David Daney | a79f248 | 2012-04-19 14:59:55 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * sortextable.c: Sort the kernel's exception table |
| 3 | * |
| 4 | * Copyright 2011 Cavium, Inc. |
| 5 | * |
| 6 | * Based on code taken from recortmcount.c which is: |
| 7 | * |
| 8 | * Copyright 2009 John F. Reiser <jreiser@BitWagon.com>. All rights reserved. |
| 9 | * Licensed under the GNU General Public License, version 2 (GPLv2). |
| 10 | * |
| 11 | * Restructured to fit Linux format, as well as other updates: |
| 12 | * Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc. |
| 13 | */ |
| 14 | |
| 15 | /* |
| 16 | * Strategy: alter the vmlinux file in-place. |
| 17 | */ |
| 18 | |
| 19 | #include <sys/types.h> |
| 20 | #include <sys/mman.h> |
| 21 | #include <sys/stat.h> |
| 22 | #include <getopt.h> |
| 23 | #include <elf.h> |
| 24 | #include <fcntl.h> |
| 25 | #include <setjmp.h> |
| 26 | #include <stdio.h> |
| 27 | #include <stdlib.h> |
| 28 | #include <string.h> |
| 29 | #include <unistd.h> |
| 30 | |
| 31 | static int fd_map; /* File descriptor for file being modified. */ |
| 32 | static int mmap_failed; /* Boolean flag. */ |
| 33 | static void *ehdr_curr; /* current ElfXX_Ehdr * for resource cleanup */ |
| 34 | static struct stat sb; /* Remember .st_size, etc. */ |
| 35 | static jmp_buf jmpenv; /* setjmp/longjmp per-file error escape */ |
| 36 | |
| 37 | /* setjmp() return values */ |
| 38 | enum { |
| 39 | SJ_SETJMP = 0, /* hardwired first return */ |
| 40 | SJ_FAIL, |
| 41 | SJ_SUCCEED |
| 42 | }; |
| 43 | |
| 44 | /* Per-file resource cleanup when multiple files. */ |
| 45 | static void |
| 46 | cleanup(void) |
| 47 | { |
| 48 | if (!mmap_failed) |
| 49 | munmap(ehdr_curr, sb.st_size); |
| 50 | close(fd_map); |
| 51 | } |
| 52 | |
| 53 | static void __attribute__((noreturn)) |
| 54 | fail_file(void) |
| 55 | { |
| 56 | cleanup(); |
| 57 | longjmp(jmpenv, SJ_FAIL); |
| 58 | } |
| 59 | |
| 60 | static void __attribute__((noreturn)) |
| 61 | succeed_file(void) |
| 62 | { |
| 63 | cleanup(); |
| 64 | longjmp(jmpenv, SJ_SUCCEED); |
| 65 | } |
| 66 | |
| 67 | |
| 68 | /* |
| 69 | * Get the whole file as a programming convenience in order to avoid |
| 70 | * malloc+lseek+read+free of many pieces. If successful, then mmap |
| 71 | * avoids copying unused pieces; else just read the whole file. |
| 72 | * Open for both read and write. |
| 73 | */ |
| 74 | static void *mmap_file(char const *fname) |
| 75 | { |
| 76 | void *addr; |
| 77 | |
| 78 | fd_map = open(fname, O_RDWR); |
| 79 | if (fd_map < 0 || fstat(fd_map, &sb) < 0) { |
| 80 | perror(fname); |
| 81 | fail_file(); |
| 82 | } |
| 83 | if (!S_ISREG(sb.st_mode)) { |
| 84 | fprintf(stderr, "not a regular file: %s\n", fname); |
| 85 | fail_file(); |
| 86 | } |
| 87 | addr = mmap(0, sb.st_size, PROT_READ|PROT_WRITE, MAP_SHARED, |
| 88 | fd_map, 0); |
| 89 | if (addr == MAP_FAILED) { |
| 90 | mmap_failed = 1; |
| 91 | fprintf(stderr, "Could not mmap file: %s\n", fname); |
| 92 | fail_file(); |
| 93 | } |
| 94 | return addr; |
| 95 | } |
| 96 | |
| 97 | /* w8rev, w8nat, ...: Handle endianness. */ |
| 98 | |
| 99 | static uint64_t w8rev(uint64_t const x) |
| 100 | { |
| 101 | return ((0xff & (x >> (0 * 8))) << (7 * 8)) |
| 102 | | ((0xff & (x >> (1 * 8))) << (6 * 8)) |
| 103 | | ((0xff & (x >> (2 * 8))) << (5 * 8)) |
| 104 | | ((0xff & (x >> (3 * 8))) << (4 * 8)) |
| 105 | | ((0xff & (x >> (4 * 8))) << (3 * 8)) |
| 106 | | ((0xff & (x >> (5 * 8))) << (2 * 8)) |
| 107 | | ((0xff & (x >> (6 * 8))) << (1 * 8)) |
| 108 | | ((0xff & (x >> (7 * 8))) << (0 * 8)); |
| 109 | } |
| 110 | |
| 111 | static uint32_t w4rev(uint32_t const x) |
| 112 | { |
| 113 | return ((0xff & (x >> (0 * 8))) << (3 * 8)) |
| 114 | | ((0xff & (x >> (1 * 8))) << (2 * 8)) |
| 115 | | ((0xff & (x >> (2 * 8))) << (1 * 8)) |
| 116 | | ((0xff & (x >> (3 * 8))) << (0 * 8)); |
| 117 | } |
| 118 | |
| 119 | static uint32_t w2rev(uint16_t const x) |
| 120 | { |
| 121 | return ((0xff & (x >> (0 * 8))) << (1 * 8)) |
| 122 | | ((0xff & (x >> (1 * 8))) << (0 * 8)); |
| 123 | } |
| 124 | |
| 125 | static uint64_t w8nat(uint64_t const x) |
| 126 | { |
| 127 | return x; |
| 128 | } |
| 129 | |
| 130 | static uint32_t w4nat(uint32_t const x) |
| 131 | { |
| 132 | return x; |
| 133 | } |
| 134 | |
| 135 | static uint32_t w2nat(uint16_t const x) |
| 136 | { |
| 137 | return x; |
| 138 | } |
| 139 | |
| 140 | static uint64_t (*w8)(uint64_t); |
| 141 | static uint32_t (*w)(uint32_t); |
| 142 | static uint32_t (*w2)(uint16_t); |
| 143 | |
| 144 | |
| 145 | /* 32 bit and 64 bit are very similar */ |
| 146 | #include "sortextable.h" |
| 147 | #define SORTEXTABLE_64 |
| 148 | #include "sortextable.h" |
| 149 | |
| 150 | |
| 151 | static void |
| 152 | do_file(char const *const fname) |
| 153 | { |
| 154 | Elf32_Ehdr *const ehdr = mmap_file(fname); |
| 155 | |
| 156 | ehdr_curr = ehdr; |
| 157 | w = w4nat; |
| 158 | w2 = w2nat; |
| 159 | w8 = w8nat; |
| 160 | switch (ehdr->e_ident[EI_DATA]) { |
| 161 | static unsigned int const endian = 1; |
| 162 | default: |
| 163 | fprintf(stderr, "unrecognized ELF data encoding %d: %s\n", |
| 164 | ehdr->e_ident[EI_DATA], fname); |
| 165 | fail_file(); |
| 166 | break; |
| 167 | case ELFDATA2LSB: |
| 168 | if (*(unsigned char const *)&endian != 1) { |
| 169 | /* main() is big endian, file.o is little endian. */ |
| 170 | w = w4rev; |
| 171 | w2 = w2rev; |
| 172 | w8 = w8rev; |
| 173 | } |
| 174 | break; |
| 175 | case ELFDATA2MSB: |
| 176 | if (*(unsigned char const *)&endian != 0) { |
| 177 | /* main() is little endian, file.o is big endian. */ |
| 178 | w = w4rev; |
| 179 | w2 = w2rev; |
| 180 | w8 = w8rev; |
| 181 | } |
| 182 | break; |
| 183 | } /* end switch */ |
| 184 | if (memcmp(ELFMAG, ehdr->e_ident, SELFMAG) != 0 |
| 185 | || w2(ehdr->e_type) != ET_EXEC |
| 186 | || ehdr->e_ident[EI_VERSION] != EV_CURRENT) { |
| 187 | fprintf(stderr, "unrecognized ET_EXEC file %s\n", fname); |
| 188 | fail_file(); |
| 189 | } |
| 190 | |
| 191 | switch (w2(ehdr->e_machine)) { |
| 192 | default: |
| 193 | fprintf(stderr, "unrecognized e_machine %d %s\n", |
| 194 | w2(ehdr->e_machine), fname); |
| 195 | fail_file(); |
| 196 | break; |
| 197 | case EM_386: |
| 198 | case EM_MIPS: |
| 199 | case EM_X86_64: |
| 200 | break; |
| 201 | } /* end switch */ |
| 202 | |
| 203 | switch (ehdr->e_ident[EI_CLASS]) { |
| 204 | default: |
| 205 | fprintf(stderr, "unrecognized ELF class %d %s\n", |
| 206 | ehdr->e_ident[EI_CLASS], fname); |
| 207 | fail_file(); |
| 208 | break; |
| 209 | case ELFCLASS32: |
| 210 | if (w2(ehdr->e_ehsize) != sizeof(Elf32_Ehdr) |
| 211 | || w2(ehdr->e_shentsize) != sizeof(Elf32_Shdr)) { |
| 212 | fprintf(stderr, |
| 213 | "unrecognized ET_EXEC file: %s\n", fname); |
| 214 | fail_file(); |
| 215 | } |
| 216 | do32(ehdr, fname); |
| 217 | break; |
| 218 | case ELFCLASS64: { |
| 219 | Elf64_Ehdr *const ghdr = (Elf64_Ehdr *)ehdr; |
| 220 | if (w2(ghdr->e_ehsize) != sizeof(Elf64_Ehdr) |
| 221 | || w2(ghdr->e_shentsize) != sizeof(Elf64_Shdr)) { |
| 222 | fprintf(stderr, |
| 223 | "unrecognized ET_EXEC file: %s\n", fname); |
| 224 | fail_file(); |
| 225 | } |
| 226 | do64(ghdr, fname); |
| 227 | break; |
| 228 | } |
| 229 | } /* end switch */ |
| 230 | |
| 231 | cleanup(); |
| 232 | } |
| 233 | |
| 234 | int |
| 235 | main(int argc, char *argv[]) |
| 236 | { |
| 237 | int n_error = 0; /* gcc-4.3.0 false positive complaint */ |
| 238 | int i; |
| 239 | |
| 240 | if (argc < 2) { |
| 241 | fprintf(stderr, "usage: sortextable vmlinux...\n"); |
| 242 | return 0; |
| 243 | } |
| 244 | |
| 245 | /* Process each file in turn, allowing deep failure. */ |
| 246 | for (i = 1; i < argc; i++) { |
| 247 | char *file = argv[i]; |
| 248 | int const sjval = setjmp(jmpenv); |
| 249 | |
| 250 | switch (sjval) { |
| 251 | default: |
| 252 | fprintf(stderr, "internal error: %s\n", file); |
| 253 | exit(1); |
| 254 | break; |
| 255 | case SJ_SETJMP: /* normal sequence */ |
| 256 | /* Avoid problems if early cleanup() */ |
| 257 | fd_map = -1; |
| 258 | ehdr_curr = NULL; |
| 259 | mmap_failed = 1; |
| 260 | do_file(file); |
| 261 | break; |
| 262 | case SJ_FAIL: /* error in do_file or below */ |
| 263 | ++n_error; |
| 264 | break; |
| 265 | case SJ_SUCCEED: /* premature success */ |
| 266 | /* do nothing */ |
| 267 | break; |
| 268 | } /* end switch */ |
| 269 | } |
| 270 | return !!n_error; |
| 271 | } |