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Diffstat (limited to 'contrib/libarchive/examples/minitar/tree.c')
-rw-r--r-- | contrib/libarchive/examples/minitar/tree.c | 423 |
1 files changed, 423 insertions, 0 deletions
diff --git a/contrib/libarchive/examples/minitar/tree.c b/contrib/libarchive/examples/minitar/tree.c new file mode 100644 index 0000000..8af0b4d --- /dev/null +++ b/contrib/libarchive/examples/minitar/tree.c @@ -0,0 +1,423 @@ +/*- + * 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 |