hooks.c revision 33f0ca5350ccc9ded3a2bfa82a988e9bd640233f 
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 "sysdep.h"
32#include "vect.h"
33#include "dict.h"
34#include "options.h"
35
36static char *
37append(const char *str1, const char *str2)
38{
39	char *ret = malloc(strlen(str1) + strlen(str2) + 2);
40	if (ret == NULL)
41		return ret;
42	strcpy(stpcpy(ret, str1), str2);
43	return ret;
44}
45
46static void
47add_dir(struct vect *dirs, const char *str1, const char *str2)
48{
49	char *dir = append(str1, str2);
50	if (dir != NULL
51	    && VECT_PUSHBACK(dirs, &dir) < 0)
52		fprintf(stderr,
53			"Couldn't store candidate config directory %s%s: %s.\n",
54			str1, str2, strerror(errno));
55}
56
57static enum callback_status
58add_dir_component_cb(struct opt_F_t *entry, void *data)
59{
60	struct vect *dirs = data;
61	if (opt_F_get_kind(entry) == OPT_F_DIR)
62		add_dir(dirs, entry->pathname, "/ltrace");
63	return CBS_CONT;
64}
65
66static void
67destroy_opt_F_cb(struct opt_F_t *entry, void *data)
68{
69	opt_F_destroy(entry);
70}
71
72static char *g_home_dir = NULL;
73
74int
75os_get_config_dirs(int private, const char ***retp)
76{
77	/* Vector of char *.  Contains first pointers to local paths,
78	 * then NULL, then pointers to system paths, then another
79	 * NULL.  SYS_START points to the beginning of the second
80	 * part.  */
81	static struct vect dirs;
82	static ssize_t sys_start = 0;
83
84again:
85	if (sys_start != 0) {
86		if (sys_start == -1)
87			return -1;
88
89		if (retp != NULL) {
90			if (private)
91				*retp = VECT_ELEMENT(&dirs, const char *, 0);
92			else
93				*retp = VECT_ELEMENT(&dirs, const char *,
94						     (size_t)sys_start);
95		}
96
97		return 0;
98	}
99
100	VECT_INIT(&dirs, char *);
101
102	char *home = getenv("HOME");
103	if (home == NULL) {
104		struct passwd *pwd = getpwuid(getuid());
105		if (pwd != NULL)
106			home = pwd->pw_dir;
107	}
108
109	size_t home_len = home != NULL ? strlen(home) : 0;
110
111	/* The values coming from getenv and getpwuid may not be
112	 * persistent.  */
113	if (home != NULL) {
114		g_home_dir = strdup(home);
115		if (g_home_dir != NULL) {
116			home = g_home_dir;
117		} else {
118			char *tmp = alloca(home_len + 1);
119			strcpy(tmp, home);
120			home = tmp;
121		}
122	}
123
124	char *xdg_home = getenv("XDG_CONFIG_HOME");
125	if (xdg_home == NULL && home != NULL) {
126		xdg_home = alloca(home_len + sizeof "/.config");
127		sprintf(xdg_home, "%s/.config", home);
128	}
129	if (xdg_home != NULL)
130		add_dir(&dirs, xdg_home, "/ltrace");
131	if (home != NULL)
132		add_dir(&dirs, home, "/.ltrace");
133
134	char *delim = NULL;
135	if (VECT_PUSHBACK(&dirs, &delim) < 0) {
136	fail:
137		/* This can't work :(  */
138		fprintf(stderr,
139			"Couldn't initialize list of config directories: %s.\n",
140			strerror(errno));
141		VECT_DESTROY(&dirs, const char *, dict_dtor_string, NULL);
142		sys_start = -1;
143		return -1;
144	}
145	sys_start = vect_size(&dirs);
146
147	/* """preference-ordered set of base directories to search for
148	 * configuration files in addition to the $XDG_CONFIG_HOME
149	 * base directory. The directories in $XDG_CONFIG_DIRS should
150	 * be seperated with a colon ':'."""  */
151	char *xdg_sys = getenv("XDG_CONFIG_DIRS");
152	if (xdg_sys != NULL) {
153		struct vect v;
154		VECT_INIT(&v, struct opt_F_t);
155		if (parse_colon_separated_list(xdg_sys, &v) < 0
156		    || VECT_EACH(&v, struct opt_F_t, NULL,
157				 add_dir_component_cb, &dirs) != NULL)
158			fprintf(stderr,
159				"Error processing $XDG_CONFIG_DIRS '%s': %s\n",
160				xdg_sys, strerror(errno));
161		VECT_DESTROY(&v, struct opt_F_t, destroy_opt_F_cb, NULL);
162	}
163
164	/* SYSCONFDIF is passed via -D when compiling.  */
165	const char *sysconfdir = SYSCONFDIR;
166	if (sysconfdir != NULL)
167		add_dir(&dirs, sysconfdir, "");
168
169	if (VECT_PUSHBACK(&dirs, &delim) < 0)
170		goto fail;
171
172	goto again;
173}
174
175int
176os_get_ltrace_conf_filename(const char **retp)
177{
178	if (g_home_dir == NULL)
179		os_get_config_dirs(0, NULL);
180	*retp = g_home_dir;
181	return g_home_dir != NULL ? 0 : -1;
182}
183