1 #include <elf.h>
2 #include <link.h>
3 #include <stdio.h>
4 #include <stddef.h>
5 #include <string.h>
6 #include <sys/types.h>
7 #include <sys/stat.h>
8 #include <fcntl.h>
9 #include <unistd.h>
10 #include <stdlib.h>
11
12 int
main(int argc,char ** argv,char ** envp)13 main (int argc, char **argv, char **envp)
14 {
15 ElfW(auxv_t) auxv;
16 ElfW(auxv_t) *auxv_p;
17
18 void *entry0 = NULL;
19 void *entry1 = NULL;
20
21 char *platform0 = NULL;
22 char *platform1 = NULL;
23
24 // First try the "traditional" way.
25 while (*envp++ != NULL)
26 ; /* Skip, skip, skip... and after finding a NULL we have the auxv. */
27
28 for (auxv_p = (ElfW(auxv_t) *) envp;
29 auxv_p->a_type != AT_NULL;
30 auxv_p++)
31 {
32 if (auxv_p->a_type == AT_ENTRY)
33 entry0 = (void *) auxv_p->a_un.a_val;
34 if (auxv_p->a_type == AT_PLATFORM)
35 platform0 = strdup((char *) auxv_p->a_un.a_val);
36 }
37
38 // Now the /proc way as often used in libraries.
39 int fd = open("/proc/self/auxv", O_RDONLY);
40 if (fd == -1)
41 return -1;
42
43 while (read(fd, &auxv, sizeof(auxv)) == sizeof(auxv))
44 {
45 if (auxv.a_type == AT_ENTRY)
46 entry1 = (void *) auxv.a_un.a_val;
47 if (auxv.a_type == AT_PLATFORM)
48 platform1 = strdup((char *) auxv.a_un.a_val);
49 }
50 close(fd);
51
52 if (entry0 == entry1 && entry0 != NULL)
53 fprintf(stderr, "entries OK\n");
54
55 if (strcmp (platform0, platform1) == 0)
56 fprintf(stderr, "platform OK\n");
57
58 free (platform0);
59 free (platform1);
60
61 return 0;
62 }
63