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Diffstat (limited to 'examples/minitar/tree.c')
| -rw-r--r-- | examples/minitar/tree.c | 423 |
1 files changed, 0 insertions, 423 deletions
diff --git a/examples/minitar/tree.c b/examples/minitar/tree.c deleted file mode 100644 index 8af0b4d8..00000000 --- a/examples/minitar/tree.c +++ /dev/null @@ -1,423 +0,0 @@ -/*- - * 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 |