1/*
2 * $Header$
3 * $Source$
4 * $Locker$
5 *
6 * Copyright 1987 by the Student Information Processing Board
7 * of the Massachusetts Institute of Technology
8 *
9 * Permission to use, copy, modify, and distribute this software and
10 * its documentation for any purpose is hereby granted, provided that
11 * the names of M.I.T. and the M.I.T. S.I.P.B. not be used in
12 * advertising or publicity pertaining to distribution of the software
13 * without specific, written prior permission.  M.I.T. and the
14 * M.I.T. S.I.P.B. make no representations about the suitability of
15 * this software for any purpose.  It is provided "as is" without
16 * express or implied warranty.
17 */
18
19#include <stdio.h>
20#include <stdlib.h>
21#include <string.h>
22#include <errno.h>
23#ifdef HAVE_SYS_PRCTL_H
24#include <sys/prctl.h>
25#else
26#define PR_GET_DUMPABLE 3
27#endif
28#if (!defined(HAVE_PRCTL) && defined(linux))
29#include <sys/syscall.h>
30#endif
31#if HAVE_UNISTD_H
32#include <unistd.h>
33#endif
34#if HAVE_SYS_TYPES_H
35#include <sys/types.h>
36#endif
37#include "com_err.h"
38#include "error_table.h"
39#include "internal.h"
40
41#ifdef TLS
42#define THREAD_LOCAL static TLS
43#else
44#define THREAD_LOCAL static
45#endif
46
47THREAD_LOCAL char buffer[25];
48
49struct et_list * _et_list = (struct et_list *) NULL;
50struct et_list * _et_dynamic_list = (struct et_list *) NULL;
51
52
53const char * error_message (errcode_t code)
54{
55    int offset;
56    struct et_list *et;
57    errcode_t table_num;
58    int started = 0;
59    char *cp;
60
61    offset = (int) (code & ((1<<ERRCODE_RANGE)-1));
62    table_num = code - offset;
63    if (!table_num) {
64#ifdef HAS_SYS_ERRLIST
65	if (offset < sys_nerr)
66	    return(sys_errlist[offset]);
67	else
68	    goto oops;
69#else
70	cp = strerror(offset);
71	if (cp)
72	    return(cp);
73	else
74	    goto oops;
75#endif
76    }
77    for (et = _et_list; et; et = et->next) {
78	if ((et->table->base & 0xffffffL) == (table_num & 0xffffffL)) {
79	    /* This is the right table */
80	    if (et->table->n_msgs <= offset)
81		goto oops;
82	    return(et->table->msgs[offset]);
83	}
84    }
85    for (et = _et_dynamic_list; et; et = et->next) {
86	if ((et->table->base & 0xffffffL) == (table_num & 0xffffffL)) {
87	    /* This is the right table */
88	    if (et->table->n_msgs <= offset)
89		goto oops;
90	    return(et->table->msgs[offset]);
91	}
92    }
93oops:
94    strcpy (buffer, "Unknown code ");
95    if (table_num) {
96	strcat (buffer, error_table_name (table_num));
97	strcat (buffer, " ");
98    }
99    for (cp = buffer; *cp; cp++)
100	;
101    if (offset >= 100) {
102	*cp++ = '0' + offset / 100;
103	offset %= 100;
104	started++;
105    }
106    if (started || offset >= 10) {
107	*cp++ = '0' + offset / 10;
108	offset %= 10;
109    }
110    *cp++ = '0' + offset;
111    *cp = '\0';
112    return(buffer);
113}
114
115/*
116 * This routine will only return a value if the we are not running as
117 * a privileged process.
118 */
119static char *safe_getenv(const char *arg)
120{
121	if ((getuid() != geteuid()) || (getgid() != getegid()))
122		return NULL;
123#if HAVE_PRCTL
124	if (prctl(PR_GET_DUMPABLE, 0, 0, 0, 0) == 0)
125		return NULL;
126#else
127#if (defined(linux) && defined(SYS_prctl))
128	if (syscall(SYS_prctl, PR_GET_DUMPABLE, 0, 0, 0, 0) == 0)
129		return NULL;
130#endif
131#endif
132
133#ifdef HAVE___SECURE_GETENV
134	return __secure_getenv(arg);
135#else
136	return getenv(arg);
137#endif
138}
139
140#define DEBUG_INIT	0x8000
141#define DEBUG_ADDREMOVE 0x0001
142
143static int debug_mask = 0;
144static FILE *debug_f = 0;
145
146static void init_debug(void)
147{
148	char *dstr;
149	char *fn;
150
151	if (debug_mask & DEBUG_INIT)
152		return;
153
154	dstr = getenv("COMERR_DEBUG");
155	if (dstr)
156		debug_mask = strtoul(dstr, 0, 0);
157
158	fn = safe_getenv("COMERR_DEBUG_FILE");
159	if (fn)
160		debug_f = fopen(fn, "a");
161	if (!debug_f)
162		debug_f = fopen("/dev/tty", "a");
163	if (!debug_f)
164		debug_mask = 0;
165
166	debug_mask |= DEBUG_INIT;
167}
168
169/*
170 * New interface provided by krb5's com_err library
171 */
172errcode_t add_error_table(const struct error_table * et)
173{
174	struct et_list *el;
175
176	if (!(el = (struct et_list *) malloc(sizeof(struct et_list))))
177		return ENOMEM;
178
179	el->table = et;
180	el->next = _et_dynamic_list;
181	_et_dynamic_list = el;
182
183	init_debug();
184	if (debug_mask & DEBUG_ADDREMOVE)
185		fprintf(debug_f, "add_error_table: %s (0x%p)\n",
186			error_table_name(et->base),
187			(const void *) et);
188
189	return 0;
190}
191
192/*
193 * New interface provided by krb5's com_err library
194 */
195errcode_t remove_error_table(const struct error_table * et)
196{
197	struct et_list *el = _et_dynamic_list;
198	struct et_list *el2 = 0;
199
200	init_debug();
201	while (el) {
202		if (el->table->base == et->base) {
203			if (el2)	/* Not the beginning of the list */
204				el2->next = el->next;
205			else
206				_et_dynamic_list = el->next;
207			(void) free(el);
208			if (debug_mask & DEBUG_ADDREMOVE)
209				fprintf(debug_f,
210					"remove_error_table: %s (0x%p)\n",
211					error_table_name(et->base),
212					(const void *) et);
213			return 0;
214		}
215		el2 = el;
216		el = el->next;
217	}
218	if (debug_mask & DEBUG_ADDREMOVE)
219		fprintf(debug_f, "remove_error_table FAILED: %s (0x%p)\n",
220			error_table_name(et->base),
221			(const void *) et);
222	return ENOENT;
223}
224
225/*
226 * Variant of the interface provided by Heimdal's com_err library
227 */
228void
229add_to_error_table(struct et_list *new_table)
230{
231	add_error_table(new_table->table);
232}
233