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-rw-r--r--Utilities/cmlibarchive/examples/minitar/tree.c423
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diff --git a/Utilities/cmlibarchive/examples/minitar/tree.c b/Utilities/cmlibarchive/examples/minitar/tree.c
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+/*-
+ * Copyright (c) 2003-2004 Tim Kientzle
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer
+ * in this position and unchanged.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*-
+ * There is a single list of "tree_entry" items that represent
+ * filesystem objects that require further attention. Non-directories
+ * are not kept in memory: they are pulled from readdir(), returned to
+ * the client, then freed as soon as possible. Any directory entry to
+ * be traversed gets pushed onto the stack.
+ *
+ * There is surprisingly little information that needs to be kept for
+ * each item on the stack. Just the name, depth (represented here as the
+ * string length of the parent directory's pathname), and some markers
+ * indicating how to get back to the parent (via chdir("..") for a
+ * regular dir or via fchdir(2) for a symlink).
+ */
+
+#include <sys/stat.h>
+#include <dirent.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "tree.h"
+
+/*
+ * TODO:
+ * 1) Loop checking.
+ * 3) Arbitrary logical traversals by closing/reopening intermediate fds.
+ */
+
+struct tree_entry {
+ struct tree_entry *next;
+ char *name;
+ size_t dirname_length;
+ int fd;
+ int flags;
+};
+
+/* Definitions for tree_entry.flags bitmap. */
+#define isDir 1 /* This entry is a regular directory. */
+#define isDirLink 2 /* This entry is a symbolic link to a directory. */
+#define needsTraversal 4 /* This entry hasn't yet been traversed. */
+
+/*
+ * Local data for this package.
+ */
+struct tree {
+ struct tree_entry *stack;
+ DIR *d;
+ int initialDirFd;
+ int flags;
+
+ char *buff;
+ char *basename;
+ size_t buff_length;
+ size_t path_length;
+ size_t dirname_length;
+
+ int depth;
+ int openCount;
+ int maxOpenCount;
+
+ struct stat lst;
+ struct stat st;
+};
+
+/* Definitions for tree.flags bitmap. */
+#define needsReturn 8 /* Marks first entry as not having been returned yet. */
+#define hasStat 16 /* The st entry is set. */
+#define hasLstat 32 /* The lst entry is set. */
+
+
+#define HAVE_DIRENT_D_NAMLEN 1
+#ifdef HAVE_DIRENT_D_NAMLEN
+/* BSD extension; avoids need for a strlen() call. */
+#define D_NAMELEN(dp) (dp)->d_namlen
+#else
+#define D_NAMELEN(dp) (strlen((dp)->d_name))
+#endif
+
+#if 0
+static void
+dumpStack(struct tree *t)
+{
+ struct tree_entry *te;
+
+ printf("\tbuff: %s\n", t->buff);
+ printf("\tpwd: "); fflush(stdout); system("pwd");
+ printf("\tstack:\n");
+ for (te = t->stack; te != NULL; te = te->next) {
+ printf("\t\tte->name: %s %s\n", te->name, te->flags & needsTraversal ? "" : "*");
+ }
+}
+#endif
+
+/*
+ * Add a directory path to the current stack.
+ */
+static void
+tree_add(struct tree *t, const char *path)
+{
+ struct tree_entry *te;
+
+ te = malloc(sizeof(*te));
+ memset(te, 0, sizeof(*te));
+ te->next = t->stack;
+ t->stack = te;
+ te->fd = -1;
+ te->name = strdup(path);
+ te->flags = needsTraversal;
+ te->dirname_length = t->dirname_length;
+}
+
+/*
+ * Append a name to the current path.
+ */
+static void
+tree_append(struct tree *t, const char *name, size_t name_length)
+{
+ if (t->buff != NULL)
+ t->buff[t->dirname_length] = '\0';
+
+ /* Resize pathname buffer as needed. */
+ while (name_length + 1 + t->dirname_length >= t->buff_length) {
+ t->buff_length *= 2;
+ if (t->buff_length < 1024)
+ t->buff_length = 1024;
+ t->buff = realloc(t->buff, t->buff_length);
+ }
+ t->basename = t->buff + t->dirname_length;
+ t->path_length = t->dirname_length + name_length;
+ if (t->dirname_length > 0) {
+ *t->basename++ = '/';
+ t->path_length ++;
+ }
+ strcpy(t->basename, name);
+}
+
+/*
+ * Open a directory tree for traversal.
+ */
+struct tree *
+tree_open(const char *path)
+{
+ struct tree *t;
+
+ t = malloc(sizeof(*t));
+ memset(t, 0, sizeof(*t));
+ tree_append(t, path, strlen(path));
+ t->initialDirFd = open(".", O_RDONLY);
+ /*
+ * During most of the traversal, items are set up and then
+ * returned immediately from tree_next(). That doesn't work
+ * for the very first entry, so we set a flag for this special
+ * case.
+ */
+ t->flags = needsReturn;
+ return (t);
+}
+
+/*
+ * We've finished a directory; ascend back to the parent.
+ */
+static void
+tree_ascend(struct tree *t)
+{
+ struct tree_entry *te;
+
+ te = t->stack;
+ t->depth--;
+ if (te->flags & isDirLink) {
+ fchdir(te->fd);
+ close(te->fd);
+ t->openCount--;
+ } else {
+ chdir("..");
+ }
+}
+
+/*
+ * Pop the working stack.
+ */
+static void
+tree_pop(struct tree *t)
+{
+ struct tree_entry *te;
+
+ te = t->stack;
+ t->stack = te->next;
+ t->dirname_length = te->dirname_length;
+ free(te->name);
+ free(te);
+}
+
+/*
+ * Get the next item in the tree traversal.
+ */
+int
+tree_next(struct tree *t)
+{
+ struct dirent *de = NULL;
+
+ /* Handle the startup case by returning the initial entry. */
+ if (t->flags & needsReturn) {
+ t->flags &= ~needsReturn;
+ return (1);
+ }
+
+ while (t->stack != NULL) {
+ /* If there's an open dir, get the next entry from there. */
+ while (t->d != NULL) {
+ de = readdir(t->d);
+ if (de == NULL) {
+ closedir(t->d);
+ t->d = NULL;
+ } else if (de->d_name[0] == '.'
+ && de->d_name[1] == '\0') {
+ /* Skip '.' */
+ } else if (de->d_name[0] == '.'
+ && de->d_name[1] == '.'
+ && de->d_name[2] == '\0') {
+ /* Skip '..' */
+ } else {
+ /*
+ * Append the path to the current path
+ * and return it.
+ */
+ tree_append(t, de->d_name, D_NAMELEN(de));
+ t->flags &= ~hasLstat;
+ t->flags &= ~hasStat;
+ return (1);
+ }
+ }
+
+ /* If the current dir needs to be traversed, set it up. */
+ if (t->stack->flags & needsTraversal) {
+ tree_append(t, t->stack->name, strlen(t->stack->name));
+ t->stack->flags &= ~needsTraversal;
+ /* If it is a link, set up fd for the ascent. */
+ if (t->stack->flags & isDirLink) {
+ t->stack->fd = open(".", O_RDONLY);
+ t->openCount++;
+ if (t->openCount > t->maxOpenCount)
+ t->maxOpenCount = t->openCount;
+ }
+ if (chdir(t->stack->name) == 0) {
+ t->depth++;
+ t->dirname_length = t->path_length;
+ t->d = opendir(".");
+ } else
+ tree_pop(t);
+ continue;
+ }
+
+ /* We've done everything necessary for the top stack entry. */
+ tree_ascend(t);
+ tree_pop(t);
+ }
+ return (0);
+}
+
+/*
+ * Called by the client to mark the directory just returned from
+ * tree_next() as needing to be visited.
+ */
+void
+tree_descend(struct tree *t)
+{
+ const struct stat *s = tree_current_lstat(t);
+
+ if (S_ISDIR(s->st_mode)) {
+ tree_add(t, t->basename);
+ t->stack->flags |= isDir;
+ }
+
+ if (S_ISLNK(s->st_mode) && S_ISDIR(tree_current_stat(t)->st_mode)) {
+ tree_add(t, t->basename);
+ t->stack->flags |= isDirLink;
+ }
+}
+
+/*
+ * Get the stat() data for the entry just returned from tree_next().
+ */
+const struct stat *
+tree_current_stat(struct tree *t)
+{
+ if (!(t->flags & hasStat)) {
+ stat(t->basename, &t->st);
+ t->flags |= hasStat;
+ }
+ return (&t->st);
+}
+
+/*
+ * Get the lstat() data for the entry just returned from tree_next().
+ */
+const struct stat *
+tree_current_lstat(struct tree *t)
+{
+ if (!(t->flags & hasLstat)) {
+ lstat(t->basename, &t->lst);
+ t->flags |= hasLstat;
+ }
+ return (&t->lst);
+}
+
+/*
+ * Return the access path for the entry just returned from tree_next().
+ */
+const char *
+tree_current_access_path(struct tree *t)
+{
+ return (t->basename);
+}
+
+/*
+ * Return the full path for the entry just returned from tree_next().
+ */
+const char *
+tree_current_path(struct tree *t)
+{
+ return (t->buff);
+}
+
+/*
+ * Return the length of the path for the entry just returned from tree_next().
+ */
+size_t
+tree_current_pathlen(struct tree *t)
+{
+ return (t->path_length);
+}
+
+/*
+ * Return the nesting depth of the entry just returned from tree_next().
+ */
+int
+tree_current_depth(struct tree *t)
+{
+ return (t->depth);
+}
+
+/*
+ * Terminate the traversal and release any resources.
+ */
+void
+tree_close(struct tree *t)
+{
+ /* Release anything remaining in the stack. */
+ while (t->stack != NULL)
+ tree_pop(t);
+ if (t->buff)
+ free(t->buff);
+ /* chdir() back to where we started. */
+ if (t->initialDirFd >= 0) {
+ fchdir(t->initialDirFd);
+ close(t->initialDirFd);
+ t->initialDirFd = -1;
+ }
+ free(t);
+}
+
+
+#if 0
+/* Main function for testing. */
+#include <stdio.h>
+
+int main(int argc, char **argv)
+{
+ size_t max_path_len = 0;
+ int max_depth = 0;
+
+ system("pwd");
+ while (*++argv) {
+ struct tree *t = tree_open(*argv);
+ while (tree_next(t)) {
+ size_t path_len = tree_current_pathlen(t);
+ int depth = tree_current_depth(t);
+ if (path_len > max_path_len)
+ max_path_len = path_len;
+ if (depth > max_depth)
+ max_depth = depth;
+ printf("%s\n", tree_current_path(t));
+ if (S_ISDIR(tree_current_lstat(t)->st_mode))
+ tree_descend(t); /* Descend into every dir. */
+ }
+ tree_close(t);
+ printf("Max path length: %d\n", max_path_len);
+ printf("Max depth: %d\n", max_depth);
+ printf("Final open count: %d\n", t->openCount);
+ printf("Max open count: %d\n", t->maxOpenCount);
+ fflush(stdout);
+ system("pwd");
+ }
+ return (0);
+}
+#endif
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