1 /*
2 * Copyright (C) 2016 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include <elf.h>
18 #include <errno.h>
19 #include <fcntl.h>
20 #include <stdint.h>
21 #include <stdio.h>
22 #include <string.h>
23 #include <sys/stat.h>
24 #include <sys/types.h>
25 #include <unistd.h>
26
27 #include <string>
28
29 #if !defined(EM_AARCH64)
30 #define EM_AARCH64 183
31 #endif
32
33 template <typename Ehdr>
InitEhdr(Ehdr * ehdr,uint32_t elf_class,uint32_t machine)34 void InitEhdr(Ehdr* ehdr, uint32_t elf_class, uint32_t machine) {
35 memset(ehdr, 0, sizeof(Ehdr));
36 memcpy(&ehdr->e_ident[0], ELFMAG, SELFMAG);
37 ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
38 ehdr->e_ident[EI_VERSION] = EV_CURRENT;
39 ehdr->e_ident[EI_OSABI] = ELFOSABI_SYSV;
40 ehdr->e_ident[EI_CLASS] = elf_class;
41 ehdr->e_type = ET_DYN;
42 ehdr->e_machine = machine;
43 ehdr->e_version = EV_CURRENT;
44 ehdr->e_ehsize = sizeof(Ehdr);
45 }
46
47 template <typename Ehdr, typename Shdr>
GenElf(Ehdr * ehdr,int fd)48 void GenElf(Ehdr* ehdr, int fd) {
49 uint64_t offset = sizeof(Ehdr);
50 ehdr->e_shoff = offset;
51 ehdr->e_shnum = 3;
52 ehdr->e_shentsize = sizeof(Shdr);
53 ehdr->e_shstrndx = 2;
54 TEMP_FAILURE_RETRY(write(fd, ehdr, sizeof(Ehdr)));
55
56 Shdr shdr;
57 memset(&shdr, 0, sizeof(shdr));
58 shdr.sh_name = 0;
59 shdr.sh_type = SHT_NULL;
60 TEMP_FAILURE_RETRY(write(fd, &shdr, sizeof(Shdr)));
61 offset += ehdr->e_shentsize;
62
63 memset(&shdr, 0, sizeof(shdr));
64 shdr.sh_type = SHT_PROGBITS;
65 shdr.sh_name = 11;
66 shdr.sh_addr = 0x5000;
67 shdr.sh_offset = 0x5000;
68 shdr.sh_entsize = 0x100;
69 shdr.sh_size = 0x800;
70 TEMP_FAILURE_RETRY(write(fd, &shdr, sizeof(Shdr)));
71 offset += ehdr->e_shentsize;
72
73 memset(&shdr, 0, sizeof(shdr));
74 shdr.sh_type = SHT_STRTAB;
75 shdr.sh_name = 1;
76 shdr.sh_offset = 0x200;
77 shdr.sh_size = 24;
78 TEMP_FAILURE_RETRY(write(fd, &shdr, sizeof(Shdr)));
79
80 // Write out the name entries information.
81 lseek(fd, 0x200, SEEK_SET);
82 std::string name;
83 TEMP_FAILURE_RETRY(write(fd, name.data(), name.size() + 1));
84 name = ".shstrtab";
85 TEMP_FAILURE_RETRY(write(fd, name.data(), name.size() + 1));
86 name = ".debug_frame";
87 TEMP_FAILURE_RETRY(write(fd, name.data(), name.size() + 1));
88 }
89
main()90 int main() {
91 int elf32_fd = TEMP_FAILURE_RETRY(open("elf32", O_RDWR | O_CREAT | O_TRUNC | O_CLOEXEC, 0644));
92 if (elf32_fd == -1) {
93 printf("Failed to create elf32: %s\n", strerror(errno));
94 return 1;
95 }
96
97 int elf64_fd = TEMP_FAILURE_RETRY(open("elf64", O_RDWR | O_CREAT | O_TRUNC | O_CLOEXEC, 0644));
98 if (elf64_fd == -1) {
99 printf("Failed to create elf64: %s\n", strerror(errno));
100 return 1;
101 }
102
103 Elf32_Ehdr ehdr32;
104 InitEhdr<Elf32_Ehdr>(&ehdr32, ELFCLASS32, EM_ARM);
105 GenElf<Elf32_Ehdr, Elf32_Shdr>(&ehdr32, elf32_fd);
106 close(elf32_fd);
107
108 Elf64_Ehdr ehdr64;
109 InitEhdr<Elf64_Ehdr>(&ehdr64, ELFCLASS64, EM_AARCH64);
110 GenElf<Elf64_Ehdr, Elf64_Shdr>(&ehdr64, elf64_fd);
111 close(elf64_fd);
112 }
113