Merge remote-tracking branch 'remotes/vivier2/tags/linux-user-for-6.2-pull-request...
[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 "qemu/osdep.h"
7 #include <sys/param.h>
8 #include <dirent.h>
9 #include "qemu/cutils.h"
10 #include "qemu/path.h"
11 #include "qemu/thread.h"
12
13 static const char *base;
14 static GHashTable *hash;
15 static QemuMutex lock;
16
17 void init_paths(const char *prefix)
18 {
19 if (prefix[0] == '\0' || !strcmp(prefix, "/")) {
20 return;
21 }
22
23 if (prefix[0] == '/') {
24 base = g_strdup(prefix);
25 } else {
26 char *cwd = g_get_current_dir();
27 base = g_build_filename(cwd, prefix, NULL);
28 g_free(cwd);
29 }
30
31 hash = g_hash_table_new(g_str_hash, g_str_equal);
32 qemu_mutex_init(&lock);
33 }
34
35 /* Look for path in emulation dir, otherwise return name. */
36 const char *path(const char *name)
37 {
38 gpointer key, value;
39 const char *ret;
40
41 /* Only do absolute paths: quick and dirty, but should mostly be OK. */
42 if (!base || !name || name[0] != '/') {
43 return name;
44 }
45
46 qemu_mutex_lock(&lock);
47
48 /* Have we looked up this file before? */
49 if (g_hash_table_lookup_extended(hash, name, &key, &value)) {
50 ret = value ? value : name;
51 } else {
52 char *save = g_strdup(name);
53 char *full = g_build_filename(base, name, NULL);
54
55 /* Look for the path; record the result, pass or fail. */
56 if (access(full, F_OK) == 0) {
57 /* Exists. */
58 g_hash_table_insert(hash, save, full);
59 ret = full;
60 } else {
61 /* Does not exist. */
62 g_free(full);
63 g_hash_table_insert(hash, save, NULL);
64 ret = name;
65 }
66 }
67
68 qemu_mutex_unlock(&lock);
69 return ret;
70 }