text: /*
   * Copyright (c) 1997 Christopher G. Demetriou.  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.
   * 3. All advertising materials mentioning features or use of this software
   *    must display the following acknowledgement:
   *      This product includes software developed by Christopher G. Demetriou
   *	for the NetBSD Project.
   * 4. The name of the author may not be used to endorse or promote products
   *    derived from this software without specific prior written permission
   *
   * 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.
   */
  
  #ifndef ELFSIZE
  #define ELFSIZE         32
  #endif
  
  #include <sys/types.h>
  #include <sys/endian.h>
  #include <sys/stat.h>
  
  #include <errno.h>
  #include <limits.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <unistd.h>
  
  #include "extern.h"
  
  #if (defined(NLIST_ELF32) && (ELFSIZE == 32)) || \
      (defined(NLIST_ELF64) && (ELFSIZE == 64))
  
  #define	__ELF_WORD_SIZE ELFSIZE
  #if (ELFSIZE == 32)
  #include <sys/elf32.h>
  #define	xewtoh(x)	((data == ELFDATA2MSB) ? be32toh(x) : le32toh(x))
  #define	htoxew(x)	((data == ELFDATA2MSB) ? htobe32(x) : htole32(x))
  #define	wewtoh(x)	((data == ELFDATA2MSB) ? be32toh(x) : le32toh(x))
  #define	htowew(x)	((data == ELFDATA2MSB) ? htobe32(x) : htole32(x))
  #elif (ELFSIZE == 64)
  #include <sys/elf64.h>
  #define	xewtoh(x)	((data == ELFDATA2MSB) ? be64toh(x) : le64toh(x))
  #define	htoxew(x)	((data == ELFDATA2MSB) ? htobe64(x) : htole64(x))
  /* elf64 Elf64_Word are 32 bits */
  #define	wewtoh(x)	((data == ELFDATA2MSB) ? be32toh(x) : le32toh(x))
  #define	htowew(x)	((data == ELFDATA2MSB) ? htobe32(x) : htole32(x))
  #endif
  #include <sys/elf_generic.h>
  
  #define CONCAT(x,y)     __CONCAT(x,y)
  #define ELFNAME(x)      CONCAT(elf,CONCAT(ELFSIZE,CONCAT(_,x)))
  #define ELFNAME2(x,y)   CONCAT(x,CONCAT(_elf,CONCAT(ELFSIZE,CONCAT(_,y))))
  #define ELFNAMEEND(x)   CONCAT(x,CONCAT(_elf,ELFSIZE))
  #define ELFDEFNNAME(x)  CONCAT(ELF,CONCAT(ELFSIZE,CONCAT(_,x)))
  
  #define	xe16toh(x)	((data == ELFDATA2MSB) ? be16toh(x) : le16toh(x))
  #define	xe32toh(x)	((data == ELFDATA2MSB) ? be32toh(x) : le32toh(x))
  #define	htoxe32(x)	((data == ELFDATA2MSB) ? htobe32(x) : htole32(x))
  
  struct shlayout {
  	Elf_Shdr *shdr;
  	void *bufp;
  };
  
  static ssize_t
  xreadatoff(int fd, void *buf, off_t off, size_t size, const char *fn)
  {
  	ssize_t rv;
  
  	if (lseek(fd, off, SEEK_SET) != off) {
  		perror(fn);
  		return -1;
  	}
  	if ((size_t)(rv = read(fd, buf, size)) != size) {
  		fprintf(stderr, "%s: read error: %s\n", fn,
  		    rv == -1 ? strerror(errno) : "short read");
  		return -1;
  	}
  	return size;
  }
  
  static ssize_t
  xwriteatoff(int fd, void *buf, off_t off, size_t size, const char *fn)
  {
  	ssize_t rv;
  
  	if (lseek(fd, off, SEEK_SET) != off) {
  		perror(fn);
  		return -1;
  	}
  	if ((size_t)(rv = write(fd, buf, size)) != size) {
  		fprintf(stderr, "%s: write error: %s\n", fn,
  		    rv == -1 ? strerror(errno) : "short write");
  		return -1;
  	}
  	return size;
  }
  
  static void *
  xmalloc(size_t size, const char *fn, const char *use)
  {
  	void *rv;
  
  	rv = malloc(size);
  	if (rv == NULL)
  		fprintf(stderr, "%s: out of memory (allocating for %s)\n",
  		    fn, use);
  	return (rv);
  }
  
  static void *
  xrealloc(void *ptr, size_t size, const char *fn, const char *use)
  {
  	void *rv;
  		
  	rv = realloc(ptr, size);
  	if (rv == NULL) {
  		free(ptr);
  		fprintf(stderr, "%s: out of memory (reallocating for %s)\n",
  		    fn, use);
  	}
  	return (rv);
  } 
  
  int
  ELFNAMEEND(check)(int fd, const char *fn)
  {
  	Elf_Ehdr eh;
  	struct stat sb;
  	unsigned char data;
  
  	/*
  	 * Check the header to maek sure it's an ELF file (of the
  	 * appropriate size).
  	 */
  	if (fstat(fd, &sb) == -1)
  		return 0;
  	if (sb.st_size < (off_t)(sizeof eh))
  		return 0;
  	if (read(fd, &eh, sizeof eh) != sizeof eh)
  		return 0;
  
  	if (IS_ELF(eh) == 0)
                  return 0;
  
  	data = eh.e_ident[EI_DATA];
  
  	switch (xe16toh(eh.e_machine)) {
  	case EM_386: break;
  	case EM_ALPHA: break;
  #ifndef EM_ARM
  #define EM_ARM		40
  #endif
  	case EM_ARM: break;
  #ifndef EM_MIPS
  #define EM_MIPS		8
  #endif
  #ifndef EM_MIPS_RS4_BE		/* same as EM_MIPS_RS3_LE */
  #define EM_MIPS_RS4_BE	10
  #endif
  	case EM_MIPS: break;
  	case /* EM_MIPS_RS3_LE */ EM_MIPS_RS4_BE: break;
  #ifndef EM_IA_64
  #define	EM_IA_64	50
  #endif
  	case EM_IA_64: break;
  #ifndef EM_PPC
  #define	EM_PPC		20
  #endif
  	case EM_PPC: break;
  #ifndef EM_PPC64
  #define	EM_PPC64	21
  #endif
  	case EM_PPC64: break;
  #ifndef EM_SPARCV9
  #define	EM_SPARCV9	43
  #endif
  	case EM_SPARCV9: break;
  #ifndef EM_X86_64
  #define	EM_X86_64	62
  #endif
  	case EM_X86_64: break;
  /*        ELFDEFNNAME(MACHDEP_ID_CASES) */
  
          default:
                  return 0;
          }
  
  	return 1;
  }
  
  /*
   * This function 'hides' (some of) ELF executable file's symbols.
   * It hides them by renaming them to "_$$hide$$ <filename> <symbolname>".
   * Symbols in the global keep list, or which are marked as being undefined,
   * are left alone.
   *
   * An old version of this code shuffled various tables around, turning
   * global symbols to be hidden into local symbols.  That lost on the
   * mips, because CALL16 relocs must reference global symbols, and, if
   * those symbols were being hidden, they were no longer global.
   *
   * The new renaming behaviour doesn't take global symbols out of the
   * namespace.  However, it's ... unlikely that there will ever be
   * any collisions in practice because of the new method.
   */
  int
  ELFNAMEEND(hide)(int fd, const char *fn)
  {
  	Elf_Ehdr ehdr;
  	struct shlayout *layoutp = NULL;
  	Elf_Shdr *shdrp = NULL, *symtabshdr, *strtabshdr, *shstrtabshdr;
  	Elf_Shdr shdrshdr;
  	Elf_Sym *symtabp = NULL;
  	char *shstrtabp = NULL, *strtabp = NULL;
  	Elf_Size nsyms, ewi;
  	Elf_Off off;
  	ssize_t shdrsize;
  	int rv, i, weird, l, m, r, strtabidx;
  	size_t nstrtab_size, nstrtab_nextoff, fn_size, size;
  	char *nstrtabp = NULL;
  	unsigned char data;
  	const char *weirdreason = NULL;
  	void *buf;
  	Elf_Half shnum;
  
  	rv = 0;
  	if (xreadatoff(fd, &ehdr, 0, sizeof ehdr, fn) != sizeof ehdr)
  		goto bad;
  
  	data = ehdr.e_ident[EI_DATA];
  	shnum = xe16toh(ehdr.e_shnum);
  
  	shdrsize = shnum * xe16toh(ehdr.e_shentsize);
  	if ((shdrp = xmalloc(shdrsize, fn, "section header table")) == NULL)
  		goto bad;
  	if (xreadatoff(fd, shdrp, xewtoh(ehdr.e_shoff), shdrsize, fn) !=
  	    shdrsize)
  		goto bad;
  
  	symtabshdr = strtabshdr = shstrtabshdr = NULL;
  	weird = 0;
  	for (i = 0; i < shnum; i++) {
  		switch (xe32toh(shdrp[i].sh_type)) {
  		case SHT_SYMTAB:
  			if (symtabshdr != NULL) {
  				weird = 1;
  				weirdreason = "multiple symbol tables";
  			}
  			symtabshdr = &shdrp[i];
  			strtabshdr = &shdrp[xe32toh(shdrp[i].sh_link)];
  			break;
  		case SHT_STRTAB:
  			if (i == xe16toh(ehdr.e_shstrndx))
  				shstrtabshdr = &shdrp[i];
  			break;
  		}
  	}
  	if (symtabshdr == NULL)
  		goto out;
  	if (strtabshdr == NULL) {
  		weird = 1;
  		weirdreason = "string table does not exist";
  	}
  	if (shstrtabshdr == NULL) {
  		weird = 1;
  		weirdreason = "section header string table does not exist";
  	}
  	if (weirdreason == NULL)
  		weirdreason = "unsupported";
  	if (weird) {
  		fprintf(stderr, "%s: weird executable (%s)\n", fn, weirdreason);
  		goto bad;
  	}
  
  	/*
  	 * sort section layout table by offset
  	 */
  	layoutp = xmalloc((shnum + 1) * sizeof(struct shlayout),
  	    fn, "layout table");
  	if (layoutp == NULL)
  		goto bad;
  
  	/* add a pseudo entry to represent the section header table */
  	shdrshdr.sh_offset = ehdr.e_shoff;
  	shdrshdr.sh_size = htoxew(shdrsize);
  	shdrshdr.sh_addralign = htoxew(ELFSIZE / 8);
  	layoutp[shnum].shdr = &shdrshdr;
  
  	/* insert and sort normal section headers */
  	for (i = shnum; i-- != 0;) {
  		l = i + 1;
  		r = shnum;
  		while (l <= r) {
  			m = ( l + r) / 2;
  			if (xewtoh(shdrp[i].sh_offset) >
  			    xewtoh(layoutp[m].shdr->sh_offset))
  				l = m + 1;
  			else
  				r = m - 1;
  		}
  
  		if (r != i) {
  			memmove(&layoutp[i], &layoutp[i + 1],
  			    sizeof(struct shlayout) * (r - i));
  		}
  
  		layoutp[r].shdr = &shdrp[i];
  		layoutp[r].bufp = NULL;
  	}
  	++shnum;
  
  	/*
  	 * load up everything we need
  	 */
  
  	/* load section string table for debug use */
  	if ((shstrtabp = xmalloc(xewtoh(shstrtabshdr->sh_size), fn,
  	    "section string table")) == NULL)
  		goto bad;
  	if ((size_t)xreadatoff(fd, shstrtabp, xewtoh(shstrtabshdr->sh_offset),
  	    xewtoh(shstrtabshdr->sh_size), fn) != xewtoh(shstrtabshdr->sh_size))
  		goto bad;
  
  	/* we need symtab, strtab, and everything behind strtab */
  	strtabidx = INT_MAX;
  	for (i = 0; i < shnum; i++) {
  		if (layoutp[i].shdr == &shdrshdr) {
  			/* not load section header again */
  			layoutp[i].bufp = shdrp;
  			continue;
  		}
  		if (layoutp[i].shdr == shstrtabshdr) {
  			/* not load section string table again */
  			layoutp[i].bufp = shstrtabp;
  			continue;
  		}
  
  		if (layoutp[i].shdr == strtabshdr)
  			strtabidx = i;
  		if (layoutp[i].shdr == symtabshdr || i >= strtabidx) {
  			off = xewtoh(layoutp[i].shdr->sh_offset);
  			size = xewtoh(layoutp[i].shdr->sh_size);
  			layoutp[i].bufp = xmalloc(size, fn,
  			    shstrtabp + xewtoh(layoutp[i].shdr->sh_name));
  			if (layoutp[i].bufp == NULL)
  				goto bad;
  			if ((size_t)xreadatoff(fd, layoutp[i].bufp, off, size, fn) !=
  			    size)
  				goto bad;
  
  			/* set symbol table and string table */
  			if (layoutp[i].shdr == symtabshdr)
  				symtabp = layoutp[i].bufp;
  			else if (layoutp[i].shdr == strtabshdr)
  				strtabp = layoutp[i].bufp;
  		}
  	}
  
  	nstrtab_size = 256;
  	nstrtabp = xmalloc(nstrtab_size, fn, "new string table");
  	if (nstrtabp == NULL)
  		goto bad;
  	nstrtab_nextoff = 0;
  
  	fn_size = strlen(fn);
  
  	/* Prepare data structures for symbol movement. */
  	nsyms = xewtoh(symtabshdr->sh_size) / xewtoh(symtabshdr->sh_entsize);
  
  	/* move symbols, making them local */
  	for (ewi = 0; ewi < nsyms; ewi++) {
  		Elf_Sym *sp = &symtabp[ewi];
  		const char *symname = strtabp + xe32toh(sp->st_name);
  		size_t newent_len;
  		/*
  		 * make sure there's size for the next entry, even if it's
  		 * as large as it can be.
  		 *
  		 * "_$$hide$$ <filename> <symname><NUL>" ->
  		 *    9 + 3 + sizes of fn and sym name
  		 */
  		while ((nstrtab_size - nstrtab_nextoff) <
  		    strlen(symname) + fn_size + 12) {
  			nstrtab_size *= 2;
  			nstrtabp = xrealloc(nstrtabp, nstrtab_size, fn,
  			    "new string table");
  			if (nstrtabp == NULL)
  				goto bad;
  		}
  
  		sp->st_name = htowew(nstrtab_nextoff);
  
  		/* if it's a keeper or is undefined, don't rename it. */
  		if (in_keep_list(symname) ||
  		    (xe16toh(sp->st_shndx) == SHN_UNDEF)) {
  			newent_len = sprintf(nstrtabp + nstrtab_nextoff,
  			    "%s", symname) + 1;
  		} else {
  			newent_len = sprintf(nstrtabp + nstrtab_nextoff,
  			    "_$$hide$$ %s %s", fn, symname) + 1;
  		}
  		nstrtab_nextoff += newent_len;
  	}
  	strtabshdr->sh_size = htoxew(nstrtab_nextoff);
  
  	/*
  	 * update section header table in ascending order of offset
  	 */
  	for (i = strtabidx + 1; i < shnum; i++) {
  		Elf_Off off, align;
  		off = xewtoh(layoutp[i - 1].shdr->sh_offset) +
  		    xewtoh(layoutp[i - 1].shdr->sh_size);
  		align = xewtoh(layoutp[i].shdr->sh_addralign);
  		off = (off + (align - 1)) & ~(align - 1);
  		layoutp[i].shdr->sh_offset = htoxew(off);
  	}
  
  	/*
  	 * write data to the file in descending order of offset
  	 */
  	for (i = shnum; i-- != 0;) {
  		if (layoutp[i].shdr == strtabshdr) {
  			/* new string table */
  			buf = nstrtabp;
  		} else
  			buf = layoutp[i].bufp;
  
  		if (layoutp[i].shdr == &shdrshdr ||
  		    layoutp[i].shdr == symtabshdr || i >= strtabidx) {
  			if (buf == NULL)
  				goto bad;
  
  			/*
  			 * update the offset of section header table in elf
  			 * header if needed.
  			 */
  			if (layoutp[i].shdr == &shdrshdr &&
  			    ehdr.e_shoff != shdrshdr.sh_offset) {
  				ehdr.e_shoff = shdrshdr.sh_offset;
  				off = (ELFSIZE == 32) ? 32 : 44;
  				size = sizeof(Elf_Off);
  				if ((size_t)xwriteatoff(fd, &ehdr.e_shoff, off, size,
  				    fn) != size)
  					goto bad;
  			}
  
  			off = xewtoh(layoutp[i].shdr->sh_offset);
  			size = xewtoh(layoutp[i].shdr->sh_size);
  			if ((size_t)xwriteatoff(fd, buf, off, size, fn) != size)
  				goto bad;
  		}
  	}
  
  out:
  	if (layoutp != NULL) {
  		for (i = 0; i < shnum; i++) {
  			if (layoutp[i].bufp != NULL)
  				free(layoutp[i].bufp);
  		}
  		free(layoutp);
  	}
  	free(nstrtabp);
  	return (rv);
  
  bad:
  	rv = 1;
  	goto out;
  }
  
  #endif /* include this size of ELF */
  