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Diffstat (limited to 'contrib/libarchive/contrib/shar/tree.c')
| -rw-r--r-- | contrib/libarchive/contrib/shar/tree.c | 542 |
1 files changed, 542 insertions, 0 deletions
diff --git a/contrib/libarchive/contrib/shar/tree.c b/contrib/libarchive/contrib/shar/tree.c new file mode 100644 index 0000000..d5a04ab --- /dev/null +++ b/contrib/libarchive/contrib/shar/tree.c @@ -0,0 +1,542 @@ +/*- + * Copyright (c) 2003-2007 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. + * 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. + */ + +/*- + * This is a new directory-walking system that addresses a number + * of problems I've had with fts(3). In particular, it has no + * pathname-length limits (other than the size of 'int'), handles + * deep logical traversals, uses considerably less memory, and has + * an opaque interface (easier to modify in the future). + * + * Internally, it keeps 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 "tree_config.h" +__FBSDID("$FreeBSD$"); + +#ifdef HAVE_SYS_STAT_H +#include <sys/stat.h> +#endif +#ifdef HAVE_DIRENT_H +#include <dirent.h> +#endif +#ifdef HAVE_ERRNO_H +#include <errno.h> +#endif +#ifdef HAVE_FCNTL_H +#include <fcntl.h> +#endif +#ifdef HAVE_STDLIB_H +#include <stdlib.h> +#endif +#ifdef HAVE_STRING_H +#include <string.h> +#endif +#ifdef HAVE_UNISTD_H +#include <unistd.h> +#endif + +#include "tree.h" + +/* + * TODO: + * 1) Loop checking. + * 3) Arbitrary logical traversals by closing/reopening intermediate fds. + */ + +struct tree_entry { + struct tree_entry *next; + struct tree_entry *parent; + char *name; + size_t dirname_length; + dev_t dev; + ino_t ino; + 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 needsPreVisit 4 /* This entry needs to be previsited. */ +#define needsPostVisit 8 /* This entry needs to be postvisited. */ + +/* + * Local data for this package. + */ +struct tree { + struct tree_entry *stack; + struct tree_entry *current; + DIR *d; + int initialDirFd; + int flags; + int visit_type; + int tree_errno; /* Error code from last failed operation. */ + + char *buff; + const 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. */ + + +#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 +#include <stdio.h> +void +tree_dump(struct tree *t, FILE *out) +{ + struct tree_entry *te; + + fprintf(out, "\tdepth: %d\n", t->depth); + fprintf(out, "\tbuff: %s\n", t->buff); + fprintf(out, "\tpwd: "); fflush(stdout); system("pwd"); + fprintf(out, "\taccess: %s\n", t->basename); + fprintf(out, "\tstack:\n"); + for (te = t->stack; te != NULL; te = te->next) { + fprintf(out, "\t\tte->name: %s%s%s\n", te->name, + te->flags & needsPreVisit ? "" : " *", + t->current == te ? " (current)" : ""); + } +} +#endif + +/* + * Add a directory path to the current stack. + */ +static void +tree_push(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 = needsPreVisit | needsPostVisit; + 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) +{ + char *p; + + if (t->buff != NULL) + t->buff[t->dirname_length] = '\0'; + /* Strip trailing '/' from name, unless entire name is "/". */ + while (name_length > 1 && name[name_length - 1] == '/') + name_length--; + + /* 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); + } + p = t->buff + t->dirname_length; + t->path_length = t->dirname_length + name_length; + /* Add a separating '/' if it's needed. */ + if (t->dirname_length > 0 && p[-1] != '/') { + *p++ = '/'; + t->path_length ++; + } + strncpy(p, name, name_length); + p[name_length] = '\0'; + t->basename = p; +} + +/* + * 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; + + t->buff[t->dirname_length] = '\0'; + if (t->stack == t->current && t->current != NULL) + t->current = t->current->parent; + te = t->stack; + t->stack = te->next; + t->dirname_length = te->dirname_length; + t->basename = t->buff + t->dirname_length; + /* Special case: starting dir doesn't skip leading '/'. */ + if (t->dirname_length > 0) + t->basename++; + 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 (t->visit_type = TREE_REGULAR); + } + + 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 (t->visit_type = TREE_REGULAR); + } + } + + /* If the current dir needs to be visited, set it up. */ + if (t->stack->flags & needsPreVisit) { + t->current = t->stack; + tree_append(t, t->stack->name, strlen(t->stack->name)); + t->stack->flags &= ~needsPreVisit; + /* 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; + } + t->dirname_length = t->path_length; + if (chdir(t->stack->name) != 0) { + /* chdir() failed; return error */ + tree_pop(t); + t->tree_errno = errno; + return (t->visit_type = TREE_ERROR_DIR); + } + t->depth++; + t->d = opendir("."); + if (t->d == NULL) { + tree_ascend(t); /* Undo "chdir" */ + tree_pop(t); + t->tree_errno = errno; + return (t->visit_type = TREE_ERROR_DIR); + } + t->flags &= ~hasLstat; + t->flags &= ~hasStat; + t->basename = "."; + return (t->visit_type = TREE_POSTDESCENT); + } + + /* We've done everything necessary for the top stack entry. */ + if (t->stack->flags & needsPostVisit) { + tree_ascend(t); + tree_pop(t); + t->flags &= ~hasLstat; + t->flags &= ~hasStat; + return (t->visit_type = TREE_POSTASCENT); + } + } + return (t->visit_type = 0); +} + +/* + * Return error code. + */ +int +tree_errno(struct tree *t) +{ + return (t->tree_errno); +} + +/* + * Called by the client to mark the directory just returned from + * tree_next() as needing to be visited. + */ +void +tree_descend(struct tree *t) +{ + if (t->visit_type != TREE_REGULAR) + return; + + if (tree_current_is_physical_dir(t)) { + tree_push(t, t->basename); + t->stack->flags |= isDir; + } else if (tree_current_is_dir(t)) { + tree_push(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)) { + if (stat(t->basename, &t->st) != 0) + return NULL; + 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)) { + if (lstat(t->basename, &t->lst) != 0) + return NULL; + t->flags |= hasLstat; + } + return (&t->lst); +} + +/* + * Test whether current entry is a dir or link to a dir. + */ +int +tree_current_is_dir(struct tree *t) +{ + const struct stat *st; + + /* + * If we already have lstat() info, then try some + * cheap tests to determine if this is a dir. + */ + if (t->flags & hasLstat) { + /* If lstat() says it's a dir, it must be a dir. */ + if (S_ISDIR(tree_current_lstat(t)->st_mode)) + return 1; + /* Not a dir; might be a link to a dir. */ + /* If it's not a link, then it's not a link to a dir. */ + if (!S_ISLNK(tree_current_lstat(t)->st_mode)) + return 0; + /* + * It's a link, but we don't know what it's a link to, + * so we'll have to use stat(). + */ + } + + st = tree_current_stat(t); + /* If we can't stat it, it's not a dir. */ + if (st == NULL) + return 0; + /* Use the definitive test. Hopefully this is cached. */ + return (S_ISDIR(st->st_mode)); +} + +/* + * Test whether current entry is a physical directory. Usually, we + * already have at least one of stat() or lstat() in memory, so we + * use tricks to try to avoid an extra trip to the disk. + */ +int +tree_current_is_physical_dir(struct tree *t) +{ + const struct stat *st; + + /* + * If stat() says it isn't a dir, then it's not a dir. + * If stat() data is cached, this check is free, so do it first. + */ + if ((t->flags & hasStat) + && (!S_ISDIR(tree_current_stat(t)->st_mode))) + return 0; + + /* + * Either stat() said it was a dir (in which case, we have + * to determine whether it's really a link to a dir) or + * stat() info wasn't available. So we use lstat(), which + * hopefully is already cached. + */ + + st = tree_current_lstat(t); + /* If we can't stat it, it's not a dir. */ + if (st == NULL) + return 0; + /* Use the definitive test. Hopefully this is cached. */ + return (S_ISDIR(st->st_mode)); +} + +/* + * Test whether current entry is a symbolic link. + */ +int +tree_current_is_physical_link(struct tree *t) +{ + const struct stat *st = tree_current_lstat(t); + if (st == NULL) + return 0; + return (S_ISLNK(st->st_mode)); +} + +/* + * 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); +} |
