mips: Ensure PC update with MTC0 single-stepping
[qemu.git] / util / path.c
1 /* Code to mangle pathnames into those matching a given prefix.
2 eg. open("/lib/foo.so") => open("/usr/gnemul/i386-linux/lib/foo.so");
3
4 The assumption is that this area does not change.
5 */
6 #include <sys/types.h>
7 #include <sys/param.h>
8 #include <dirent.h>
9 #include <unistd.h>
10 #include <stdlib.h>
11 #include <string.h>
12 #include <errno.h>
13 #include <stdio.h>
14 #include "qemu-common.h"
15
16 struct pathelem
17 {
18 /* Name of this, eg. lib */
19 char *name;
20 /* Full path name, eg. /usr/gnemul/x86-linux/lib. */
21 char *pathname;
22 struct pathelem *parent;
23 /* Children */
24 unsigned int num_entries;
25 struct pathelem *entries[0];
26 };
27
28 static struct pathelem *base;
29
30 /* First N chars of S1 match S2, and S2 is N chars long. */
31 static int strneq(const char *s1, unsigned int n, const char *s2)
32 {
33 unsigned int i;
34
35 for (i = 0; i < n; i++)
36 if (s1[i] != s2[i])
37 return 0;
38 return s2[i] == 0;
39 }
40
41 static struct pathelem *add_entry(struct pathelem *root, const char *name,
42 unsigned type);
43
44 static struct pathelem *new_entry(const char *root,
45 struct pathelem *parent,
46 const char *name)
47 {
48 struct pathelem *new = g_malloc(sizeof(*new));
49 new->name = g_strdup(name);
50 new->pathname = g_strdup_printf("%s/%s", root, name);
51 new->num_entries = 0;
52 return new;
53 }
54
55 #define streq(a,b) (strcmp((a), (b)) == 0)
56
57 /* Not all systems provide this feature */
58 #if defined(DT_DIR) && defined(DT_UNKNOWN) && defined(DT_LNK)
59 # define dirent_type(dirent) ((dirent)->d_type)
60 # define is_dir_maybe(type) \
61 ((type) == DT_DIR || (type) == DT_UNKNOWN || (type) == DT_LNK)
62 #else
63 # define dirent_type(dirent) (1)
64 # define is_dir_maybe(type) (type)
65 #endif
66
67 static struct pathelem *add_dir_maybe(struct pathelem *path)
68 {
69 DIR *dir;
70
71 if ((dir = opendir(path->pathname)) != NULL) {
72 struct dirent *dirent;
73
74 while ((dirent = readdir(dir)) != NULL) {
75 if (!streq(dirent->d_name,".") && !streq(dirent->d_name,"..")){
76 path = add_entry(path, dirent->d_name, dirent_type(dirent));
77 }
78 }
79 closedir(dir);
80 }
81 return path;
82 }
83
84 static struct pathelem *add_entry(struct pathelem *root, const char *name,
85 unsigned type)
86 {
87 struct pathelem **e;
88
89 root->num_entries++;
90
91 root = g_realloc(root, sizeof(*root)
92 + sizeof(root->entries[0])*root->num_entries);
93 e = &root->entries[root->num_entries-1];
94
95 *e = new_entry(root->pathname, root, name);
96 if (is_dir_maybe(type)) {
97 *e = add_dir_maybe(*e);
98 }
99
100 return root;
101 }
102
103 /* This needs to be done after tree is stabilized (ie. no more reallocs!). */
104 static void set_parents(struct pathelem *child, struct pathelem *parent)
105 {
106 unsigned int i;
107
108 child->parent = parent;
109 for (i = 0; i < child->num_entries; i++)
110 set_parents(child->entries[i], child);
111 }
112
113 /* FIXME: Doesn't handle DIR/.. where DIR is not in emulated dir. */
114 static const char *
115 follow_path(const struct pathelem *cursor, const char *name)
116 {
117 unsigned int i, namelen;
118
119 name += strspn(name, "/");
120 namelen = strcspn(name, "/");
121
122 if (namelen == 0)
123 return cursor->pathname;
124
125 if (strneq(name, namelen, ".."))
126 return follow_path(cursor->parent, name + namelen);
127
128 if (strneq(name, namelen, "."))
129 return follow_path(cursor, name + namelen);
130
131 for (i = 0; i < cursor->num_entries; i++)
132 if (strneq(name, namelen, cursor->entries[i]->name))
133 return follow_path(cursor->entries[i], name + namelen);
134
135 /* Not found */
136 return NULL;
137 }
138
139 void init_paths(const char *prefix)
140 {
141 char pref_buf[PATH_MAX];
142
143 if (prefix[0] == '\0' ||
144 !strcmp(prefix, "/"))
145 return;
146
147 if (prefix[0] != '/') {
148 char *cwd = getcwd(NULL, 0);
149 size_t pref_buf_len = sizeof(pref_buf);
150
151 if (!cwd)
152 abort();
153 pstrcpy(pref_buf, sizeof(pref_buf), cwd);
154 pstrcat(pref_buf, pref_buf_len, "/");
155 pstrcat(pref_buf, pref_buf_len, prefix);
156 free(cwd);
157 } else
158 pstrcpy(pref_buf, sizeof(pref_buf), prefix + 1);
159
160 base = new_entry("", NULL, pref_buf);
161 base = add_dir_maybe(base);
162 if (base->num_entries == 0) {
163 g_free(base->pathname);
164 g_free(base->name);
165 g_free(base);
166 base = NULL;
167 } else {
168 set_parents(base, base);
169 }
170 }
171
172 /* Look for path in emulation dir, otherwise return name. */
173 const char *path(const char *name)
174 {
175 /* Only do absolute paths: quick and dirty, but should mostly be OK.
176 Could do relative by tracking cwd. */
177 if (!base || !name || name[0] != '/')
178 return name;
179
180 return follow_path(base, name) ?: name;
181 }