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1 | /* | |
2 | * GRUB -- GRand Unified Bootloader | |
3 | * Copyright (C) 1999,2000,2001,2002,2003,2004,2005,2007,2008,2009 Free Software Foundation, Inc. | |
4 | * | |
5 | * GRUB is free software: you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License as published by | |
7 | * the Free Software Foundation, either version 3 of the License, or | |
8 | * (at your option) any later version. | |
9 | * | |
10 | * GRUB is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License | |
16 | * along with GRUB. If not, see <http://www.gnu.org/licenses/>. | |
17 | */ | |
18 | ||
19 | #if defined(MULTIBOOT_LOAD_ELF32) | |
20 | # define XX 32 | |
21 | # define E_MACHINE MULTIBOOT_ELF32_MACHINE | |
22 | # define ELFCLASSXX ELFCLASS32 | |
23 | # define Elf_Ehdr Elf32_Ehdr | |
24 | # define Elf_Phdr Elf32_Phdr | |
25 | #elif defined(MULTIBOOT_LOAD_ELF64) | |
26 | # define XX 64 | |
27 | # define E_MACHINE MULTIBOOT_ELF64_MACHINE | |
28 | # define ELFCLASSXX ELFCLASS64 | |
29 | # define Elf_Ehdr Elf64_Ehdr | |
30 | # define Elf_Phdr Elf64_Phdr | |
31 | #else | |
32 | #error "I'm confused" | |
33 | #endif | |
34 | ||
35 | #include <grub/i386/relocator.h> | |
36 | ||
37 | #define CONCAT(a,b) CONCAT_(a, b) | |
38 | #define CONCAT_(a,b) a ## b | |
39 | ||
40 | /* Check if BUFFER contains ELF32 (or ELF64). */ | |
41 | static int | |
42 | CONCAT(grub_multiboot_is_elf, XX) (void *buffer) | |
43 | { | |
44 | Elf_Ehdr *ehdr = (Elf_Ehdr *) buffer; | |
45 | ||
46 | return ehdr->e_ident[EI_CLASS] == ELFCLASSXX; | |
47 | } | |
48 | ||
49 | static grub_err_t | |
50 | CONCAT(grub_multiboot_load_elf, XX) (grub_file_t file, void *buffer) | |
51 | { | |
52 | Elf_Ehdr *ehdr = (Elf_Ehdr *) buffer; | |
53 | char *phdr_base; | |
54 | int lowest_segment = -1, highest_segment = -1; | |
55 | int i; | |
56 | grub_size_t code_size; | |
57 | ||
58 | if (ehdr->e_ident[EI_CLASS] != ELFCLASSXX) | |
59 | return grub_error (GRUB_ERR_UNKNOWN_OS, "invalid ELF class"); | |
60 | ||
61 | if (ehdr->e_ident[EI_MAG0] != ELFMAG0 | |
62 | || ehdr->e_ident[EI_MAG1] != ELFMAG1 | |
63 | || ehdr->e_ident[EI_MAG2] != ELFMAG2 | |
64 | || ehdr->e_ident[EI_MAG3] != ELFMAG3 | |
65 | || ehdr->e_version != EV_CURRENT | |
66 | || ehdr->e_ident[EI_DATA] != ELFDATA2LSB | |
67 | || ehdr->e_machine != E_MACHINE) | |
68 | return grub_error(GRUB_ERR_UNKNOWN_OS, "no valid ELF header found"); | |
69 | ||
70 | if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN) | |
71 | return grub_error (GRUB_ERR_UNKNOWN_OS, "invalid ELF file type"); | |
72 | ||
73 | /* FIXME: Should we support program headers at strange locations? */ | |
74 | if (ehdr->e_phoff + ehdr->e_phnum * ehdr->e_phentsize > MULTIBOOT_SEARCH) | |
75 | return grub_error (GRUB_ERR_BAD_OS, "program header at a too high offset"); | |
76 | ||
77 | #ifdef MULTIBOOT_LOAD_ELF64 | |
78 | /* We still in 32-bit mode. */ | |
79 | if (ehdr->e_entry > 0xffffffff) | |
80 | return grub_error (GRUB_ERR_BAD_OS, "invalid entry point for ELF64"); | |
81 | #endif | |
82 | ||
83 | phdr_base = (char *) buffer + ehdr->e_phoff; | |
84 | #define phdr(i) ((Elf_Phdr *) (phdr_base + (i) * ehdr->e_phentsize)) | |
85 | ||
86 | for (i = 0; i < ehdr->e_phnum; i++) | |
87 | if (phdr(i)->p_type == PT_LOAD && phdr(i)->p_filesz != 0) | |
88 | { | |
89 | /* Beware that segment 0 isn't necessarily loadable */ | |
90 | if (lowest_segment == -1 | |
91 | || phdr(i)->p_paddr < phdr(lowest_segment)->p_paddr) | |
92 | lowest_segment = i; | |
93 | if (highest_segment == -1 | |
94 | || phdr(i)->p_paddr > phdr(highest_segment)->p_paddr) | |
95 | highest_segment = i; | |
96 | } | |
97 | ||
98 | if (lowest_segment == -1) | |
99 | return grub_error (GRUB_ERR_BAD_OS, "ELF contains no loadable segments"); | |
100 | ||
101 | code_size = (phdr(highest_segment)->p_paddr + phdr(highest_segment)->p_memsz) - phdr(lowest_segment)->p_paddr; | |
102 | grub_multiboot_payload_dest = phdr(lowest_segment)->p_paddr; | |
103 | ||
104 | grub_multiboot_pure_size += code_size; | |
105 | ||
106 | grub_multiboot_alloc_mbi = grub_multiboot_get_mbi_size () + 65536; | |
107 | grub_multiboot_payload_orig | |
108 | = grub_relocator32_alloc (grub_multiboot_pure_size + grub_multiboot_alloc_mbi); | |
109 | ||
110 | if (!grub_multiboot_payload_orig) | |
111 | return grub_errno; | |
112 | ||
113 | /* Load every loadable segment in memory. */ | |
114 | for (i = 0; i < ehdr->e_phnum; i++) | |
115 | { | |
116 | if (phdr(i)->p_type == PT_LOAD && phdr(i)->p_filesz != 0) | |
117 | { | |
118 | char *load_this_module_at = (char *) (grub_multiboot_payload_orig + (long) (phdr(i)->p_paddr - phdr(lowest_segment)->p_paddr)); | |
119 | ||
120 | grub_dprintf ("multiboot_loader", "segment %d: paddr=0x%lx, memsz=0x%lx, vaddr=0x%lx\n", | |
121 | i, (long) phdr(i)->p_paddr, (long) phdr(i)->p_memsz, (long) phdr(i)->p_vaddr); | |
122 | ||
123 | if (grub_file_seek (file, (grub_off_t) phdr(i)->p_offset) | |
124 | == (grub_off_t) -1) | |
125 | return grub_error (GRUB_ERR_BAD_OS, | |
126 | "invalid offset in program header"); | |
127 | ||
128 | if (grub_file_read (file, load_this_module_at, phdr(i)->p_filesz) | |
129 | != (grub_ssize_t) phdr(i)->p_filesz) | |
130 | return grub_error (GRUB_ERR_BAD_OS, | |
131 | "couldn't read segment from file"); | |
132 | ||
133 | if (phdr(i)->p_filesz < phdr(i)->p_memsz) | |
134 | grub_memset (load_this_module_at + phdr(i)->p_filesz, 0, | |
135 | phdr(i)->p_memsz - phdr(i)->p_filesz); | |
136 | } | |
137 | } | |
138 | ||
139 | for (i = 0; i < ehdr->e_phnum; i++) | |
140 | if (phdr(i)->p_vaddr <= ehdr->e_entry | |
141 | && phdr(i)->p_vaddr + phdr(i)->p_memsz > ehdr->e_entry) | |
142 | { | |
143 | grub_multiboot_payload_eip = grub_multiboot_payload_dest | |
144 | + (ehdr->e_entry - phdr(i)->p_vaddr) + (phdr(i)->p_paddr - phdr(lowest_segment)->p_paddr); | |
145 | break; | |
146 | } | |
147 | ||
148 | if (i == ehdr->e_phnum) | |
149 | return grub_error (GRUB_ERR_BAD_OS, "entry point isn't in a segment"); | |
150 | ||
151 | #undef phdr | |
152 | ||
153 | return grub_errno; | |
154 | } | |
155 | ||
156 | #undef XX | |
157 | #undef E_MACHINE | |
158 | #undef ELFCLASSXX | |
159 | #undef Elf_Ehdr | |
160 | #undef Elf_Phdr |