# if 0
/*      $NetBSD: rcorder.c,v 1.7 2000/08/04 07:33:55 enami Exp $        */
#endif

/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 1998, 1999 Matthew R. Green
 * All rights reserved.
 * Copyright (c) 1998
 *      Perry E. Metzger.  All rights reserved.
 * Copyright (c) 2020
 *     Boris N. Lytochkin. 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.
 * 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 Perry E. Metzger.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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/types.h>
#include <sys/stat.h>

#include <err.h>
#include <stdio.h>
#include <libutil.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <libgen.h>
#include <stdbool.h>

#include "ealloc.h"
#include "sprite.h"
#include "hash.h"

#ifdef DEBUG
static int debug = 0;
# define        DPRINTF(args) if (debug) { fflush(stdout); fprintf args; }
#else
# define        DPRINTF(args)
#endif

#define REQUIRE_STR     "# REQUIRE:"
#define REQUIRE_LEN     (sizeof(REQUIRE_STR) - 1)
#define REQUIRES_STR    "# REQUIRES:"
#define REQUIRES_LEN    (sizeof(REQUIRES_STR) - 1)
#define PROVIDE_STR     "# PROVIDE:"
#define PROVIDE_LEN     (sizeof(PROVIDE_STR) - 1)
#define PROVIDES_STR    "# PROVIDES:"
#define PROVIDES_LEN    (sizeof(PROVIDES_STR) - 1)
#define BEFORE_STR      "# BEFORE:"
#define BEFORE_LEN      (sizeof(BEFORE_STR) - 1)
#define KEYWORD_STR     "# KEYWORD:"
#define KEYWORD_LEN     (sizeof(KEYWORD_STR) - 1)
#define KEYWORDS_STR    "# KEYWORDS:"
#define KEYWORDS_LEN    (sizeof(KEYWORDS_STR) - 1)

#define FAKE_PROV_NAME  "fake_prov_"

static int exit_code;
static int file_count;
static char **file_list;

#define TRUE 1
#define FALSE 0
typedef bool flag;
#define SET TRUE
#define RESET FALSE

static flag do_graphviz = false;
static flag do_parallel = false;

static Hash_Table provide_hash_s, *provide_hash;

typedef struct provnode provnode;
typedef struct filenode filenode;
typedef struct f_provnode f_provnode;
typedef struct f_reqnode f_reqnode;
typedef struct strnodelist strnodelist;

struct provnode {
        flag            head;
        flag            in_progress;
        int             sequence;
        filenode        *fnode;
        provnode        *next, *last;
};

struct f_provnode {
        provnode        *pnode;
        Hash_Entry      *entry;
        f_provnode      *next;
};

struct f_reqnode {
        Hash_Entry      *entry;
        f_reqnode       *next;
};

struct strnodelist {
        filenode        *node;
        strnodelist     *next;
        char            s[1];
};

struct filenode {
        char            *filename;
        flag            in_progress;
        filenode        *next, *last;
        f_reqnode       *req_list;
        f_provnode      *prov_list;
        strnodelist     *keyword_list;
        int             issues_count;
        int             sequence;
};

static filenode fn_head_s, *fn_head, **fn_seqlist;
static int max_sequence = 0;

static strnodelist *bl_list;
static strnodelist *keep_list;
static strnodelist *skip_list;

static void do_file(filenode *fnode, strnodelist *);
static void strnode_add(strnodelist **, char *, filenode *);
static int skip_ok(filenode *fnode);
static int keep_ok(filenode *fnode);
static char *generate_loop_for_req(strnodelist *, provnode *, filenode *);
static void satisfy_req(f_reqnode *rnode, filenode *fnode, strnodelist *);
static void crunch_file(char *);
static void parse_require(filenode *, char *);
static void parse_provide(filenode *, char *);
static void parse_before(filenode *, char *);
static void parse_keywords(filenode *, char *);
static filenode *filenode_new(char *);
static void add_require(filenode *, char *);
static void add_provide(filenode *, char *);
static void add_before(filenode *, char *);
static void add_keyword(filenode *, char *);
static void insert_before(void);
static Hash_Entry *make_fake_provision(filenode *);
static void crunch_all_files(void);
static void initialize(void);
static void generate_graphviz_header(void);
static void generate_graphviz_footer(void);
static void generate_graphviz_file_links(Hash_Entry *, filenode *);
static void generate_graphviz_providers(void);
static inline int is_fake_prov(const char *);
static int sequence_cmp(const void *, const void *);
static void generate_ordering(void);

int
main(int argc, char *argv[])
{
        int ch;

        while ((ch = getopt(argc, argv, "dgk:ps:")) != -1)
                switch (ch) {
                case 'd':
#ifdef DEBUG
                        debug = 1;
#else
                        warnx("debugging not compiled in, -d ignored");
#endif
                        break;
                case 'g':
                        do_graphviz = true;
                        break;
                case 'k':
                        strnode_add(&keep_list, optarg, 0);
                        break;
                case 'p':
                        do_parallel = true;
                        break;
                case 's':
                        strnode_add(&skip_list, optarg, 0);
                        break;
                default:
                        /* XXX should crunch it? */
                        break;
                }
        argc -= optind;
        argv += optind;

        file_count = argc;
        file_list = argv;

        DPRINTF((stderr, "parse_args\n"));
        initialize();
        DPRINTF((stderr, "initialize\n"));
        generate_graphviz_header();
        crunch_all_files();
        DPRINTF((stderr, "crunch_all_files\n"));
        generate_graphviz_providers();
        generate_ordering();
        DPRINTF((stderr, "generate_ordering\n"));
        generate_graphviz_footer();

        exit(exit_code);
}

/*
 * initialise various variables.
 */
static void
initialize(void)
{

        fn_head = &fn_head_s;

        provide_hash = &provide_hash_s;
        Hash_InitTable(provide_hash, file_count);
}

/* generic function to insert a new strnodelist element */
static void
strnode_add(strnodelist **listp, char *s, filenode *fnode)
{
        strnodelist *ent;

        ent = emalloc(sizeof *ent + strlen(s));
        ent->node = fnode;
        strcpy(ent->s, s);
        ent->next = *listp;
        *listp = ent;
}

/*
 * below are the functions that deal with creating the lists
 * from the filename's given dependencies and provisions
 * in each of these files.  no ordering or checking is done here.
 */

/*
 * we have a new filename, create a new filenode structure.
 * fill in the bits, and put it in the filenode linked list
 */
static filenode *
filenode_new(char *filename)
{
        filenode *temp;

        temp = emalloc(sizeof(*temp));
        memset(temp, 0, sizeof(*temp));
        temp->filename = estrdup(filename);
        temp->req_list = NULL;
        temp->prov_list = NULL;
        temp->keyword_list = NULL;
        temp->in_progress = RESET;
        /*
         * link the filenode into the list of filenodes.
         * note that the double linking means we can delete a
         * filenode without searching for where it belongs.
         */
        temp->next = fn_head->next;
        if (temp->next != NULL)
                temp->next->last = temp;
        temp->last = fn_head;
        fn_head->next = temp;
        return (temp);
}

/*
 * add a requirement to a filenode.
 */
static void
add_require(filenode *fnode, char *s)
{
        Hash_Entry *entry;
        f_reqnode *rnode;
        int new;

        entry = Hash_CreateEntry(provide_hash, s, &new);
        if (new)
                Hash_SetValue(entry, NULL);
        rnode = emalloc(sizeof(*rnode));
        rnode->entry = entry;
        rnode->next = fnode->req_list;
        fnode->req_list = rnode;
}

/*
 * add a provision to a filenode.  if this provision doesn't
 * have a head node, create one here.
 */
static void
add_provide(filenode *fnode, char *s)
{
        Hash_Entry *entry;
        f_provnode *f_pnode;
        provnode *pnode, *head;
        int new;

        entry = Hash_CreateEntry(provide_hash, s, &new);
        head = Hash_GetValue(entry);

        /* create a head node if necessary. */
        if (head == NULL) {
                head = emalloc(sizeof(*head));
                head->head = SET;
                head->in_progress = RESET;
                head->fnode = NULL;
                head->sequence = 0;
                head->last = head->next = NULL;
                Hash_SetValue(entry, head);
        }
#if 0
        /*
         * Don't warn about this.  We want to be able to support
         * scripts that do two complex things:
         *
         *      - Two independent scripts which both provide the
         *        same thing.  Both scripts must be executed in
         *        any order to meet the barrier.  An example:
         *
         *              Script 1:
         *
         *                      PROVIDE: mail
         *                      REQUIRE: LOGIN
         *
         *              Script 2:
         *
         *                      PROVIDE: mail
         *                      REQUIRE: LOGIN
         *
         *      - Two interdependent scripts which both provide the
         *        same thing.  Both scripts must be executed in
         *        graph order to meet the barrier.  An example:
         *
         *              Script 1:
         *
         *                      PROVIDE: nameservice dnscache
         *                      REQUIRE: SERVERS
         *
         *              Script 2:
         *
         *                      PROVIDE: nameservice nscd
         *                      REQUIRE: dnscache
         */
        else if (new == 0) {
                warnx("file `%s' provides `%s'.", fnode->filename, s);
                warnx("\tpreviously seen in `%s'.",
                    head->next->fnode->filename);
        }
#endif

        pnode = emalloc(sizeof(*pnode));
        pnode->head = RESET;
        pnode->in_progress = RESET;
        pnode->fnode = fnode;
        pnode->next = head->next;
        pnode->last = head;
        head->next = pnode;
        if (pnode->next != NULL)
                pnode->next->last = pnode;

        f_pnode = emalloc(sizeof(*f_pnode));
        f_pnode->pnode = pnode;
        f_pnode->entry = entry;
        f_pnode->next = fnode->prov_list;
        fnode->prov_list = f_pnode;
}

/*
 * put the BEFORE: lines to a list and handle them later.
 */
static void
add_before(filenode *fnode, char *s)
{
        strnodelist *bf_ent;

        bf_ent = emalloc(sizeof *bf_ent + strlen(s));
        bf_ent->node = fnode;
        strcpy(bf_ent->s, s);
        bf_ent->next = bl_list;
        bl_list = bf_ent;
}

/*
 * add a key to a filenode.
 */
static void
add_keyword(filenode *fnode, char *s)
{

        strnode_add(&fnode->keyword_list, s, fnode);
}

/*
 * loop over the rest of a REQUIRE line, giving each word to
 * add_require() to do the real work.
 */
static void
parse_require(filenode *node, char *buffer)
{
        char *s;
        
        while ((s = strsep(&buffer, " \t\n")) != NULL)
                if (*s != '\0')
                        add_require(node, s);
}

/*
 * loop over the rest of a PROVIDE line, giving each word to
 * add_provide() to do the real work.
 */
static void
parse_provide(filenode *node, char *buffer)
{
        char *s;
        
        while ((s = strsep(&buffer, " \t\n")) != NULL)
                if (*s != '\0')
                        add_provide(node, s);
}

/*
 * loop over the rest of a BEFORE line, giving each word to
 * add_before() to do the real work.
 */
static void
parse_before(filenode *node, char *buffer)
{
        char *s;
        
        while ((s = strsep(&buffer, " \t\n")) != NULL)
                if (*s != '\0')
                        add_before(node, s);
}

/*
 * loop over the rest of a KEYWORD line, giving each word to
 * add_keyword() to do the real work.
 */
static void
parse_keywords(filenode *node, char *buffer)
{
        char *s;
        
        while ((s = strsep(&buffer, " \t\n")) != NULL)
                if (*s != '\0')
                        add_keyword(node, s);
}

/*
 * given a file name, create a filenode for it, read in lines looking
 * for provision and requirement lines, building the graphs as needed.
 */
static void
crunch_file(char *filename)
{
        FILE *fp;
        char *buf;
        int require_flag, provide_flag, before_flag, keywords_flag;
        enum { BEFORE_PARSING, PARSING, PARSING_DONE } state;
        filenode *node;
        char delims[3] = { '\\', '\\', '\0' };
        struct stat st;

        if ((fp = fopen(filename, "r")) == NULL) {
                warn("could not open %s", filename);
                return;
        }

        if (fstat(fileno(fp), &st) == -1) {
                warn("could not stat %s", filename);
                fclose(fp);
                return;
        }

        if (!S_ISREG(st.st_mode)) {
#if 0
                warnx("%s is not a file", filename);
#endif
                fclose(fp);
                return;
        }

        node = filenode_new(filename);

        /*
         * we don't care about length, line number, don't want # for comments,
         * and have no flags.
         */
        for (state = BEFORE_PARSING; state != PARSING_DONE &&
            (buf = fparseln(fp, NULL, NULL, delims, 0)) != NULL; free(buf)) {
                require_flag = provide_flag = before_flag = keywords_flag = 0;
                if (strncmp(REQUIRE_STR, buf, REQUIRE_LEN) == 0)
                        require_flag = REQUIRE_LEN;
                else if (strncmp(REQUIRES_STR, buf, REQUIRES_LEN) == 0)
                        require_flag = REQUIRES_LEN;
                else if (strncmp(PROVIDE_STR, buf, PROVIDE_LEN) == 0)
                        provide_flag = PROVIDE_LEN;
                else if (strncmp(PROVIDES_STR, buf, PROVIDES_LEN) == 0)
                        provide_flag = PROVIDES_LEN;
                else if (strncmp(BEFORE_STR, buf, BEFORE_LEN) == 0)
                        before_flag = BEFORE_LEN;
                else if (strncmp(KEYWORD_STR, buf, KEYWORD_LEN) == 0)
                        keywords_flag = KEYWORD_LEN;
                else if (strncmp(KEYWORDS_STR, buf, KEYWORDS_LEN) == 0)
                        keywords_flag = KEYWORDS_LEN;
                else {
                        if (state == PARSING)
                                state = PARSING_DONE;
                        continue;
                }

                state = PARSING;
                if (require_flag)
                        parse_require(node, buf + require_flag);
                else if (provide_flag)
                        parse_provide(node, buf + provide_flag);
                else if (before_flag)
                        parse_before(node, buf + before_flag);
                else if (keywords_flag)
                        parse_keywords(node, buf + keywords_flag);
        }
        fclose(fp);
}

static Hash_Entry *
make_fake_provision(filenode *node)
{
        Hash_Entry *entry;
        f_provnode *f_pnode;
        provnode *head, *pnode;
        static  int i = 0;
        int     new;
        char buffer[30];

        do {
                snprintf(buffer, sizeof buffer, FAKE_PROV_NAME "%08d", i++);
                entry = Hash_CreateEntry(provide_hash, buffer, &new);
        } while (new == 0);
        head = emalloc(sizeof(*head));
        head->head = SET;
        head->in_progress = RESET;
        head->fnode = NULL;
        head->last = head->next = NULL;
        Hash_SetValue(entry, head);

        pnode = emalloc(sizeof(*pnode));
        pnode->head = RESET;
        pnode->in_progress = RESET;
        pnode->fnode = node;
        pnode->next = head->next;
        pnode->last = head;
        head->next = pnode;
        if (pnode->next != NULL)
                pnode->next->last = pnode;

        f_pnode = emalloc(sizeof(*f_pnode));
        f_pnode->entry = entry;
        f_pnode->pnode = pnode;
        f_pnode->next = node->prov_list;
        node->prov_list = f_pnode;

        return (entry);
}

/*
 * go through the BEFORE list, inserting requirements into the graph(s)
 * as required.  in the before list, for each entry B, we have a file F
 * and a string S.  we create a "fake" provision (P) that F provides.
 * for each entry in the provision list for S, add a requirement to
 * that provisions filenode for P.
 */
static void
insert_before(void)
{
        Hash_Entry *entry, *fake_prov_entry;
        provnode *pnode;
        f_reqnode *rnode;
        strnodelist *bl;
        int new;
        
        while (bl_list != NULL) {
                bl = bl_list->next;

                fake_prov_entry = make_fake_provision(bl_list->node);

                entry = Hash_CreateEntry(provide_hash, bl_list->s, &new);
                if (new == 1)
                        warnx("file `%s' is before unknown provision `%s'", bl_list->node->filename, bl_list->s);

                if (new == 1 && do_graphviz == true)
                        generate_graphviz_file_links(
                            Hash_FindEntry(provide_hash, bl_list->s),
                            bl_list->node);

                for (pnode = Hash_GetValue(entry); pnode; pnode = pnode->next) {
                        if (pnode->head)
                                continue;

                        rnode = emalloc(sizeof(*rnode));
                        rnode->entry = fake_prov_entry;
                        rnode->next = pnode->fnode->req_list;
                        pnode->fnode->req_list = rnode;
                }

                free(bl_list);
                bl_list = bl;
        }
}

/*
 * loop over all the files calling crunch_file() on them to do the
 * real work.  after we have built all the nodes, insert the BEFORE:
 * lines into graph(s).
 */
static void
crunch_all_files(void)
{
        int i;
        
        for (i = 0; i < file_count; i++)
                crunch_file(file_list[i]);
        insert_before();
}

static inline int
is_fake_prov(const char *name)
{

        return (name == strstr(name, FAKE_PROV_NAME));
}

/* loop though provide list of vnode drawing all non-fake dependencies */
static void
generate_graphviz_file_links(Hash_Entry *entry, filenode *fnode)
{
        char *dep_name, *fname;
        provnode *head;
        f_provnode *fpnode, *rfpnode;
        int is_before = 0;

        dep_name = Hash_GetKey(entry);
        if (is_fake_prov(dep_name))
                is_before = 1;
        head = Hash_GetValue(entry);

        for (fpnode = fnode->prov_list; fpnode && fpnode->entry;
            fpnode = fpnode->next) {
                fname = Hash_GetKey(fpnode->entry);
                if (is_fake_prov(fname))
                        continue;
                rfpnode = NULL;
                do {
                        if (rfpnode)
                                dep_name = Hash_GetKey(rfpnode->entry);
                        else
                                dep_name = Hash_GetKey(entry);

                        if (!is_fake_prov(dep_name)) {
                                printf("\"%s\" -> \"%s\" [%s%s];\n",
                                    fname, dep_name,
                                    /* edge style */
                                    (is_before ? "style=dashed" : "style=solid"),
                                    /* circular dep? */
                                    ((head == NULL ||
                                    (head->next && head->in_progress == SET)) ?
                                    ", color=red, penwidth=4" : ""));
                                if (rfpnode == NULL)
                                        break;
                        }
                        /* dependency is solved already */
                        if (head == NULL || head->next == NULL)
                                break;

                        if (rfpnode == NULL)
                                rfpnode = head->next->fnode->prov_list;
                        else
                                rfpnode = rfpnode->next;
                } while (rfpnode);
        }
}

/*
 * Walk the stack, find the looping point and generate traceback.
 * NULL is returned on failure, otherwize pointer to a buffer holding
 * text representation is returned, caller must run free(3) for the
 * pointer.
 */
static char *
generate_loop_for_req(strnodelist *stack_tail, provnode *head,
    filenode *fnode)
{
        provnode *pnode;
        strnodelist *stack_ptr, *loop_entry;
        char *buf, **revstack;
        size_t bufsize;
        int i, stack_depth;

        loop_entry = NULL;
        /* fast forward stack to the component that is required now */
        for (pnode = head->next; pnode; pnode = pnode->next) {
                if (loop_entry)
                        break;
                stack_depth = 0;
                for (stack_ptr = stack_tail; stack_ptr;
                    stack_ptr = stack_ptr->next) {
                        stack_depth++;
                        if (stack_ptr->node == pnode->fnode) {
                                loop_entry = stack_ptr;
                                break;
                        }
                }
        }

        if (loop_entry == NULL)
                return (NULL);

        stack_depth += 2; /* fnode + loop_entry */
        revstack = emalloc(sizeof(char *) * stack_depth);
        bzero(revstack, (sizeof(char *) * stack_depth));

        /* reverse stack and estimate buffer size to allocate */
        bufsize = 1; /* tralining \0 */

        revstack[stack_depth - 1] = loop_entry->node->filename;
        bufsize += strlen(revstack[stack_depth - 1]);

        revstack[stack_depth - 2] = fnode->filename;
        bufsize += strlen(revstack[stack_depth - 2]);
        fnode->issues_count++;

        stack_ptr = stack_tail;
        for (i = stack_depth - 3; i >= 0; i--) {
                revstack[i] = stack_ptr->node->filename;
                stack_ptr->node->issues_count++;
                stack_ptr = stack_ptr->next;
                bufsize += strlen(revstack[i]);
        }
        bufsize += strlen(" -> ") * (stack_depth - 1);

        buf = emalloc(bufsize);
        bzero(buf, bufsize);

        for (i = 0; i < stack_depth; i++) {
                strlcat(buf, revstack[i], bufsize);
                if (i < stack_depth - 1)
                        strlcat(buf, " -> ", bufsize);
        }

        free(revstack);
        return (buf);
}
/*
 * below are the functions that traverse the graphs we have built
 * finding out the desired ordering, printing each file in turn.
 * if missing requirements, or cyclic graphs are detected, a
 * warning will be issued, and we will continue on..
 */

/*
 * given a requirement node (in a filename) we attempt to satisfy it.
 * we do some sanity checking first, to ensure that we have providers,
 * aren't already satisfied and aren't already being satisfied (ie,
 * cyclic).  if we pass all this, we loop over the provision list
 * calling do_file() (enter recursion) for each filenode in this
 * provision.
 */
static void
satisfy_req(f_reqnode *rnode, filenode *fnode, strnodelist *stack_ptr)
{
        Hash_Entry *entry;
        provnode *head;
        strnodelist stack_item;
        char *buf;

        entry = rnode->entry;
        head = Hash_GetValue(entry);

        if (do_graphviz == true)
                generate_graphviz_file_links(entry, fnode);

        if (head == NULL) {
                warnx("requirement `%s' in file `%s' has no providers.",
                    Hash_GetKey(entry), fnode->filename);
                exit_code = 1;
                return;
        }

        /* return if the requirement is already satisfied. */
        if (head->next == NULL)
                return;

        /* 
         * if list is marked as in progress,
         *      print that there is a circular dependency on it and abort
         */
        if (head->in_progress == SET) {
                exit_code = 1;
                buf = generate_loop_for_req(stack_ptr, head,
                    fnode);

                if (buf == NULL) {
                        warnx("Circular dependency on provision `%s' in "
                            "file `%s' (tracing has failed).",
                            Hash_GetKey(entry), fnode->filename);
                        return;
                }

                warnx("Circular dependency on provision `%s': %s.",
                    Hash_GetKey(entry), buf);
                free(buf);
                return;
        }

        head->in_progress = SET;
        
        stack_item.next = stack_ptr;
        stack_item.node = fnode;

        /*
         * while provision_list is not empty
         *      do_file(first_member_of(provision_list));
         */
        while (head->next != NULL)
                do_file(head->next->fnode, &stack_item);
}

static int
skip_ok(filenode *fnode)
{
        strnodelist *s;
        strnodelist *k;

        for (s = skip_list; s; s = s->next)
                for (k = fnode->keyword_list; k; k = k->next)
                        if (strcmp(k->s, s->s) == 0)
                                return (0);

        return (1);
}

static int
keep_ok(filenode *fnode)
{
        strnodelist *s;
        strnodelist *k;

        for (s = keep_list; s; s = s->next)
                for (k = fnode->keyword_list; k; k = k->next)
                        if (strcmp(k->s, s->s) == 0)
                                return (1);

        /* an empty keep_list means every one */
        return (!keep_list);
}

/*
 * given a filenode, we ensure we are not a cyclic graph.  if this
 * is ok, we loop over the filenodes requirements, calling satisfy_req()
 * for each of them.. once we have done this, remove this filenode
 * from each provision table, as we are now done.
 *
 * NOTE: do_file() is called recursively from several places and cannot
 * safely free() anything related to items that may be recursed on.
 * Circular dependencies will cause problems if we do.
 */
static void
do_file(filenode *fnode, strnodelist *stack_ptr)
{
        f_reqnode *r;
        f_provnode *p, *p_tmp;
        provnode *pnode, *head;
        int was_set;    
        char *dep_name;

        DPRINTF((stderr, "do_file on %s.\n", fnode->filename));

        /*
         * if fnode is marked as in progress,
         *       print that fnode; is circularly depended upon and abort.
         */
        if (fnode->in_progress == SET) {
                warnx("Circular dependency on file `%s'.",
                        fnode->filename);
                was_set = exit_code = 1;
        } else
                was_set = 0;

        /* mark fnode */
        fnode->in_progress = SET;

        /*
         * for each requirement of fnode -> r
         *      satisfy_req(r, filename)
         */
        r = fnode->req_list;
        fnode->sequence = 0;
        while (r != NULL) {
                satisfy_req(r, fnode, stack_ptr);
                /* find sequence number where all requirements are satisfied */
                head = Hash_GetValue(r->entry);
                if (head && head->sequence > fnode->sequence)
                        fnode->sequence = head->sequence;
                r = r->next;
        }
        fnode->req_list = NULL;
        fnode->sequence++;

        /* if we've seen issues with this file - put it to the tail */
        if (fnode->issues_count)
                fnode->sequence = max_sequence + 1;

        if (max_sequence < fnode->sequence)
                max_sequence = fnode->sequence;

        /*
         * for each provision of fnode -> p
         *      remove fnode from provision list for p in hash table
         */
        p = fnode->prov_list;
        while (p != NULL) {
                /* mark all troublemakers on graphviz */
                if (do_graphviz == true && fnode->issues_count) {
                        dep_name = Hash_GetKey(p->entry);
                        if (!is_fake_prov(dep_name))
                                printf("\"%s\" [ color=red, penwidth=4 ];\n",
                                    dep_name);
                }

                /* update sequence when provided requirements are satisfied */
                head = Hash_GetValue(p->entry);
                if (head->sequence < fnode->sequence)
                        head->sequence = fnode->sequence;

                p_tmp = p;
                pnode = p->pnode;
                if (pnode->next != NULL) {
                        pnode->next->last = pnode->last;
                }
                if (pnode->last != NULL) {
                        pnode->last->next = pnode->next;
                }
                free(pnode);
                p = p->next;
                free(p_tmp);
        }
        fnode->prov_list = NULL;

        /* do_it(fnode) */
        DPRINTF((stderr, "next do: "));

        /* if we were already in progress, don't print again */
        if (do_graphviz != true && was_set == 0 && skip_ok(fnode) &&
            keep_ok(fnode)) {
                *fn_seqlist = fnode;
                fn_seqlist++;
        }
        
        if (fnode->next != NULL) {
                fnode->next->last = fnode->last;
        }
        if (fnode->last != NULL) {
                fnode->last->next = fnode->next;
        }

        if (fnode->issues_count) {
                warnx("`%s' was seen in circular dependencies %d time%s.",
                    fnode->filename, fnode->issues_count,
                    fnode->issues_count > 1 ? "s" : "");
        }

        DPRINTF((stderr, "nuking %s\n", fnode->filename));
}

static void
generate_graphviz_header(void)
{

        if (do_graphviz != true)
                return;

        printf("digraph rcorder {\n"
            "rankdir=\"BT\";\n"
            "node [style=rounded, shape=record];\n"
            "graph [overlap = false];\n");
}

static void
generate_graphviz_footer(void)
{

        if (do_graphviz == true)
                printf("}\n");
}

static void
generate_graphviz_providers(void)
{
        Hash_Entry *entry;
        Hash_Search psearch;
        provnode *head, *pnode;
        char *dep_name;

        if (do_graphviz != true)
                return;

        entry = Hash_EnumFirst(provide_hash, &psearch);
        if (entry == NULL)
                return;

        do {
                dep_name = Hash_GetKey(entry);
                if (is_fake_prov(dep_name))
                        continue;
                head = Hash_GetValue(entry);
                /* no providers for this requirement */
                if (head == NULL || head->next == NULL) {
                        printf("\"%s\" [label=\"{ %s | ENOENT }\", "
                            "style=\"rounded,filled\", color=red];\n",
                            dep_name, dep_name);
                        continue;
                }
                /* one PROVIDE word for one file that matches */
                if (head->next->next == NULL &&
                    strcmp(dep_name,
                    basename(head->next->fnode->filename)) == 0) {
                        continue;
                }
                printf("\"%s\" [label=\"{ %s | ", dep_name, dep_name);
                for (pnode = head->next; pnode; pnode = pnode->next)
                        printf("%s\\n", basename(pnode->fnode->filename));

                printf("}\"];\n");
        } while (NULL != (entry = Hash_EnumNext(&psearch)));
}

static int
sequence_cmp(const void *a, const void *b)
{
        const filenode *fna = *((const filenode * const *)a);
        const filenode *fnb = *((const filenode * const *)b);
        int left, right;

        /* push phantom files to the end */
        if (fna == NULL || fnb == NULL)
                return ((fna < fnb) - (fna > fnb));

        left =  fna->sequence;
        right = fnb->sequence;

        return ((left > right) - (left < right));
}

static void
generate_ordering(void)
{
        filenode **seqlist, **psl;
        int last_seq = 0;

        /* Prepare order buffer, use an additional one as a list terminator */
        seqlist = emalloc(sizeof(filenode *) * (file_count + 1));
        bzero(seqlist, sizeof(filenode *) * (file_count + 1));
        fn_seqlist = seqlist;

        /*
         * while there remain undone files{f},
         *      pick an arbitrary f, and do_file(f)
         * Note that the first file in the file list is perfectly
         * arbitrary, and easy to find, so we use that.
         */

        /*
         * N.B.: the file nodes "self delete" after they execute, so
         * after each iteration of the loop, the head will be pointing
         * to something totally different. The loop ends up being
         * executed only once for every strongly connected set of
         * nodes.
         */
        while (fn_head->next != NULL) {
                DPRINTF((stderr, "generate on %s\n", fn_head->next->filename));
                do_file(fn_head->next, NULL);
        }

        /* Sort filenode list based on sequence */
        qsort(seqlist, file_count, sizeof(filenode *), sequence_cmp);

        for (psl = seqlist; *psl; psl++) {
                printf("%s%s",
                    (last_seq == 0 ? "" :
                    (do_parallel != true || last_seq != (*psl)->sequence) ?
                    "\n" : " "),
                (*psl)->filename);
                last_seq = (*psl)->sequence;
                free((*psl)->filename);
                free(*psl);
        }
        if (last_seq)
                printf("\n");

        free(seqlist);
}