1/*
2 * This file is part of ltrace.
3 * Copyright (C) 2012, 2013 Petr Machata
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
7 * published by the Free Software Foundation; either version 2 of the
8 * License, or (at your option) any later version.
9 *
10 * This program 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 GNU
13 * 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, write to the Free Software
17 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
18 * 02110-1301 USA
19 */
20
21#define _POSIX_C_SOURCE 200809L
22#include <sys/types.h>
23#include <alloca.h>
24#include <errno.h>
25#include <pwd.h>
26#include <stdio.h>
27#include <stdlib.h>
28#include <string.h>
29#include <unistd.h>
30
31#include "backend.h"
32#include "dict.h"
33#include "options.h"
34#include "sysdep.h"
35#include "vect.h"
36
37static char *
38append(const char *str1, const char *str2)
39{
40	char *ret = malloc(strlen(str1) + strlen(str2) + 2);
41	if (ret == NULL)
42		return ret;
43	strcpy(stpcpy(ret, str1), str2);
44	return ret;
45}
46
47static void
48add_dir(struct vect *dirs, const char *str1, const char *str2)
49{
50	char *dir = append(str1, str2);
51	if (dir != NULL
52	    && VECT_PUSHBACK(dirs, &dir) < 0)
53		fprintf(stderr,
54			"Couldn't store candidate config directory %s%s: %s.\n",
55			str1, str2, strerror(errno));
56}
57
58static enum callback_status
59add_dir_component_cb(struct opt_F_t *entry, void *data)
60{
61	struct vect *dirs = data;
62	if (opt_F_get_kind(entry) == OPT_F_DIR)
63		add_dir(dirs, entry->pathname, "/ltrace");
64	return CBS_CONT;
65}
66
67static void
68destroy_opt_F_cb(struct opt_F_t *entry, void *data)
69{
70	opt_F_destroy(entry);
71}
72
73static char *g_home_dir = NULL;
74
75int
76os_get_config_dirs(int private, const char ***retp)
77{
78	/* Vector of char *.  Contains first pointers to local paths,
79	 * then NULL, then pointers to system paths, then another
80	 * NULL.  SYS_START points to the beginning of the second
81	 * part.  */
82	static struct vect dirs;
83	static ssize_t sys_start = 0;
84
85again:
86	if (sys_start != 0) {
87		if (sys_start == -1)
88			return -1;
89
90		if (retp != NULL) {
91			if (private)
92				*retp = VECT_ELEMENT(&dirs, const char *, 0);
93			else
94				*retp = VECT_ELEMENT(&dirs, const char *,
95						     (size_t)sys_start);
96		}
97
98		return 0;
99	}
100
101	VECT_INIT(&dirs, char *);
102
103	char *home = getenv("HOME");
104	if (home == NULL) {
105		struct passwd *pwd = getpwuid(getuid());
106		if (pwd != NULL)
107			home = pwd->pw_dir;
108	}
109
110	size_t home_len = home != NULL ? strlen(home) : 0;
111
112	/* The values coming from getenv and getpwuid may not be
113	 * persistent.  */
114	if (home != NULL) {
115		free(g_home_dir);
116		g_home_dir = strdup(home);
117		if (g_home_dir != NULL) {
118			home = g_home_dir;
119		} else {
120			char *tmp = alloca(home_len + 1);
121			strcpy(tmp, home);
122			home = tmp;
123		}
124	}
125
126	char *xdg_home = getenv("XDG_CONFIG_HOME");
127	if (xdg_home == NULL && home != NULL) {
128		xdg_home = alloca(home_len + sizeof "/.config");
129		sprintf(xdg_home, "%s/.config", home);
130	}
131	if (xdg_home != NULL)
132		add_dir(&dirs, xdg_home, "/ltrace");
133	if (home != NULL)
134		add_dir(&dirs, home, "/.ltrace");
135
136	char *delim = NULL;
137	if (VECT_PUSHBACK(&dirs, &delim) < 0) {
138	fail:
139		/* This can't work :(  */
140		fprintf(stderr,
141			"Couldn't initialize list of config directories: %s.\n",
142			strerror(errno));
143		VECT_DESTROY(&dirs, const char *, dict_dtor_string, NULL);
144		sys_start = -1;
145		return -1;
146	}
147	sys_start = vect_size(&dirs);
148
149	/* """preference-ordered set of base directories to search for
150	 * configuration files in addition to the $XDG_CONFIG_HOME
151	 * base directory. The directories in $XDG_CONFIG_DIRS should
152	 * be seperated with a colon ':'."""  */
153	char *xdg_sys = getenv("XDG_CONFIG_DIRS");
154	if (xdg_sys != NULL) {
155		struct vect v;
156		VECT_INIT(&v, struct opt_F_t);
157		if (parse_colon_separated_list(xdg_sys, &v) < 0
158		    || VECT_EACH(&v, struct opt_F_t, NULL,
159				 add_dir_component_cb, &dirs) != NULL)
160			fprintf(stderr,
161				"Error processing $XDG_CONFIG_DIRS '%s': %s\n",
162				xdg_sys, strerror(errno));
163		VECT_DESTROY(&v, struct opt_F_t, destroy_opt_F_cb, NULL);
164	}
165
166	/* PKGDATADIR is passed via -D when compiling.  */
167	const char *pkgdatadir = PKGDATADIR;
168	if (pkgdatadir != NULL)
169		add_dir(&dirs, pkgdatadir, "");
170
171	if (VECT_PUSHBACK(&dirs, &delim) < 0)
172		goto fail;
173
174	goto again;
175}
176
177int
178os_get_ltrace_conf_filenames(struct vect *retp)
179{
180	char *homepath = NULL;
181	char *syspath = NULL;
182
183#define FN ".ltrace.conf"
184	if (g_home_dir == NULL)
185		os_get_config_dirs(0, NULL);
186
187	if (g_home_dir != NULL) {
188		homepath = malloc(strlen(g_home_dir) + 1 + sizeof FN);
189		if (homepath == NULL
190		    || sprintf(homepath, "%s/%s", g_home_dir, FN) < 0) {
191		fail:
192			free(syspath);
193			free(homepath);
194			return -1;
195		}
196	}
197
198	/* SYSCONFDIR is passed via -D when compiling.  */
199	const char *sysconfdir = SYSCONFDIR;
200	if (sysconfdir != NULL && *sysconfdir != '\0') {
201		/* No +1, we skip the initial period.  */
202		syspath = malloc(strlen(sysconfdir) + sizeof FN);
203		if (syspath == NULL
204		    || sprintf(syspath, "%s/%s", sysconfdir, FN + 1) < 0)
205			goto fail;
206	}
207
208	if (VECT_PUSHBACK(retp, &homepath) < 0
209	    || VECT_PUSHBACK(retp, &syspath) < 0)
210		goto fail;
211
212	return 0;
213}
214