/*      $NetBSD: walk.c,v 1.24 2008/12/28 21:51:46 christos Exp $       */

/*
 * SPDX-License-Identifier: BSD-4-Clause
 *
 * Copyright (c) 2001 Wasabi Systems, Inc.
 * All rights reserved.
 *
 * Written by Luke Mewburn for Wasabi Systems, Inc.
 *
 * 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed for the NetBSD Project by
 *      Wasabi Systems, Inc.
 * 4. The name of Wasabi Systems, Inc. may not be used to endorse
 *    or promote products derived from this software without specific prior
 *    written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``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 WASABI SYSTEMS, INC
 * 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.
 */

#include <sys/param.h>
#include <sys/stat.h>
#include <sys/time.h>

#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <dirent.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "makefs.h"
#include "mtree.h"
#include "extern.h"

static  void     apply_specdir(const char *, NODE *, fsnode *, int);
static  void     apply_specentry(const char *, NODE *, fsnode *);
static  fsnode  *create_fsnode(const char *, const char *, const char *,
                               struct stat *);

static int
cmp(const void *_a, const void *_b)
{
        const fsnode * const *a = _a;
        const fsnode * const *b = _b;

        assert(strcmp((*a)->name, (*b)->name) != 0);
        if (strcmp((*a)->name, ".") == 0)
                return (-1);
        if (strcmp((*b)->name, ".") == 0)
                return (1);
        return (strcoll((*a)->name, (*b)->name));
}

/*
 * Sort the entries rather than relying on the order given by readdir(3),
 * which might not be reproducible.
 */
static fsnode *
sort_dir(fsnode *list)
{
        fsnode          **array;
        fsnode          *cur;
        size_t          nitems, i;

        nitems = 0;
        for (cur = list; cur != NULL; cur = cur->next)
                nitems++;
        assert(nitems > 0);

        array = malloc(nitems * sizeof(fsnode *));
        if (array == NULL)
                err(1, "malloc");
        for (i = 0, cur = list; cur != NULL; i++, cur = cur->next)
                array[i] = cur;
        qsort(array, nitems, sizeof(fsnode *), cmp);
        for (i = 0; i < nitems; i++) {
                array[i]->first = array[0];
                array[i]->next = i == nitems - 1 ? NULL : array[i + 1];
        }
        cur = array[0];
        free(array);
        return (cur);
}

/*
 * walk_dir --
 *      build a tree of fsnodes from `root' and `dir', with a parent
 *      fsnode of `parent' (which may be NULL for the root of the tree).
 *      append the tree to a fsnode of `join' if it is not NULL.
 *      each "level" is a directory, with the "." entry guaranteed to be
 *      at the start of the list, and without ".." entries.
 */
fsnode *
walk_dir(const char *root, const char *dir, fsnode *parent, fsnode *join)
{
        fsnode          *first, *cur;
        DIR             *dirp;
        struct dirent   *dent;
        char            path[MAXPATHLEN + 1];
        struct stat     stbuf;
        char            *name, *rp;
        size_t          len;
        int             dot;

        assert(root != NULL);
        assert(dir != NULL);

        len = snprintf(path, sizeof(path), "%s/%s", root, dir);
        if (len >= sizeof(path))
                errx(1, "Pathname too long.");
        if (debug & DEBUG_WALK_DIR)
                printf("walk_dir: %s %p\n", path, parent);
        if ((dirp = opendir(path)) == NULL)
                err(1, "Can't opendir `%s'", path);
        rp = path + strlen(root) + 1;
        if (join != NULL) {
                first = cur = join;
                while (cur->next != NULL)
                        cur = cur->next;
        } else
                first = NULL;
        while ((dent = readdir(dirp)) != NULL) {
                name = dent->d_name;
                dot = 0;
                if (name[0] == '.')
                        switch (name[1]) {
                        case '\0':      /* "." */
                                if (join != NULL)
                                        continue;
                                dot = 1;
                                break;
                        case '.':       /* ".." */
                                if (name[2] == '\0')
                                        continue;
                                /* FALLTHROUGH */
                        default:
                                dot = 0;
                        }
                if (debug & DEBUG_WALK_DIR_NODE)
                        printf("scanning %s/%s/%s\n", root, dir, name);
                if ((size_t)snprintf(path + len, sizeof(path) - len, "/%s",
                    name) >= sizeof(path) - len)
                        errx(1, "Pathname too long.");
                if (lstat(path, &stbuf) == -1)
                        err(1, "Can't lstat `%s'", path);
#ifdef S_ISSOCK
                if (S_ISSOCK(stbuf.st_mode & S_IFMT)) {
                        if (debug & DEBUG_WALK_DIR_NODE)
                                printf("  skipping socket %s\n", path);
                        continue;
                }
#endif

                if (join != NULL) {
                        cur = join->next;
                        for (;;) {
                                if (cur == NULL || strcmp(cur->name, name) == 0)
                                        break;
                                cur = cur->next;
                        }
                        if (cur != NULL) {
                                if (S_ISDIR(cur->type) &&
                                    S_ISDIR(stbuf.st_mode)) {
                                        if (debug & DEBUG_WALK_DIR_NODE)
                                                printf("merging %s with %p\n",
                                                    path, cur->child);
                                        cur->child = walk_dir(root, rp, cur,
                                            cur->child);
                                        continue;
                                }
                                errx(1, "Can't merge %s `%s' with existing %s",
                                    inode_type(stbuf.st_mode), path,
                                    inode_type(cur->type));
                        }
                }

                cur = create_fsnode(root, dir, name, &stbuf);
                cur->parent = parent;
                cur->next = first;
                first = cur;
                if (!dot && S_ISDIR(cur->type)) {
                        cur->child = walk_dir(root, rp, cur, NULL);
                        continue;
                }
                if (stbuf.st_nlink > 1) {
                        fsinode *curino;

                        curino = link_check(cur->inode);
                        if (curino != NULL) {
                                free(cur->inode);
                                cur->inode = curino;
                                cur->inode->nlink++;
                                if (debug & DEBUG_WALK_DIR_LINKCHECK)
                                        printf("link_check: found [%llu, %llu]\n",
                                            (unsigned long long)curino->st.st_dev,
                                            (unsigned long long)curino->st.st_ino);
                        }
                }
                if (S_ISLNK(cur->type)) {
                        char    slink[PATH_MAX+1];
                        int     llen;

                        llen = readlink(path, slink, sizeof(slink) - 1);
                        if (llen == -1)
                                err(1, "Readlink `%s'", path);
                        slink[llen] = '\0';
                        cur->symlink = estrdup(slink);
                }
        }
        if (closedir(dirp) == -1)
                err(1, "Can't closedir `%s/%s'", root, dir);
        return (sort_dir(first));
}

static fsnode *
create_fsnode(const char *root, const char *path, const char *name,
    struct stat *stbuf)
{
        fsnode *cur;

        cur = ecalloc(1, sizeof(*cur));
        cur->path = estrdup(path);
        cur->name = estrdup(name);
        cur->inode = ecalloc(1, sizeof(*cur->inode));
        cur->root = root;
        cur->type = stbuf->st_mode & S_IFMT;
        cur->inode->nlink = 1;
        cur->inode->st = *stbuf;
        if (stampst.st_ino != 0)
                set_tstamp(cur);
        return (cur);
}

/*
 * free_fsnodes --
 *      Removes node from tree and frees it and all of
 *   its descendants.
 */
void
free_fsnodes(fsnode *node)
{
        fsnode  *cur, *next;

        assert(node != NULL);

        /* for ".", start with actual parent node */
        if (node->first == node) {
                assert(node->name[0] == '.' && node->name[1] == '\0');
                if (node->parent) {
                        assert(node->parent->child == node);
                        node = node->parent;
                }
        }

        /* Find ourselves in our sibling list and unlink */
        if (node->first != node) {
                for (cur = node->first; cur->next; cur = cur->next) {
                        if (cur->next == node) {
                                cur->next = node->next;
                                node->next = NULL;
                                break;
                        }
                }
        }

        for (cur = node; cur != NULL; cur = next) {
                next = cur->next;
                if (cur->child) {
                        cur->child->parent = NULL;
                        free_fsnodes(cur->child);
                }
                if (cur->inode->nlink-- == 1)
                        free(cur->inode);
                if (cur->symlink)
                        free(cur->symlink);
                free(cur->path);
                free(cur->name);
                free(cur);
        }
}

/*
 * apply_specfile --
 *      read in the mtree(8) specfile, and apply it to the tree
 *      at dir,parent. parameters in parent on equivalent types
 *      will be changed to those found in specfile, and missing
 *      entries will be added.
 */
void
apply_specfile(const char *specfile, const char *dir, fsnode *parent, int speconly)
{
        struct timeval   start;
        FILE    *fp;
        NODE    *root;

        assert(specfile != NULL);
        assert(parent != NULL);

        if (debug & DEBUG_APPLY_SPECFILE)
                printf("apply_specfile: %s, %s %p\n", specfile, dir, parent);

                                /* read in the specfile */
        if ((fp = fopen(specfile, "r")) == NULL)
                err(1, "Can't open `%s'", specfile);
        TIMER_START(start);
        root = spec(fp);
        TIMER_RESULTS(start, "spec");
        if (fclose(fp) == EOF)
                err(1, "Can't close `%s'", specfile);

                                /* perform some sanity checks */
        if (root == NULL)
                errx(1, "Specfile `%s' did not contain a tree", specfile);
        assert(strcmp(root->name, ".") == 0);
        assert(root->type == F_DIR);

                                /* merge in the changes */
        apply_specdir(dir, root, parent, speconly);

        free_nodes(root);
}

static void
apply_specdir(const char *dir, NODE *specnode, fsnode *dirnode, int speconly)
{
        char     path[MAXPATHLEN + 1];
        NODE    *curnode;
        fsnode  *curfsnode;

        assert(specnode != NULL);
        assert(dirnode != NULL);

        if (debug & DEBUG_APPLY_SPECFILE)
                printf("apply_specdir: %s %p %p\n", dir, specnode, dirnode);

        if (specnode->type != F_DIR)
                errx(1, "Specfile node `%s/%s' is not a directory",
                    dir, specnode->name);
        if (dirnode->type != S_IFDIR)
                errx(1, "Directory node `%s/%s' is not a directory",
                    dir, dirnode->name);

        apply_specentry(dir, specnode, dirnode);

        /* Remove any filesystem nodes not found in specfile */
        /* XXX inefficient.  This is O^2 in each dir and it would
         * have been better never to have walked this part of the tree
         * to begin with
         */
        if (speconly) {
                fsnode *next;
                assert(dirnode->name[0] == '.' && dirnode->name[1] == '\0');
                for (curfsnode = dirnode->next; curfsnode != NULL; curfsnode = next) {
                        next = curfsnode->next;
                        for (curnode = specnode->child; curnode != NULL;
                             curnode = curnode->next) {
                                if (strcmp(curnode->name, curfsnode->name) == 0)
                                        break;
                        }
                        if (curnode == NULL) {
                                if (debug & DEBUG_APPLY_SPECONLY) {
                                        printf("apply_specdir: trimming %s/%s %p\n", dir, curfsnode->name, curfsnode);
                                }
                                free_fsnodes(curfsnode);
                        }
                }
        }

                        /* now walk specnode->child matching up with dirnode */
        for (curnode = specnode->child; curnode != NULL;
            curnode = curnode->next) {
                if (debug & DEBUG_APPLY_SPECENTRY)
                        printf("apply_specdir:  spec %s\n",
                            curnode->name);
                for (curfsnode = dirnode->next; curfsnode != NULL;
                    curfsnode = curfsnode->next) {
#if 0   /* too verbose for now */
                        if (debug & DEBUG_APPLY_SPECENTRY)
                                printf("apply_specdir:  dirent %s\n",
                                    curfsnode->name);
#endif
                        if (strcmp(curnode->name, curfsnode->name) == 0)
                                break;
                }
                if ((size_t)snprintf(path, sizeof(path), "%s/%s", dir,
                    curnode->name) >= sizeof(path))
                        errx(1, "Pathname too long.");
                if (curfsnode == NULL) {        /* need new entry */
                        struct stat     stbuf;

                                            /*
                                             * don't add optional spec entries
                                             * that lack an existing fs entry
                                             */
                        if ((curnode->flags & F_OPT) &&
                            lstat(path, &stbuf) == -1)
                                        continue;

                                        /* check that enough info is provided */
#define NODETEST(t, m)                                                  \
                        if (!(t))                                       \
                                errx(1, "`%s': %s not provided", path, m)
                        NODETEST(curnode->flags & F_TYPE, "type");
                        NODETEST(curnode->flags & F_MODE, "mode");
                                /* XXX: require F_TIME ? */
                        NODETEST(curnode->flags & F_GID ||
                            curnode->flags & F_GNAME, "group");
                        NODETEST(curnode->flags & F_UID ||
                            curnode->flags & F_UNAME, "user");
/*                      if (curnode->type == F_BLOCK || curnode->type == F_CHAR)
                                NODETEST(curnode->flags & F_DEV,
                                    "device number");*/
#undef NODETEST

                        if (debug & DEBUG_APPLY_SPECFILE)
                                printf("apply_specdir: adding %s\n",
                                    curnode->name);
                                        /* build minimal fsnode */
                        memset(&stbuf, 0, sizeof(stbuf));
                        stbuf.st_mode = nodetoino(curnode->type);
                        stbuf.st_nlink = 1;
                        stbuf.st_mtime = stbuf.st_atime =
                            stbuf.st_ctime = start_time.tv_sec;
#if HAVE_STRUCT_STAT_ST_MTIMENSEC
                        stbuf.st_mtimensec = stbuf.st_atimensec =
                            stbuf.st_ctimensec = start_time.tv_nsec;
#endif
                        curfsnode = create_fsnode(".", ".", curnode->name,
                            &stbuf);
                        curfsnode->parent = dirnode->parent;
                        curfsnode->first = dirnode;
                        curfsnode->next = dirnode->next;
                        dirnode->next = curfsnode;
                        if (curfsnode->type == S_IFDIR) {
                                        /* for dirs, make "." entry as well */
                                curfsnode->child = create_fsnode(".", ".", ".",
                                    &stbuf);
                                curfsnode->child->parent = curfsnode;
                                curfsnode->child->first = curfsnode->child;
                        }
                        if (curfsnode->type == S_IFLNK) {
                                assert(curnode->slink != NULL);
                                        /* for symlinks, copy the target */
                                curfsnode->symlink = estrdup(curnode->slink);
                        }
                }
                apply_specentry(dir, curnode, curfsnode);
                if (curnode->type == F_DIR) {
                        if (curfsnode->type != S_IFDIR)
                                errx(1, "`%s' is not a directory", path);
                        assert (curfsnode->child != NULL);
                        apply_specdir(path, curnode, curfsnode->child, speconly);
                }
        }
}

static void
apply_specentry(const char *dir, NODE *specnode, fsnode *dirnode)
{

        assert(specnode != NULL);
        assert(dirnode != NULL);

        if (nodetoino(specnode->type) != dirnode->type)
                errx(1, "`%s/%s' type mismatch: specfile %s, tree %s",
                    dir, specnode->name, inode_type(nodetoino(specnode->type)),
                    inode_type(dirnode->type));

        if (debug & DEBUG_APPLY_SPECENTRY)
                printf("apply_specentry: %s/%s\n", dir, dirnode->name);

#define ASEPRINT(t, b, o, n) \
                if (debug & DEBUG_APPLY_SPECENTRY) \
                        printf("\t\t\tchanging %s from " b " to " b "\n", \
                            t, o, n)

        if (specnode->flags & (F_GID | F_GNAME)) {
                ASEPRINT("gid", "%d",
                    dirnode->inode->st.st_gid, specnode->st_gid);
                dirnode->inode->st.st_gid = specnode->st_gid;
        }
        if (specnode->flags & F_MODE) {
                ASEPRINT("mode", "%#o",
                    dirnode->inode->st.st_mode & ALLPERMS, specnode->st_mode);
                dirnode->inode->st.st_mode &= ~ALLPERMS;
                dirnode->inode->st.st_mode |= (specnode->st_mode & ALLPERMS);
        }
                /* XXX: ignoring F_NLINK for now */
        if (specnode->flags & F_SIZE) {
                ASEPRINT("size", "%lld",
                    (long long)dirnode->inode->st.st_size,
                    (long long)specnode->st_size);
                dirnode->inode->st.st_size = specnode->st_size;
        }
        if (specnode->flags & F_SLINK) {
                assert(dirnode->symlink != NULL);
                assert(specnode->slink != NULL);
                ASEPRINT("symlink", "%s", dirnode->symlink, specnode->slink);
                free(dirnode->symlink);
                dirnode->symlink = estrdup(specnode->slink);
        }
        if (specnode->flags & F_TIME) {
                ASEPRINT("time", "%ld",
                    (long)dirnode->inode->st.st_mtime,
                    (long)specnode->st_mtimespec.tv_sec);
                dirnode->inode->st.st_mtime =           specnode->st_mtimespec.tv_sec;
                dirnode->inode->st.st_atime =           specnode->st_mtimespec.tv_sec;
                dirnode->inode->st.st_ctime =           start_time.tv_sec;
#if HAVE_STRUCT_STAT_ST_MTIMENSEC
                dirnode->inode->st.st_mtimensec =       specnode->st_mtimespec.tv_nsec;
                dirnode->inode->st.st_atimensec =       specnode->st_mtimespec.tv_nsec;
                dirnode->inode->st.st_ctimensec =       start_time.tv_nsec;
#endif
        }
        if (specnode->flags & (F_UID | F_UNAME)) {
                ASEPRINT("uid", "%d",
                    dirnode->inode->st.st_uid, specnode->st_uid);
                dirnode->inode->st.st_uid = specnode->st_uid;
        }
        if (specnode->flags & F_FLAGS) {
                ASEPRINT("flags", "%#lX",
                    (unsigned long)FSINODE_ST_FLAGS(*dirnode->inode),
                    (unsigned long)specnode->st_flags);
                FSINODE_ST_FLAGS(*dirnode->inode) = specnode->st_flags;
        }
/*      if (specnode->flags & F_DEV) {
                ASEPRINT("rdev", "%#llx",
                    (unsigned long long)dirnode->inode->st.st_rdev,
                    (unsigned long long)specnode->st_rdev);
                dirnode->inode->st.st_rdev = specnode->st_rdev;
        }*/
#undef ASEPRINT

        dirnode->flags |= FSNODE_F_HASSPEC;
}


/*
 * dump_fsnodes --
 *      dump the fsnodes from `cur'
 */
void
dump_fsnodes(fsnode *root)
{
        fsnode  *cur;
        char    path[MAXPATHLEN + 1];

        printf("dump_fsnodes: %s %p\n", root->path, root);
        for (cur = root; cur != NULL; cur = cur->next) {
                if (snprintf(path, sizeof(path), "%s/%s", cur->path,
                    cur->name) >= (int)sizeof(path))
                        errx(1, "Pathname too long.");

                if (debug & DEBUG_DUMP_FSNODES_VERBOSE)
                        printf("cur=%8p parent=%8p first=%8p ",
                            cur, cur->parent, cur->first);
                printf("%7s: %s", inode_type(cur->type), path);
                if (S_ISLNK(cur->type)) {
                        assert(cur->symlink != NULL);
                        printf(" -> %s", cur->symlink);
                } else {
                        assert (cur->symlink == NULL);
                }
                if (cur->inode->nlink > 1)
                        printf(", nlinks=%d", cur->inode->nlink);
                putchar('\n');

                if (cur->child) {
                        assert (cur->type == S_IFDIR);
                        dump_fsnodes(cur->child);
                }
        }
        printf("dump_fsnodes: finished %s/%s\n", root->path, root->name);
}


/*
 * inode_type --
 *      for a given inode type `mode', return a descriptive string.
 *      for most cases, uses inotype() from mtree/misc.c
 */
const char *
inode_type(mode_t mode)
{
        if (S_ISREG(mode))
                return ("file");
        if (S_ISLNK(mode))
                return ("symlink");
        if (S_ISDIR(mode))
                return ("dir");
        if (S_ISFIFO(mode))
                return ("fifo");
        if (S_ISSOCK(mode))
                return ("socket");
        /* XXX should not happen but handle them */
        if (S_ISCHR(mode))
                return ("char");
        if (S_ISBLK(mode))
                return ("block");
        return ("unknown");
}


/*
 * link_check --
 *      return pointer to fsinode matching `entry's st_ino & st_dev if it exists,
 *      otherwise add `entry' to table and return NULL
 */
/* This was borrowed from du.c and tweaked to keep an fsnode 
 * pointer instead. -- dbj@netbsd.org
 */
fsinode *
link_check(fsinode *entry)
{
        static struct entry {
                fsinode *data;
        } *htable;
        static int htshift;  /* log(allocated size) */
        static int htmask;   /* allocated size - 1 */
        static int htused;   /* 2*number of insertions */
        int h, h2;
        uint64_t tmp;
        /* this constant is (1<<64)/((1+sqrt(5))/2)
         * aka (word size)/(golden ratio)
         */
        const uint64_t HTCONST = 11400714819323198485ULL;
        const int HTBITS = 64;
        
        /* Never store zero in hashtable */
        assert(entry);

        /* Extend hash table if necessary, keep load under 0.5 */
        if (htused<<1 >= htmask) {
                struct entry *ohtable;

                if (!htable)
                        htshift = 10;   /* starting hashtable size */
                else
                        htshift++;   /* exponential hashtable growth */

                htmask  = (1 << htshift) - 1;
                htused = 0;

                ohtable = htable;
                htable = ecalloc(htmask+1, sizeof(*htable));
                /* populate newly allocated hashtable */
                if (ohtable) {
                        int i;
                        for (i = 0; i <= htmask>>1; i++)
                                if (ohtable[i].data)
                                        link_check(ohtable[i].data);
                        free(ohtable);
                }
        }

        /* multiplicative hashing */
        tmp = entry->st.st_dev;
        tmp <<= HTBITS>>1;
        tmp |=  entry->st.st_ino;
        tmp *= HTCONST;
        h  = tmp >> (HTBITS - htshift);
        h2 = 1 | ( tmp >> (HTBITS - (htshift<<1) - 1)); /* must be odd */
        
        /* open address hashtable search with double hash probing */
        while (htable[h].data) {
                if ((htable[h].data->st.st_ino == entry->st.st_ino) &&
                    (htable[h].data->st.st_dev == entry->st.st_dev)) {
                        return htable[h].data;
                }
                h = (h + h2) & htmask;
        }

        /* Insert the current entry into hashtable */
        htable[h].data = entry;
        htused++;
        return NULL;
}