/* 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) free(path); } if (parent) parent->symlink = (char *)1; free(dt); return 0; } // Return path to this node, assembled recursively. // 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) { char *path; int len; if (!node) { 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, O_CLOEXEC); flags = dirtree_recurse(new, callback, flags); } } // 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(). int dirtree_recurse(struct dirtree *node, int (*callback)(struct dirtree *node), int flags) { 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 flags; } // 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, flags&DIRTREE_SYMFOLLOW))) continue; new = dirtree_handle_callback(new, callback); if (new == DIRTREE_ABORTVAL) break; if (new) { *ddt = new; ddt = &((*ddt)->next); } } if (flags & DIRTREE_COMEAGAIN) { node->again++; flags = callback(node); } // This closes filehandle as well, so note it closedir(dir); node->data = -1; return flags; } // 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; }