diff options
Diffstat (limited to 'unexelf.c')
| -rw-r--r-- | unexelf.c | 908 |
1 files changed, 908 insertions, 0 deletions
diff --git a/unexelf.c b/unexelf.c new file mode 100644 index 0000000..60e82cc --- /dev/null +++ b/unexelf.c @@ -0,0 +1,908 @@ +/* Copyright (C) 1985, 1986, 1987, 1988, 1990, 1992 + Free Software Foundation, Inc. + +This file is part of GNU Emacs. + +GNU Emacs is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Emacs is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +GNU General Public License for more details. + +You should have received a copy of the GNU General Public License +along with GNU Emacs; see the file COPYING. If not, write to +the Free Software Foundation, Inc., 59 Temple Place - Suite 330, +Boston, MA 02111-1307, USA. + +In other words, you are welcome to use, share and improve this program. +You are forbidden to forbid anyone else to use, share and improve +what you give them. Help stamp out software-hoarding! */ + + +/* + * unexec.c - Convert a running program into an a.out file. + * + * Author: Spencer W. Thomas + * Computer Science Dept. + * University of Utah + * Date: Tue Mar 2 1982 + * Modified heavily since then. + * + * Synopsis: + * unexec (new_name, a_name, data_start, bss_start, entry_address) + * char *new_name, *a_name; + * unsigned data_start, bss_start, entry_address; + * + * Takes a snapshot of the program and makes an a.out format file in the + * file named by the string argument new_name. + * If a_name is non-NULL, the symbol table will be taken from the given file. + * On some machines, an existing a_name file is required. + * + * The boundaries within the a.out file may be adjusted with the data_start + * and bss_start arguments. Either or both may be given as 0 for defaults. + * + * Data_start gives the boundary between the text segment and the data + * segment of the program. The text segment can contain shared, read-only + * program code and literal data, while the data segment is always unshared + * and unprotected. Data_start gives the lowest unprotected address. + * The value you specify may be rounded down to a suitable boundary + * as required by the machine you are using. + * + * Specifying zero for data_start means the boundary between text and data + * should not be the same as when the program was loaded. + * If NO_REMAP is defined, the argument data_start is ignored and the + * segment boundaries are never changed. + * + * Bss_start indicates how much of the data segment is to be saved in the + * a.out file and restored when the program is executed. It gives the lowest + * unsaved address, and is rounded up to a page boundary. The default when 0 + * is given assumes that the entire data segment is to be stored, including + * the previous data and bss as well as any additional storage allocated with + * break (2). + * + * The new file is set up to start at entry_address. + * + * If you make improvements I'd like to get them too. + * harpo!utah-cs!thomas, thomas@Utah-20 + * + */ + +/* Even more heavily modified by james@bigtex.cactus.org of Dell Computer Co. + * ELF support added. + * + * Basic theory: the data space of the running process needs to be + * dumped to the output file. Normally we would just enlarge the size + * of .data, scooting everything down. But we can't do that in ELF, + * because there is often something between the .data space and the + * .bss space. + * + * In the temacs dump below, notice that the Global Offset Table + * (.got) and the Dynamic link data (.dynamic) come between .data1 and + * .bss. It does not work to overlap .data with these fields. + * + * The solution is to create a new .data segment. This segment is + * filled with data from the current process. Since the contents of + * various sections refer to sections by index, the new .data segment + * is made the last in the table to avoid changing any existing index. + + * This is an example of how the section headers are changed. "Addr" + * is a process virtual address. "Offset" is a file offset. + +raid:/nfs/raid/src/dist-18.56/src> dump -h temacs + +temacs: + + **** SECTION HEADER TABLE **** +[No] Type Flags Addr Offset Size Name + Link Info Adralgn Entsize + +[1] 1 2 0x80480d4 0xd4 0x13 .interp + 0 0 0x1 0 + +[2] 5 2 0x80480e8 0xe8 0x388 .hash + 3 0 0x4 0x4 + +[3] 11 2 0x8048470 0x470 0x7f0 .dynsym + 4 1 0x4 0x10 + +[4] 3 2 0x8048c60 0xc60 0x3ad .dynstr + 0 0 0x1 0 + +[5] 9 2 0x8049010 0x1010 0x338 .rel.plt + 3 7 0x4 0x8 + +[6] 1 6 0x8049348 0x1348 0x3 .init + 0 0 0x4 0 + +[7] 1 6 0x804934c 0x134c 0x680 .plt + 0 0 0x4 0x4 + +[8] 1 6 0x80499cc 0x19cc 0x3c56f .text + 0 0 0x4 0 + +[9] 1 6 0x8085f3c 0x3df3c 0x3 .fini + 0 0 0x4 0 + +[10] 1 2 0x8085f40 0x3df40 0x69c .rodata + 0 0 0x4 0 + +[11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1 + 0 0 0x4 0 + +[12] 1 3 0x8088330 0x3f330 0x20afc .data + 0 0 0x4 0 + +[13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1 + 0 0 0x4 0 + +[14] 1 3 0x80a96cc 0x606cc 0x1a8 .got + 0 0 0x4 0x4 + +[15] 6 3 0x80a9874 0x60874 0x80 .dynamic + 4 0 0x4 0x8 + +[16] 8 3 0x80a98f4 0x608f4 0x449c .bss + 0 0 0x4 0 + +[17] 2 0 0 0x608f4 0x9b90 .symtab + 18 371 0x4 0x10 + +[18] 3 0 0 0x6a484 0x8526 .strtab + 0 0 0x1 0 + +[19] 3 0 0 0x729aa 0x93 .shstrtab + 0 0 0x1 0 + +[20] 1 0 0 0x72a3d 0x68b7 .comment + 0 0 0x1 0 + +raid:/nfs/raid/src/dist-18.56/src> dump -h xemacs + +xemacs: + + **** SECTION HEADER TABLE **** +[No] Type Flags Addr Offset Size Name + Link Info Adralgn Entsize + +[1] 1 2 0x80480d4 0xd4 0x13 .interp + 0 0 0x1 0 + +[2] 5 2 0x80480e8 0xe8 0x388 .hash + 3 0 0x4 0x4 + +[3] 11 2 0x8048470 0x470 0x7f0 .dynsym + 4 1 0x4 0x10 + +[4] 3 2 0x8048c60 0xc60 0x3ad .dynstr + 0 0 0x1 0 + +[5] 9 2 0x8049010 0x1010 0x338 .rel.plt + 3 7 0x4 0x8 + +[6] 1 6 0x8049348 0x1348 0x3 .init + 0 0 0x4 0 + +[7] 1 6 0x804934c 0x134c 0x680 .plt + 0 0 0x4 0x4 + +[8] 1 6 0x80499cc 0x19cc 0x3c56f .text + 0 0 0x4 0 + +[9] 1 6 0x8085f3c 0x3df3c 0x3 .fini + 0 0 0x4 0 + +[10] 1 2 0x8085f40 0x3df40 0x69c .rodata + 0 0 0x4 0 + +[11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1 + 0 0 0x4 0 + +[12] 1 3 0x8088330 0x3f330 0x20afc .data + 0 0 0x4 0 + +[13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1 + 0 0 0x4 0 + +[14] 1 3 0x80a96cc 0x606cc 0x1a8 .got + 0 0 0x4 0x4 + +[15] 6 3 0x80a9874 0x60874 0x80 .dynamic + 4 0 0x4 0x8 + +[16] 8 3 0x80c6800 0x7d800 0 .bss + 0 0 0x4 0 + +[17] 2 0 0 0x7d800 0x9b90 .symtab + 18 371 0x4 0x10 + +[18] 3 0 0 0x87390 0x8526 .strtab + 0 0 0x1 0 + +[19] 3 0 0 0x8f8b6 0x93 .shstrtab + 0 0 0x1 0 + +[20] 1 0 0 0x8f949 0x68b7 .comment + 0 0 0x1 0 + +[21] 1 3 0x80a98f4 0x608f4 0x1cf0c .data + 0 0 0x4 0 + + * This is an example of how the file header is changed. "Shoff" is + * the section header offset within the file. Since that table is + * after the new .data section, it is moved. "Shnum" is the number of + * sections, which we increment. + * + * "Phoff" is the file offset to the program header. "Phentsize" and + * "Shentsz" are the program and section header entries sizes respectively. + * These can be larger than the apparent struct sizes. + +raid:/nfs/raid/src/dist-18.56/src> dump -f temacs + +temacs: + + **** ELF HEADER **** +Class Data Type Machine Version +Entry Phoff Shoff Flags Ehsize +Phentsize Phnum Shentsz Shnum Shstrndx + +1 1 2 3 1 +0x80499cc 0x34 0x792f4 0 0x34 +0x20 5 0x28 21 19 + +raid:/nfs/raid/src/dist-18.56/src> dump -f xemacs + +xemacs: + + **** ELF HEADER **** +Class Data Type Machine Version +Entry Phoff Shoff Flags Ehsize +Phentsize Phnum Shentsz Shnum Shstrndx + +1 1 2 3 1 +0x80499cc 0x34 0x96200 0 0x34 +0x20 5 0x28 22 19 + + * These are the program headers. "Offset" is the file offset to the + * segment. "Vaddr" is the memory load address. "Filesz" is the + * segment size as it appears in the file, and "Memsz" is the size in + * memory. Below, the third segment is the code and the fourth is the + * data: the difference between Filesz and Memsz is .bss + +raid:/nfs/raid/src/dist-18.56/src> dump -o temacs + +temacs: + ***** PROGRAM EXECUTION HEADER ***** +Type Offset Vaddr Paddr +Filesz Memsz Flags Align + +6 0x34 0x8048034 0 +0xa0 0xa0 5 0 + +3 0xd4 0 0 +0x13 0 4 0 + +1 0x34 0x8048034 0 +0x3f2f9 0x3f2f9 5 0x1000 + +1 0x3f330 0x8088330 0 +0x215c4 0x25a60 7 0x1000 + +2 0x60874 0x80a9874 0 +0x80 0 7 0 + +raid:/nfs/raid/src/dist-18.56/src> dump -o xemacs + +xemacs: + ***** PROGRAM EXECUTION HEADER ***** +Type Offset Vaddr Paddr +Filesz Memsz Flags Align + +6 0x34 0x8048034 0 +0xa0 0xa0 5 0 + +3 0xd4 0 0 +0x13 0 4 0 + +1 0x34 0x8048034 0 +0x3f2f9 0x3f2f9 5 0x1000 + +1 0x3f330 0x8088330 0 +0x3e4d0 0x3e4d0 7 0x1000 + +2 0x60874 0x80a9874 0 +0x80 0 7 0 + + + */ + +/* Modified by wtien@urbana.mcd.mot.com of Motorola Inc. + * + * The above mechanism does not work if the unexeced ELF file is being + * re-layout by other applications (such as `strip'). All the applications + * that re-layout the internal of ELF will layout all sections in ascending + * order of their file offsets. After the re-layout, the data2 section will + * still be the LAST section in the section header vector, but its file offset + * is now being pushed far away down, and causes part of it not to be mapped + * in (ie. not covered by the load segment entry in PHDR vector), therefore + * causes the new binary to fail. + * + * The solution is to modify the unexec algorithm to insert the new data2 + * section header right before the new bss section header, so their file + * offsets will be in the ascending order. Since some of the section's (all + * sections AFTER the bss section) indexes are now changed, we also need to + * modify some fields to make them point to the right sections. This is done + * by macro PATCH_INDEX. All the fields that need to be patched are: + * + * 1. ELF header e_shstrndx field. + * 2. section header sh_link and sh_info field. + * 3. symbol table entry st_shndx field. + * + * The above example now should look like: + + **** SECTION HEADER TABLE **** +[No] Type Flags Addr Offset Size Name + Link Info Adralgn Entsize + +[1] 1 2 0x80480d4 0xd4 0x13 .interp + 0 0 0x1 0 + +[2] 5 2 0x80480e8 0xe8 0x388 .hash + 3 0 0x4 0x4 + +[3] 11 2 0x8048470 0x470 0x7f0 .dynsym + 4 1 0x4 0x10 + +[4] 3 2 0x8048c60 0xc60 0x3ad .dynstr + 0 0 0x1 0 + +[5] 9 2 0x8049010 0x1010 0x338 .rel.plt + 3 7 0x4 0x8 + +[6] 1 6 0x8049348 0x1348 0x3 .init + 0 0 0x4 0 + +[7] 1 6 0x804934c 0x134c 0x680 .plt + 0 0 0x4 0x4 + +[8] 1 6 0x80499cc 0x19cc 0x3c56f .text + 0 0 0x4 0 + +[9] 1 6 0x8085f3c 0x3df3c 0x3 .fini + 0 0 0x4 0 + +[10] 1 2 0x8085f40 0x3df40 0x69c .rodata + 0 0 0x4 0 + +[11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1 + 0 0 0x4 0 + +[12] 1 3 0x8088330 0x3f330 0x20afc .data + 0 0 0x4 0 + +[13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1 + 0 0 0x4 0 + +[14] 1 3 0x80a96cc 0x606cc 0x1a8 .got + 0 0 0x4 0x4 + +[15] 6 3 0x80a9874 0x60874 0x80 .dynamic + 4 0 0x4 0x8 + +[16] 1 3 0x80a98f4 0x608f4 0x1cf0c .data + 0 0 0x4 0 + +[17] 8 3 0x80c6800 0x7d800 0 .bss + 0 0 0x4 0 + +[18] 2 0 0 0x7d800 0x9b90 .symtab + 19 371 0x4 0x10 + +[19] 3 0 0 0x87390 0x8526 .strtab + 0 0 0x1 0 + +[20] 3 0 0 0x8f8b6 0x93 .shstrtab + 0 0 0x1 0 + +[21] 1 0 0 0x8f949 0x68b7 .comment + 0 0 0x1 0 + + */ + +#include <sys/types.h> +#include <stdio.h> +#include <sys/stat.h> +#include <memory.h> +#include <string.h> +#include <errno.h> +#include <unistd.h> +#include <fcntl.h> +#include <elf.h> +#include <sys/mman.h> + +#ifndef emacs +#define fatal(a, b, c) fprintf (stderr, a, b, c), exit (1) +#else +#include <config.h> +extern void fatal (char *, ...); +#endif + +#ifndef ELF_BSS_SECTION_NAME +#define ELF_BSS_SECTION_NAME ".bss" +#endif + +/* Get the address of a particular section or program header entry, + * accounting for the size of the entries. + */ +/* + On PPC Reference Platform running Solaris 2.5.1 + the plt section is also of type NOBI like the bss section. + (not really stored) and therefore sections after the bss + section start at the plt offset. The plt section is always + the one just before the bss section. + Thus, we modify the test from + if (NEW_SECTION_H (nn).sh_offset >= new_data2_offset) + to + if (NEW_SECTION_H (nn).sh_offset >= + OLD_SECTION_H (old_bss_index-1).sh_offset) + This is just a hack. We should put the new data section + before the .plt section. + And we should not have this routine at all but use + the libelf library to read the old file and create the new + file. + The changed code is minimal and depends on prep set in m/prep.h + Erik Deumens + Quantum Theory Project + University of Florida + deumens@qtp.ufl.edu + Apr 23, 1996 + */ + +#define OLD_SECTION_H(n) \ + (*(Elf32_Shdr *) ((byte *) old_section_h + old_file_h->e_shentsize * (n))) +#define NEW_SECTION_H(n) \ + (*(Elf32_Shdr *) ((byte *) new_section_h + new_file_h->e_shentsize * (n))) +#define OLD_PROGRAM_H(n) \ + (*(Elf32_Phdr *) ((byte *) old_program_h + old_file_h->e_phentsize * (n))) +#define NEW_PROGRAM_H(n) \ + (*(Elf32_Phdr *) ((byte *) new_program_h + new_file_h->e_phentsize * (n))) + +#define PATCH_INDEX(n) \ + do { \ + if ((int) (n) >= old_bss_index) \ + (n)++; } while (0) +typedef unsigned char byte; + +/* Round X up to a multiple of Y. */ + +int +round_up (x, y) + int x, y; +{ + int rem = x % y; + if (rem == 0) + return x; + return x - rem + y; +} + +/* **************************************************************** + * unexec + * + * driving logic. + * + * In ELF, this works by replacing the old .bss section with a new + * .data section, and inserting an empty .bss immediately afterwards. + * + */ +void +unexec (new_name, old_name, data_start, bss_start, entry_address) + char *new_name, *old_name; + unsigned data_start, bss_start, entry_address; +{ + int new_file, old_file, new_file_size; + + /* Pointers to the base of the image of the two files. */ + caddr_t old_base, new_base; + + /* Pointers to the file, program and section headers for the old and new + * files. + */ + Elf32_Ehdr *old_file_h, *new_file_h; + Elf32_Phdr *old_program_h, *new_program_h; + Elf32_Shdr *old_section_h, *new_section_h; + + /* Point to the section name table in the old file */ + char *old_section_names; + + Elf32_Addr old_bss_addr, new_bss_addr; + Elf32_Word old_bss_size, new_data2_size; + Elf32_Off new_data2_offset; + Elf32_Addr new_data2_addr; + + int n, nn, old_bss_index, old_data_index, new_data2_index; + struct stat stat_buf; + + /* Open the old file & map it into the address space. */ + + old_file = open (old_name, O_RDONLY); + + if (old_file < 0) + fatal ("Can't open %s for reading: errno %d\n", old_name, errno); + + if (fstat (old_file, &stat_buf) == -1) + fatal ("Can't fstat (%s): errno %d\n", old_name, errno); + + old_base = mmap (0, stat_buf.st_size, PROT_READ, MAP_SHARED, old_file, 0); + + if (old_base == (caddr_t) -1) + fatal ("Can't mmap (%s): errno %d\n", old_name, errno); + +#ifdef DEBUG + fprintf (stderr, "mmap (%s, %x) -> %x\n", old_name, stat_buf.st_size, + old_base); +#endif + + /* Get pointers to headers & section names */ + + old_file_h = (Elf32_Ehdr *) old_base; + old_program_h = (Elf32_Phdr *) ((byte *) old_base + old_file_h->e_phoff); + old_section_h = (Elf32_Shdr *) ((byte *) old_base + old_file_h->e_shoff); + old_section_names = (char *) old_base + + OLD_SECTION_H (old_file_h->e_shstrndx).sh_offset; + + /* Find the old .bss section. Figure out parameters of the new + * data2 and bss sections. + */ + + for (old_bss_index = 1; old_bss_index < (int) old_file_h->e_shnum; + old_bss_index++) + { +#ifdef DEBUG + fprintf (stderr, "Looking for .bss - found %s\n", + old_section_names + OLD_SECTION_H (old_bss_index).sh_name); +#endif + if (!strcmp (old_section_names + OLD_SECTION_H (old_bss_index).sh_name, + ELF_BSS_SECTION_NAME)) + break; + } + if (old_bss_index == old_file_h->e_shnum) + fatal ("Can't find .bss in %s.\n", old_name, 0); + + old_bss_addr = OLD_SECTION_H (old_bss_index).sh_addr; + old_bss_size = OLD_SECTION_H (old_bss_index).sh_size; +#if defined(emacs) || !defined(DEBUG) + new_bss_addr = (Elf32_Addr) sbrk (0); +#else + new_bss_addr = old_bss_addr + old_bss_size + 0x1234; +#endif + new_data2_addr = old_bss_addr; + new_data2_size = new_bss_addr - old_bss_addr; + new_data2_offset = OLD_SECTION_H (old_bss_index).sh_offset; + +#ifdef DEBUG + fprintf (stderr, "old_bss_index %d\n", old_bss_index); + fprintf (stderr, "old_bss_addr %x\n", old_bss_addr); + fprintf (stderr, "old_bss_size %x\n", old_bss_size); + fprintf (stderr, "new_bss_addr %x\n", new_bss_addr); + fprintf (stderr, "new_data2_addr %x\n", new_data2_addr); + fprintf (stderr, "new_data2_size %x\n", new_data2_size); + fprintf (stderr, "new_data2_offset %x\n", new_data2_offset); +#endif + + if ((unsigned) new_bss_addr < (unsigned) old_bss_addr + old_bss_size) + fatal (".bss shrank when undumping???\n", 0, 0); + + /* Set the output file to the right size and mmap it. Set + * pointers to various interesting objects. stat_buf still has + * old_file data. + */ + + new_file = open (new_name, O_RDWR | O_CREAT, 0666); + if (new_file < 0) + fatal ("Can't creat (%s): errno %d\n", new_name, errno); + + new_file_size = stat_buf.st_size + old_file_h->e_shentsize + new_data2_size; + + if (ftruncate (new_file, new_file_size)) + fatal ("Can't ftruncate (%s): errno %d\n", new_name, errno); + +#ifdef UNEXEC_USE_MAP_PRIVATE + new_base = mmap (0, new_file_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, + new_file, 0); +#else + new_base = mmap (0, new_file_size, PROT_READ | PROT_WRITE, MAP_SHARED, + new_file, 0); +#endif + + if (new_base == (caddr_t) -1) + fatal ("Can't mmap (%s): errno %d\n", new_name, errno); + + new_file_h = (Elf32_Ehdr *) new_base; + new_program_h = (Elf32_Phdr *) ((byte *) new_base + old_file_h->e_phoff); + new_section_h = (Elf32_Shdr *) + ((byte *) new_base + old_file_h->e_shoff + new_data2_size); + + /* Make our new file, program and section headers as copies of the + * originals. + */ + + memcpy (new_file_h, old_file_h, old_file_h->e_ehsize); + memcpy (new_program_h, old_program_h, + old_file_h->e_phnum * old_file_h->e_phentsize); + + /* Modify the e_shstrndx if necessary. */ + PATCH_INDEX (new_file_h->e_shstrndx); + + /* Fix up file header. We'll add one section. Section header is + * further away now. + */ + + new_file_h->e_shoff += new_data2_size; + new_file_h->e_shnum += 1; + +#ifdef DEBUG + fprintf (stderr, "Old section offset %x\n", old_file_h->e_shoff); + fprintf (stderr, "Old section count %d\n", old_file_h->e_shnum); + fprintf (stderr, "New section offset %x\n", new_file_h->e_shoff); + fprintf (stderr, "New section count %d\n", new_file_h->e_shnum); +#endif + + /* Fix up a new program header. Extend the writable data segment so + * that the bss area is covered too. Find that segment by looking + * for a segment that ends just before the .bss area. Make sure + * that no segments are above the new .data2. Put a loop at the end + * to adjust the offset and address of any segment that is above + * data2, just in case we decide to allow this later. + */ + + for (n = new_file_h->e_phnum - 1; n >= 0; n--) + { + /* Compute maximum of all requirements for alignment of section. */ + int alignment = (NEW_PROGRAM_H (n)).p_align; + if ((OLD_SECTION_H (old_bss_index)).sh_addralign > alignment) + alignment = OLD_SECTION_H (old_bss_index).sh_addralign; + + if (NEW_PROGRAM_H (n).p_vaddr + NEW_PROGRAM_H (n).p_filesz > old_bss_addr) + fatal ("Program segment above .bss in %s\n", old_name, 0); + + if (NEW_PROGRAM_H (n).p_type == PT_LOAD + && (round_up ((NEW_PROGRAM_H (n)).p_vaddr + + (NEW_PROGRAM_H (n)).p_filesz, + alignment) + == round_up (old_bss_addr, alignment))) + break; + } + if (n < 0) + fatal ("Couldn't find segment next to .bss in %s\n", old_name, 0); + + NEW_PROGRAM_H (n).p_filesz += new_data2_size; + NEW_PROGRAM_H (n).p_memsz = NEW_PROGRAM_H (n).p_filesz; + +#if 0 /* Maybe allow section after data2 - does this ever happen? */ + for (n = new_file_h->e_phnum - 1; n >= 0; n--) + { + if (NEW_PROGRAM_H (n).p_vaddr + && NEW_PROGRAM_H (n).p_vaddr >= new_data2_addr) + NEW_PROGRAM_H (n).p_vaddr += new_data2_size - old_bss_size; + + if (NEW_PROGRAM_H (n).p_offset >= new_data2_offset) + NEW_PROGRAM_H (n).p_offset += new_data2_size; + } +#endif + + /* Fix up section headers based on new .data2 section. Any section + * whose offset or virtual address is after the new .data2 section + * gets its value adjusted. .bss size becomes zero and new address + * is set. data2 section header gets added by copying the existing + * .data header and modifying the offset, address and size. + */ + for (old_data_index = 1; old_data_index < (int) old_file_h->e_shnum; + old_data_index++) + if (!strcmp (old_section_names + OLD_SECTION_H (old_data_index).sh_name, + ".data")) + break; + if (old_data_index == old_file_h->e_shnum) + fatal ("Can't find .data in %s.\n", old_name, 0); + + /* Walk through all section headers, insert the new data2 section right + before the new bss section. */ + for (n = 1, nn = 1; n < (int) old_file_h->e_shnum; n++, nn++) + { + caddr_t src; + /* If it is bss section, insert the new data2 section before it. */ + if (n == old_bss_index) + { + /* Steal the data section header for this data2 section. */ + memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (old_data_index), + new_file_h->e_shentsize); + + NEW_SECTION_H (nn).sh_addr = new_data2_addr; + NEW_SECTION_H (nn).sh_offset = new_data2_offset; + NEW_SECTION_H (nn).sh_size = new_data2_size; + /* Use the bss section's alignment. This will assure that the + new data2 section always be placed in the same spot as the old + bss section by any other application. */ + NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (n).sh_addralign; + + /* Now copy over what we have in the memory now. */ + memcpy (NEW_SECTION_H (nn).sh_offset + new_base, + (caddr_t) OLD_SECTION_H (n).sh_addr, + new_data2_size); + nn++; + } + + memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (n), + old_file_h->e_shentsize); + + /* The new bss section's size is zero, and its file offset and virtual + address should be off by NEW_DATA2_SIZE. */ + if (n == old_bss_index) + { + /* NN should be `old_bss_index + 1' at this point. */ + NEW_SECTION_H (nn).sh_offset += new_data2_size; + NEW_SECTION_H (nn).sh_addr += new_data2_size; + /* Let the new bss section address alignment be the same as the + section address alignment followed the old bss section, so + this section will be placed in exactly the same place. */ + NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (nn).sh_addralign; + NEW_SECTION_H (nn).sh_size = 0; + } + else + { + /* Any section that was original placed AFTER the bss + section should now be off by NEW_DATA2_SIZE. */ +#ifdef SOLARIS_POWERPC + /* On PPC Reference Platform running Solaris 2.5.1 + the plt section is also of type NOBI like the bss section. + (not really stored) and therefore sections after the bss + section start at the plt offset. The plt section is always + the one just before the bss section. + It would be better to put the new data section before + the .plt section, or use libelf instead. + Erik Deumens, deumens@qtp.ufl.edu. */ + if (NEW_SECTION_H (nn).sh_offset + >= OLD_SECTION_H (old_bss_index-1).sh_offset) + NEW_SECTION_H (nn).sh_offset += new_data2_size; +#else + if (round_up (NEW_SECTION_H (nn).sh_offset, + OLD_SECTION_H (old_bss_index).sh_addralign) + >= new_data2_offset) + NEW_SECTION_H (nn).sh_offset += new_data2_size; +#endif + /* Any section that was originally placed after the section + header table should now be off by the size of one section + header table entry. */ + if (NEW_SECTION_H (nn).sh_offset > new_file_h->e_shoff) + NEW_SECTION_H (nn).sh_offset += new_file_h->e_shentsize; + } + + /* If any section hdr refers to the section after the new .data + section, make it refer to next one because we have inserted + a new section in between. */ + + PATCH_INDEX (NEW_SECTION_H (nn).sh_link); + /* For symbol tables, info is a symbol table index, + so don't change it. */ + if (NEW_SECTION_H (nn).sh_type != SHT_SYMTAB + && NEW_SECTION_H (nn).sh_type != SHT_DYNSYM) + PATCH_INDEX (NEW_SECTION_H (nn).sh_info); + + /* Now, start to copy the content of sections. */ + if (NEW_SECTION_H (nn).sh_type == SHT_NULL + || NEW_SECTION_H (nn).sh_type == SHT_NOBITS) + continue; + + /* Write out the sections. .data and .data1 (and data2, called + ".data" in the strings table) get copied from the current process + instead of the old file. */ + if (!strcmp (old_section_names + NEW_SECTION_H (n).sh_name, ".data") + || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name), + ".data1")) + src = (caddr_t) OLD_SECTION_H (n).sh_addr; + else + src = old_base + OLD_SECTION_H (n).sh_offset; + + memcpy (NEW_SECTION_H (nn).sh_offset + new_base, src, + NEW_SECTION_H (nn).sh_size); + + /* If it is the symbol table, its st_shndx field needs to be patched. */ + if (NEW_SECTION_H (nn).sh_type == SHT_SYMTAB + || NEW_SECTION_H (nn).sh_type == SHT_DYNSYM) + { + Elf32_Shdr *spt = &NEW_SECTION_H (nn); + unsigned int num = spt->sh_size / spt->sh_entsize; + Elf32_Sym * sym = (Elf32_Sym *) (NEW_SECTION_H (nn).sh_offset + + new_base); + for (; num--; sym++) + { + if ((sym->st_shndx == SHN_UNDEF) + || (sym->st_shndx == SHN_ABS) + || (sym->st_shndx == SHN_COMMON)) + continue; + + PATCH_INDEX (sym->st_shndx); + } + } + } + + /* Update the symbol values of _edata and _end. */ + for (n = new_file_h->e_shnum - 1; n; n--) + { + byte *symnames; + Elf32_Sym *symp, *symendp; + + if (NEW_SECTION_H (n).sh_type != SHT_DYNSYM + && NEW_SECTION_H (n).sh_type != SHT_SYMTAB) + continue; + + symnames = ((byte *) new_base + + NEW_SECTION_H (NEW_SECTION_H (n).sh_link).sh_offset); + symp = (Elf32_Sym *) (NEW_SECTION_H (n).sh_offset + new_base); + symendp = (Elf32_Sym *) ((byte *)symp + NEW_SECTION_H (n).sh_size); + + for (; symp < symendp; symp ++) + if (strcmp ((char *) (symnames + symp->st_name), "_end") == 0 + || strcmp ((char *) (symnames + symp->st_name), "_edata") == 0) + memcpy (&symp->st_value, &new_bss_addr, sizeof (new_bss_addr)); + } + + /* This loop seeks out relocation sections for the data section, so + that it can undo relocations performed by the runtime linker. */ + for (n = new_file_h->e_shnum - 1; n; n--) + { + Elf32_Shdr section = NEW_SECTION_H (n); + switch (section.sh_type) { + default: + break; + case SHT_REL: + case SHT_RELA: + /* This code handles two different size structs, but there should + be no harm in that provided that r_offset is always the first + member. */ + nn = section.sh_info; + if (!strcmp (old_section_names + NEW_SECTION_H (nn).sh_name, ".data") + || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name), + ".data1")) + { + Elf32_Addr offset = NEW_SECTION_H (nn).sh_addr - + NEW_SECTION_H (nn).sh_offset; + caddr_t reloc = old_base + section.sh_offset, end; + for (end = reloc + section.sh_size; reloc < end; + reloc += section.sh_entsize) + { + Elf32_Addr addr = ((Elf32_Rel *) reloc)->r_offset - offset; + memcpy (new_base + addr, old_base + addr, 4); + } + } + break; + } + } + +#ifdef UNEXEC_USE_MAP_PRIVATE + if (lseek (new_file, 0, SEEK_SET) == -1) + fatal ("Can't rewind (%s): errno %d\n", new_name, errno); + + if (write (new_file, new_base, new_file_size) != new_file_size) + fatal ("Can't write (%s): errno %d\n", new_name, errno); +#endif + + /* Close the files and make the new file executable. */ + + if (close (old_file)) + fatal ("Can't close (%s): errno %d\n", old_name, errno); + + if (close (new_file)) + fatal ("Can't close (%s): errno %d\n", new_name, errno); + + if (stat (new_name, &stat_buf) == -1) + fatal ("Can't stat (%s): errno %d\n", new_name, errno); + + n = umask (777); + umask (n); + stat_buf.st_mode |= 0111 & ~n; + if (chmod (new_name, stat_buf.st_mode) == -1) + fatal ("Can't chmod (%s): errno %d\n", new_name, errno); +} |