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comparison elf.c @ 1:bbbfb3f97919

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implement 32 and 64 bit support
author Peter Meerwald <p.meerwald@bct-electronic.com>
date Fri, 20 Jul 2012 11:26:24 +0200
parents b8f7423e385c
children
comparison
equal deleted inserted replaced
0:b8f7423e385c 1:bbbfb3f97919
15 #include <errno.h> 15 #include <errno.h>
16 #include <fcntl.h> 16 #include <fcntl.h>
17 #include "protos.h" 17 #include "protos.h"
18 18
19 int 19 int
20 elf_open(const char *filename, int flags, Elf_Ehdr *ehdr) 20 elf32_open(const char *filename, int flags, Elf32_Ehdr *ehdr)
21 { 21 {
22 int fd; 22 int fd;
23 23
24 fd = open(filename, flags); 24 fd = open(filename, flags);
25 if (fd == -1) 25 if (fd == -1)
34 close(fd); 34 close(fd);
35 return -1; 35 return -1;
36 } 36 }
37 37
38 if (0 != memcmp(ehdr->e_ident, ELFMAG, SELFMAG) || 38 if (0 != memcmp(ehdr->e_ident, ELFMAG, SELFMAG) ||
39 ehdr->e_ident[EI_CLASS] != ELFCLASS || 39 ehdr->e_ident[EI_CLASS] != ELFCLASS32 ||
40 ehdr->e_ident[EI_DATA] != ELFDATA2 || 40 ehdr->e_ident[EI_DATA] != ELFDATA2 ||
41 ehdr->e_ident[EI_VERSION] != EV_CURRENT) 41 ehdr->e_ident[EI_VERSION] != EV_CURRENT)
42 { 42 {
43 fprintf(stderr, 43 fprintf(stderr,
44 #ifdef WORDS_BIGENDIAN 44 #ifdef WORDS_BIGENDIAN
45 "`%s' probably isn't a %d-bit MSB-first ELF file.\n", 45 "`%s' probably isn't a %d-bit MSB-first ELF file.\n",
46 #else /* not WORD_BIGENDIAN */ 46 #else /* not WORD_BIGENDIAN */
47 "`%s' probably isn't a %d-bit LSB-first ELF file.\n", 47 "`%s' probably isn't a %d-bit LSB-first ELF file.\n",
48 #endif /* not WORD_BIGENDIAN */ 48 #endif /* not WORD_BIGENDIAN */
49 filename, SIZEOF_VOID_P * 8); 49 filename, 32);
50 close(fd); 50 close(fd);
51 errno = ENOEXEC; /* Hm, is this the best errno code to use? */ 51 errno = ENOEXEC; /* Hm, is this the best errno code to use? */
52 return -1; 52 return -1;
53 } 53 }
54 54
55 if (ehdr->e_phentsize != sizeof(Elf_Phdr)) 55 printf("32-bit ELF file\n");
56 { 56
57 fprintf(stderr, "section size was read as %d, not %d!\n", 57 if (ehdr->e_phentsize != sizeof(Elf32_Phdr))
58 ehdr->e_phentsize, sizeof(Elf_Phdr)); 58 {
59 fprintf(stderr, "section size was read as %d, not %lu!\n",
60 ehdr->e_phentsize, sizeof(Elf32_Phdr));
59 close(fd); 61 close(fd);
60 return -1; 62 return -1;
61 } 63 }
62 return fd; 64 return fd;
63 } 65 }
64 66
65 int 67 int
66 elf_find_dynamic_section(int fd, Elf_Ehdr *ehdr, Elf_Phdr *phdr) 68 elf64_open(const char *filename, int flags, Elf64_Ehdr *ehdr)
69 {
70 int fd;
71
72 fd = open(filename, flags);
73 if (fd == -1)
74 {
75 perror ("open");
76 return -1;
77 }
78
79 if (read(fd, ehdr, sizeof(*ehdr)) != sizeof(*ehdr))
80 {
81 perror ("reading header");
82 close(fd);
83 return -1;
84 }
85
86 if (0 != memcmp(ehdr->e_ident, ELFMAG, SELFMAG) ||
87 ehdr->e_ident[EI_CLASS] != ELFCLASS64 ||
88 ehdr->e_ident[EI_DATA] != ELFDATA2 ||
89 ehdr->e_ident[EI_VERSION] != EV_CURRENT)
90 {
91 fprintf(stderr,
92 #ifdef WORDS_BIGENDIAN
93 "`%s' probably isn't a %d-bit MSB-first ELF file.\n",
94 #else /* not WORD_BIGENDIAN */
95 "`%s' probably isn't a %d-bit LSB-first ELF file.\n",
96 #endif /* not WORD_BIGENDIAN */
97 filename, 64);
98 close(fd);
99 errno = ENOEXEC; /* Hm, is this the best errno code to use? */
100 return -1;
101 }
102
103 printf("64-bit ELF file\n");
104
105 if (ehdr->e_phentsize != sizeof(Elf64_Phdr))
106 {
107 fprintf(stderr, "section size was read as %d, not %lu!\n",
108 ehdr->e_phentsize, sizeof(Elf64_Phdr));
109 close(fd);
110 return -1;
111 }
112 return fd;
113 }
114
115 int
116 elf32_find_dynamic_section(int fd, Elf32_Ehdr *ehdr, Elf32_Phdr *phdr)
117 {
118 int i;
119 if (lseek(fd, ehdr->e_phoff, SEEK_SET) == -1)
120 {
121 perror ("positioning for sections");
122 return 1;
123 }
124
125 for (i = 0; i < ehdr->e_phnum; i++)
126 {
127 if (read(fd, phdr, sizeof(*phdr)) != sizeof(*phdr))
128 {
129 perror ("reading section header");
130 return 1;
131 }
132 if (phdr->p_type == PT_DYNAMIC)
133 break;
134 }
135 if (i == ehdr->e_phnum)
136 {
137 fprintf (stderr, "No dynamic section found.\n");
138 return 2;
139 }
140
141 if (0 == phdr->p_filesz)
142 {
143 fprintf (stderr, "Length of dynamic section is zero.\n");
144 return 3;
145 }
146
147 return 0;
148 }
149
150 int
151 elf64_find_dynamic_section(int fd, Elf64_Ehdr *ehdr, Elf64_Phdr *phdr)
67 { 152 {
68 int i; 153 int i;
69 if (lseek(fd, ehdr->e_phoff, SEEK_SET) == -1) 154 if (lseek(fd, ehdr->e_phoff, SEEK_SET) == -1)
70 { 155 {
71 perror ("positioning for sections"); 156 perror ("positioning for sections");

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