic-gate  * When distributing Covered Code, include this CDDL HEADER in each
147c478bd9Sstevel@tonic-gate  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
157c478bd9Sstevel@tonic-gate  * If applicable, add the following below this CDDL HEADER, with the
167c478bd9Sstevel@tonic-gate  * fields enclosed by brackets "[]" replaced with your own identifying
177c478bd9Sstevel@tonic-gate  * information: Portions Copyright [yyyy] [name of copyright owner]
187c478bd9Sstevel@tonic-gate  *
197c478bd9Sstevel@tonic-gate  * CDDL HEADER END
207c478bd9Sstevel@tonic-gate  */
217c478bd9Sstevel@tonic-gate 
227c478bd9Sstevel@tonic-gate /*
238fd04b83SRoger A. Faulkner  * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
248fd04b83SRoger A. Faulkner  * Use is subject to license terms.
257c478bd9Sstevel@tonic-gate  */
267c478bd9Sstevel@tonic-gate 
277c478bd9Sstevel@tonic-gate /*
288fd04b83SRoger A. Faulkner  * Redirection ld.so.  Based on the 4.x binary compatibility ld.so, used
298fd04b83SRoger A. Faulkner  * to redirect aliases for ld.so to the real one.
307c478bd9Sstevel@tonic-gate  */
317c478bd9Sstevel@tonic-gate 
327c478bd9Sstevel@tonic-gate /*
337c478bd9Sstevel@tonic-gate  * Import data structures
347c478bd9Sstevel@tonic-gate  */
357c478bd9Sstevel@tonic-gate #include <sys/types.h>
367c478bd9Sstevel@tonic-gate #include <sys/mman.h>
377c478bd9Sstevel@tonic-gate #include <sys/fcntl.h>
387c478bd9Sstevel@tonic-gate #include <sys/stat.h>
397c478bd9Sstevel@tonic-gate #include <sys/sysconfig.h>
407c478bd9Sstevel@tonic-gate #include <sys/auxv.h>
417c478bd9Sstevel@tonic-gate #include <elf.h>
427c478bd9Sstevel@tonic-gate #include <link.h>
437c478bd9Sstevel@tonic-gate #include <string.h>
447c478bd9Sstevel@tonic-gate #include "alias_boot.h"
457c478bd9Sstevel@tonic-gate 
467c478bd9Sstevel@tonic-gate /*
477c478bd9Sstevel@tonic-gate  * Local manifest constants and macros.
487c478bd9Sstevel@tonic-gate  */
497c478bd9Sstevel@tonic-gate #define	ALIGN(x, a)		((int)(x) & ~((int)(a) - 1))
507c478bd9Sstevel@tonic-gate #define	ROUND(x, a)		(((int)(x) + ((int)(a) - 1)) & \
517c478bd9Sstevel@tonic-gate 				    ~((int)(a) - 1))
527c478bd9Sstevel@tonic-gate 
537c478bd9Sstevel@tonic-gate #define	EMPTY	strings[EMPTY_S]
547c478bd9Sstevel@tonic-gate #define	LDSO	strings[LDSO_S]
557c478bd9Sstevel@tonic-gate #define	ZERO	strings[ZERO_S]
567c478bd9Sstevel@tonic-gate #define	CLOSE	(*(funcs[CLOSE_F]))
578fd04b83SRoger A. Faulkner #define	FSTATAT	(*(funcs[FSTATAT_F]))
587c478bd9Sstevel@tonic-gate #define	MMAP	(*(funcs[MMAP_F]))
597c478bd9Sstevel@tonic-gate #define	MUNMAP	(*(funcs[MUNMAP_F]))
608fd04b83SRoger A. Faulkner #define	OPENAT	(*(funcs[OPENAT_F]))
617c478bd9Sstevel@tonic-gate #define	PANIC	(*(funcs[PANIC_F]))
627c478bd9Sstevel@tonic-gate #define	SYSCONFIG (*(funcs[SYSCONFIG_F]))
637c478bd9Sstevel@tonic-gate 
647c478bd9Sstevel@tonic-gate #include <link.h>
657c478bd9Sstevel@tonic-gate 
667c478bd9Sstevel@tonic-gate /*
677c478bd9Sstevel@tonic-gate  * Alias ld.so entry point -- receives a bootstrap structure and a vector
687c478bd9Sstevel@tonic-gate  * of strings.  The vector is "well-known" to us, and consists of pointers
697c478bd9Sstevel@tonic-gate  * to string constants.  This aliasing bootstrap requires no relocation in
707c478bd9Sstevel@tonic-gate  * order to run, save for the pointers of constant strings.  This second
717c478bd9Sstevel@tonic-gate  * parameter provides this.  Note that this program is carefully coded in
727c478bd9Sstevel@tonic-gate  * order to maintain the "no bootstrapping" requirement -- it calls only
737c478bd9Sstevel@tonic-gate  * local functions, uses no intrinsics, etc.
747c478bd9Sstevel@tonic-gate  */
757c478bd9Sstevel@tonic-gate void *
__rtld(Elf32_Boot * ebp,const char * strings[],int (* funcs[])())767c478bd9Sstevel@tonic-gate __rtld(Elf32_Boot *ebp, const char *strings[], int (*funcs[])())
777c478bd9Sstevel@tonic-gate {
787c478bd9Sstevel@tonic-gate 	int i, j, p;			/* working */
797c478bd9Sstevel@tonic-gate 	int page_size = 0;		/* size of a page */
807c478bd9Sstevel@tonic-gate 	const char *program_name = EMPTY; /* our name */
817c478bd9Sstevel@tonic-gate 	int ldfd;			/* fd assigned to ld.so */
827c478bd9Sstevel@tonic-gate 	int dzfd = 0;			/* fd assigned to /dev/zero */
837c478bd9Sstevel@tonic-gate 	Elf32_Ehdr *ehdr;		/* ELF header of ld.so */
847c478bd9Sstevel@tonic-gate 	Elf32_Phdr *phdr;		/* first Phdr in file */
857c478bd9Sstevel@tonic-gate 	Elf32_Phdr *pptr;		/* working Phdr */
867c478bd9Sstevel@tonic-gate 	Elf32_Phdr *lph;		/* last loadable Phdr */
877c478bd9Sstevel@tonic-gate 	Elf32_Phdr *fph = 0;		/* first loadable Phdr */
887c478bd9Sstevel@tonic-gate 	caddr_t	maddr;			/* pointer to mapping claim */
897c478bd9Sstevel@tonic-gate 	Elf32_Off mlen;			/* total mapping claim */
907c478bd9Sstevel@tonic-gate 	caddr_t faddr;			/* first program mapping of ld.so */
917c478bd9Sstevel@tonic-gate 	Elf32_Off foff;			/* file offset for segment mapping */
927c478bd9Sstevel@tonic-gate 	Elf32_Off flen;			/* file length for segment mapping */
937c478bd9Sstevel@tonic-gate 	caddr_t addr;			/* working mapping address */
947c478bd9Sstevel@tonic-gate 	caddr_t zaddr;			/* /dev/zero working mapping addr */
957c478bd9Sstevel@tonic-gate 	struct stat sb;			/* stat buffer for sizing */
967c478bd9Sstevel@tonic-gate 	auxv_t *ap;			/* working aux pointer */
977c478bd9Sstevel@tonic-gate 
987c478bd9Sstevel@tonic-gate 	/*
997c478bd9Sstevel@tonic-gate 	 * Discover things about our environment: auxiliary vector (if
1007c478bd9Sstevel@tonic-gate 	 * any), arguments, program name, and the like.
1017c478bd9Sstevel@tonic-gate 	 */
102*e86c3f00SToomas Soome 	while (ebp->eb_tag != 0) {
1037c478bd9Sstevel@tonic-gate 		switch (ebp->eb_tag) {
1047c478bd9Sstevel@tonic-gate 		case EB_ARGV:
1057c478bd9Sstevel@tonic-gate 			program_name = *((char **)ebp->eb_un.eb_ptr);
1067c478bd9Sstevel@tonic-gate 			break;
1077c478bd9Sstevel@tonic-gate 		case EB_AUXV:
1087c478bd9Sstevel@tonic-gate 			for (ap = (auxv_t *)ebp->eb_un.eb_ptr;
1097c478bd9Sstevel@tonic-gate 			    ap->a_type != AT_NULL; ap++)
1107c478bd9Sstevel@tonic-gate 				if (ap->a_type == AT_PAGESZ) {
1117c478bd9Sstevel@tonic-gate 					page_size = ap->a_un.a_val;
1127c478bd9Sstevel@tonic-gate 					break;
1137c478bd9Sstevel@tonic-gate 				}
1147c478bd9Sstevel@tonic-gate 			break;
1157c478bd9Sstevel@tonic-gate 		}
1167c478bd9Sstevel@tonic-gate 		ebp++;
1177c478bd9Sstevel@tonic-gate 	}
1187c478bd9Sstevel@tonic-gate 
1197c478bd9Sstevel@tonic-gate 	/*
1207c478bd9Sstevel@tonic-gate 	 * If we didn't get a page size from looking in the auxiliary
1217c478bd9Sstevel@tonic-gate 	 * vector, we need to get one now.
1227c478bd9Sstevel@tonic-gate 	 */
1237c478bd9Sstevel@tonic-gate 	if (page_size == 0) {
1247c478bd9Sstevel@tonic-gate 		page_size = SYSCONFIG(_CONFIG_PAGESIZE);
1257c478bd9Sstevel@tonic-gate 		ebp->eb_tag = EB_PAGESIZE, (ebp++)->eb_un.eb_val =
1267c478bd9Sstevel@tonic-gate 		    (Elf32_Word)page_size;
1277c478bd9Sstevel@tonic-gate 	}
1287c478bd9Sstevel@tonic-gate 
1297c478bd9Sstevel@tonic-gate 	/*
1307c478bd9Sstevel@tonic-gate 	 * Map in the real ld.so.  Note that we're mapping it as
1317c478bd9Sstevel@tonic-gate 	 * an ELF database, not as a program -- we just want to walk it's
1327c478bd9Sstevel@tonic-gate 	 * data structures.  Further mappings will actually establish the
1337c478bd9Sstevel@tonic-gate 	 * program in the address space.
1347c478bd9Sstevel@tonic-gate 	 */
1358fd04b83SRoger A. Faulkner 	if ((ldfd = OPENAT(AT_FDCWD, LDSO, O_RDONLY)) == -1)
1367c478bd9Sstevel@tonic-gate 		PANIC(program_name);
1378fd04b83SRoger A. Faulkner 	if (FSTATAT(ldfd, NULL, &sb, 0) == -1)
1387c478bd9Sstevel@tonic-gate 		PANIC(program_name);
1397c478bd9Sstevel@tonic-gate 	ehdr = (Elf32_Ehdr *)MMAP(0, sb.st_size, PROT_READ | PROT_EXEC,
1407c478bd9Sstevel@tonic-gate 	    MAP_SHARED, ldfd, 0);
1417c478bd9Sstevel@tonic-gate 	if (ehdr == (Elf32_Ehdr *)-1)
1427c478bd9Sstevel@tonic-gate 		PANIC(program_name);
1437c478bd9Sstevel@tonic-gate 
1447c478bd9Sstevel@tonic-gate 	/*
1457c478bd9Sstevel@tonic-gate 	 * Validate the file we're looking at, ensure it has the correct
1467c478bd9Sstevel@tonic-gate 	 * ELF structures, such as: ELF magic numbers, coded for 386,
1477c478bd9Sstevel@tonic-gate 	 * is a ".so", etc.
1487c478bd9Sstevel@tonic-gate 	 */
1497c478bd9Sstevel@tonic-gate 	if (ehdr->e_ident[EI_MAG0] != ELFMAG0 ||
1507c478bd9Sstevel@tonic-gate 	    ehdr->e_ident[EI_MAG1] != ELFMAG1 ||
1517c478bd9Sstevel@tonic-gate 	    ehdr->e_ident[EI_MAG2] != ELFMAG2 ||
1527c478bd9Sstevel@tonic-gate 	    ehdr->e_ident[EI_MAG3] != ELFMAG3)
1537c478bd9Sstevel@tonic-gate 		PANIC(program_name);
1547c478bd9Sstevel@tonic-gate 	if (ehdr->e_ident[EI_CLASS] != ELFCLASS32 ||
1557c478bd9Sstevel@tonic-gate 	    ehdr->e_ident[EI_DATA] != ELFDATA2LSB)
1567c478bd9Sstevel@tonic-gate 		PANIC(program_name);
1577c478bd9Sstevel@tonic-gate 	if (ehdr->e_type != ET_DYN)
1587c478bd9Sstevel@tonic-gate 		PANIC(program_name);
1597c478bd9Sstevel@tonic-gate 	if (ehdr->e_machine != EM_386)
1607c478bd9Sstevel@tonic-gate 		PANIC(program_name);
1617c478bd9Sstevel@tonic-gate 	if (ehdr->e_version > EV_CURRENT)
1627c478bd9Sstevel@tonic-gate 		PANIC(program_name);
1637c478bd9Sstevel@tonic-gate 
1647c478bd9Sstevel@tonic-gate 	/*
1657c478bd9Sstevel@tonic-gate 	 * Point at program headers and start figuring out what to load.
1667c478bd9Sstevel@tonic-gate 	 */
1677c478bd9Sstevel@tonic-gate 	phdr = (Elf32_Phdr *)((caddr_t)ehdr + ehdr->e_phoff);
1687c478bd9Sstevel@tonic-gate 	for (p = 0, pptr = phdr; p < (int)ehdr->e_phnum; p++,
1697c478bd9Sstevel@tonic-gate 	    pptr = (Elf32_Phdr *)((caddr_t)pptr + ehdr->e_phentsize))
1707c478bd9Sstevel@tonic-gate 		if (pptr->p_type == PT_LOAD) {
1717c478bd9Sstevel@tonic-gate 			if (fph == 0) {
1727c478bd9Sstevel@tonic-gate 				fph = pptr;
1737c478bd9Sstevel@tonic-gate 			} else if (pptr->p_vaddr <= lph->p_vaddr)
1747c478bd9Sstevel@tonic-gate 				PANIC(program_name);
1757c478bd9Sstevel@tonic-gate 			lph = pptr;
1767c478bd9Sstevel@tonic-gate 		}
1777c478bd9Sstevel@tonic-gate 
1787c478bd9Sstevel@tonic-gate 	/*
1797c478bd9Sstevel@tonic-gate 	 * We'd better have at least one loadable segment.
1807c478bd9Sstevel@tonic-gate 	 */
1817c478bd9Sstevel@tonic-gate 	if (fph == 0)
1827c478bd9Sstevel@tonic-gate 		PANIC(program_name);
1837c478bd9Sstevel@tonic-gate 
1847c478bd9Sstevel@tonic-gate 	/*
1857c478bd9Sstevel@tonic-gate 	 * Map enough address space to hold the program (as opposed to the
1867c478bd9Sstevel@tonic-gate 	 * file) represented by ld.so.  The amount to be assigned is the
1877c478bd9Sstevel@tonic-gate 	 * range between the end of the last loadable segment and the
1887c478bd9Sstevel@tonic-gate 	 * beginning of the first PLUS the alignment of the first segment.
1897c478bd9Sstevel@tonic-gate 	 * mmap() can assign us any page-aligned address, but the relocations
1907c478bd9Sstevel@tonic-gate 	 * assume the alignments included in the program header.  As an
1917c478bd9Sstevel@tonic-gate 	 * optimization, however, let's assume that mmap() will actually
1927c478bd9Sstevel@tonic-gate 	 * give us an aligned address -- since if it does, we can save
1937c478bd9Sstevel@tonic-gate 	 * an munmap() later on.  If it doesn't -- then go try it again.
1947c478bd9Sstevel@tonic-gate 	 */
1957c478bd9Sstevel@tonic-gate 	mlen = ROUND((lph->p_vaddr + lph->p_memsz) -
1967c478bd9Sstevel@tonic-gate 	    ALIGN(fph->p_vaddr, page_size), page_size);
1977c478bd9Sstevel@tonic-gate 	maddr = (caddr_t)MMAP(0, mlen, PROT_READ | PROT_EXEC,
1987c478bd9Sstevel@tonic-gate 	    MAP_SHARED, ldfd, 0);
1997c478bd9Sstevel@tonic-gate 	if (maddr == (caddr_t)-1)
2007c478bd9Sstevel@tonic-gate 		PANIC(program_name);
2017c478bd9Sstevel@tonic-gate 	faddr = (caddr_t)ROUND(maddr, fph->p_align);
2027c478bd9Sstevel@tonic-gate 
2037c478bd9Sstevel@tonic-gate 	/*
2047c478bd9Sstevel@tonic-gate 	 * Check to see whether alignment skew was really needed.
2057c478bd9Sstevel@tonic-gate 	 */
2067c478bd9Sstevel@tonic-gate 	if (faddr != maddr) {
2077c478bd9Sstevel@tonic-gate 		(void) MUNMAP(maddr, mlen);
2087c478bd9Sstevel@tonic-gate 		mlen = ROUND((lph->p_vaddr + lph->p_memsz) -
2097c478bd9Sstevel@tonic-gate 		    ALIGN(fph->p_vaddr, fph->p_align) + fph->p_align,
2107c478bd9Sstevel@tonic-gate 		    page_size);
2117c478bd9Sstevel@tonic-gate 		maddr = (caddr_t)MMAP(0, mlen, PROT_READ | PROT_EXEC,
2127c478bd9Sstevel@tonic-gate 		    MAP_SHARED, ldfd, 0);
2137c478bd9Sstevel@tonic-gate 		if (maddr == (caddr_t)-1)
2147c478bd9Sstevel@tonic-gate 			PANIC(program_name);
2157c478bd9Sstevel@tonic-gate 		faddr = (caddr_t)ROUND(maddr, fph->p_align);
2167c478bd9Sstevel@tonic-gate 	}
2177c478bd9Sstevel@tonic-gate 
2187c478bd9Sstevel@tonic-gate 	/*
2197c478bd9Sstevel@tonic-gate 	 * We have the address space reserved, so map each loadable segment.
2207c478bd9Sstevel@tonic-gate 	 */
2217c478bd9Sstevel@tonic-gate 	for (p = 0, pptr = phdr; p < (int)ehdr->e_phnum; p++,
2227c478bd9Sstevel@tonic-gate 	    pptr = (Elf32_Phdr *)((caddr_t)pptr + ehdr->e_phentsize)) {
2237c478bd9Sstevel@tonic-gate 
2247c478bd9Sstevel@tonic-gate 		/*
2257c478bd9Sstevel@tonic-gate 		 * Skip non-loadable segments or segments that don't occupy
2267c478bd9Sstevel@tonic-gate 		 * any memory.
2277c478bd9Sstevel@tonic-gate 		 */
2287c478bd9Sstevel@tonic-gate 		if ((pptr->p_type != PT_LOAD) || (pptr->p_memsz == 0))
2297c478bd9Sstevel@tonic-gate 			continue;
2307c478bd9Sstevel@tonic-gate 
2317c478bd9Sstevel@tonic-gate 		/*
2327c478bd9Sstevel@tonic-gate 		 * Determine the file offset to which the mapping will
2337c478bd9Sstevel@tonic-gate 		 * directed (must be aligned) and how much to map (might
2347c478bd9Sstevel@tonic-gate 		 * be more than the file in the case of .bss.)
2357c478bd9Sstevel@tonic-gate 		 */
2367c478bd9Sstevel@tonic-gate 		foff = ALIGN(pptr->p_offset, page_size);
2377c478bd9Sstevel@tonic-gate 		flen = pptr->p_memsz + (pptr->p_offset - foff);
2387c478bd9Sstevel@tonic-gate 
2397c478bd9Sstevel@tonic-gate 		/*
2407c478bd9Sstevel@tonic-gate 		 * Set address of this segment relative to our base.
2417c478bd9Sstevel@tonic-gate 		 */
2427c478bd9Sstevel@tonic-gate 		addr = (caddr_t)ALIGN(faddr + pptr->p_vaddr, page_size);
2437c478bd9Sstevel@tonic-gate 
2447c478bd9Sstevel@tonic-gate 		/*
2457c478bd9Sstevel@tonic-gate 		 * If this is the first program header, record our base
2467c478bd9Sstevel@tonic-gate 		 * address for later use.
2477c478bd9Sstevel@tonic-gate 		 */
2487c478bd9Sstevel@tonic-gate 		if (pptr == phdr) {
2497c478bd9Sstevel@tonic-gate 			ebp->eb_tag = EB_LDSO_BASE;
2507c478bd9Sstevel@tonic-gate 			(ebp++)->eb_un.eb_ptr = (Elf32_Addr)addr;
2517c478bd9Sstevel@tonic-gate 		}
2527c478bd9Sstevel@tonic-gate 
2537c478bd9Sstevel@tonic-gate 		/*
2547c478bd9Sstevel@tonic-gate 		 * Unmap anything from the last mapping address to this
2557c478bd9Sstevel@tonic-gate 		 * one.
2567c478bd9Sstevel@tonic-gate 		 */
2577c478bd9Sstevel@tonic-gate 		if (addr - maddr) {
2587c478bd9Sstevel@tonic-gate 			(void) MUNMAP(maddr, addr - maddr);
2597c478bd9Sstevel@tonic-gate 			mlen -= addr - maddr;
2607c478bd9Sstevel@tonic-gate 		}
2617c478bd9Sstevel@tonic-gate 
2627c478bd9Sstevel@tonic-gate 		/*
2637c478bd9Sstevel@tonic-gate 		 * Determine the mapping protection from the section
2647c478bd9Sstevel@tonic-gate 		 * attributes.
2657c478bd9Sstevel@tonic-gate 		 */
2667c478bd9Sstevel@tonic-gate 		i = 0;
2677c478bd9Sstevel@tonic-gate 		if (pptr->p_flags & PF_R)
2687c478bd9Sstevel@tonic-gate 			i |= PROT_READ;
2697c478bd9Sstevel@tonic-gate 		if (pptr->p_flags & PF_W)
2707c478bd9Sstevel@tonic-gate 			i |= PROT_WRITE;
2717c478bd9Sstevel@tonic-gate 		if (pptr->p_flags & PF_X)
2727c478bd9Sstevel@tonic-gate 			i |= PROT_EXEC;
2737c478bd9Sstevel@tonic-gate 		if ((caddr_t)MMAP((caddr_t)addr, flen, i,
2747c478bd9Sstevel@tonic-gate 		    MAP_FIXED | MAP_PRIVATE, ldfd, foff) == (caddr_t)-1)
2757c478bd9Sstevel@tonic-gate 			PANIC(program_name);
2767c478bd9Sstevel@tonic-gate 
2777c478bd9Sstevel@tonic-gate 		/*
2787c478bd9Sstevel@tonic-gate 		 * If the memory occupancy of the segment overflows the
2797c478bd9Sstevel@tonic-gate 		 * definition in the file, we need to "zero out" the
2807c478bd9Sstevel@tonic-gate 		 * end of the mapping we've established, and if necessary,
2817c478bd9Sstevel@tonic-gate 		 * map some more space from /dev/zero.
2827c478bd9Sstevel@tonic-gate 		 */
2837c478bd9Sstevel@tonic-gate 		if (pptr->p_memsz > pptr->p_filesz) {
2847c478bd9Sstevel@tonic-gate 			foff = (int)faddr + pptr->p_vaddr + pptr->p_filesz;
2857c478bd9Sstevel@tonic-gate 			zaddr = (caddr_t)ROUND(foff, page_size);
2867c478bd9Sstevel@tonic-gate 			for (j = 0; j < (int)(zaddr - foff); j++)
2877c478bd9Sstevel@tonic-gate 				*((char *)foff + j) = 0;
2887c478bd9Sstevel@tonic-gate 			j = (faddr + pptr->p_vaddr + pptr->p_memsz) - zaddr;
2897c478bd9Sstevel@tonic-gate 			if (j > 0) {
2907c478bd9Sstevel@tonic-gate 				if (dzfd == 0) {
2918fd04b83SRoger A. Faulkner 					dzfd = OPENAT(AT_FDCWD, ZERO, O_RDWR);
2927c478bd9Sstevel@tonic-gate 					if (dzfd == -1)
2937c478bd9Sstevel@tonic-gate 						PANIC(program_name);
2947c478bd9Sstevel@tonic-gate 				}
2957c478bd9Sstevel@tonic-gate 				if ((caddr_t)MMAP((caddr_t)zaddr, j, i,
2967c478bd9Sstevel@tonic-gate 				    MAP_FIXED | MAP_PRIVATE, dzfd,
2977c478bd9Sstevel@tonic-gate 				    0) == (caddr_t)-1)
2987c478bd9Sstevel@tonic-gate 					PANIC(program_name);
2997c478bd9Sstevel@tonic-gate 			}
3007c478bd9Sstevel@tonic-gate 		}
3017c478bd9Sstevel@tonic-gate 
3027c478bd9Sstevel@tonic-gate 		/*
3037c478bd9Sstevel@tonic-gate 		 * Update the mapping claim pointer.
3047c478bd9Sstevel@tonic-gate 		 */
3057c478bd9Sstevel@tonic-gate 		maddr = addr + ROUND(flen, page_size);
3067c478bd9Sstevel@tonic-gate 		mlen -= maddr - addr;
3077c478bd9Sstevel@tonic-gate 	}
3087c478bd9Sstevel@tonic-gate 
3097c478bd9Sstevel@tonic-gate 	/*
3107c478bd9Sstevel@tonic-gate 	 * Unmap any final reservation.
3117c478bd9Sstevel@tonic-gate 	 */
3127c478bd9Sstevel@tonic-gate 	if (mlen > 0)
3137c478bd9Sstevel@tonic-gate 		(void) MUNMAP(maddr, mlen);
3147c478bd9Sstevel@tonic-gate 
3157c478bd9Sstevel@tonic-gate 	/*
3167c478bd9Sstevel@tonic-gate 	 * Clean up file descriptor space we've consumed.  Pass along
3177c478bd9Sstevel@tonic-gate 	 * the /dev/zero file descriptor we got -- every cycle counts.
3187c478bd9Sstevel@tonic-gate 	 */
3197c478bd9Sstevel@tonic-gate 	(void) CLOSE(ldfd);
3207c478bd9Sstevel@tonic-gate 	if (dzfd != 0)
3217c478bd9Sstevel@tonic-gate 		ebp->eb_tag = EB_DEVZERO, (ebp++)->eb_un.eb_val = dzfd;
3227c478bd9Sstevel@tonic-gate 
3237c478bd9Sstevel@tonic-gate 	ebp->eb_tag = EB_NULL, ebp->eb_un.eb_val = 0;
3247c478bd9Sstevel@tonic-gate 
3257c478bd9Sstevel@tonic-gate 	/* The two bytes before _rt_boot is for the alias entry point */
3267c478bd9Sstevel@tonic-gate 	return (void *) (ehdr->e_entry + faddr - 2);
3277c478bd9Sstevel@tonic-gate }
328