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1 | // vim:shiftwidth=2:expandtab |
2 | #include <stdio.h> |
3 | #include <stdlib.h> |
4 | #include <string.h> |
5 | #include <elf.h> |
6 | #include <sys/mman.h> |
7 | |
11913091 |
8 | #include "header.h" |
9 | |
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10 | #define CHECK_(val, fail_operator, expect, err_msg) \ |
11 | if (val fail_operator expect) { \ |
12 | fprintf(stderr, err_msg ", exiting (%d)\n", (int)(long)val); \ |
13 | return 1; \ |
14 | } |
15 | |
16 | #define CHECK_EQ(val, expect, err_msg) \ |
17 | CHECK_(val, !=, expect, err_msg) |
18 | |
19 | #define CHECK_NE(val, expect, err_msg) \ |
20 | CHECK_(val, ==, expect, err_msg) |
21 | |
22 | #define HDR_CHECK_EQ(field, expect, err_msg) \ |
23 | CHECK_(hdr.field, !=, expect, err_msg) |
24 | |
25 | #define HDR_CHECK_NE(field, expect, err_msg) \ |
26 | CHECK_(hdr.field, ==, expect, err_msg) |
27 | |
28 | #define FAIL_PERROR(msg) { \ |
29 | perror(msg); \ |
30 | return 1; \ |
31 | } |
32 | |
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33 | typedef struct { |
34 | unsigned long start; |
35 | unsigned long end; |
36 | } maps_range; |
37 | |
38 | static int is_range_used(maps_range *maps, int map_cnt, unsigned long start, unsigned long end) |
39 | { |
40 | int i; |
41 | for (i = 0; i < map_cnt; i++) { |
42 | if (maps[i].end <= start) |
43 | continue; |
44 | if (end <= maps[i].start) |
45 | continue; |
46 | |
47 | return i + 1; |
48 | } |
49 | |
50 | return 0; |
51 | } |
52 | |
53 | extern char **environ; |
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54 | |
55 | int main(int argc, char *argv[]) |
56 | { |
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57 | void *lowest_segment = (void *)-1; |
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58 | Elf32_Ehdr hdr; |
59 | Elf32_Phdr *phdr; |
60 | FILE *fi; |
61 | maps_range maps[16]; |
62 | int map_cnt; |
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63 | int i, ret, envc, sfp; |
64 | long *stack_frame; |
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65 | |
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66 | if (argc < 2) { |
67 | fprintf(stderr, "usage: %s <program> [args]\n", argv[0]); |
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68 | return 1; |
69 | } |
70 | |
71 | fi = fopen("/proc/self/maps", "r"); |
72 | CHECK_NE(fi, NULL, "fopen maps"); |
73 | |
74 | for (i = 0; i < ARRAY_SIZE(maps); i++) { |
75 | ret = fscanf(fi, "%lx-%lx %*s %*s %*s %*s %*s\n", &maps[i].start, &maps[i].end); |
76 | if (ret == 0) |
77 | break; |
78 | CHECK_EQ(ret, 2, "maps parse error"); |
79 | } |
80 | fclose(fi); |
81 | map_cnt = i; |
82 | CHECK_NE(map_cnt, 0, "no maps"); |
83 | CHECK_NE(map_cnt, ARRAY_SIZE(maps), "too many maps"); |
84 | |
85 | fi = fopen(argv[1], "rb"); |
86 | if (fi == NULL) |
87 | FAIL_PERROR("fopen"); |
88 | |
89 | if (fread(&hdr, 1, sizeof(hdr), fi) != sizeof(hdr)) |
90 | FAIL_PERROR("too small or"); |
91 | |
92 | if (memcmp(hdr.e_ident, ELFMAG "\x01\x01", SELFMAG + 2) != 0) { |
93 | fprintf(stderr, "not 32bit LE ELF?\n"); |
94 | return 1; |
95 | } |
96 | |
97 | HDR_CHECK_EQ(e_type, ET_EXEC, "not executable"); |
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98 | HDR_CHECK_EQ(e_machine, EM_ARM, "not ARM"); |
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99 | HDR_CHECK_EQ(e_phentsize, sizeof(Elf32_Phdr), "bad PH entry size"); |
100 | HDR_CHECK_NE(e_phnum, 0, "no PH entries"); |
101 | |
102 | phdr = malloc(hdr.e_phnum * hdr.e_phentsize); |
103 | CHECK_NE(phdr, NULL, "OOM"); |
104 | |
105 | if (fread(phdr, hdr.e_phentsize, hdr.e_phnum, fi) != hdr.e_phnum) |
106 | FAIL_PERROR("too small or"); |
107 | |
108 | for (i = 0; i < hdr.e_phnum; i++) { |
109 | Elf32_Addr end_addr = phdr[i].p_vaddr + phdr[i].p_memsz; |
110 | Elf32_Addr align; |
111 | void *ptr, *map_ptr; |
112 | |
113 | if (phdr[i].p_type == PT_NOTE) |
114 | continue; |
115 | if (phdr[i].p_type != PT_LOAD) { |
116 | fprintf(stderr, "skipping section %d\n", phdr[i].p_type); |
117 | continue; |
118 | } |
119 | |
120 | ret = is_range_used(maps, map_cnt, phdr[i].p_vaddr, end_addr); |
121 | if (ret) { |
122 | fprintf(stderr, "segment %d (%08x-%08x) hits %08lx-%08lx in maps\n", |
123 | i, phdr[i].p_vaddr, end_addr, maps[ret - 1].start, maps[ret - 1].end); |
124 | return 1; |
125 | } |
126 | |
127 | printf("load %d %08x-%08x from %08x\n", phdr[i].p_type, |
128 | phdr[i].p_vaddr, end_addr, phdr[i].p_offset); |
129 | |
130 | align = phdr[i].p_vaddr & 0xfff; |
131 | map_ptr = (void *)(phdr[i].p_vaddr - align); |
132 | ptr = mmap(map_ptr, phdr[i].p_memsz + align, PROT_READ|PROT_WRITE|PROT_EXEC, |
133 | MAP_FIXED|MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); |
134 | if (ptr == MAP_FAILED || ptr != map_ptr) |
135 | FAIL_PERROR("mmap"); |
136 | |
137 | if (phdr[i].p_filesz > 0) { |
138 | if (fseek(fi, phdr[i].p_offset, SEEK_SET) != 0) |
139 | FAIL_PERROR("fseek"); |
140 | if (fread((char *)ptr + align, 1, phdr[i].p_filesz, fi) != phdr[i].p_filesz) |
141 | FAIL_PERROR("too small or"); |
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142 | |
143 | if (phdr[i].p_flags & PF_X) |
144 | do_patches((char *)ptr + align, phdr[i].p_filesz); |
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145 | } |
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146 | |
147 | if (map_ptr < lowest_segment) |
148 | lowest_segment = map_ptr; |
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149 | } |
150 | |
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151 | emu_init(lowest_segment); |
152 | |
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153 | // generate stack frame: argc, argv[], NULL, env[], NULL |
154 | for (envc = 0; environ[envc] != NULL; envc++) |
155 | ; |
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156 | |
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157 | stack_frame = calloc(argc + envc + 3, sizeof(stack_frame[0])); |
158 | if (stack_frame == NULL) { |
159 | fprintf(stderr, "stack_frame OOM\n"); |
160 | return 1; |
161 | } |
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162 | |
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163 | sfp = 0; |
164 | stack_frame[sfp++] = argc - 1; |
165 | for (i = 1; i < argc; i++) |
166 | stack_frame[sfp++] = (long)argv[i]; |
167 | stack_frame[sfp++] = 0; |
168 | for (i = 0; i < envc; i++) |
169 | stack_frame[sfp++] = (long)environ[i]; |
170 | stack_frame[sfp++] = 0; |
171 | |
172 | printf("entering %08x, %d stack entries\n", hdr.e_entry, sfp); |
173 | do_entry(hdr.e_entry, stack_frame, sfp, NULL); |
174 | |
175 | fprintf(stderr, "do_entry failed!\n"); |
176 | return 1; |
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177 | } |
178 | |