/* * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code 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 * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ /* * Name: add_gnu_debuglink.c * * Description: Add a ".gnu_debuglink" section that refers to the specified * debug_info_path to the specified ELF object. * * This program is adapted from the example program shown on the * elf(3elf) man page and from code from the Solaris compiler * driver. */ /* * needed to define SHF_EXCLUDE */ #define ELF_TARGET_ALL #include #include #include #include #include #include static void failure(void); static unsigned int gnu_debuglink_crc32(unsigned int crc, unsigned char *buf, size_t len); void main(int argc, char ** argv) { /* new ELF section name */ static char SEC_NAME[] = ".gnu_debuglink"; unsigned char buffer[8 * 1024]; /* I/O buffer */ int buffer_len; /* buffer length */ char * debug_info_path; /* debug info path */ void * ehdr; /* ELF header */ Elf * elf; /* ELF descriptor */ char * elf_ident; /* ELF identity string */ char * elf_obj; /* elf_obj file */ int fd; /* descriptor for files */ unsigned int file_crc = 0; /* CRC for debug info file */ int is_elfclass64; /* is an ELFCLASS64 file? */ Elf_Data * link_dat; /* ELF data for new debug info link */ Elf_Data * name_dat; /* ELF data for new section name */ Elf_Scn * new_scn; /* new ELF section descriptor */ void * new_shdr; /* new ELF section header */ Elf_Scn * scn; /* ELF section descriptor */ void * shdr; /* ELF section header */ if (argc != 3) { (void) fprintf(stderr, "Usage: %s debug_info_path elf_obj\n", argv[0]); exit(2); } debug_info_path = argv[1]; /* save for later */ if ((fd = open(debug_info_path, O_RDONLY)) == -1) { (void) fprintf(stderr, "%s: cannot open file.\n", debug_info_path); exit(3); } (void) printf("Computing CRC for '%s'\n", debug_info_path); (void) fflush(stdout); /* compute CRC for the debug info file */ for (;;) { int len = read(fd, buffer, sizeof buffer); if (len <= 0) { break; } file_crc = gnu_debuglink_crc32(file_crc, buffer, len); } (void) close(fd); /* open the elf_obj */ elf_obj = argv[2]; if ((fd = open(elf_obj, O_RDWR)) == -1) { (void) fprintf(stderr, "%s: cannot open file.\n", elf_obj); exit(4); } (void) printf("Opening '%s' for update\n", elf_obj); (void) fflush(stdout); (void) elf_version(EV_CURRENT); /* coordinate ELF versions */ /* obtain the ELF descriptors from the input file */ if ((elf = elf_begin(fd, ELF_C_RDWR, NULL)) == NULL) { failure(); } /* determine if ELFCLASS64 or not? */ elf_ident = elf_getident(elf, NULL); is_elfclass64 = (elf_ident[EI_CLASS] == ELFCLASS64); /* get the ELF header */ if (is_elfclass64) { ehdr = elf64_getehdr(elf); } else { ehdr = elf32_getehdr(elf); } if (ehdr == NULL) { failure(); } /* get the ELF section descriptor */ if (is_elfclass64) { scn = elf_getscn(elf, ((Elf64_Ehdr *) ehdr)->e_shstrndx); } else { scn = elf_getscn(elf, ((Elf32_Ehdr *) ehdr)->e_shstrndx); } if (scn == NULL) { failure(); } /* get the section header */ if (is_elfclass64) { shdr = elf64_getshdr(scn); } else { shdr = elf32_getshdr(scn); } if (shdr == NULL) { failure(); } (void) printf("Adding ELF data for new section name\n"); (void) fflush(stdout); name_dat = elf_newdata(scn); name_dat->d_buf = (void *) SEC_NAME; if (is_elfclass64) { name_dat->d_off = ((Elf64_Shdr *) shdr)->sh_size + 1; } else { name_dat->d_off = ((Elf32_Shdr *) shdr)->sh_size + 1; } name_dat->d_align = 1; name_dat->d_size = strlen(SEC_NAME) + 1; new_scn = elf_newscn(elf); if (is_elfclass64) { new_shdr = elf64_getshdr(new_scn); ((Elf64_Shdr *) new_shdr)->sh_flags = SHF_EXCLUDE; ((Elf64_Shdr *) new_shdr)->sh_type = SHT_PROGBITS; ((Elf64_Shdr *) new_shdr)->sh_name = ((Elf64_Shdr *) shdr)->sh_size; ((Elf64_Shdr *) new_shdr)->sh_addralign = 1; ((Elf64_Shdr *) shdr)->sh_size += (strlen(SEC_NAME) + 1); } else { new_shdr = elf32_getshdr(new_scn); ((Elf32_Shdr *) new_shdr)->sh_flags = SHF_EXCLUDE; ((Elf32_Shdr *) new_shdr)->sh_type = SHT_PROGBITS; ((Elf32_Shdr *) new_shdr)->sh_name = ((Elf32_Shdr *) shdr)->sh_size; ((Elf32_Shdr *) new_shdr)->sh_addralign = 1; ((Elf32_Shdr *) shdr)->sh_size += (strlen(SEC_NAME) + 1); } (void) printf("Adding ELF data for debug_info_path value\n"); (void) fflush(stdout); (void) memset(buffer, 0, sizeof buffer); buffer_len = strlen(debug_info_path) + 1; /* +1 for NUL */ (void) strncpy((char *) buffer, debug_info_path, buffer_len); if (buffer_len % 4 != 0) { /* not on a 4 byte boundary so pad to the next one */ buffer_len += (4 - buffer_len % 4); } /* save the CRC */ (void) memcpy(&buffer[buffer_len], &file_crc, sizeof file_crc); buffer_len += sizeof file_crc; link_dat = elf_newdata(new_scn); link_dat->d_type = ELF_T_BYTE; link_dat->d_size = buffer_len; link_dat->d_buf = buffer; link_dat->d_align = 1; (void) printf("Saving updates to '%s'\n", elf_obj); (void) fflush(stdout); (void) elf_update(elf, ELF_C_NULL); /* recalc ELF memory structures */ (void) elf_update(elf, ELF_C_WRITE); /* write out changes to ELF obj */ (void) elf_end(elf); /* done with ELF obj */ (void) close(fd); (void) printf("Done updating '%s'\n", elf_obj); (void) fflush(stdout); exit(0); } /* end main */ static void failure() { (void) fprintf(stderr, "%s\n", elf_errmsg(elf_errno())); exit(5); } /* * The CRC used in gnu_debuglink, retrieved from * http://sourceware.org/gdb/current/onlinedocs/gdb/Separate-Debug-Files.html#Separate-Debug-Files. */ static unsigned int gnu_debuglink_crc32(unsigned int crc, unsigned char *buf, size_t len) { static const unsigned int crc32_table[256] = { 0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7, 0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59, 0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924, 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433, 0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65, 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f, 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1, 0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b, 0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236, 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d, 0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777, 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9, 0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d }; unsigned char *end; crc = ~crc & 0xffffffff; for (end = buf + len; buf < end; ++buf) { crc = crc32_table[(crc ^ *buf) & 0xff] ^ (crc >> 8); } return ~crc & 0xffffffff; }