1#include <elf.h>
2#include <poll.h>
3#include <fcntl.h>
4#include <signal.h>
5#include "syscall.h"
6#include "atomic.h"
7#include "libc.h"
8
9void __init_tls(size_t *);
10
11static void dummy(void) {}
12weak_alias(dummy, _init);
13
14__attribute__((__weak__, __visibility__("hidden")))
15extern void (*const __init_array_start)(void), (*const __init_array_end)(void);
16
17static void dummy1(void *p) {}
18weak_alias(dummy1, __init_ssp);
19
20#define AUX_CNT 38
21
22void __init_libc(char **envp, char *pn)
23{
24	size_t i, *auxv, aux[AUX_CNT] = { 0 };
25	__environ = envp;
26	for (i=0; envp[i]; i++);
27	libc.auxv = auxv = (void *)(envp+i+1);
28	for (i=0; auxv[i]; i+=2) if (auxv[i]<AUX_CNT) aux[auxv[i]] = auxv[i+1];
29	__hwcap = aux[AT_HWCAP];
30	__sysinfo = aux[AT_SYSINFO];
31	libc.page_size = aux[AT_PAGESZ];
32
33	if (pn) {
34		__progname = __progname_full = pn;
35		for (i=0; pn[i]; i++) if (pn[i]=='/') __progname = pn+i+1;
36	}
37
38	__init_tls(aux);
39	__init_ssp((void *)aux[AT_RANDOM]);
40
41	if (aux[AT_UID]==aux[AT_EUID] && aux[AT_GID]==aux[AT_EGID]
42		&& !aux[AT_SECURE]) return;
43
44	struct pollfd pfd[3] = { {.fd=0}, {.fd=1}, {.fd=2} };
45#ifdef SYS_poll
46	__syscall(SYS_poll, pfd, 3, 0);
47#else
48	__syscall(SYS_ppoll, pfd, 3, &(struct timespec){0}, 0, _NSIG/8);
49#endif
50	for (i=0; i<3; i++) if (pfd[i].revents&POLLNVAL)
51		if (__sys_open("/dev/null", O_RDWR)<0)
52			a_crash();
53	libc.secure = 1;
54}
55
56static void libc_start_init(void)
57{
58	_init();
59	uintptr_t a = (uintptr_t)&__init_array_start;
60	for (; a<(uintptr_t)&__init_array_end; a+=sizeof(void(*)()))
61		(*(void (**)())a)();
62}
63
64weak_alias(libc_start_init, __libc_start_init);
65
66int __libc_start_main(int (*main)(int,char **,char **), int argc, char **argv)
67{
68	char **envp = argv+argc+1;
69
70	__init_libc(envp, argv[0]);
71	__libc_start_init();
72
73	/* Pass control to the application */
74	exit(main(argc, argv, envp));
75	return 0;
76}
77