/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2011 Marcel Moolenaar
 * 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.
 */

#if HAVE_NBTOOL_CONFIG_H
#include "nbtool_config.h"
#endif

#include <sys/param.h>
#include <sys/queue.h>
#include <sys/sbuf.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <grp.h>
#include <inttypes.h>
#include <pwd.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <time.h>
#include <unistd.h>
#include <util.h>
#include <vis.h>

#include "makefs.h"

#ifndef ENOATTR
#define ENOATTR ENODATA
#endif

#define IS_DOT(nm)      ((nm)[0] == '.' && (nm)[1] == '\0')
#define IS_DOTDOT(nm)   ((nm)[0] == '.' && (nm)[1] == '.' && (nm)[2] == '\0')

struct mtree_fileinfo {
        SLIST_ENTRY(mtree_fileinfo) next;
        FILE *fp;
        const char *name;
        u_int line;
};

/* Global state used while parsing. */
static SLIST_HEAD(, mtree_fileinfo) mtree_fileinfo =
    SLIST_HEAD_INITIALIZER(mtree_fileinfo);
static fsnode *mtree_root;
static fsnode *mtree_current;
static fsnode mtree_global;
static fsinode mtree_global_inode;
static u_int errors, warnings;

static void mtree_error(const char *, ...) __printflike(1, 2);
static void mtree_warning(const char *, ...) __printflike(1, 2);

static int
mtree_file_push(const char *name, FILE *fp)
{
        struct mtree_fileinfo *fi;

        fi = emalloc(sizeof(*fi));
        if (strcmp(name, "-") == 0)
                fi->name = estrdup("(stdin)");
        else
                fi->name = estrdup(name);
        if (fi->name == NULL) {
                free(fi);
                return (ENOMEM);
        }

        fi->fp = fp;
        fi->line = 0;

        SLIST_INSERT_HEAD(&mtree_fileinfo, fi, next);
        return (0);
}

static void
mtree_print(const char *msgtype, const char *fmt, va_list ap)
{
        struct mtree_fileinfo *fi;

        if (msgtype != NULL) {
                fi = SLIST_FIRST(&mtree_fileinfo);
                if (fi != NULL)
                        fprintf(stderr, "%s:%u: ", fi->name, fi->line);
                fprintf(stderr, "%s: ", msgtype);
        }
        vfprintf(stderr, fmt, ap);
}

static void
mtree_error(const char *fmt, ...)
{
        va_list ap;

        va_start(ap, fmt);
        mtree_print("error", fmt, ap);
        va_end(ap);

        errors++;
        fputc('\n', stderr);
}

static void
mtree_warning(const char *fmt, ...)
{
        va_list ap;

        va_start(ap, fmt);
        mtree_print("warning", fmt, ap);
        va_end(ap);

        warnings++;
        fputc('\n', stderr);
}

#ifndef MAKEFS_MAX_TREE_DEPTH
# define MAKEFS_MAX_TREE_DEPTH (MAXPATHLEN/2)
#endif

/* construct path to node->name */
static char *
mtree_file_path(fsnode *node)
{
        fsnode *pnode;
        struct sbuf *sb;
        char *res, *rp[MAKEFS_MAX_TREE_DEPTH];
        int depth;

        depth = 0;
        rp[depth] = node->name;
        for (pnode = node->parent; pnode && depth < MAKEFS_MAX_TREE_DEPTH - 1;
             pnode = pnode->parent) {
                if (strcmp(pnode->name, ".") == 0)
                        break;
                rp[++depth] = pnode->name;
        }
        
        sb = sbuf_new_auto();
        if (sb == NULL) {
                errno = ENOMEM;
                return (NULL);
        }
        while (depth > 0) {
                sbuf_cat(sb, rp[depth--]);
                sbuf_putc(sb, '/');
        }
        sbuf_cat(sb, rp[depth]);
        sbuf_finish(sb);
        res = estrdup(sbuf_data(sb));
        sbuf_delete(sb);
        if (res == NULL)
                errno = ENOMEM;
        return res;

}

/* mtree_resolve() sets errno to indicate why NULL was returned. */
static char *
mtree_resolve(const char *spec, int *istemp)
{
        struct sbuf *sb;
        char *res, *var = NULL;
        const char *base, *p, *v;
        size_t len;
        int c, error, quoted, subst;

        len = strlen(spec);
        if (len == 0) {
                errno = EINVAL;
                return (NULL);
        }

        c = (len > 1) ? (spec[0] == spec[len - 1]) ? spec[0] : 0 : 0;
        *istemp = (c == '`') ? 1 : 0;
        subst = (c == '`' || c == '"') ? 1 : 0;
        quoted = (subst || c == '\'') ? 1 : 0;

        if (!subst) {
                res = estrdup(spec + quoted);
                if (quoted)
                        res[len - 2] = '\0';
                return (res);
        }

        sb = sbuf_new_auto();
        if (sb == NULL) {
                errno = ENOMEM;
                return (NULL);
        }

        base = spec + 1;
        len -= 2;
        error = 0;
        while (len > 0) {
                p = strchr(base, '$');
                if (p == NULL) {
                        sbuf_bcat(sb, base, len);
                        base += len;
                        len = 0;
                        continue;
                }
                /* The following is safe. spec always starts with a quote. */
                if (p[-1] == '\\')
                        p--;
                if (base != p) {
                        sbuf_bcat(sb, base, p - base);
                        len -= p - base;
                        base = p;
                }
                if (*p == '\\') {
                        sbuf_putc(sb, '$');
                        base += 2;
                        len -= 2;
                        continue;
                }
                /* Skip the '$'. */
                base++;
                len--;
                /* Handle ${X} vs $X. */
                v = base;
                if (*base == '{') {
                        p = strchr(v, '}');
                        if (p == NULL)
                                p = v;
                } else
                        p = v;
                len -= (p + 1) - base;
                base = p + 1;

                if (v == p) {
                        sbuf_putc(sb, *v);
                        continue;
                }

                error = ENOMEM;
                var = ecalloc(p - v, 1);
                memcpy(var, v + 1, p - v - 1);
                if (strcmp(var, ".CURDIR") == 0) {
                        res = getcwd(NULL, 0);
                        if (res == NULL)
                                break;
                } else if (strcmp(var, ".PROG") == 0) {
                        res = estrdup(getprogname());
                } else {
                        v = getenv(var);
                        if (v != NULL) {
                                res = estrdup(v);
                        } else
                                res = NULL;
                }
                error = 0;

                if (res != NULL) {
                        sbuf_cat(sb, res);
                        free(res);
                }
                free(var);
                var = NULL;
        }

        free(var);
        sbuf_finish(sb);
        res = (error == 0) ? strdup(sbuf_data(sb)) : NULL;
        sbuf_delete(sb);
        if (res == NULL)
                errno = ENOMEM;
        return (res);
}

static int
skip_over(FILE *fp, const char *cs)
{
        int c;

        c = getc(fp);
        while (c != EOF && strchr(cs, c) != NULL)
                c = getc(fp);
        if (c != EOF) {
                ungetc(c, fp);
                return (0);
        }
        return (ferror(fp) ? errno : -1);
}

static int
skip_to(FILE *fp, const char *cs)
{
        int c;

        c = getc(fp);
        while (c != EOF && strchr(cs, c) == NULL)
                c = getc(fp);
        if (c != EOF) {
                ungetc(c, fp);
                return (0);
        }
        return (ferror(fp) ? errno : -1);
}

static int
read_word(FILE *fp, char *buf, size_t bufsz)
{
        struct mtree_fileinfo *fi;
        size_t idx, qidx;
        int c, done, error, esc, qlvl;

        if (bufsz == 0)
                return (EINVAL);

        done = 0;
        esc = 0;
        idx = 0;
        qidx = -1;
        qlvl = 0;
        do {
                c = getc(fp);
                switch (c) {
                case EOF:
                        buf[idx] = '\0';
                        error = ferror(fp) ? errno : -1;
                        if (error == -1)
                                mtree_error("unexpected end of file");
                        return (error);
                case '#':               /* comment -- skip to end of line. */
                        if (!esc) {
                                error = skip_to(fp, "\n");
                                if (!error)
                                        continue;
                        }
                        break;
                case '\\':
                        esc++;
                        break;
                case '`':
                case '\'':
                case '"':
                        if (esc)
                                break;
                        if (qlvl == 0) {
                                qlvl++;
                                qidx = idx;
                        } else if (c == buf[qidx]) {
                                qlvl--;
                                if (qlvl > 0) {
                                        do {
                                                qidx--;
                                        } while (buf[qidx] != '`' &&
                                            buf[qidx] != '\'' &&
                                            buf[qidx] != '"');
                                } else
                                        qidx = -1;
                        } else {
                                qlvl++;
                                qidx = idx;
                        }
                        break;
                case ' ':
                case '\t':
                case '\n':
                        if (!esc && qlvl == 0) {
                                ungetc(c, fp);
                                c = '\0';
                                done = 1;
                                break;
                        }
                        if (c == '\n') {
                                /*
                                 * We going to eat the newline ourselves.
                                 */
                                if (qlvl > 0)
                                        mtree_warning("quoted word straddles "
                                            "onto next line.");
                                fi = SLIST_FIRST(&mtree_fileinfo);
                                fi->line++;
                        }
                        break;
                default:
                        if (esc)
                                buf[idx++] = '\\';
                        break;
                }
                buf[idx++] = c;
                esc = 0;
        } while (idx < bufsz && !done);

        if (idx >= bufsz) {
                mtree_error("word too long to fit buffer (max %zu characters)",
                    bufsz);
                skip_to(fp, " \t\n");
        }
        return (0);
}

static fsnode *
create_node(const char *name, u_int type, fsnode *parent, fsnode *global)
{
        fsnode *n;

        n = ecalloc(1, sizeof(*n));
        n->name = estrdup(name);
        n->type = (type == 0) ? global->type : type;
        n->parent = parent;

        n->inode = ecalloc(1, sizeof(*n->inode));

        /* Assign global options/defaults. */
        memcpy(n->inode, global->inode, sizeof(*n->inode));
        n->inode->st.st_mode = (n->inode->st.st_mode & ~S_IFMT) | n->type;

        if (n->type == S_IFLNK)
                n->symlink = global->symlink;
        else if (n->type == S_IFREG)
                n->contents = global->contents;

        return (n);
}

static void
destroy_node(fsnode *n)
{

        assert(n != NULL);
        assert(n->name != NULL);
        assert(n->inode != NULL);

        free(n->inode);
        free(n->name);
        free(n);
}

static int
read_number(const char *tok, u_int base, intmax_t *res, intmax_t min,
    intmax_t max)
{
        char *end;
        intmax_t val;

        val = strtoimax(tok, &end, base);
        if (end == tok || end[0] != '\0')
                return (EINVAL);
        if (val < min || val > max)
                return (EDOM);
        *res = val;
        return (0);
}

static int
read_mtree_keywords(FILE *fp, fsnode *node)
{
        char keyword[PATH_MAX];
        char *name, *p, *value;
        gid_t gid;
        uid_t uid;
        struct stat *st, sb;
        intmax_t num;
        u_long flset, flclr;
        int error, istemp;
        uint32_t type;

        st = &node->inode->st;
        do {
                error = skip_over(fp, " \t");
                if (error)
                        break;

                error = read_word(fp, keyword, sizeof(keyword));
                if (error)
                        break;

                if (keyword[0] == '\0')
                        break;

                value = strchr(keyword, '=');
                if (value != NULL)
                        *value++ = '\0';

                /*
                 * We use EINVAL, ENOATTR, ENOSYS and ENXIO to signal
                 * certain conditions:
                 *   EINVAL -   Value provided for a keyword that does
                 *              not take a value. The value is ignored.
                 *   ENOATTR -  Value missing for a keyword that needs
                 *              a value. The keyword is ignored.
                 *   ENOSYS -   Unsupported keyword encountered. The
                 *              keyword is ignored.
                 *   ENXIO -    Value provided for a keyword that does
                 *              not take a value. The value is ignored.
                 */
                switch (keyword[0]) {
                case 'c':
                        if (strcmp(keyword, "contents") == 0) {
                                if (value == NULL) {
                                        error = ENOATTR;
                                        break;
                                }
                                node->contents = estrdup(value);
                        } else
                                error = ENOSYS;
                        break;
                case 'f':
                        if (strcmp(keyword, "flags") == 0) {
                                if (value == NULL) {
                                        error = ENOATTR;
                                        break;
                                }
                                flset = flclr = 0;
                                if (!strtofflags(&value, &flset, &flclr)) {
                                        FSINODE_ST_FLAGS(*node->inode) &= ~flclr;
                                        FSINODE_ST_FLAGS(*node->inode) |= flset;
                                } else
                                        error = errno;
                        } else
                                error = ENOSYS;
                        break;
                case 'g':
                        if (strcmp(keyword, "gid") == 0) {
                                if (value == NULL) {
                                        error = ENOATTR;
                                        break;
                                }
                                error = read_number(value, 10, &num,
                                    0, UINT_MAX);
                                if (!error)
                                        st->st_gid = num;
                        } else if (strcmp(keyword, "gname") == 0) {
                                if (value == NULL) {
                                        error = ENOATTR;
                                        break;
                                }
                                if (gid_from_group(value, &gid) == 0)
                                        st->st_gid = gid;
                                else
                                        error = EINVAL;
                        } else
                                error = ENOSYS;
                        break;
                case 'l':
                        if (strcmp(keyword, "link") == 0) {
                                if (value == NULL) {
                                        error = ENOATTR;
                                        break;
                                }
                                node->symlink = emalloc(strlen(value) + 1);
                                if (node->symlink == NULL) {
                                        error = errno;
                                        break;
                                }
                                if (strunvis(node->symlink, value) < 0) {
                                        error = errno;
                                        break;
                                }
                        } else
                                error = ENOSYS;
                        break;
                case 'm':
                        if (strcmp(keyword, "mode") == 0) {
                                if (value == NULL) {
                                        error = ENOATTR;
                                        break;
                                }
                                if (value[0] >= '0' && value[0] <= '9') {
                                        error = read_number(value, 8, &num,
                                            0, 07777);
                                        if (!error) {
                                                st->st_mode &= S_IFMT;
                                                st->st_mode |= num;
                                        }
                                } else {
                                        /* Symbolic mode not supported. */
                                        error = EINVAL;
                                        break;
                                }
                        } else
                                error = ENOSYS;
                        break;
                case 'o':
                        if (strcmp(keyword, "optional") == 0) {
                                if (value != NULL)
                                        error = ENXIO;
                                node->flags |= FSNODE_F_OPTIONAL;
                        } else
                                error = ENOSYS;
                        break;
                case 's':
                        if (strcmp(keyword, "size") == 0) {
                                if (value == NULL) {
                                        error = ENOATTR;
                                        break;
                                }
                                error = read_number(value, 10, &num,
                                    0, INTMAX_MAX);
                                if (!error)
                                        st->st_size = num;
                        } else
                                error = ENOSYS;
                        break;
                case 't':
                        if (strcmp(keyword, "tags") == 0) {
                                if (value == NULL) {
                                        error = ENOATTR;
                                        break;
                                }
                                /* Ignore. */
                        } else if (strcmp(keyword, "time") == 0) {
                                /* Ignore if a default timestamp is present. */
                                if (stampst.st_ino != 0)
                                        break;
                                if (value == NULL) {
                                        error = ENOATTR;
                                        break;
                                }
                                p = strchr(value, '.');
                                if (p != NULL)
                                        *p++ = '\0';
                                error = read_number(value, 10, &num, 0,
                                    INTMAX_MAX);
                                if (error)
                                        break;
                                st->st_atime = num;
                                st->st_ctime = num;
                                st->st_mtime = num;
#if HAVE_STRUCT_STAT_ST_MTIMENSEC
                                if (p == NULL)
                                        break;
                                error = read_number(p, 10, &num, 0,
                                    INTMAX_MAX);
                                if (error)
                                        break;
                                st->st_atimensec = num;
                                st->st_ctimensec = num;
                                st->st_mtimensec = num;
#endif
                        } else if (strcmp(keyword, "type") == 0) {
                                if (value == NULL) {
                                        error = ENOATTR;
                                        break;
                                }
                                if (strcmp(value, "dir") == 0)
                                        node->type = S_IFDIR;
                                else if (strcmp(value, "file") == 0)
                                        node->type = S_IFREG;
                                else if (strcmp(value, "link") == 0)
                                        node->type = S_IFLNK;
                                else
                                        error = EINVAL;
                        } else
                                error = ENOSYS;
                        break;
                case 'u':
                        if (strcmp(keyword, "uid") == 0) {
                                if (value == NULL) {
                                        error = ENOATTR;
                                        break;
                                }
                                error = read_number(value, 10, &num,
                                    0, UINT_MAX);
                                if (!error)
                                        st->st_uid = num;
                        } else if (strcmp(keyword, "uname") == 0) {
                                if (value == NULL) {
                                        error = ENOATTR;
                                        break;
                                }
                                if (uid_from_user(value, &uid) == 0)
                                        st->st_uid = uid;
                                else
                                        error = EINVAL;
                        } else
                                error = ENOSYS;
                        break;
                default:
                        error = ENOSYS;
                        break;
                }

                switch (error) {
                case EINVAL:
                        mtree_error("%s: invalid value '%s'", keyword, value);
                        break;
                case ENOATTR:
                        mtree_error("%s: keyword needs a value", keyword);
                        break;
                case ENOSYS:
                        mtree_warning("%s: unsupported keyword", keyword);
                        break;
                case ENXIO:
                        mtree_error("%s: keyword does not take a value",
                            keyword);
                        break;
                }
        } while (1);

        if (error)
                return (error);

        st->st_mode = (st->st_mode & ~S_IFMT) | node->type;
        /* Store default timestamp, if present. */
        if (stampst.st_ino != 0)
                set_tstamp(node);
        /* Nothing more to do for the global defaults. */
        if (node->name == NULL)
                return (0);

        /*
         * Be intelligent about the file type.
         */
        if (node->contents != NULL) {
                if (node->symlink != NULL) {
                        mtree_error("%s: both link and contents keywords "
                            "defined", node->name);
                        return (0);
                }
                type = S_IFREG;
        } else if (node->type != 0) {
                type = node->type;
                if (type == S_IFLNK && node->symlink == NULL) {
                        mtree_error("%s: link type requires link keyword", node->name);
                        return (0);
                } else if (type == S_IFREG) {
                        /* the named path is the default contents */
                        node->contents = mtree_file_path(node);
                }
        } else
                type = (node->symlink != NULL) ? S_IFLNK : S_IFDIR;

        if (node->type == 0)
                node->type = type;

        if (node->type != type) {
                mtree_error("%s: file type and defined keywords to not match",
                    node->name);
                return (0);
        }

        st->st_mode = (st->st_mode & ~S_IFMT) | node->type;

        if (node->contents == NULL)
                return (0);

        name = mtree_resolve(node->contents, &istemp);
        if (name == NULL)
                return (errno);

        if (stat(name, &sb) != 0) {
                mtree_error("%s: contents file '%s' not found", node->name,
                    name);
                free(name);
                return (0);
        }

        /*
         * Check for hardlinks. If the contents key is used, then the check
         * will only trigger if the contents file is a link even if it is used
         * by more than one file
         */
        if (sb.st_nlink > 1) {
                fsinode *curino;

                st->st_ino = sb.st_ino;
                st->st_dev = sb.st_dev;
                curino = link_check(node->inode);
                if (curino != NULL) {
                        free(node->inode);
                        node->inode = curino;
                        node->inode->nlink++;
                        /* Reset st since node->inode has been updated. */
                        st = &node->inode->st;
                }
        }

        free(node->contents);
        node->contents = name;
        st->st_size = sb.st_size;
        return (0);
}

static int
read_mtree_command(FILE *fp)
{
        char cmd[10];
        int error;

        error = read_word(fp, cmd, sizeof(cmd));
        if (error)
                goto out;

        error = read_mtree_keywords(fp, &mtree_global);

 out:
        skip_to(fp, "\n");
        (void)getc(fp);
        return (error);
}

static int
read_mtree_spec1(FILE *fp, bool def, const char *name)
{
        fsnode *last, *node, *parent;
        u_int type;
        int error;

        assert(name[0] != '\0');

        /*
         * Treat '..' specially, because it only changes our current
         * directory. We don't create a node for it. We simply ignore
         * any keywords that may appear on the line as well.
         * Going up a directory is a little non-obvious. A directory
         * node has a corresponding '.' child. The parent of '.' is
         * not the '.' node of the parent directory, but the directory
         * node within the parent to which the child relates. However,
         * going up a directory means we need to find the '.' node to
         * which the directory node is linked.  This we can do via the
         * first * pointer, because '.' is always the first entry in a
         * directory.
         */
        if (IS_DOTDOT(name)) {
                /* This deals with NULL pointers as well. */
                if (mtree_current == mtree_root) {
                        mtree_warning("ignoring .. in root directory");
                        return (0);
                }

                node = mtree_current;

                assert(node != NULL);
                assert(IS_DOT(node->name));
                assert(node->first == node);

                /* Get the corresponding directory node in the parent. */
                node = mtree_current->parent;

                assert(node != NULL);
                assert(!IS_DOT(node->name));

                node = node->first;

                assert(node != NULL);
                assert(IS_DOT(node->name));
                assert(node->first == node);

                mtree_current = node;
                return (0);
        }

        /*
         * If we don't have a current directory and the first specification
         * (either implicit or defined) is not '.', then we need to create
         * a '.' node first (using a recursive call).
         */
        if (!IS_DOT(name) && mtree_current == NULL) {
                error = read_mtree_spec1(fp, false, ".");
                if (error)
                        return (error);
        }

        /*
         * Lookup the name in the current directory (if we have a current
         * directory) to make sure we do not create multiple nodes for the
         * same component. For non-definitions, if we find a node with the
         * same name, simply change the current directory. For definitions
         * more happens.
         */
        last = NULL;
        node = mtree_current;
        while (node != NULL) {
                assert(node->first == mtree_current);

                if (strcmp(name, node->name) == 0) {
                        if (def == true) {
                                if (dupsok == 0)
                                        mtree_error(
                                            "duplicate definition of %s",
                                            name);
                                else if (dupsok == 1)
                                        mtree_warning(
                                            "duplicate definition of %s",
                                            name);
                                return (0);
                        }

                        if (node->type != S_IFDIR) {
                                mtree_error("%s is not a directory", name);
                                return (0);
                        }

                        assert(!IS_DOT(name));

                        node = node->child;

                        assert(node != NULL);
                        assert(IS_DOT(node->name));

                        mtree_current = node;
                        return (0);
                }

                last = node;
                node = last->next;
        }

        parent = (mtree_current != NULL) ? mtree_current->parent : NULL;
        type = (def == false || IS_DOT(name)) ? S_IFDIR : 0;
        node = create_node(name, type, parent, &mtree_global);
        if (node == NULL)
                return (ENOMEM);

        if (def == true) {
                error = read_mtree_keywords(fp, node);
                if (error) {
                        destroy_node(node);
                        return (error);
                }
        }

        node->first = (mtree_current != NULL) ? mtree_current : node;

        if (last != NULL)
                last->next = node;

        if (node->type != S_IFDIR)
                return (0);

        if (!IS_DOT(node->name)) {
                parent = node;
                node = create_node(".", S_IFDIR, parent, parent);
                if (node == NULL) {
                        last->next = NULL;
                        destroy_node(parent);
                        return (ENOMEM);
                }
                parent->child = node;
                node->first = node;
        }

        assert(node != NULL);
        assert(IS_DOT(node->name));
        assert(node->first == node);

        mtree_current = node;
        if (mtree_root == NULL)
                mtree_root = node;

        return (0);
}

static int
read_mtree_spec(FILE *fp)
{
        char pathspec[PATH_MAX], pathtmp[4*PATH_MAX + 1];
        char *cp;
        int error;

        error = read_word(fp, pathtmp, sizeof(pathtmp));
        if (error)
                goto out;
        if (strnunvis(pathspec, PATH_MAX, pathtmp) == -1) {
                error = errno;
                goto out;
        }
        error = 0;

        cp = strchr(pathspec, '/');
        if (cp != NULL) {
                /* Absolute pathname */
                mtree_current = mtree_root;

                do {
                        *cp++ = '\0';

                        /* Disallow '..' as a component. */
                        if (IS_DOTDOT(pathspec)) {
                                mtree_error("absolute path cannot contain "
                                    ".. component");
                                goto out;
                        }

                        /* Ignore multiple adjacent slashes and '.'. */
                        if (pathspec[0] != '\0' && !IS_DOT(pathspec))
                                error = read_mtree_spec1(fp, false, pathspec);
                        memmove(pathspec, cp, strlen(cp) + 1);
                        cp = strchr(pathspec, '/');
                } while (!error && cp != NULL);

                /* Disallow '.' and '..' as the last component. */
                if (!error && (IS_DOT(pathspec) || IS_DOTDOT(pathspec))) {
                        mtree_error("absolute path cannot contain . or .. "
                            "components");
                        goto out;
                }
        }

        /* Ignore absolute specifications that end with a slash. */
        if (!error && pathspec[0] != '\0')
                error = read_mtree_spec1(fp, true, pathspec);

 out:
        skip_to(fp, "\n");
        (void)getc(fp);
        return (error);
}

fsnode *
read_mtree(const char *fname, fsnode *node)
{
        struct mtree_fileinfo *fi;
        FILE *fp;
        int c, error;

        /* We do not yet support nesting... */
        assert(node == NULL);

        if (strcmp(fname, "-") == 0)
                fp = stdin;
        else {
                fp = fopen(fname, "r");
                if (fp == NULL)
                        err(1, "Can't open `%s'", fname);
        }

        error = mtree_file_push(fname, fp);
        if (error)
                goto out;

        memset(&mtree_global, 0, sizeof(mtree_global));
        memset(&mtree_global_inode, 0, sizeof(mtree_global_inode));
        mtree_global.inode = &mtree_global_inode;
        mtree_global_inode.nlink = 1;
        mtree_global_inode.st.st_nlink = 1;
        if (stampst.st_ino != 0) {
                set_tstamp(&mtree_global);
        } else {
#if HAVE_STRUCT_STAT_BIRTHTIME
                mtree_global_inode.st.st_birthtime =
#endif
                    mtree_global_inode.st.st_atime =
                    mtree_global_inode.st.st_ctime =
                    mtree_global_inode.st.st_mtime = time(NULL);
        }
        errors = warnings = 0;

        setgroupent(1);
        setpassent(1);

        mtree_root = node;
        mtree_current = node;
        do {
                /* Start of a new line... */
                fi = SLIST_FIRST(&mtree_fileinfo);
                fi->line++;

                error = skip_over(fp, " \t");
                if (error)
                        break;

                c = getc(fp);
                if (c == EOF) {
                        error = ferror(fp) ? errno : -1;
                        break;
                }

                switch (c) {
                case '\n':              /* empty line */
                        error = 0;
                        break;
                case '#':               /* comment -- skip to end of line. */
                        error = skip_to(fp, "\n");
                        if (!error)
                                (void)getc(fp);
                        break;
                case '/':               /* special commands */
                        error = read_mtree_command(fp);
                        break;
                default:                /* specification */
                        ungetc(c, fp);
                        error = read_mtree_spec(fp);
                        break;
                }
        } while (!error);

        endpwent();
        endgrent();

        if (error <= 0 && (errors || warnings)) {
                warnx("%u error(s) and %u warning(s) in mtree manifest",
                    errors, warnings);
                if (errors)
                        exit(1);
        }

 out:
        if (error > 0)
                errc(1, error, "Error reading mtree file");

        if (fp != stdin)
                fclose(fp);

        if (mtree_root != NULL)
                return (mtree_root);

        /* Handle empty specifications. */
        node = create_node(".", S_IFDIR, NULL, &mtree_global);
        node->first = node;
        return (node);
}