[dragonfly.git] / libexec / rtld-elf / map_object.c

/*-
 * Copyright 1996-1998 John D. Polstra.
 * All rights reserved.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 *
 * $FreeBSD: src/libexec/rtld-elf/map_object.c,v 1.25 2011/01/25 21:12:31 kib Exp $
 */

#include <sys/param.h>
#include <sys/mman.h>
#include <sys/stat.h>

#include <errno.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "debug.h"
#include "rtld.h"

static Elf_Ehdr *get_elf_header (int, const char *);
static int convert_prot(int);	/* Elf flags -> mmap protection */
static int convert_flags(int); /* Elf flags -> mmap flags */

/*
 * Map a shared object into memory.  The "fd" argument is a file descriptor,
 * which must be open on the object and positioned at its beginning.
 * The "path" argument is a pathname that is used only for error messages.
 *
 * The return value is a pointer to a newly-allocated Obj_Entry structure
 * for the shared object.  Returns NULL on failure.
 */
Obj_Entry *
map_object(int fd, const char *path, const struct stat *sb)
{
    Obj_Entry *obj;
    Elf_Ehdr *hdr;
    int i;
    Elf_Phdr *phdr;
    Elf_Phdr *phlimit;
    Elf_Phdr **segs;
    int nsegs;
    Elf_Phdr *phdyn;
    Elf_Phdr *phinterp;
    Elf_Phdr *phtls;
    caddr_t mapbase;
    size_t mapsize;
    Elf_Off base_offset;
    Elf_Addr base_vaddr;
    Elf_Addr base_vlimit;
    caddr_t base_addr;
    Elf_Off data_offset;
    Elf_Addr data_vaddr;
    Elf_Addr data_vlimit;
    caddr_t data_addr;
    int data_prot;
    int data_flags;
    Elf_Addr clear_vaddr;
    caddr_t clear_addr;
    caddr_t clear_page;
    Elf_Addr phdr_vaddr;
    size_t nclear, phsize;
    Elf_Addr bss_vaddr;
    Elf_Addr bss_vlimit;
    caddr_t bss_addr;
    Elf_Addr relro_page;
    size_t relro_size;

    hdr = get_elf_header(fd, path);
    if (hdr == NULL)
	return (NULL);

    /*
     * Scan the program header entries, and save key information.
     *
     * We expect that the loadable segments are ordered by load address.
     */
    phdr = (Elf_Phdr *) ((char *)hdr + hdr->e_phoff);
    phsize  = hdr->e_phnum * sizeof (phdr[0]);
    phlimit = phdr + hdr->e_phnum;
    nsegs = -1;
    phdyn = phinterp = phtls = NULL;
    phdr_vaddr = 0;
    relro_page = 0;
    relro_size = 0;
    segs = alloca(sizeof(segs[0]) * hdr->e_phnum);
    while (phdr < phlimit) {
	switch (phdr->p_type) {

	case PT_INTERP:
	    phinterp = phdr;
	    break;

	case PT_LOAD:
	    segs[++nsegs] = phdr;
	    if ((segs[nsegs]->p_align & (PAGE_SIZE - 1)) != 0) {
		_rtld_error("%s: PT_LOAD segment %d not page-aligned",
		    path, nsegs);
		return NULL;
	    }
	    break;

	case PT_PHDR:
	    phdr_vaddr = phdr->p_vaddr;
	    phsize = phdr->p_memsz;
	    break;

	case PT_DYNAMIC:
	    phdyn = phdr;
	    break;

	case PT_TLS:
	    phtls = phdr;
	    break;

	case PT_GNU_RELRO:
	    relro_page = phdr->p_vaddr;
	    relro_size = phdr->p_memsz;
	    break;
	}

	++phdr;
    }
    if (phdyn == NULL) {
	_rtld_error("%s: object is not dynamically-linked", path);
	return NULL;
    }

    if (nsegs < 0) {
	_rtld_error("%s: too few PT_LOAD segments", path);
	return NULL;
    }

    /*
     * Map the entire address space of the object, to stake out our
     * contiguous region, and to establish the base address for relocation.
     */
    base_offset = trunc_page(segs[0]->p_offset);
    base_vaddr = trunc_page(segs[0]->p_vaddr);
    base_vlimit = round_page(segs[nsegs]->p_vaddr + segs[nsegs]->p_memsz);
    mapsize = base_vlimit - base_vaddr;
    base_addr = hdr->e_type == ET_EXEC ? (caddr_t) base_vaddr : NULL;

    mapbase = mmap(base_addr, mapsize, PROT_NONE, MAP_ANON | MAP_PRIVATE |
      MAP_NOCORE, -1, 0);
    if (mapbase == (caddr_t) -1) {
	_rtld_error("%s: mmap of entire address space failed: %s",
	  path, strerror(errno));
	return NULL;
    }
    if (base_addr != NULL && mapbase != base_addr) {
	_rtld_error("%s: mmap returned wrong address: wanted %p, got %p",
	  path, base_addr, mapbase);
	munmap(mapbase, mapsize);
	return NULL;
    }

    for (i = 0; i <= nsegs; i++) {
	/* Overlay the segment onto the proper region. */
	data_offset = trunc_page(segs[i]->p_offset);
	data_vaddr = trunc_page(segs[i]->p_vaddr);
	data_vlimit = round_page(segs[i]->p_vaddr + segs[i]->p_filesz);
	data_addr = mapbase + (data_vaddr - base_vaddr);
	data_prot = convert_prot(segs[i]->p_flags);
	data_flags = convert_flags(segs[i]->p_flags) | MAP_FIXED;
	if (mmap(data_addr, data_vlimit - data_vaddr, data_prot,
	  data_flags, fd, data_offset) == (caddr_t) -1) {
	    _rtld_error("%s: mmap of data failed: %s", path, strerror(errno));
	    return NULL;
	}

	/* Do BSS setup */
	if (segs[i]->p_filesz != segs[i]->p_memsz) {

	    /* Clear any BSS in the last page of the segment. */
	    clear_vaddr = segs[i]->p_vaddr + segs[i]->p_filesz;
	    clear_addr = mapbase + (clear_vaddr - base_vaddr);
	    clear_page = mapbase + (trunc_page(clear_vaddr) - base_vaddr);

	    if ((nclear = data_vlimit - clear_vaddr) > 0) {
		/* Make sure the end of the segment is writable */
		if ((data_prot & PROT_WRITE) == 0 && -1 ==
		     mprotect(clear_page, PAGE_SIZE, data_prot|PROT_WRITE)) {
			_rtld_error("%s: mprotect failed: %s", path,
			    strerror(errno));
			return NULL;
		}

		memset(clear_addr, 0, nclear);

		/*
		 * reset the data protection back, enable the segment to be
		 * coredumped since we modified it.
		 */
		if ((data_prot & PROT_WRITE) == 0) {
		    madvise(clear_page, PAGE_SIZE, MADV_CORE);
		    mprotect(clear_page, PAGE_SIZE, data_prot);
		}
	    }

	    /* Overlay the BSS segment onto the proper region. */
	    bss_vaddr = data_vlimit;
	    bss_vlimit = round_page(segs[i]->p_vaddr + segs[i]->p_memsz);
	    bss_addr = mapbase +  (bss_vaddr - base_vaddr);
	    if (bss_vlimit > bss_vaddr) {	/* There is something to do */
		if (mmap(bss_addr, bss_vlimit - bss_vaddr, data_prot,
		    data_flags | MAP_ANON, -1, 0) == (caddr_t)-1) {
		    _rtld_error("%s: mmap of bss failed: %s", path,
			strerror(errno));
		    return NULL;
		}
	    }
	}

	if (phdr_vaddr == 0 && data_offset <= hdr->e_phoff &&
	  (data_vlimit - data_vaddr + data_offset) >=
	  (hdr->e_phoff + hdr->e_phnum * sizeof (Elf_Phdr))) {
	    phdr_vaddr = data_vaddr + hdr->e_phoff - data_offset;
	}
    }

    obj = obj_new();
    if (sb != NULL) {
	obj->dev = sb->st_dev;
	obj->ino = sb->st_ino;
    }
    obj->mapbase = mapbase;
    obj->mapsize = mapsize;
    obj->textsize = round_page(segs[0]->p_vaddr + segs[0]->p_memsz) -
      base_vaddr;
    obj->vaddrbase = base_vaddr;
    obj->relocbase = mapbase - base_vaddr;
    obj->dynamic = (const Elf_Dyn *) (obj->relocbase + phdyn->p_vaddr);
    if (hdr->e_entry != 0)
	obj->entry = (caddr_t) (obj->relocbase + hdr->e_entry);
    if (phdr_vaddr != 0) {
	obj->phdr = (const Elf_Phdr *) (obj->relocbase + phdr_vaddr);
    } else {
	obj->phdr = malloc(phsize);
	if (obj->phdr == NULL) {
	    obj_free(obj);
	    _rtld_error("%s: cannot allocate program header", path);
	     return NULL;
	}
	memcpy((char *)obj->phdr, (char *)hdr + hdr->e_phoff, phsize);
	obj->phdr_alloc = true;
    }
    obj->phsize = phsize;
    if (phinterp != NULL)
	obj->interp = (const char *) (obj->relocbase + phinterp->p_vaddr);
    if (phtls != NULL) {
	tls_dtv_generation++;
	obj->tlsindex = ++tls_max_index;
	obj->tlssize = phtls->p_memsz;
	obj->tlsalign = phtls->p_align;
	obj->tlsinitsize = phtls->p_filesz;
	obj->tlsinit = mapbase + phtls->p_vaddr;
    }

    if (relro_size) {
        obj->relro_page = obj->relocbase + trunc_page(relro_page);
        obj->relro_size = round_page(relro_size);
    }
    return obj;
}

static Elf_Ehdr *
get_elf_header (int fd, const char *path)
{
    static union {
	Elf_Ehdr hdr;
	char buf[PAGE_SIZE];
    } u;
    ssize_t nbytes;

    if ((nbytes = pread(fd, u.buf, PAGE_SIZE, 0)) == -1) {
	_rtld_error("%s: read error: %s", path, strerror(errno));
	return NULL;
    }

    /* Make sure the file is valid */
    if (nbytes < (ssize_t)sizeof(Elf_Ehdr) || !IS_ELF(u.hdr)) {
	_rtld_error("%s: invalid file format", path);
	return NULL;
    }
    if (u.hdr.e_ident[EI_CLASS] != ELF_TARG_CLASS
      || u.hdr.e_ident[EI_DATA] != ELF_TARG_DATA) {
	_rtld_error("%s: unsupported file layout", path);
	return NULL;
    }
    if (u.hdr.e_ident[EI_VERSION] != EV_CURRENT
      || u.hdr.e_version != EV_CURRENT) {
	_rtld_error("%s: unsupported file version", path);
	return NULL;
    }
    if (u.hdr.e_type != ET_EXEC && u.hdr.e_type != ET_DYN) {
	_rtld_error("%s: unsupported file type", path);
	return NULL;
    }
    if (u.hdr.e_machine != ELF_TARG_MACH) {
	_rtld_error("%s: unsupported machine", path);
	return NULL;
    }

    /*
     * We rely on the program header being in the first page.  This is
     * not strictly required by the ABI specification, but it seems to
     * always true in practice.  And, it simplifies things considerably.
     */
    if (u.hdr.e_phentsize != sizeof(Elf_Phdr)) {
	_rtld_error(
	  "%s: invalid shared object: e_phentsize != sizeof(Elf_Phdr)", path);
	return NULL;
    }
    if (u.hdr.e_phoff + u.hdr.e_phnum * sizeof(Elf_Phdr) > (size_t)nbytes) {
	_rtld_error("%s: program header too large", path);
	return NULL;
    }

    return (&u.hdr);
}

void
obj_free(Obj_Entry *obj)
{
    Objlist_Entry *elm;

    if (obj->tls_done)
	free_tls_offset(obj);
    while (obj->needed != NULL) {
	Needed_Entry *needed = obj->needed;
	obj->needed = needed->next;
	free(needed);
    }
    while (!STAILQ_EMPTY(&obj->names)) {
	Name_Entry *entry = STAILQ_FIRST(&obj->names);
	STAILQ_REMOVE_HEAD(&obj->names, link);
	free(entry);
    }
    while (!STAILQ_EMPTY(&obj->dldags)) {
	elm = STAILQ_FIRST(&obj->dldags);
	STAILQ_REMOVE_HEAD(&obj->dldags, link);
	free(elm);
    }
    while (!STAILQ_EMPTY(&obj->dagmembers)) {
	elm = STAILQ_FIRST(&obj->dagmembers);
	STAILQ_REMOVE_HEAD(&obj->dagmembers, link);
	free(elm);
    }
    if (obj->vertab)
	free(obj->vertab);
    if (obj->origin_path)
	free(obj->origin_path);
    if (obj->z_origin)
	free(obj->rpath);
    if (obj->priv)
	free(obj->priv);
    if (obj->path)
	free(obj->path);
    if (obj->phdr_alloc)
	free((void *)obj->phdr);
    free(obj);
}

Obj_Entry *
obj_new(void)
{
    Obj_Entry *obj;

    obj = CNEW(Obj_Entry);
    STAILQ_INIT(&obj->dldags);
    STAILQ_INIT(&obj->dagmembers);
    STAILQ_INIT(&obj->names);
    return obj;
}

/*
 * Given a set of ELF protection flags, return the corresponding protection
 * flags for MMAP.
 */
static int
convert_prot(int elfflags)
{
    int prot = 0;
    if (elfflags & PF_R)
	prot |= PROT_READ;
    if (elfflags & PF_W)
	prot |= PROT_WRITE;
    if (elfflags & PF_X)
	prot |= PROT_EXEC;
    return prot;
}

static int
convert_flags(int elfflags)
{
    int flags = MAP_PRIVATE; /* All mappings are private */

    /*
     * Readonly mappings are marked "MAP_NOCORE", because they can be
     * reconstructed by a debugger.
     */
    if (!(elfflags & PF_W))
	flags |= MAP_NOCORE;
    return flags;
}
Commit	Line	Data
984263bc MD	1	/*-
	2	* Copyright 1996-1998 John D. Polstra.
	3	* All rights reserved.
	4	*
	5	* Redistribution and use in source and binary forms, with or without
	6	* modification, are permitted provided that the following conditions
	7	* are met:
	8	* 1. Redistributions of source code must retain the above copyright
	9	* notice, this list of conditions and the following disclaimer.
	10	* 2. Redistributions in binary form must reproduce the above copyright
	11	* notice, this list of conditions and the following disclaimer in the
	12	* documentation and/or other materials provided with the distribution.
	13	*
	14	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
	15	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	16	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	17	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	18	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	19	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	20	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	21	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	22	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	23	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	24	*
fcf53d9b	25	* $FreeBSD: src/libexec/rtld-elf/map_object.c,v 1.25 2011/01/25 21:12:31 kib Exp $
984263bc MD	26	*/
	27
	28	#include <sys/param.h>
	29	#include <sys/mman.h>
	30	#include <sys/stat.h>
	31
	32	#include <errno.h>
	33	#include <stddef.h>
	34	#include <stdlib.h>
	35	#include <string.h>
	36	#include <unistd.h>
	37
fcf53d9b	38	#include "debug.h"
984263bc MD	39	#include "rtld.h"
984263bc MD	40
1c76efe5	41	static Elf_Ehdr get_elf_header (int, const char );
984263bc MD	42	static int convert_prot(int); /* Elf flags -> mmap protection */
	43	static int convert_flags(int); /* Elf flags -> mmap flags */
	44
	45	/*
	46	* Map a shared object into memory. The "fd" argument is a file descriptor,
	47	* which must be open on the object and positioned at its beginning.
	48	* The "path" argument is a pathname that is used only for error messages.
	49	*
	50	* The return value is a pointer to a newly-allocated Obj_Entry structure
	51	* for the shared object. Returns NULL on failure.
	52	*/
	53	Obj_Entry *
	54	map_object(int fd, const char path, const struct stat sb)
	55	{
	56	Obj_Entry *obj;
1c76efe5 MD	57	Elf_Ehdr *hdr;
1c76efe5 MD	58	int i;
984263bc MD	59	Elf_Phdr *phdr;
	60	Elf_Phdr *phlimit;
	61	Elf_Phdr **segs;
	62	int nsegs;
	63	Elf_Phdr *phdyn;
984263bc	64	Elf_Phdr *phinterp;
55b88cae	65	Elf_Phdr *phtls;
984263bc MD	66	caddr_t mapbase;
	67	size_t mapsize;
	68	Elf_Off base_offset;
	69	Elf_Addr base_vaddr;
	70	Elf_Addr base_vlimit;
	71	caddr_t base_addr;
	72	Elf_Off data_offset;
	73	Elf_Addr data_vaddr;
	74	Elf_Addr data_vlimit;
	75	caddr_t data_addr;
	76	int data_prot;
	77	int data_flags;
	78	Elf_Addr clear_vaddr;
	79	caddr_t clear_addr;
	80	caddr_t clear_page;
fcf53d9b JM	81	Elf_Addr phdr_vaddr;
fcf53d9b JM	82	size_t nclear, phsize;
984263bc MD	83	Elf_Addr bss_vaddr;
	84	Elf_Addr bss_vlimit;
	85	caddr_t bss_addr;
007f494e JM	86	Elf_Addr relro_page;
007f494e JM	87	size_t relro_size;
984263bc	88
1c76efe5 MD	89	hdr = get_elf_header(fd, path);
1c76efe5 MD	90	if (hdr == NULL)
fcf53d9b	91	return (NULL);
984263bc MD	92
	93	/*
	94	* Scan the program header entries, and save key information.
	95	*
fcf53d9b	96	* We expect that the loadable segments are ordered by load address.
984263bc	97	*/
1c76efe5	98	phdr = (Elf_Phdr ) ((char )hdr + hdr->e_phoff);
fcf53d9b	99	phsize = hdr->e_phnum * sizeof (phdr[0]);
1c76efe5	100	phlimit = phdr + hdr->e_phnum;
984263bc	101	nsegs = -1;
fcf53d9b JM	102	phdyn = phinterp = phtls = NULL;
fcf53d9b JM	103	phdr_vaddr = 0;
007f494e JM	104	relro_page = 0;
007f494e JM	105	relro_size = 0;
1c76efe5	106	segs = alloca(sizeof(segs[0]) * hdr->e_phnum);
984263bc MD	107	while (phdr < phlimit) {
	108	switch (phdr->p_type) {
	109
	110	case PT_INTERP:
	111	phinterp = phdr;
	112	break;
	113
	114	case PT_LOAD:
	115	segs[++nsegs] = phdr;
fcf53d9b	116	if ((segs[nsegs]->p_align & (PAGE_SIZE - 1)) != 0) {
984263bc MD	117	_rtld_error("%s: PT_LOAD segment %d not page-aligned",
	118	path, nsegs);
	119	return NULL;
	120	}
	121	break;
	122
	123	case PT_PHDR:
fcf53d9b JM	124	phdr_vaddr = phdr->p_vaddr;
fcf53d9b JM	125	phsize = phdr->p_memsz;
984263bc MD	126	break;
	127
	128	case PT_DYNAMIC:
	129	phdyn = phdr;
	130	break;
139b8f34	131
55b88cae DX	132	case PT_TLS:
	133	phtls = phdr;
	134	break;
007f494e JM	135
	136	case PT_GNU_RELRO:
	137	relro_page = phdr->p_vaddr;
	138	relro_size = phdr->p_memsz;
	139	break;
984263bc MD	140	}
	141
	142	++phdr;
	143	}
	144	if (phdyn == NULL) {
	145	_rtld_error("%s: object is not dynamically-linked", path);
	146	return NULL;
	147	}
	148
	149	if (nsegs < 0) {
	150	_rtld_error("%s: too few PT_LOAD segments", path);
	151	return NULL;
	152	}
	153
	154	/*
	155	* Map the entire address space of the object, to stake out our
	156	* contiguous region, and to establish the base address for relocation.
	157	*/
	158	base_offset = trunc_page(segs[0]->p_offset);
	159	base_vaddr = trunc_page(segs[0]->p_vaddr);
	160	base_vlimit = round_page(segs[nsegs]->p_vaddr + segs[nsegs]->p_memsz);
	161	mapsize = base_vlimit - base_vaddr;
1c76efe5	162	base_addr = hdr->e_type == ET_EXEC ? (caddr_t) base_vaddr : NULL;
984263bc	163
fcf53d9b JM	164	mapbase = mmap(base_addr, mapsize, PROT_NONE, MAP_ANON \| MAP_PRIVATE \|
fcf53d9b JM	165	MAP_NOCORE, -1, 0);
984263bc MD	166	if (mapbase == (caddr_t) -1) {
	167	_rtld_error("%s: mmap of entire address space failed: %s",
	168	path, strerror(errno));
	169	return NULL;
	170	}
	171	if (base_addr != NULL && mapbase != base_addr) {
	172	_rtld_error("%s: mmap returned wrong address: wanted %p, got %p",
	173	path, base_addr, mapbase);
	174	munmap(mapbase, mapsize);
	175	return NULL;
	176	}
	177
fcf53d9b	178	for (i = 0; i <= nsegs; i++) {
984263bc MD	179	/* Overlay the segment onto the proper region. */
	180	data_offset = trunc_page(segs[i]->p_offset);
	181	data_vaddr = trunc_page(segs[i]->p_vaddr);
	182	data_vlimit = round_page(segs[i]->p_vaddr + segs[i]->p_filesz);
	183	data_addr = mapbase + (data_vaddr - base_vaddr);
	184	data_prot = convert_prot(segs[i]->p_flags);
	185	data_flags = convert_flags(segs[i]->p_flags) \| MAP_FIXED;
fcf53d9b	186	if (mmap(data_addr, data_vlimit - data_vaddr, data_prot,
984263bc MD	187	data_flags, fd, data_offset) == (caddr_t) -1) {
	188	_rtld_error("%s: mmap of data failed: %s", path, strerror(errno));
	189	return NULL;
	190	}
	191
fcf53d9b JM	192	/* Do BSS setup */
	193	if (segs[i]->p_filesz != segs[i]->p_memsz) {
	194
	195	/* Clear any BSS in the last page of the segment. */
	196	clear_vaddr = segs[i]->p_vaddr + segs[i]->p_filesz;
	197	clear_addr = mapbase + (clear_vaddr - base_vaddr);
	198	clear_page = mapbase + (trunc_page(clear_vaddr) - base_vaddr);
	199
	200	if ((nclear = data_vlimit - clear_vaddr) > 0) {
	201	/* Make sure the end of the segment is writable */
9b53619b JM	202	if ((data_prot & PROT_WRITE) == 0 && -1 ==
9b53619b JM	203	mprotect(clear_page, PAGE_SIZE, data_prot\|PROT_WRITE)) {
984263bc MD	204	_rtld_error("%s: mprotect failed: %s", path,
	205	strerror(errno));
	206	return NULL;
4b89341e	207	}
984263bc	208
fcf53d9b	209	memset(clear_addr, 0, nclear);
984263bc	210
fcf53d9b JM	211	/*
	212	* reset the data protection back, enable the segment to be
	213	* coredumped since we modified it.
	214	*/
	215	if ((data_prot & PROT_WRITE) == 0) {
	216	madvise(clear_page, PAGE_SIZE, MADV_CORE);
	217	mprotect(clear_page, PAGE_SIZE, data_prot);
	218	}
4b89341e	219	}
984263bc	220
fcf53d9b JM	221	/* Overlay the BSS segment onto the proper region. */
	222	bss_vaddr = data_vlimit;
	223	bss_vlimit = round_page(segs[i]->p_vaddr + segs[i]->p_memsz);
	224	bss_addr = mapbase + (bss_vaddr - base_vaddr);
	225	if (bss_vlimit > bss_vaddr) { /* There is something to do */
55071f75 JM	226	if (mmap(bss_addr, bss_vlimit - bss_vaddr, data_prot,
	227	data_flags \| MAP_ANON, -1, 0) == (caddr_t)-1) {
	228	_rtld_error("%s: mmap of bss failed: %s", path,
984263bc	229	strerror(errno));
fcf53d9b JM	230	return NULL;
fcf53d9b JM	231	}
984263bc MD	232	}
984263bc MD	233	}
fcf53d9b JM	234
	235	if (phdr_vaddr == 0 && data_offset <= hdr->e_phoff &&
	236	(data_vlimit - data_vaddr + data_offset) >=
	237	(hdr->e_phoff + hdr->e_phnum * sizeof (Elf_Phdr))) {
	238	phdr_vaddr = data_vaddr + hdr->e_phoff - data_offset;
	239	}
984263bc MD	240	}
	241
	242	obj = obj_new();
	243	if (sb != NULL) {
	244	obj->dev = sb->st_dev;
	245	obj->ino = sb->st_ino;
	246	}
	247	obj->mapbase = mapbase;
	248	obj->mapsize = mapsize;
	249	obj->textsize = round_page(segs[0]->p_vaddr + segs[0]->p_memsz) -
	250	base_vaddr;
	251	obj->vaddrbase = base_vaddr;
	252	obj->relocbase = mapbase - base_vaddr;
	253	obj->dynamic = (const Elf_Dyn *) (obj->relocbase + phdyn->p_vaddr);
1c76efe5 MD	254	if (hdr->e_entry != 0)
1c76efe5 MD	255	obj->entry = (caddr_t) (obj->relocbase + hdr->e_entry);
fcf53d9b JM	256	if (phdr_vaddr != 0) {
	257	obj->phdr = (const Elf_Phdr *) (obj->relocbase + phdr_vaddr);
	258	} else {
	259	obj->phdr = malloc(phsize);
	260	if (obj->phdr == NULL) {
	261	obj_free(obj);
	262	_rtld_error("%s: cannot allocate program header", path);
	263	return NULL;
	264	}
	265	memcpy((char )obj->phdr, (char )hdr + hdr->e_phoff, phsize);
	266	obj->phdr_alloc = true;
984263bc	267	}
fcf53d9b	268	obj->phsize = phsize;
984263bc MD	269	if (phinterp != NULL)
984263bc MD	270	obj->interp = (const char *) (obj->relocbase + phinterp->p_vaddr);
55b88cae DX	271	if (phtls != NULL) {
	272	tls_dtv_generation++;
	273	obj->tlsindex = ++tls_max_index;
	274	obj->tlssize = phtls->p_memsz;
	275	obj->tlsalign = phtls->p_align;
	276	obj->tlsinitsize = phtls->p_filesz;
	277	obj->tlsinit = mapbase + phtls->p_vaddr;
	278	}
007f494e JM	279
	280	if (relro_size) {
	281	obj->relro_page = obj->relocbase + trunc_page(relro_page);
	282	obj->relro_size = round_page(relro_size);
	283	}
984263bc MD	284	return obj;
	285	}
	286
1c76efe5 MD	287	static Elf_Ehdr *
	288	get_elf_header (int fd, const char *path)
	289	{
	290	static union {
	291	Elf_Ehdr hdr;
	292	char buf[PAGE_SIZE];
	293	} u;
	294	ssize_t nbytes;
	295
fcf53d9b	296	if ((nbytes = pread(fd, u.buf, PAGE_SIZE, 0)) == -1) {
1c76efe5 MD	297	_rtld_error("%s: read error: %s", path, strerror(errno));
	298	return NULL;
	299	}
	300
	301	/* Make sure the file is valid */
	302	if (nbytes < (ssize_t)sizeof(Elf_Ehdr) \|\| !IS_ELF(u.hdr)) {
	303	_rtld_error("%s: invalid file format", path);
	304	return NULL;
	305	}
	306	if (u.hdr.e_ident[EI_CLASS] != ELF_TARG_CLASS
	307	\|\| u.hdr.e_ident[EI_DATA] != ELF_TARG_DATA) {
	308	_rtld_error("%s: unsupported file layout", path);
	309	return NULL;
	310	}
	311	if (u.hdr.e_ident[EI_VERSION] != EV_CURRENT
	312	\|\| u.hdr.e_version != EV_CURRENT) {
	313	_rtld_error("%s: unsupported file version", path);
	314	return NULL;
	315	}
	316	if (u.hdr.e_type != ET_EXEC && u.hdr.e_type != ET_DYN) {
	317	_rtld_error("%s: unsupported file type", path);
	318	return NULL;
	319	}
	320	if (u.hdr.e_machine != ELF_TARG_MACH) {
	321	_rtld_error("%s: unsupported machine", path);
	322	return NULL;
	323	}
	324
	325	/*
	326	* We rely on the program header being in the first page. This is
	327	* not strictly required by the ABI specification, but it seems to
	328	* always true in practice. And, it simplifies things considerably.
	329	*/
	330	if (u.hdr.e_phentsize != sizeof(Elf_Phdr)) {
	331	_rtld_error(
	332	"%s: invalid shared object: e_phentsize != sizeof(Elf_Phdr)", path);
	333	return NULL;
	334	}
	335	if (u.hdr.e_phoff + u.hdr.e_phnum * sizeof(Elf_Phdr) > (size_t)nbytes) {
	336	_rtld_error("%s: program header too large", path);
	337	return NULL;
	338	}
	339
	340	return (&u.hdr);
	341	}
	342
984263bc MD	343	void
	344	obj_free(Obj_Entry *obj)
	345	{
	346	Objlist_Entry *elm;
	347
fcf53d9b	348	if (obj->tls_done)
55b88cae	349	free_tls_offset(obj);
984263bc MD	350	while (obj->needed != NULL) {
	351	Needed_Entry *needed = obj->needed;
	352	obj->needed = needed->next;
	353	free(needed);
	354	}
fcf53d9b JM	355	while (!STAILQ_EMPTY(&obj->names)) {
	356	Name_Entry *entry = STAILQ_FIRST(&obj->names);
	357	STAILQ_REMOVE_HEAD(&obj->names, link);
	358	free(entry);
	359	}
984263bc MD	360	while (!STAILQ_EMPTY(&obj->dldags)) {
	361	elm = STAILQ_FIRST(&obj->dldags);
	362	STAILQ_REMOVE_HEAD(&obj->dldags, link);
	363	free(elm);
	364	}
	365	while (!STAILQ_EMPTY(&obj->dagmembers)) {
	366	elm = STAILQ_FIRST(&obj->dagmembers);
	367	STAILQ_REMOVE_HEAD(&obj->dagmembers, link);
	368	free(elm);
	369	}
fcf53d9b JM	370	if (obj->vertab)
	371	free(obj->vertab);
	372	if (obj->origin_path)
	373	free(obj->origin_path);
	374	if (obj->z_origin)
	375	free(obj->rpath);
	376	if (obj->priv)
	377	free(obj->priv);
	378	if (obj->path)
	379	free(obj->path);
	380	if (obj->phdr_alloc)
	381	free((void *)obj->phdr);
984263bc MD	382	free(obj);
	383	}
	384
	385	Obj_Entry *
	386	obj_new(void)
	387	{
	388	Obj_Entry *obj;
	389
	390	obj = CNEW(Obj_Entry);
	391	STAILQ_INIT(&obj->dldags);
	392	STAILQ_INIT(&obj->dagmembers);
fcf53d9b	393	STAILQ_INIT(&obj->names);
984263bc MD	394	return obj;
	395	}
	396
	397	/*
	398	* Given a set of ELF protection flags, return the corresponding protection
	399	* flags for MMAP.
	400	*/
	401	static int
	402	convert_prot(int elfflags)
	403	{
	404	int prot = 0;
	405	if (elfflags & PF_R)
	406	prot \|= PROT_READ;
	407	if (elfflags & PF_W)
	408	prot \|= PROT_WRITE;
	409	if (elfflags & PF_X)
	410	prot \|= PROT_EXEC;
	411	return prot;
	412	}
	413
	414	static int
	415	convert_flags(int elfflags)
	416	{
	417	int flags = MAP_PRIVATE; /* All mappings are private */
	418
	419	/*
	420	* Readonly mappings are marked "MAP_NOCORE", because they can be
	421	* reconstructed by a debugger.
	422	*/
	423	if (!(elfflags & PF_W))
	424	flags \|= MAP_NOCORE;
	425	return flags;
	426	}