/*      $OpenBSD: diffdir.c,v 1.45 2015/10/05 20:15:00 millert Exp $    */

/*
 * Copyright (c) 2003, 2010 Todd C. Miller <Todd.Miller@courtesan.com>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 * Sponsored in part by the Defense Advanced Research Projects
 * Agency (DARPA) and Air Force Research Laboratory, Air Force
 * Materiel Command, USAF, under agreement number F39502-99-1-0512.
 */

#include <sys/stat.h>
#include <sys/tree.h>

#include <dirent.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <fnmatch.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "diff.h"

static int selectfile(const struct dirent *);
static void diffit(struct dirent *, char *, size_t, struct dirent *,
        char *, size_t, int);
static void print_only(const char *, size_t, const char *);

struct inode {
        dev_t dev;
        ino_t ino;
        RB_ENTRY(inode) entry;
};

static int
inodecmp(struct inode *a, struct inode *b)
{
        return (a->dev < b->dev ? -1 : a->dev > b->dev ? 1 :
            a->ino < b->ino ? -1 : a->ino > b->ino ? 1 : 0);
}

RB_HEAD(inodetree, inode);
static struct inodetree v1 = RB_INITIALIZER(&v1);
static struct inodetree v2 = RB_INITIALIZER(&v2);
RB_GENERATE_STATIC(inodetree, inode, entry, inodecmp);

static int
vscandir(struct inodetree *tree, struct inode **inop,
    const char *path, struct dirent ***dirp,
    int (*selectf)(const struct dirent *),
    int (*comparf)(const struct dirent **, const struct dirent **))
{
        struct stat sb;
        struct inode *ino = NULL;
        int fd = -1, ret, serrno;

        if ((fd = open(path, O_DIRECTORY | O_RDONLY)) < 0 ||
            (ino = calloc(1, sizeof(*ino))) == NULL ||
            fstat(fd, &sb) != 0)
                goto fail;
        ino->dev = sb.st_dev;
        ino->ino = sb.st_ino;
        if (RB_FIND(inodetree, tree, ino)) {
                free(ino);
                close(fd);
                warnx("%s: Directory loop detected", path);
                *dirp = NULL;
                return (0);
        }
        if ((ret = fdscandir(fd, dirp, selectf, comparf)) < 0)
                goto fail;
        RB_INSERT(inodetree, tree, ino);
        close(fd);
        *inop = ino;
        return (ret);
fail:
        serrno = errno;
        if (ino != NULL)
                free(ino);
        if (fd >= 0)
                close(fd);
        errno = serrno;
        return (-1);
}

static void
leavedir(struct inodetree *tree, struct inode *ino)
{
        RB_REMOVE(inodetree, tree, ino);
        free(ino);
}

/*
 * Diff directory traversal. Will be called recursively if -r was specified.
 */
void
diffdir(char *p1, char *p2, int flags)
{
        struct dirent *dent1, **dp1, **edp1, **dirp1 = NULL;
        struct dirent *dent2, **dp2, **edp2, **dirp2 = NULL;
        struct inode *ino1 = NULL, *ino2 = NULL;
        size_t dirlen1, dirlen2;
        char path1[PATH_MAX], path2[PATH_MAX];
        int pos;

        edp1 = edp2 = NULL;

        dirlen1 = strlcpy(path1, *p1 ? p1 : ".", sizeof(path1));
        if (dirlen1 >= sizeof(path1) - 1) {
                warnc(ENAMETOOLONG, "%s", p1);
                status |= 2;
                return;
        }
        while (dirlen1 > 1 && path1[dirlen1 - 1] == '/')
                path1[--dirlen1] = '\0';
        dirlen2 = strlcpy(path2, *p2 ? p2 : ".", sizeof(path2));
        if (dirlen2 >= sizeof(path2) - 1) {
                warnc(ENAMETOOLONG, "%s", p2);
                status |= 2;
                return;
        }
        while (dirlen2 > 1 && path2[dirlen2 - 1] == '/')
                path2[--dirlen2] = '\0';

        /*
         * Get a list of entries in each directory, skipping "excluded" files
         * and sorting alphabetically.
         */
        pos = vscandir(&v1, &ino1, path1, &dirp1, selectfile, alphasort);
        if (pos == -1) {
                if (errno == ENOENT && (Nflag || Pflag)) {
                        pos = 0;
                } else {
                        warn("%s", path1);
                        goto closem;
                }
        }
        dp1 = dirp1;
        edp1 = dirp1 + pos;

        pos = vscandir(&v2, &ino2, path2, &dirp2, selectfile, alphasort);
        if (pos == -1) {
                if (errno == ENOENT && Nflag) {
                        pos = 0;
                } else {
                        warn("%s", path2);
                        goto closem;
                }
        }
        dp2 = dirp2;
        edp2 = dirp2 + pos;

        /*
         * If we were given a starting point, find it.
         */
        if (start != NULL) {
                while (dp1 != edp1 && strcmp((*dp1)->d_name, start) < 0)
                        dp1++;
                while (dp2 != edp2 && strcmp((*dp2)->d_name, start) < 0)
                        dp2++;
        }

        /*
         * Append separator so children's names can be appended directly.
         */
        if (path1[dirlen1 - 1] != '/') {
                path1[dirlen1++] = '/';
                path1[dirlen1] = '\0';
        }
        if (path2[dirlen2 - 1] != '/') {
                path2[dirlen2++] = '/';
                path2[dirlen2] = '\0';
        }

        /*
         * Iterate through the two directory lists, diffing as we go.
         */
        while (dp1 != edp1 || dp2 != edp2) {
                dent1 = dp1 != edp1 ? *dp1 : NULL;
                dent2 = dp2 != edp2 ? *dp2 : NULL;

                pos = dent1 == NULL ? 1 : dent2 == NULL ? -1 :
                    ignore_file_case ? strcasecmp(dent1->d_name, dent2->d_name) :
                    strcmp(dent1->d_name, dent2->d_name) ;
                if (pos == 0) {
                        /* file exists in both dirs, diff it */
                        diffit(dent1, path1, dirlen1, dent2, path2, dirlen2, flags);
                        dp1++;
                        dp2++;
                } else if (pos < 0) {
                        /* file only in first dir, only diff if -N */
                        if (Nflag) {
                                diffit(dent1, path1, dirlen1, dent2, path2,
                                        dirlen2, flags);
                        } else {
                                print_only(path1, dirlen1, dent1->d_name);
                                status |= 1;
                        }
                        dp1++;
                } else {
                        /* file only in second dir, only diff if -N or -P */
                        if (Nflag || Pflag)
                                diffit(dent2, path1, dirlen1, dent1, path2,
                                        dirlen2, flags);
                        else {
                                print_only(path2, dirlen2, dent2->d_name);
                                status |= 1;
                        }
                        dp2++;
                }
        }

closem:
        if (dirp1 != NULL) {
                if (ino1 != NULL)
                        leavedir(&v1, ino1);
                for (dp1 = dirp1; dp1 < edp1; dp1++)
                        free(*dp1);
                free(dirp1);
        }
        if (dirp2 != NULL) {
                if (ino2 != NULL)
                        leavedir(&v2, ino2);
                for (dp2 = dirp2; dp2 < edp2; dp2++)
                        free(*dp2);
                free(dirp2);
        }
}

/*
 * Do the actual diff by calling either diffreg() or diffdir().
 */
static void
diffit(struct dirent *dp, char *path1, size_t plen1, struct dirent *dp2,
        char *path2, size_t plen2, int flags)
{
        int rc;

        flags |= D_HEADER;
        strlcpy(path1 + plen1, dp->d_name, PATH_MAX - plen1);

        /*
         * If we are ignoring file case, use dent2s name here if both names are
         * the same apart from case.
         */
        if (ignore_file_case && strcasecmp(dp2->d_name, dp2->d_name) == 0)
                strlcpy(path2 + plen2, dp2->d_name, PATH_MAX - plen2);
        else
                strlcpy(path2 + plen2, dp->d_name, PATH_MAX - plen2);

        if (noderef) {
                if (lstat(path1, &stb1) != 0) {
                        if (!(Nflag || Pflag) || errno != ENOENT) {
                                warn("%s", path1);
                                return;
                        }
                        flags |= D_EMPTY1;
                        memset(&stb1, 0, sizeof(stb1));
                }
                if (lstat(path2, &stb2) != 0) {
                        if (!Nflag || errno != ENOENT) {
                                warn("%s", path2);
                                return;
                        }
                        flags |= D_EMPTY2;
                        memset(&stb2, 0, sizeof(stb2));
                        stb2.st_mode = stb1.st_mode;
                }
                if (stb1.st_mode == 0)
                        stb1.st_mode = stb2.st_mode;
                if (S_ISLNK(stb1.st_mode) || S_ISLNK(stb2.st_mode)) {
                        if  (S_ISLNK(stb1.st_mode) && S_ISLNK(stb2.st_mode)) {
                                char buf1[PATH_MAX];
                                char buf2[PATH_MAX];
                                ssize_t len1 = 0;
                                ssize_t len2 = 0;

                                len1 = readlink(path1, buf1, sizeof(buf1));
                                len2 = readlink(path2, buf2, sizeof(buf2));

                                if (len1 < 0 || len2 < 0) {
                                        perror("reading links");
                                        return;
                                }
                                buf1[len1] = '\0';
                                buf2[len2] = '\0';

                                if (len1 != len2 || strncmp(buf1, buf2, len1) != 0) {
                                        printf("Symbolic links %s and %s differ\n",
                                                path1, path2);
                                        status |= 1;
                                }

                                return;
                        }

                        printf("File %s is a %s while file %s is a %s\n",
                                path1, S_ISLNK(stb1.st_mode) ? "symbolic link" :
                                        (S_ISDIR(stb1.st_mode) ? "directory" :
                                        (S_ISREG(stb1.st_mode) ? "file" : "error")),
                                path2, S_ISLNK(stb2.st_mode) ? "symbolic link" :
                                        (S_ISDIR(stb2.st_mode) ? "directory" :
                                        (S_ISREG(stb2.st_mode) ? "file" : "error")));
                        status |= 1;
                        return;
                }
        } else {
                if (stat(path1, &stb1) != 0) {
                        if (!(Nflag || Pflag) || errno != ENOENT) {
                                warn("%s", path1);
                                return;
                        }
                        flags |= D_EMPTY1;
                        memset(&stb1, 0, sizeof(stb1));
                }
                if (stat(path2, &stb2) != 0) {
                        if (!Nflag || errno != ENOENT) {
                                warn("%s", path2);
                                return;
                        }
                        flags |= D_EMPTY2;
                        memset(&stb2, 0, sizeof(stb2));
                        stb2.st_mode = stb1.st_mode;
                }
                if (stb1.st_mode == 0)
                        stb1.st_mode = stb2.st_mode;
        }
        if (stb1.st_dev == stb2.st_dev && stb1.st_ino == stb2.st_ino)
                return;
        if (S_ISDIR(stb1.st_mode) && S_ISDIR(stb2.st_mode)) {
                if (rflag)
                        diffdir(path1, path2, flags);
                else
                        printf("Common subdirectories: %s and %s\n",
                            path1, path2);
                return;
        }
        if (!S_ISREG(stb1.st_mode) && !S_ISDIR(stb1.st_mode))
                rc = D_SKIPPED1;
        else if (!S_ISREG(stb2.st_mode) && !S_ISDIR(stb2.st_mode))
                rc = D_SKIPPED2;
        else
                rc = diffreg(path1, path2, flags, 0);
        print_status(rc, path1, path2, "");
}

/*
 * Returns 1 if the directory entry should be included in the
 * diff, else 0.  Checks the excludes list.
 */
static int
selectfile(const struct dirent *dp)
{
        struct excludes *excl;

        if (dp->d_fileno == 0)
                return (0);

        /* always skip "." and ".." */
        if (dp->d_name[0] == '.' && (dp->d_name[1] == '\0' ||
            (dp->d_name[1] == '.' && dp->d_name[2] == '\0')))
                return (0);

        /* check excludes list */
        for (excl = excludes_list; excl != NULL; excl = excl->next)
                if (fnmatch(excl->pattern, dp->d_name, FNM_PATHNAME) == 0)
                        return (0);

        return (1);
}

void
print_only(const char *path, size_t dirlen, const char *entry)
{
        if (dirlen > 1)
                dirlen--;
        printf("Only in %.*s: %s\n", (int)dirlen, path, entry);
}