1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
|
/* dirtree.c - Functions for dealing with directory trees.
*
* Copyright 2007 Rob Landley <rob@landley.net>
*/
#include "toys.h"
static int notdotdot(char *name)
{
if (name[0]=='.' && (!name[1] || (name[1]=='.' && !name[2]))) return 0;
return 1;
}
// Default callback, filters out "." and "..".
int dirtree_notdotdot(struct dirtree *catch)
{
// Should we skip "." and ".."?
return notdotdot(catch->name) ? DIRTREE_SAVE|DIRTREE_RECURSE : 0;
}
// Create a dirtree node from a path, with stat and symlink info.
// (This doesn't open directory filehandles yet so as not to exhaust the
// filehandle space on large trees, dirtree_handle_callback() does that.)
struct dirtree *dirtree_add_node(struct dirtree *parent, char *name,
int symfollow)
{
struct dirtree *dt = NULL;
struct stat st;
char buf[4096];
int len = 0, linklen = 0;
if (name) {
// open code this because haven't got node to call dirtree_parentfd() on yet
int fd = parent ? parent->data : AT_FDCWD;
if (fstatat(fd, name, &st, symfollow ? 0 : AT_SYMLINK_NOFOLLOW)) goto error;
if (S_ISLNK(st.st_mode)) {
if (0>(linklen = readlinkat(fd, name, buf, 4095))) goto error;
buf[linklen++]=0;
}
len = strlen(name);
}
dt = xzalloc((len = sizeof(struct dirtree)+len+1)+linklen);
dt->parent = parent;
if (name) {
memcpy(&(dt->st), &st, sizeof(struct stat));
strcpy(dt->name, name);
if (linklen) {
dt->symlink = memcpy(len+(char *)dt, buf, linklen);
dt->data = --linklen;
}
}
return dt;
error:
if (notdotdot(name)) {
char *path = parent ? dirtree_path(parent, 0) : "";
perror_msg("%s%s%s",path, parent ? "/" : "", name);
}
if (parent) parent->symlink = (char *)1;
free(dt);
return 0;
}
// Return path to this node, assembled recursively.
char *dirtree_path(struct dirtree *node, int *plen)
{
char *path;
int len;
if (!node || !node->name) {
path = xmalloc(*plen);
*plen = 0;
return path;
}
len = (plen ? *plen : 0)+strlen(node->name)+1;
path = dirtree_path(node->parent, &len);
if (len && path[len-1] != '/') path[len++]='/';
len = (stpcpy(path+len, node->name) - path);
if (plen) *plen = len;
return path;
}
int dirtree_parentfd(struct dirtree *node)
{
return node->parent ? node->parent->data : AT_FDCWD;
}
// Handle callback for a node in the tree. Returns saved node(s) or NULL.
//
// By default, allocates a tree of struct dirtree, not following symlinks
// If callback==NULL, or callback always returns 0, allocate tree of struct
// dirtree and return root of tree. Otherwise call callback(node) on each
// hit, free structures after use, and return NULL.
//
struct dirtree *dirtree_handle_callback(struct dirtree *new,
int (*callback)(struct dirtree *node))
{
int flags, dir = S_ISDIR(new->st.st_mode);
if (!callback) callback = dirtree_notdotdot;
flags = callback(new);
if (dir) {
if (flags & (DIRTREE_RECURSE|DIRTREE_COMEAGAIN)) {
new->data = openat(dirtree_parentfd(new), new->name, 0);
dirtree_recurse(new, callback, flags & DIRTREE_SYMFOLLOW);
if (flags & DIRTREE_COMEAGAIN) flags = callback(new);
}
}
// If this had children, it was callback's job to free them already.
if (!(flags & DIRTREE_SAVE)) {
free(new);
new = NULL;
}
return (flags & DIRTREE_ABORT)==DIRTREE_ABORT ? DIRTREE_ABORTVAL : new;
}
// Recursively read/process children of directory node (with dirfd in data),
// filtering through callback().
void dirtree_recurse(struct dirtree *node,
int (*callback)(struct dirtree *node), int symfollow)
{
struct dirtree *new, **ddt = &(node->child);
struct dirent *entry;
DIR *dir;
if (node->data == -1 || !(dir = fdopendir(node->data))) {
char *path = dirtree_path(node, 0);
perror_msg("No %s", path);
free(path);
close(node->data);
return;
}
// according to the fddir() man page, the filehandle in the DIR * can still
// be externally used by things that don't lseek() it.
// The extra parentheses are to shut the stupid compiler up.
while ((entry = readdir(dir))) {
if (!(new = dirtree_add_node(node, entry->d_name, symfollow)))
continue;
new = dirtree_handle_callback(new, callback);
if (new == DIRTREE_ABORTVAL) break;
if (new) {
*ddt = new;
ddt = &((*ddt)->next);
}
}
// This closes filehandle as well, so note it
closedir(dir);
node->data = -1;
}
// Create dirtree from path, using callback to filter nodes.
// If callback == NULL allocate a tree of struct dirtree nodes and return
// pointer to root node.
// symfollow is just for the top of tree, callback return code controls children
struct dirtree *dirtree_read(char *path, int (*callback)(struct dirtree *node))
{
struct dirtree *root = dirtree_add_node(0, path, 0);
return root ? dirtree_handle_callback(root, callback) : DIRTREE_ABORTVAL;
}
|
