PPC: e500: msync is 440 only, e500 has real sync
[qemu.git] / 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 char type);
43
44 static struct pathelem *new_entry(const char *root,
45 struct pathelem *parent,
46 const char *name)
47 {
48 struct pathelem *new = malloc(sizeof(*new));
49 new->name = strdup(name);
50 if (asprintf(&new->pathname, "%s/%s", root, name) == -1) {
51 printf("Cannot allocate memory\n");
52 exit(1);
53 }
54 new->num_entries = 0;
55 return new;
56 }
57
58 #define streq(a,b) (strcmp((a), (b)) == 0)
59
60 /* Not all systems provide this feature */
61 #if defined(DT_DIR) && defined(DT_UNKNOWN)
62 # define dirent_type(dirent) ((dirent)->d_type)
63 # define is_dir_maybe(type) ((type) == DT_DIR || (type) == DT_UNKNOWN)
64 #else
65 # define dirent_type(dirent) (1)
66 # define is_dir_maybe(type) (type)
67 #endif
68
69 static struct pathelem *add_dir_maybe(struct pathelem *path)
70 {
71 DIR *dir;
72
73 if ((dir = opendir(path->pathname)) != NULL) {
74 struct dirent *dirent;
75
76 while ((dirent = readdir(dir)) != NULL) {
77 if (!streq(dirent->d_name,".") && !streq(dirent->d_name,"..")){
78 path = add_entry(path, dirent->d_name, dirent_type(dirent));
79 }
80 }
81 closedir(dir);
82 }
83 return path;
84 }
85
86 static struct pathelem *add_entry(struct pathelem *root, const char *name,
87 unsigned char type)
88 {
89 struct pathelem **e;
90
91 root->num_entries++;
92
93 root = realloc(root, sizeof(*root)
94 + sizeof(root->entries[0])*root->num_entries);
95 e = &root->entries[root->num_entries-1];
96
97 *e = new_entry(root->pathname, root, name);
98 if (is_dir_maybe(type)) {
99 *e = add_dir_maybe(*e);
100 }
101
102 return root;
103 }
104
105 /* This needs to be done after tree is stabilized (ie. no more reallocs!). */
106 static void set_parents(struct pathelem *child, struct pathelem *parent)
107 {
108 unsigned int i;
109
110 child->parent = parent;
111 for (i = 0; i < child->num_entries; i++)
112 set_parents(child->entries[i], child);
113 }
114
115 /* FIXME: Doesn't handle DIR/.. where DIR is not in emulated dir. */
116 static const char *
117 follow_path(const struct pathelem *cursor, const char *name)
118 {
119 unsigned int i, namelen;
120
121 name += strspn(name, "/");
122 namelen = strcspn(name, "/");
123
124 if (namelen == 0)
125 return cursor->pathname;
126
127 if (strneq(name, namelen, ".."))
128 return follow_path(cursor->parent, name + namelen);
129
130 if (strneq(name, namelen, "."))
131 return follow_path(cursor, name + namelen);
132
133 for (i = 0; i < cursor->num_entries; i++)
134 if (strneq(name, namelen, cursor->entries[i]->name))
135 return follow_path(cursor->entries[i], name + namelen);
136
137 /* Not found */
138 return NULL;
139 }
140
141 void init_paths(const char *prefix)
142 {
143 char pref_buf[PATH_MAX];
144
145 if (prefix[0] == '\0' ||
146 !strcmp(prefix, "/"))
147 return;
148
149 if (prefix[0] != '/') {
150 char *cwd = getcwd(NULL, 0);
151 size_t pref_buf_len = sizeof(pref_buf);
152
153 if (!cwd)
154 abort();
155 pstrcpy(pref_buf, sizeof(pref_buf), cwd);
156 pstrcat(pref_buf, pref_buf_len, "/");
157 pstrcat(pref_buf, pref_buf_len, prefix);
158 free(cwd);
159 } else
160 pstrcpy(pref_buf, sizeof(pref_buf), prefix + 1);
161
162 base = new_entry("", NULL, pref_buf);
163 base = add_dir_maybe(base);
164 if (base->num_entries == 0) {
165 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 }