reactos/ntoskrnl/mm
diff -N elf.c
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ elf.c 3 Dec 2004 14:17:10 -0000 1.1.2.1
@@ -0,0 +1,379 @@
+/* $Id: elf.c,v 1.1.2.1 2004/12/03 14:17:10 hyperion Exp $
+*/
+
+/*
+ * REACTOS ELF MAPPER
+ *
+ * ELF mapper, ported from FreeBSD by KJK::Hyperion as part of the ELF support
+ * initiative. Original copyright, licensing and disclaimers follow
+ */
+
+/*-
+ * 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 1.15 2004/08/03 08:50:58 dfr 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 *phphdr;
+ 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;
+ size_t nclear;
+ Elf_Addr bss_vaddr;
+ Elf_Addr bss_vlimit;
+ caddr_t bss_addr;
+
+ hdr = get_elf_header(fd, path);
+ if (hdr == NULL)
+ return (NULL);
+
+ /*
+ * Scan the program header entries, and save key information.
+ *
+ * We rely on there being exactly two load segments, text and data,
+ * in that order.
+ */
+ phdr = (Elf_Phdr *) ((char *)hdr + hdr->e_phoff);
+ phlimit = phdr + hdr->e_phnum;
+ nsegs = -1;
+ phdyn = phphdr = phinterp = phtls = NULL;
+ 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) {
+ _rtld_error("%s: PT_LOAD segment %d not page-aligned",
+ path, nsegs);
+ return NULL;
+ }
+ break;
+
+ case PT_PHDR:
+ phphdr = phdr;
+ break;
+
+ case PT_DYNAMIC:
+ phdyn = phdr;
+ break;
+
+ case PT_TLS:
+ phtls = phdr;
+ 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, convert_prot(segs[0]->p_flags),
+ convert_flags(segs[0]->p_flags), fd, base_offset);
+ 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;
+ /* Do not call mmap on the first segment - this is redundant */
+ if (i && 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;
+ }
+
+ /* 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 */
+ if ((data_prot & PROT_WRITE) == 0)
+ 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,
+ MAP_PRIVATE|MAP_FIXED|MAP_ANON, -1, 0) == (caddr_t) -1) {
+ _rtld_error("%s: mmap of bss failed: %s", path,
+ strerror(errno));
+ return NULL;
+ }
+ }
+ }
+
+ 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 (phphdr != NULL) {
+ obj->phdr = (const Elf_Phdr *) (obj->relocbase + phphdr->p_vaddr);
+ obj->phsize = phphdr->p_memsz;
+ }
+ 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;
+ }
+ 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 = read(fd, u.buf, PAGE_SIZE)) == -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;
+
+ free(obj->path);
+ while (obj->needed != NULL) {
+ Needed_Entry *needed = obj->needed;
+ obj->needed = needed->next;
+ free(needed);
+ }
+ 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);
+ }
+ free(obj->origin_path);
+ free(obj->priv);
+ free(obj);
+}
+
+Obj_Entry *
+obj_new(void)
+{
+ Obj_Entry *obj;
+
+ obj = CNEW(Obj_Entry);
+ STAILQ_INIT(&obj->dldags);
+ STAILQ_INIT(&obj->dagmembers);
+ 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;
+}