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Commit | Line | Data |
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84778508 BS |
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.h" | |
15 | #include "qemu-common.h" | |
16 | ||
17 | struct pathelem | |
18 | { | |
19 | /* Name of this, eg. lib */ | |
20 | char *name; | |
21 | /* Full path name, eg. /usr/gnemul/x86-linux/lib. */ | |
22 | char *pathname; | |
23 | struct pathelem *parent; | |
24 | /* Children */ | |
25 | unsigned int num_entries; | |
26 | struct pathelem *entries[0]; | |
27 | }; | |
28 | ||
29 | static struct pathelem *base; | |
30 | ||
31 | /* First N chars of S1 match S2, and S2 is N chars long. */ | |
32 | static int strneq(const char *s1, unsigned int n, const char *s2) | |
33 | { | |
34 | unsigned int i; | |
35 | ||
36 | for (i = 0; i < n; i++) | |
37 | if (s1[i] != s2[i]) | |
38 | return 0; | |
39 | return s2[i] == 0; | |
40 | } | |
41 | ||
42 | static struct pathelem *add_entry(struct pathelem *root, const char *name); | |
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 | asprintf(&new->pathname, "%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 | static struct pathelem *add_dir_maybe(struct pathelem *path) | |
58 | { | |
59 | DIR *dir; | |
60 | ||
61 | if ((dir = opendir(path->pathname)) != NULL) { | |
62 | struct dirent *dirent; | |
63 | ||
64 | while ((dirent = readdir(dir)) != NULL) { | |
65 | if (!streq(dirent->d_name,".") && !streq(dirent->d_name,"..")){ | |
66 | path = add_entry(path, dirent->d_name); | |
67 | } | |
68 | } | |
69 | closedir(dir); | |
70 | } | |
71 | return path; | |
72 | } | |
73 | ||
74 | static struct pathelem *add_entry(struct pathelem *root, const char *name) | |
75 | { | |
76 | root->num_entries++; | |
77 | ||
78 | root = realloc(root, sizeof(*root) | |
79 | + sizeof(root->entries[0])*root->num_entries); | |
80 | ||
81 | root->entries[root->num_entries-1] = new_entry(root->pathname, root, name); | |
82 | root->entries[root->num_entries-1] | |
83 | = add_dir_maybe(root->entries[root->num_entries-1]); | |
84 | return root; | |
85 | } | |
86 | ||
87 | /* This needs to be done after tree is stabilized (ie. no more reallocs!). */ | |
88 | static void set_parents(struct pathelem *child, struct pathelem *parent) | |
89 | { | |
90 | unsigned int i; | |
91 | ||
92 | child->parent = parent; | |
93 | for (i = 0; i < child->num_entries; i++) | |
94 | set_parents(child->entries[i], child); | |
95 | } | |
96 | ||
97 | /* FIXME: Doesn't handle DIR/.. where DIR is not in emulated dir. */ | |
98 | static const char * | |
99 | follow_path(const struct pathelem *cursor, const char *name) | |
100 | { | |
101 | unsigned int i, namelen; | |
102 | ||
103 | name += strspn(name, "/"); | |
104 | namelen = strcspn(name, "/"); | |
105 | ||
106 | if (namelen == 0) | |
107 | return cursor->pathname; | |
108 | ||
109 | if (strneq(name, namelen, "..")) | |
110 | return follow_path(cursor->parent, name + namelen); | |
111 | ||
112 | if (strneq(name, namelen, ".")) | |
113 | return follow_path(cursor, name + namelen); | |
114 | ||
115 | for (i = 0; i < cursor->num_entries; i++) | |
116 | if (strneq(name, namelen, cursor->entries[i]->name)) | |
117 | return follow_path(cursor->entries[i], name + namelen); | |
118 | ||
119 | /* Not found */ | |
120 | return NULL; | |
121 | } | |
122 | ||
123 | void init_paths(const char *prefix) | |
124 | { | |
125 | char pref_buf[PATH_MAX]; | |
126 | ||
127 | if (prefix[0] == '\0' || | |
128 | !strcmp(prefix, "/")) | |
129 | return; | |
130 | ||
131 | if (prefix[0] != '/') { | |
132 | char *cwd = getcwd(NULL, 0); | |
133 | size_t pref_buf_len = sizeof(pref_buf); | |
134 | ||
135 | if (!cwd) | |
136 | abort(); | |
137 | pstrcpy(pref_buf, sizeof(pref_buf), cwd); | |
138 | pstrcat(pref_buf, pref_buf_len, "/"); | |
139 | pstrcat(pref_buf, pref_buf_len, prefix); | |
140 | free(cwd); | |
141 | } else | |
142 | pstrcpy(pref_buf, sizeof(pref_buf), prefix + 1); | |
143 | ||
144 | base = new_entry("", NULL, pref_buf); | |
145 | base = add_dir_maybe(base); | |
146 | if (base->num_entries == 0) { | |
147 | free (base); | |
148 | base = NULL; | |
149 | } else { | |
150 | set_parents(base, base); | |
151 | } | |
152 | } | |
153 | ||
154 | /* Look for path in emulation dir, otherwise return name. */ | |
155 | const char *path(const char *name) | |
156 | { | |
157 | /* Only do absolute paths: quick and dirty, but should mostly be OK. | |
158 | Could do relative by tracking cwd. */ | |
159 | if (!base || name[0] != '/') | |
160 | return name; | |
161 | ||
162 | return follow_path(base, name) ?: name; | |
163 | } |