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/* dirtree.c - Functions for dealing with directory trees.
*
* Copyright 2007 Rob Landley <rob@landley.net>
*/
#include "toys.h"
int isdotdot(char *name)
{
if (name[0]=='.' && (!name[1] || (name[1]=='.' && !name[2]))) return 1;
return 0;
}
// Default callback, filters out "." and ".." except at top level.
int dirtree_notdotdot(struct dirtree *catch)
{
// Should we skip "." and ".."?
return (!catch->parent||!isdotdot(catch->name))
*(DIRTREE_SAVE|DIRTREE_RECURSE);
}
// 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 flags)
{
struct dirtree *dt = 0;
struct stat st;
int len = 0, linklen = 0, statless = 0;
if (name) {
// open code fd = because haven't got node to call dirtree_parentfd() on yet
int fd = parent ? parent->dirfd : AT_FDCWD,
sym = AT_SYMLINK_NOFOLLOW*!(flags&DIRTREE_SYMFOLLOW);
// stat dangling symlinks
if (fstatat(fd, name, &st, sym)) {
// If we got ENOENT without NOFOLLOW, try again with NOFOLLOW.
if (errno!=ENOENT || sym || fstatat(fd, name, &st, AT_SYMLINK_NOFOLLOW)) {
if (flags&DIRTREE_STATLESS) statless++;
else goto error;
}
}
if (!statless && S_ISLNK(st.st_mode)) {
if (0>(linklen = readlinkat(fd, name, libbuf, 4095))) goto error;
libbuf[linklen++]=0;
}
len = strlen(name);
}
// Allocate/populate return structure
memset(dt = xmalloc((len = sizeof(struct dirtree)+len+1)+linklen), 0,
statless ? sizeof(struct dirtree) : offsetof(struct dirtree, st));
dt->parent = parent;
dt->again = statless ? 2 : 0;
if (!statless) memcpy(&dt->st, &st, sizeof(struct stat));
if (name) strcpy(dt->name, name);
else *dt->name = 0, dt->st.st_mode = S_IFDIR;
if (linklen) dt->symlink = memcpy(len+(char *)dt, libbuf, linklen);
return dt;
error:
if (!(flags&DIRTREE_SHUTUP) && !isdotdot(name)) {
char *path = parent ? dirtree_path(parent, 0) : "";
perror_msg("%s%s%s", path, parent ? "/" : "", name);
if (parent) free(path);
}
if (parent) parent->symlink = (char *)1;
free(dt);
return 0;
}
// Return path to this node.
// Initial call can pass in NULL to plen, or point to an int initialized to 0
// to return the length of the path, or a value greater than 0 to allocate
// extra space if you want to append your own text to the string.
char *dirtree_path(struct dirtree *node, int *plen)
{
struct dirtree *nn;
char *path;
int ii, ll, len;
ll = len = plen ? *plen : 0;
if (!node->parent)
return strcpy(xmalloc(strlen(node->name)+ll+1), node->name);
for (nn = node; nn; nn = nn->parent)
if ((ii = strlen(nn->name))) len += ii+1-(nn->name[ii-1]=='/');
if (plen) *plen = len;
path = xmalloc(len)+len-ll;
for (nn = node; nn; nn = nn->parent) if ((len = strlen(nn->name))) {
*--path = '/'*(nn != node);
if (nn->name[len-1]=='/') len--;
memcpy(path -= len, nn->name, len);
}
return path;
}
int dirtree_parentfd(struct dirtree *node)
{
return node->parent ? node->parent->dirfd : AT_FDCWD;
}
// Handle callback for a node in the tree. Returns saved node(s) if
// callback returns DIRTREE_SAVE, otherwise frees consumed nodes and
// returns NULL. If !callback return top node unchanged.
// If !new return DIRTREE_ABORTVAL
static struct dirtree *dirtree_handle_callback(struct dirtree *new,
int (*callback)(struct dirtree *node))
{
int flags;
if (!new) return DIRTREE_ABORTVAL;
if (!callback) return new;
flags = callback(new);
if (S_ISDIR(new->st.st_mode) && (flags & (DIRTREE_RECURSE|DIRTREE_COMEAGAIN)))
flags = dirtree_recurse(new, callback, !*new->name ? AT_FDCWD :
openat(dirtree_parentfd(new), new->name, O_CLOEXEC), flags);
// Free node that didn't request saving and has no saved children.
if (!new->child && !(flags & DIRTREE_SAVE)) {
free(new);
new = 0;
}
return (flags & DIRTREE_ABORT)==DIRTREE_ABORT ? DIRTREE_ABORTVAL : new;
}
// Recursively read/process children of directory node, filtering through
// callback(). Uses and closes supplied ->dirfd.
int dirtree_recurse(struct dirtree *node,
int (*callback)(struct dirtree *node), int dirfd, int flags)
{
struct dirtree *new, **ddt = &(node->child);
struct dirent *entry;
DIR *dir = 0;
// Why doesn't fdopendir() support AT_FDCWD?
if (AT_FDCWD == (node->dirfd = dirfd)) dir = opendir(".");
else if (node->dirfd != -1) dir = fdopendir(node->dirfd);
if (!dir) {
if (!(flags & DIRTREE_SHUTUP)) {
char *path = dirtree_path(node, 0);
perror_msg_raw(path);
free(path);
}
close(node->dirfd);
return flags;
}
// according to the fddir() man page, the filehandle in the DIR * can still
// be externally used by things that don't lseek() it.
while ((entry = readdir(dir))) {
if ((flags&DIRTREE_PROC) && !isdigit(*entry->d_name)) continue;
if (!(new = dirtree_add_node(node, entry->d_name, flags))) continue;
if (!new->st.st_blksize && !new->st.st_mode)
new->st.st_mode = entry->d_type<<12;
new = dirtree_handle_callback(new, callback);
if (new == DIRTREE_ABORTVAL) break;
if (new) {
*ddt = new;
ddt = &((*ddt)->next);
}
}
if (flags & DIRTREE_COMEAGAIN) {
node->again |= 1;
flags = callback(node);
}
// This closes filehandle as well, so note it
closedir(dir);
node->dirfd = -1;
return flags;
}
// Create dirtree from path, using callback to filter nodes. If !callback
// return just the top node. Use dirtree_notdotdot callback to allocate a
// tree of struct dirtree nodes and return pointer to root node for later
// processing.
// Returns DIRTREE_ABORTVAL if path didn't exist (use DIRTREE_SHUTUP to handle
// error message yourself).
struct dirtree *dirtree_flagread(char *path, int flags,
int (*callback)(struct dirtree *node))
{
return dirtree_handle_callback(dirtree_add_node(0, path, flags), callback);
}
// Common case
struct dirtree *dirtree_read(char *path, int (*callback)(struct dirtree *node))
{
return dirtree_flagread(path, 0, callback);
}
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