+/*
+ * Copyright (c) 1989 The Regents of the University of California.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by the University of California, Berkeley. The name of the
+ * University may not be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+#if defined(LIBC_SCCS) && !defined(lint)
+static char sccsid[] = "@(#)fts.c 5.1 (Berkeley) %G%";
+#endif /* LIBC_SCCS and not lint */
+
+#include <sys/param.h>
+#include <sys/stat.h>
+#include <dirent.h>
+#include <errno.h>
+#include <fts.h>
+#include <strings.h>
+
+extern int errno;
+
+FTSENT *fts_alloc(), *fts_build(), *fts_cycle(), *fts_sort(), *fts_root();
+short fts_stat();
+char *malloc(), *realloc();
+
+/*
+ * Special case a root of "/" so that slashes aren't appended causing
+ * paths to be written as "//foo".
+ */
+#define NAPPEND(p) \
+ (p->level == ROOTLEVEL && p->pathlen == 1 && \
+ p->path[0] == '/' ? 0 : p->pathlen)
+
+#define CHDIR(sp, path) (!(sp->options & FTS_NOCHDIR) && chdir(path))
+
+#define ROOTLEVEL 0
+#define ROOTPARENTLEVEL -1
+
+static FTS *stream; /* current stream pointer */
+
+FTS *
+ftsopen(argv, options, compar)
+ char *argv[];
+ register int options;
+ int (*compar)();
+{
+ register FTS *sp;
+ register FTSENT *p, *root;
+ register int nitems, maxlen;
+ FTSENT *parent, *tmp;
+ char wd[MAXPATHLEN], *getwd(), *strdup();
+
+ /* allocate/initialize the stream */
+ if (!(stream = sp = (FTS *)malloc((u_int)sizeof(FTS))))
+ return(NULL);
+ bzero(sp, sizeof(FTS));
+ sp->compar = compar;
+ sp->options = options;
+
+ /* allocate/initialize root's parent */
+ if (!(parent = fts_alloc("", 0)))
+ goto mem1;
+ parent->level = ROOTPARENTLEVEL;
+
+ /* allocate/initialize root(s) */
+ if (options & FTS_MULTIPLE) {
+ maxlen = -1;
+ for (root = NULL, nitems = 0; *argv; ++argv, ++nitems) {
+ if (!(p = fts_root(*argv)))
+ goto mem2;
+ if (maxlen < p->namelen)
+ maxlen = p->namelen;
+ /*
+ * if comparison routine supplied, traverse in sorted
+ * order; otherwise traverse in the order specified.
+ */
+ if (compar) {
+ p->link = root;
+ root = p;
+ p->accpath = p->name;
+ p->info = fts_stat(p, 0);
+ } else {
+ p->link = NULL;
+ if (!root)
+ tmp = root = p;
+ else {
+ tmp->link = p;
+ tmp = p;
+ }
+ }
+ p->level = ROOTLEVEL;
+ p->parent = parent;
+ }
+ if (compar && nitems > 1)
+ root = fts_sort(root, nitems);
+ } else {
+ if (!(root = fts_root((char *)argv)))
+ goto mem2;
+ maxlen = root->namelen;
+ root->link = NULL;
+ root->level = ROOTLEVEL;
+ root->parent = parent;
+ }
+
+ /* start out with at least 1K+ of path space */
+ if (!fts_path(MAX(maxlen, MAXPATHLEN)))
+ goto mem2;
+
+ /*
+ * some minor trickiness. Set the pointers so that ftsread thinks
+ * we've just finished the node before the root(s); set p->info to
+ * FTS_NS so that everything about the "current" node is ignored.
+ * Rather than allocate a dummy node use the root's parent's link
+ * pointer. This is handled specially in ftsclose() as well.
+ */
+ sp->cur = parent;
+ parent->link = root;
+ parent->info = FTS_NS;
+
+ /*
+ * if using chdir(2), do a getwd() to insure that we can get back
+ * here; this could be avoided for some paths, but probably not
+ * worth the effort. Slashes, symbolic links, and ".." are all
+ * fairly nasty problems. Note, if we can't get the current
+ * working directory we run anyway, just more slowly.
+ */
+ if (!(options & FTS_NOCHDIR) && (!getwd(wd) || !(sp->wd = strdup(wd))))
+ sp->options |= FTS_NOCHDIR;
+
+ return(sp);
+
+mem2: fts_lfree(root);
+ (void)free((char *)parent);
+mem1: (void)free((char *)sp);
+ return(NULL);
+}
+
+static
+fts_load(p)
+ register FTSENT *p;
+{
+ register int len;
+ register char *cp;
+
+ /*
+ * load the stream structure for the next traversal; set the
+ * accpath field specially so the chdir gets done to the right
+ * place and the user can access the first node.
+ */
+ len = p->pathlen = p->namelen;
+ bcopy(p->name, stream->path, len + 1);
+ if ((cp = rindex(p->name, '/')) && (cp != p->name || cp[1])) {
+ len = strlen(++cp);
+ bcopy(cp, p->name, len + 1);
+ p->namelen = len;
+ }
+ p->accpath = p->path = stream->path;
+}
+
+ftsclose(sp)
+ FTS *sp;
+{
+ register FTSENT *freep, *p;
+ int saved_errno;
+
+ if (sp->cur)
+ /* check for never having read anything */
+ if (sp->cur->level == ROOTPARENTLEVEL)
+ fts_lfree(sp->cur);
+ else {
+ for (p = sp->cur; p->level > ROOTPARENTLEVEL;) {
+ freep = p;
+ p = p->link ? p->link : p->parent;
+ (void)free((char *)freep);
+ }
+ (void)free((char *)p);
+ }
+
+ /* free up child linked list, sort array, path buffer */
+ if (sp->child)
+ fts_lfree(sp->child);
+ if (sp->array)
+ (void)free((char *)sp->array);
+ (void)free((char *)sp->path);
+
+ /*
+ * return to original directory, save errno if necessary;
+ * free up the directory buffer
+ */
+ if (!(sp->options & FTS_NOCHDIR)) {
+ saved_errno = chdir(sp->wd) ? errno : 0;
+ (void)free(sp->wd);
+ }
+
+ /* free up the stream pointer */
+ (void)free((char *)sp);
+
+ /* set errno and return */
+ if (!(sp->options & FTS_NOCHDIR) && saved_errno) {
+ errno = saved_errno;
+ return(-1);
+ }
+ return(0);
+}
+
+FTSENT *
+ftsread(sp)
+ register FTS *sp;
+{
+ register FTSENT *p;
+ register int instr;
+ static int cd;
+ FTSENT *tmp;
+ char *cp;
+
+ /* if finished or unrecoverable error, return NULL */
+ if (!sp->cur || sp->options & FTS__STOP)
+ return(NULL);
+
+ /* set global stream pointer, and current node pointer */
+ stream = sp;
+ p = sp->cur;
+
+ /* save and zero out user instructions */
+ instr = p->instr;
+ p->instr = 0;
+
+ /* if used link pointer for cycle detection, restore it */
+ if (sp->savelink) {
+ p->link = sp->savelink;
+ sp->savelink = NULL;
+ }
+
+ /* any type of file may be re-visited; re-stat and return */
+ if (instr == FTS_AGAIN) {
+ p->info = fts_stat(p, 0);
+ return(p);
+ }
+
+ if (p->info == FTS_D)
+ if (instr == FTS_SKIP) {
+ if (sp->child) {
+ fts_lfree(sp->child);
+ sp->child = NULL;
+ }
+ } else {
+ if (sp->child) {
+ /* cd into child directory */
+ if (CHDIR(sp, p->accpath)) {
+ sp->options |= FTS__STOP;
+ p->info = FTS_ERR;
+ return(p);
+ }
+ } else if (!(sp->child = fts_build(sp, 1)))
+ return(p);
+ p = sp->child;
+ sp->child = NULL;
+ cp = sp->path + NAPPEND(p->parent);
+ *cp++ = '/';
+ bcopy(p->name, cp, p->namelen + 1);
+ return(sp->cur = p);
+ }
+ else if (p->info == FTS_SL && instr == FTS_FOLLOW) {
+ p->info = fts_stat(p, 1);
+ return(p);
+ }
+
+ /*
+ * user may have called ftsset on pointer returned by
+ * ftschildren; handle it here.
+ */
+ for (p = p->link; p;) {
+ instr = p->instr;
+ if (instr == FTS_FOLLOW) {
+ p->info = fts_stat(p, 1);
+ p->instr = 0;
+ break;
+ }
+ if (instr == FTS_SKIP) {
+ tmp = p;
+ p = p->link;
+ (void)free((char *)tmp);
+ continue;
+ }
+ p->instr = 0;
+ break;
+ }
+
+ /* go to next node on this level */
+ if (p) {
+ /*
+ * if root level node, set up paths and return. If not the
+ * first time, and it's not an absolute pathname, get back
+ * to wherever we started from.
+ */
+ if (p->level == ROOTLEVEL) {
+ fts_load(p);
+ if (cd) {
+ (void)free((char *)sp->cur);
+ if (p->path[0] != '/' && CHDIR(sp, sp->wd)) {
+ /* return target path for error msg */
+ p->path = sp->wd;
+ p->info = FTS_ERR;
+ sp->options |= FTS__STOP;
+ return(sp->cur = p);
+ }
+ } else
+ cd = 1;
+ p->info = fts_stat(p, 0);
+ } else {
+ (void)free((char *)sp->cur);
+ cp = sp->path + NAPPEND(p->parent);
+ *cp++ = '/';
+ bcopy(p->name, cp, p->namelen + 1);
+ if (p->info == FTS_D && (tmp = fts_cycle(p))) {
+ sp->savelink = p->link;
+ p->link = tmp;
+ }
+ }
+ return(sp->cur = p);
+ }
+
+ /* go to parent */
+ p = sp->cur->parent;
+ (void)free((char *)sp->cur);
+ if (p->level == ROOTPARENTLEVEL) {
+ /*
+ * done; free everything up and set errno to 0 so the user
+ * can distinguish between error and EOF.
+ */
+ (void)free((char *)p);
+ errno = 0;
+ return(sp->cur = NULL);
+ }
+
+ sp->path[p->pathlen] = '\0';
+ if (CHDIR(sp, "..")) {
+ sp->options |= FTS__STOP;
+ p->info = FTS_ERR;
+ } else
+ p->info = FTS_DP;
+ return(sp->cur = p);
+}
+
+/*
+ * ftsset takes the stream as an argument although it's not used in this
+ * implementation; it would be necessary if anyone wanted to add global
+ * semantics to fts using ftsset. A possible error return is allowed for
+ * similar reasons.
+ */
+/* ARGSUSED */
+ftsset(sp, p, instr)
+ FTS *sp;
+ FTSENT *p;
+ int instr;
+{
+ p->instr = instr;
+ return(0);
+}
+
+FTSENT *
+ftschildren(sp)
+ register FTS *sp;
+{
+ /*
+ * set errno to 0 so that user can tell the difference between an
+ * error and a directory without entries.
+ */
+ errno = 0;
+ if (sp->cur->info != FTS_D || sp->options & FTS__STOP)
+ return(NULL);
+ if (sp->child)
+ fts_lfree(sp->child);
+ if (sp->child = fts_build(sp, 0)) {
+ /*
+ * have to cd up so that the fields of the current node
+ * as returned from readfts will be correct.
+ */
+ if (CHDIR(sp, "..")) {
+ sp->options |= FTS__STOP;
+ return(NULL);
+ }
+ }
+ return(sp->child);
+}
+
+#define ISDOT(a) (a[0] == '.' && (!a[1] || a[1] == '.' && !a[2]))
+
+static FTSENT *
+fts_build(sp, set_node_errors)
+ register FTS *sp;
+ int set_node_errors;
+{
+ register struct dirent *dp;
+ register FTSENT *p, *head;
+ register int nitems;
+ DIR *dirp;
+ int len, level, maxlen, nlinks, saved_errno;
+ char *cp;
+
+ p = sp->cur;
+ if (!(dirp = opendir(p->accpath))) {
+ if (set_node_errors) {
+ errno = 0;
+ p->info = FTS_DNR;
+ }
+ return(NULL);
+ }
+ if (CHDIR(sp, p->accpath)) {
+ if (set_node_errors) {
+ errno = 0;
+ p->info = FTS_DNX;
+ }
+ return(NULL);
+ }
+
+ /*
+ * the real slowdown in walking the tree is the stat calls. If
+ * FTS_NOSTAT is set and it's a physical walk (so that symbolic
+ * links can't be directories), fts assumes that the number of
+ * subdirectories in a node is equal to the number of links to
+ * the parent. This allows stat calls to be skipped in any leaf
+ * directories and for any nodes after the directories in the
+ * parent node have been found. This empirically cuts the stat
+ * calls by about 2/3.
+ */
+ nlinks = sp->options & FTS_NOSTAT && sp->options & FTS_PHYSICAL ?
+ p->statb.st_nlink - (sp->options & FTS_SEEDOT ? 0 : 2) : -1;
+
+ /* get max file name length that can be stored in current path */
+ maxlen = sp->pathlen - p->pathlen - 1;
+
+ cp = sp->path + (len = NAPPEND(p));
+ *cp++ = '/';
+
+ level = p->level + 1;
+
+ /* read the directory, attching each new entry to the `link' pointer */
+ for (head = NULL, nitems = 0; dp = readdir(dirp);) {
+ if (ISDOT(dp->d_name) && !(sp->options & FTS_SEEDOT))
+ continue;
+
+ if (!(p = fts_alloc(dp->d_name, dp->d_namlen))) {
+ saved_errno = errno;
+ goto mem1;
+ }
+ if (dp->d_namlen > maxlen) {
+ if (!fts_path((int)dp->d_namlen)) {
+ /* quit: this stream no longer has a path */
+ sp->options |= FTS__STOP;
+ saved_errno = errno;
+ (void)free((char *)p);
+mem1: fts_lfree(head);
+ if (set_node_errors)
+ p->info = FTS_ERR;
+ if (CHDIR(sp, "..")) {
+ saved_errno = errno;
+ sp->options |= FTS__STOP;
+ }
+ errno = saved_errno;
+ return(NULL);
+ }
+ maxlen = sp->pathlen - sp->cur->pathlen - 1;
+ }
+
+ p->pathlen = len + dp->d_namlen + 1;
+ p->accpath = sp->options & FTS_NOCHDIR ? p->path : p->name;
+
+ p->parent = sp->cur;
+ p->level = level;
+
+ if (nlinks) {
+ /* make sure fts_stat has a filename to stat */
+ if (sp->options & FTS_NOCHDIR)
+ bcopy(p->name, cp, p->namelen + 1);
+ p->info = fts_stat(p, 0);
+ if (nlinks > 0 && (p->info == FTS_D ||
+ p->info == FTS_DNR || p->info == FTS_DNX))
+ --nlinks;
+ } else
+ p->info = FTS_NS;
+
+ p->link = head;
+ head = p;
+ ++nitems;
+ }
+ (void)closedir(dirp);
+
+ if (!nitems) {
+ if (CHDIR(sp, "..")) {
+ sp->options |= FTS__STOP;
+ p->info = FTS_ERR;
+ } else if (set_node_errors)
+ p->info = FTS_DP;
+ *--cp = '\0';
+ return(NULL);
+ }
+
+ if (sp->compar && nitems > 1)
+ head = fts_sort(head, nitems);
+
+ if (set_node_errors)
+ bcopy(head->name, cp, head->namelen + 1);
+ else
+ *--cp = '\0';
+ return(head);
+}
+
+static short
+fts_stat(p, symflag)
+ register FTSENT *p;
+ int symflag;
+{
+ register int ngroups, *gp;
+ int gidset[NGROUPS];
+
+ /*
+ * detection of symbolic links w/o targets. If FTS_FOLLOW is set,
+ * the symlink structure is overwritten with the stat structure of
+ * the target.
+ */
+ if (stream->options & FTS_LOGICAL || symflag) {
+ if (stat(p->accpath, &p->statb))
+ return(symflag || !lstat(p->accpath, &p->statb) ?
+ FTS_SLNONE : FTS_ERR);
+ } else if (lstat(p->accpath, &p->statb))
+ return(FTS_ERR);
+
+ switch(p->statb.st_mode&S_IFMT) {
+ case S_IFDIR:
+ /* get new uid/groups each time, they may have changed */
+ if (getuid() == p->statb.st_uid) {
+ if (!(p->statb.st_mode&S_IRUSR))
+ return(FTS_DNR);
+ if (!(p->statb.st_mode&S_IXUSR))
+ return(FTS_DNX);
+ return(FTS_D);
+ }
+ if ((ngroups = getgroups(NGROUPS, gidset)) == -1)
+ return(FTS_ERR);
+ for (gp = gidset; ngroups--;)
+ if (*gp++ == p->statb.st_gid) {
+ if (!(p->statb.st_mode&S_IRGRP))
+ return(FTS_DNR);
+ if (!(p->statb.st_mode&S_IXGRP))
+ return(FTS_DNX);
+ return(FTS_D);
+ }
+ if (!(p->statb.st_mode&S_IROTH))
+ return(FTS_DNR);
+ if (!(p->statb.st_mode&S_IXOTH))
+ return(FTS_DNX);
+ return(FTS_D);
+ case S_IFLNK:
+ return(FTS_SL);
+ case S_IFREG:
+ return(FTS_F);
+ default:
+ return(FTS_DEFAULT);
+ }
+ /* NOTREACHED */
+}
+
+static FTSENT *
+fts_cycle(p)
+ register FTSENT *p;
+{
+ register dev_t dev;
+ register ino_t ino;
+
+ /*
+ * cycle detection is brute force; if the tree gets deep enough or
+ * the number of symbolic links to directories is really high
+ * something faster might be worthwhile.
+ */
+ dev = p->statb.st_dev;
+ ino = p->statb.st_ino;
+ for (p = p->parent; p->level > ROOTLEVEL; p = p->parent)
+ if (ino == p->statb.st_ino && dev == p->statb.st_dev)
+ return(p);
+ return(NULL);
+}
+
+#define R(type, nelem, ptr) \
+ (type *)realloc((char *)ptr, (u_int)((nelem) * sizeof(type)))
+
+static FTSENT *
+fts_sort(head, nitems)
+ FTSENT *head;
+ register int nitems;
+{
+ register FTSENT **ap, *p;
+
+ /*
+ * construct an array of pointers to the structures and call qsort(3).
+ * Reassemble the array in the order returned by qsort. If unable to
+ * sort for memory reasons, return the directory entries in their
+ * current order. Allocate enough space for the current needs plus
+ * 40 so we don't realloc one entry at a time.
+ */
+ if (nitems > stream->nitems) {
+ stream->nitems = nitems + 40;
+ if (!(stream->array =
+ R(FTSENT *, stream->nitems, stream->array))) {
+ stream->nitems = 0;
+ return(head);
+ }
+ }
+ for (ap = stream->array, p = head; p; p = p->link)
+ *ap++ = p;
+ qsort((char *)stream->array, nitems, sizeof(FTSENT *), stream->compar);
+ for (head = *(ap = stream->array); --nitems; ++ap)
+ ap[0]->link = ap[1];
+ ap[0]->link = NULL;
+ return(head);
+}
+
+static FTSENT *
+fts_alloc(name, len)
+ char *name;
+ register int len;
+{
+ register FTSENT *p;
+
+ /*
+ * variable sized structures; the name is the last element so
+ * allocate enough extra space after the structure to hold it.
+ */
+ if (!(p = (FTSENT *)malloc((u_int)(sizeof(FTSENT) + len))))
+ return(NULL);
+ bcopy(name, p->name, len + 1);
+ p->namelen = len;
+ p->path = stream->path;
+ p->instr = 0;
+ p->local.number = 0;
+ p->local.pointer = NULL;
+ return(p);
+}
+
+static
+fts_lfree(head)
+ register FTSENT *head;
+{
+ register FTSENT *p;
+
+ while (p = head) {
+ head = head->link;
+ (void)free((char *)p);
+ }
+}
+
+/*
+ * allow essentially unlimited paths; certain programs (find, remove, ls)
+ * need to work on any tree. Most systems will allow creation of paths
+ * much longer than MAXPATHLEN, even though the kernel won't resolve them.
+ * Add an extra 128 bytes to the requested size so that we don't realloc
+ * the path 2 bytes at a time.
+ */
+static
+fts_path(size)
+ int size;
+{
+ stream->pathlen += size + 128;
+ return((int)(stream->path = R(char, stream->pathlen, stream->path)));
+}
+
+static FTSENT *
+fts_root(name)
+ register char *name;
+{
+ register char *cp;
+
+ /*
+ * rip trailing slashes; it's somewhat unclear in POSIX 1003.1 what
+ * /a/b/ really is, they don't talk about what a null path component
+ * resolves to. This hopefully does what the user intended. Don't
+ * allow null pathnames.
+ */
+ for (cp = name; *cp; ++cp);
+ if (cp == name) {
+ errno = ENOENT;
+ return(NULL);
+ }
+ while (--cp > name && *cp == '/');
+ *++cp = '\0';
+ return(fts_alloc(name, cp - name));
+}
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