bellard | 32ce633 | 2003-04-11 00:16:16 +0000 | [diff] [blame] | 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 <dirent.h> |
| 8 | #include <unistd.h> |
| 9 | #include <stdlib.h> |
| 10 | #include <string.h> |
| 11 | #include <errno.h> |
| 12 | #include <stdio.h> |
| 13 | #include "qemu.h" |
| 14 | |
| 15 | struct pathelem |
| 16 | { |
| 17 | /* Name of this, eg. lib */ |
| 18 | char *name; |
| 19 | /* Full path name, eg. /usr/gnemul/x86-linux/lib. */ |
| 20 | char *pathname; |
| 21 | struct pathelem *parent; |
| 22 | /* Children */ |
| 23 | unsigned int num_entries; |
| 24 | struct pathelem *entries[0]; |
| 25 | }; |
| 26 | |
| 27 | static struct pathelem *base; |
| 28 | |
| 29 | /* First N chars of S1 match S2, and S2 is N chars long. */ |
| 30 | static int strneq(const char *s1, unsigned int n, const char *s2) |
| 31 | { |
| 32 | unsigned int i; |
| 33 | |
| 34 | for (i = 0; i < n; i++) |
| 35 | if (s1[i] != s2[i]) |
| 36 | return 0; |
| 37 | return s2[i] == 0; |
| 38 | } |
| 39 | |
| 40 | static struct pathelem *add_entry(struct pathelem *root, const char *name); |
| 41 | |
| 42 | static struct pathelem *new_entry(const char *root, |
| 43 | struct pathelem *parent, |
| 44 | const char *name) |
| 45 | { |
| 46 | struct pathelem *new = malloc(sizeof(*new)); |
| 47 | new->name = strdup(name); |
| 48 | asprintf(&new->pathname, "%s/%s", root, name); |
| 49 | new->num_entries = 0; |
| 50 | return new; |
| 51 | } |
| 52 | |
| 53 | #define streq(a,b) (strcmp((a), (b)) == 0) |
| 54 | |
| 55 | static struct pathelem *add_dir_maybe(struct pathelem *path) |
| 56 | { |
| 57 | DIR *dir; |
| 58 | |
| 59 | if ((dir = opendir(path->pathname)) != NULL) { |
| 60 | struct dirent *dirent; |
| 61 | |
| 62 | while ((dirent = readdir(dir)) != NULL) { |
| 63 | if (!streq(dirent->d_name,".") && !streq(dirent->d_name,"..")){ |
| 64 | path = add_entry(path, dirent->d_name); |
| 65 | } |
| 66 | } |
| 67 | closedir(dir); |
| 68 | } |
| 69 | return path; |
| 70 | } |
| 71 | |
| 72 | static struct pathelem *add_entry(struct pathelem *root, const char *name) |
| 73 | { |
| 74 | root->num_entries++; |
| 75 | |
| 76 | root = realloc(root, sizeof(*root) |
| 77 | + sizeof(root->entries[0])*root->num_entries); |
| 78 | |
| 79 | root->entries[root->num_entries-1] = new_entry(root->pathname, root, name); |
| 80 | root->entries[root->num_entries-1] |
| 81 | = add_dir_maybe(root->entries[root->num_entries-1]); |
| 82 | return root; |
| 83 | } |
| 84 | |
| 85 | /* This needs to be done after tree is stabalized (ie. no more reallocs!). */ |
| 86 | static void set_parents(struct pathelem *child, struct pathelem *parent) |
| 87 | { |
| 88 | unsigned int i; |
| 89 | |
| 90 | child->parent = parent; |
| 91 | for (i = 0; i < child->num_entries; i++) |
| 92 | set_parents(child->entries[i], child); |
| 93 | } |
| 94 | |
bellard | 32ce633 | 2003-04-11 00:16:16 +0000 | [diff] [blame] | 95 | /* FIXME: Doesn't handle DIR/.. where DIR is not in emulated dir. */ |
| 96 | static const char * |
| 97 | follow_path(const struct pathelem *cursor, const char *name) |
| 98 | { |
| 99 | unsigned int i, namelen; |
| 100 | |
| 101 | name += strspn(name, "/"); |
| 102 | namelen = strcspn(name, "/"); |
| 103 | |
| 104 | if (namelen == 0) |
| 105 | return cursor->pathname; |
| 106 | |
| 107 | if (strneq(name, namelen, "..")) |
| 108 | return follow_path(cursor->parent, name + namelen); |
| 109 | |
| 110 | if (strneq(name, namelen, ".")) |
| 111 | return follow_path(cursor, name + namelen); |
| 112 | |
| 113 | for (i = 0; i < cursor->num_entries; i++) |
| 114 | if (strneq(name, namelen, cursor->entries[i]->name)) |
| 115 | return follow_path(cursor->entries[i], name + namelen); |
| 116 | |
| 117 | /* Not found */ |
| 118 | return NULL; |
| 119 | } |
| 120 | |
ths | ffb04fc | 2007-06-17 15:32:30 +0000 | [diff] [blame] | 121 | void init_paths(const char *prefix) |
| 122 | { |
| 123 | char pref_buf[PATH_MAX]; |
| 124 | |
| 125 | if (prefix[0] == '\0' || |
| 126 | !strcmp(prefix, "/")) |
| 127 | return; |
| 128 | |
| 129 | if (prefix[0] != '/') { |
| 130 | char *cwd = get_current_dir_name(); |
| 131 | if (!cwd) |
| 132 | abort(); |
| 133 | strcpy(pref_buf, cwd); |
| 134 | strcat(pref_buf, "/"); |
| 135 | strcat(pref_buf, prefix); |
| 136 | free(cwd); |
| 137 | } else |
| 138 | strcpy(pref_buf,prefix + 1); |
| 139 | |
| 140 | base = new_entry("", NULL, pref_buf); |
| 141 | base = add_dir_maybe(base); |
| 142 | if (base->num_entries == 0) { |
| 143 | free (base); |
| 144 | base = NULL; |
| 145 | } else { |
| 146 | set_parents(base, base); |
| 147 | } |
| 148 | } |
| 149 | |
bellard | 32ce633 | 2003-04-11 00:16:16 +0000 | [diff] [blame] | 150 | /* Look for path in emulation dir, otherwise return name. */ |
| 151 | const char *path(const char *name) |
| 152 | { |
| 153 | /* Only do absolute paths: quick and dirty, but should mostly be OK. |
| 154 | Could do relative by tracking cwd. */ |
| 155 | if (!base || name[0] != '/') |
| 156 | return name; |
| 157 | |
| 158 | return follow_path(base, name) ?: name; |
| 159 | } |