1 /* Test program for adding section and program headers and ehdr updates.
2    Copyright (C) 2015 Red Hat, Inc.
3    This file is part of elfutils.
4 
5    This file 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    elfutils is distributed in the hope that it will be useful, but
11    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 this program.  If not, see <http://www.gnu.org/licenses/>.  */
17 
18 #include <config.h>
19 #include <assert.h>
20 #include ELFUTILS_HEADER(elf)
21 #include <gelf.h>
22 
23 #include <stdio.h>
24 #include <stdlib.h>
25 
26 #include <sys/types.h>
27 #include <sys/stat.h>
28 #include <fcntl.h>
29 #include <unistd.h>
30 
31 #include <stdbool.h>
32 
33 void
check(const char * msg,bool statement)34 check (const char *msg, bool statement)
35 {
36   if (! statement)
37     {
38       fprintf (stderr, "%s FAILED\n", msg);
39       exit (-1);
40     }
41   else
42     fprintf (stderr, "%s OK\n", msg);
43 }
44 
45 void
check_elf(const char * msg,bool statement)46 check_elf (const char *msg, bool statement)
47 {
48   if (! statement)
49     {
50       fprintf (stderr, "%s: %s\n", msg, elf_errmsg (-1));
51       exit (-1);
52     }
53   else
54     fprintf (stderr, "%s OK\n", msg);
55 }
56 
57 void
test(Elf * elf,int class,bool layout)58 test (Elf *elf, int class, bool layout)
59 {
60   fprintf (stderr, "testing ELF class: %d, layout: %d\n", class, layout);
61 
62   check_elf ("gelf_newehdr", gelf_newehdr (elf, class) != 0);
63   check_elf ("gelf_getclass", gelf_getclass (elf) == class);
64 
65   check_elf ("elf_flagelf", elf_flagelf (elf, layout ? ELF_C_SET : ELF_C_CLR,
66 					 ELF_F_LAYOUT) != 0);
67 
68   GElf_Ehdr ehdr;
69   check_elf ("gelf_getehdr", gelf_getehdr (elf, &ehdr) != NULL);
70   check ("e_shnum == 0", ehdr.e_shnum == 0);
71   check ("e_phnum == 0", ehdr.e_phnum == 0);
72   check ("e_shoff == 0", ehdr.e_shoff == 0);
73   check ("e_phoff == 0", ehdr.e_phoff == 0);
74 
75   size_t shnum;
76   check_elf ("elf_getshdrnum", elf_getshdrnum (elf, &shnum) == 0);
77   check ("shnum == 0", shnum == 0);
78 
79   size_t phnum;
80   check_elf ("elf_getphdrnum", elf_getphdrnum (elf, &phnum) == 0);
81   check ("phnum == 0", phnum == 0);
82 
83   /* Lets fill in some info we are always responsible for.  */
84   ehdr.e_ident[EI_DATA] = ELFDATANONE; /* Ask for native encoding.  */
85   ehdr.e_type = ET_EXEC;
86   ehdr.e_machine = EM_386;
87   ehdr.e_version = EV_NONE; /* Ask for current version. */
88   check_elf ("gelf_update_ehdr", gelf_update_ehdr (elf, &ehdr) != 0);
89 
90   check_elf ("elf_update", elf_update (elf, ELF_C_NULL) > 0);
91 
92   check_elf ("gelf_getehdr", gelf_getehdr (elf, &ehdr) != NULL);
93   check ("EI_DATA", ehdr.e_ident[EI_DATA] != ELFDATANONE);
94   check ("e_version", ehdr.e_version == EV_CURRENT);
95 
96   /* The sh/ph values shouldn't have changed.  */
97   check ("e_shnum == 0", ehdr.e_shnum == 0);
98   check ("e_phnum == 0", ehdr.e_phnum == 0);
99   check ("e_shoff == 0", ehdr.e_shoff == 0);
100   check ("e_phoff == 0", ehdr.e_phoff == 0);
101 
102   check_elf ("elf_getshdrnum", elf_getshdrnum (elf, &shnum) == 0);
103   check ("shnum == 0", shnum == 0);
104 
105   check_elf ("elf_getphdrnum", elf_getphdrnum (elf, &phnum) == 0);
106   check ("phnum == 0", phnum == 0);
107 
108   /* Lets add a header.  */
109   check_elf ("elf_newscn", elf_newscn (elf) != NULL);
110   check_elf ("gelf_newphdr", gelf_newphdr (elf, 1) != 0);
111 
112   /* If we are responsible for the layout ourselves we should also
113      tell where to put them.  */
114   if (layout)
115     {
116       check_elf ("gelf_getehdr", gelf_getehdr (elf, &ehdr) != NULL);
117       /* phdrs go right after the ehdr.  */
118       ehdr.e_phoff = ehdr.e_ehsize;
119       /* shdrs go right after the phdrs.  */
120       ehdr.e_shoff = ehdr.e_phoff + ehdr.e_phnum * ehdr.e_phentsize;
121       check_elf ("gelf_update_ehdr", gelf_update_ehdr (elf, &ehdr) != 0);
122     }
123 
124   check_elf ("elf_update", elf_update (elf, ELF_C_NULL) > 0);
125 
126   check_elf ("elf_getshdrnum", elf_getshdrnum (elf, &shnum) == 0);
127   check ("shnum == 1", shnum == 2); /* section zero is also created.  */
128 
129   check_elf ("elf_getphdrnum", elf_getphdrnum (elf, &phnum) == 0);
130   check ("phnum == 1", phnum == 1);
131 
132   check_elf ("gelf_getehdr", gelf_getehdr (elf, &ehdr) != NULL);
133 
134   check ("EI_DATA", ehdr.e_ident[EI_DATA] != ELFDATANONE);
135   check ("e_version", ehdr.e_version == EV_CURRENT);
136 
137   check ("e_shnum == 2", ehdr.e_shnum == 2);
138   check ("e_phnum == 1", ehdr.e_phnum == 1);
139   check ("e_shoff != 0", ehdr.e_shoff != 0);
140   check ("e_phoff != 0", ehdr.e_phoff != 0);
141 
142   size_t shentsize = (class == ELFCLASS32
143 		      ? sizeof (Elf32_Shdr) : sizeof (Elf64_Shdr));
144   check ("e_shentsize", ehdr.e_shentsize == shentsize);
145   size_t phentsize = (class == ELFCLASS32
146 		      ? sizeof (Elf32_Phdr) : sizeof (Elf64_Phdr));
147   check ("e_phentsize", ehdr.e_phentsize == phentsize);
148 }
149 
150 int
main(int argc,char ** argv __attribute ((unused)))151 main (int argc __attribute__ ((unused)), char **argv __attribute ((unused)))
152 {
153   elf_version (EV_CURRENT);
154 
155   int fd = open("/dev/null", O_WRONLY);
156   check ("open", fd >= 0);
157 
158   Elf *elf;
159 
160   elf = elf_begin (fd, ELF_C_WRITE, NULL);
161   check_elf ("elf_begin", elf != NULL);
162   test (elf, ELFCLASS32, false);
163   elf_end (elf);
164 
165   elf = elf_begin (fd, ELF_C_WRITE, NULL);
166   check_elf ("elf_begin", elf != NULL);
167   test (elf, ELFCLASS32, true);
168   elf_end (elf);
169 
170   elf = elf_begin (fd, ELF_C_WRITE, NULL);
171   check_elf ("elf_begin", elf != NULL);
172   test (elf, ELFCLASS64, false);
173   elf_end (elf);
174 
175   elf = elf_begin (fd, ELF_C_WRITE, NULL);
176   check_elf ("elf_begin", elf != NULL);
177   test (elf, ELFCLASS64, true);
178   elf_end (elf);
179 
180   close (fd);
181   return 0;
182 }
183