summaryrefslogtreecommitdiff
path: root/libbb/login.c
blob: aa2e17164d16a0c2bff36527e9289f177ebca644 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
/* vi: set sw=4 ts=4: */
/*
 * issue.c: issue printing code
 *
 * Copyright (C) 2003 Bastian Blank <waldi@tuxbox.org>
 *
 * Optimize and correcting OCRNL by Vladimir Oleynik <dzo@simtreas.ru>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */

#include "libbb.h"
/* After libbb.h, since it needs sys/types.h on some systems */
#include <sys/utsname.h>

#define LOGIN " login: "

static const char fmtstr_d[] ALIGN1 = "%A, %d %B %Y";
static const char fmtstr_t[] ALIGN1 = "%H:%M:%S";

void FAST_FUNC print_login_issue(const char *issue_file, const char *tty)
{
	FILE *fp;
	int c;
	char buf[256+1];
	const char *outbuf;
	time_t t;
	struct utsname uts;

	time(&t);
	uname(&uts);

	puts("\r");	/* start a new line */

	fp = fopen_for_read(issue_file);
	if (!fp)
		return;
	while ((c = fgetc(fp)) != EOF) {
		outbuf = buf;
		buf[0] = c;
		buf[1] = '\0';
		if (c == '\n') {
			buf[1] = '\r';
			buf[2] = '\0';
		}
		if (c == '\\' || c == '%') {
			c = fgetc(fp);
			switch (c) {
			case 's':
				outbuf = uts.sysname;
				break;
			case 'n':
			case 'h':
				outbuf = uts.nodename;
				break;
			case 'r':
				outbuf = uts.release;
				break;
			case 'v':
				outbuf = uts.version;
				break;
			case 'm':
				outbuf = uts.machine;
				break;
/* The field domainname of struct utsname is Linux specific. */
#if defined(__linux__)
			case 'D':
			case 'o':
				outbuf = uts.domainname;
				break;
#endif
			case 'd':
				strftime(buf, sizeof(buf), fmtstr_d, localtime(&t));
				break;
			case 't':
				strftime(buf, sizeof(buf), fmtstr_t, localtime(&t));
				break;
			case 'l':
				outbuf = tty;
				break;
			default:
				buf[0] = c;
			}
		}
		fputs(outbuf, stdout);
	}
	fclose(fp);
	fflush_all();
}

void FAST_FUNC print_login_prompt(void)
{
	char *hostname = safe_gethostname();

	fputs(hostname, stdout);
	fputs(LOGIN, stdout);
	fflush_all();
	free(hostname);
}

/* Clear dangerous stuff, set PATH */
static const char forbid[] ALIGN1 =
	"ENV" "\0"
	"BASH_ENV" "\0"
	"HOME" "\0"
	"IFS" "\0"
	"SHELL" "\0"
	"LD_LIBRARY_PATH" "\0"
	"LD_PRELOAD" "\0"
	"LD_TRACE_LOADED_OBJECTS" "\0"
	"LD_BIND_NOW" "\0"
	"LD_AOUT_LIBRARY_PATH" "\0"
	"LD_AOUT_PRELOAD" "\0"
	"LD_NOWARN" "\0"
	"LD_KEEPDIR" "\0";

int FAST_FUNC sanitize_env_if_suid(void)
{
	const char *p;

	if (getuid() == geteuid())
		return 0;

	p = forbid;
	do {
		unsetenv(p);
		p += strlen(p) + 1;
	} while (*p);
	putenv((char*)bb_PATH_root_path);

	return 1; /* we indeed were run by different user! */
}