/*-
 * Copyright (c) 1990, 1993, 1994
 *      The Regents of the University of California.  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. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
 *
 * @(#) Copyright (c) 1990, 1993, 1994 The Regents of the University of California.  All rights reserved.
 * @(#)rm.c     8.5 (Berkeley) 4/18/94
 * $FreeBSD: src/bin/rm/rm.c,v 1.29.2.5 2002/07/12 07:25:48 tjr Exp $
 */

#include <sys/stat.h>
#include <sys/param.h>
#include <sys/mount.h>
#include <sys/ioctl.h>

#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <fts.h>
#include <grp.h>
#include <pwd.h>
#include <signal.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <unistd.h>

static int dflag, eval, fflag, iflag, Pflag, vflag, Wflag, stdin_ok;
static int rflag, Iflag, xflag;
static uid_t uid;
static volatile sig_atomic_t info;

static int      check(const char *, const char *, struct stat *);
static int      check2(char **);
static void     checkdot(char **);
static void     rm_file(char **);
static int      rm_overwrite(const char *, struct stat *);
static void     rm_tree(char **);
#ifdef SIGINFO
static void     siginfo(int);
#endif
static void     usage(void);

/*
 * rm --
 *      This rm is different from historic rm's, but is expected to match
 *      POSIX 1003.2 behavior.  The most visible difference is that -f
 *      has two specific effects now, ignore non-existent files and force
 *      file removal.
 */
int
main(int argc, char *argv[])
{
        int ch;
        const char *p;
        pid_t tty_pgrp;

        /*
         * Test for the special case where the utility is called as
         * "unlink", for which the functionality provided is greatly
         * simplified.
         */
        if ((p = strrchr(argv[0], '/')) == NULL)
                p = argv[0];
        else
                ++p;
        if (strcmp(p, "unlink") == 0) {
                while (getopt(argc, argv, "") != -1)
                        usage();
                argc -= optind;
                argv += optind;
                if (argc != 1)
                        usage();
                rm_file(&argv[0]);
                exit(eval);
        }

        Pflag = rflag = xflag = 0;
        while ((ch = getopt(argc, argv, "dfiIPRrvWx")) != -1) {
                switch(ch) {
                case 'd':
                        dflag = 1;
                        break;
                case 'f':
                        fflag = 1;
                        iflag = 0;
                        break;
                case 'i':
                        fflag = 0;
                        iflag = 1;
                        break;
                case 'I':
                        /*
                         * The -I flag is intended to be generally aliasable
                         * in /etc/csh.cshrc.  We apply it only to foreground
                         * processes.
                         */
                        if (ioctl(0, TIOCGPGRP, &tty_pgrp) == 0) {
                                if (tty_pgrp == getpgrp())
                                        Iflag = 1;
                        }
                        break;
                case 'P':
                        Pflag = 1;
                        break;
                case 'R':
                case 'r':                       /* Compatibility. */
                        rflag = 1;
                        break;
                case 'v':
                        vflag = 1;
                        break;
                case 'W':
#ifdef S_IFWHT
                        Wflag = 1;
#endif
                        break;
                case 'x':
                        xflag = 1;
                        break;
                default:
                        usage();
                }
        }
        argc -= optind;
        argv += optind;

        if (argc < 1) {
                if (fflag)
                        return 0;
                usage();
        }

        checkdot(argv);
        uid = geteuid();

#ifdef SIGINFO
        signal(SIGINFO, siginfo);
#endif

        if (*argv) {
                stdin_ok = isatty(STDIN_FILENO);

                if (Iflag && !iflag) {
                        if (check2(argv) == 0)
                                exit (1);
                }
                if (rflag)
                        rm_tree(argv);
                else
                        rm_file(argv);
        }

        exit (eval);
}

static void
rm_tree(char **argv)
{
        FTS *fts;
        FTSENT *p;
        int needstat;
        int flags;
        int rval;

        /*
         * Remove a file hierarchy.  If forcing removal (-f), or interactive
         * (-i) or can't ask anyway (stdin_ok), don't stat the file.
         */
        needstat = !uid || (!fflag && !iflag && stdin_ok);

        /*
         * If the -i option is specified, the user can skip on the pre-order
         * visit.  The fts_number field flags skipped directories.
         */
#define SKIPPED 1

        flags = FTS_PHYSICAL;
        if (!needstat)
                flags |= FTS_NOSTAT;
#ifdef S_IFWHT
        if (Wflag)
                flags |= FTS_WHITEOUT;
#endif
        if (xflag)
                flags |= FTS_XDEV;
        if ((fts = fts_open(argv, flags, NULL)) == NULL) {
                if (fflag && errno == ENOENT)
                        return;
                err(1, "fts_open");
        }
        while ((p = fts_read(fts)) != NULL) {
                switch (p->fts_info) {
                case FTS_DNR:
                        if (!fflag || p->fts_errno != ENOENT) {
                                warnx("%s: %s",
                                    p->fts_path, strerror(p->fts_errno));
                                eval = 1;
                        }
                        continue;
                case FTS_ERR:
                        errx(1, "%s: %s", p->fts_path, strerror(p->fts_errno));
                case FTS_NS:
                       /*
                        * Assume that since fts_read() couldn't stat
                        * the file, it can't be unlinked.
                        */
                        if (!needstat)
                                break;
                        if (!fflag || p->fts_errno != ENOENT) {
                                warnx("%s: %s",
                                    p->fts_path, strerror(p->fts_errno));
                                eval = 1;
                        }
                        continue;
                case FTS_D:
                        /* Pre-order: give user chance to skip. */
                        if (!fflag && !check(p->fts_path, p->fts_accpath,
                            p->fts_statp)) {
                                fts_set(fts, p, FTS_SKIP);
                                p->fts_number = SKIPPED;
                        }
#ifdef _ST_FLAGS_PRESENT_
                        else if (!uid &&
                                 (p->fts_statp->st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
                                 !(p->fts_statp->st_flags & (SF_APPEND|SF_IMMUTABLE)) &&
                                 lchflags(p->fts_accpath,
                                         p->fts_statp->st_flags &= ~(UF_APPEND|UF_IMMUTABLE)) < 0)
                                goto err;
#endif
                        continue;
                case FTS_DP:
                        /* Post-order: see if user skipped. */
                        if (p->fts_number == SKIPPED)
                                continue;
                        break;
                default:
                        if (!fflag &&
                            !check(p->fts_path, p->fts_accpath, p->fts_statp))
                                continue;
                }

                if (info) {
                        info = 0;
                        fprintf(stderr, "Currently removing: %s\n", p->fts_path);
                }

                rval = 0;
#ifdef _ST_FLAGS_PRESENT_
                if (!uid &&
                    (p->fts_statp->st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
                    !(p->fts_statp->st_flags & (SF_APPEND|SF_IMMUTABLE)))
                        rval = lchflags(p->fts_accpath,
                                       p->fts_statp->st_flags &= ~(UF_APPEND|UF_IMMUTABLE));
#endif

                if (rval == 0) {
                        /*
                         * If we can't read or search the directory, may still be
                         * able to remove it.  Don't print out the un{read,search}able
                         * message unless the remove fails.
                         */
                        switch (p->fts_info) {
                        case FTS_DP:
                        case FTS_DNR:
                                rval = rmdir(p->fts_accpath);
                                if (rval == 0 || (fflag && errno == ENOENT)) {
                                        if (rval == 0 && vflag)
                                                printf("%s\n",
                                                    p->fts_path);
                                        continue;
                                }
                                break;
#ifdef S_IFWHT
                        case FTS_W:
                                rval = undelete(p->fts_accpath);
                                if (rval == 0 && (fflag && errno == ENOENT)) {
                                        if (vflag)
                                                printf("%s\n",
                                                    p->fts_path);
                                        continue;
                                }
                                break;
#endif
                        case FTS_NS:
                        /*
                         * Assume that since fts_read() couldn't stat
                         * the file, it can't be unlinked.
                         */
                                if (fflag)
                                        continue;
                                /* FALLTHROUGH */
                        default:
                                if (Pflag)
                                        if (!rm_overwrite(p->fts_accpath, NULL))
                                                continue;
                                rval = unlink(p->fts_accpath);
                                if (rval == 0 || (fflag && errno == ENOENT)) {
                                        if (rval == 0 && vflag)
                                                printf("%s\n",
                                                    p->fts_path);
                                        continue;
                                }
                        }
                }
#ifdef _ST_FLAGS_PRESENT_
err:
#endif
                warn("%s", p->fts_path);
                eval = 1;
        }
        if (errno)
                err(1, "fts_read");
        fts_close(fts);
}

static void
rm_file(char **argv)
{
        struct stat sb;
        int rval;
        const char *f;

        /*
         * Remove a file.  POSIX 1003.2 states that, by default, attempting
         * to remove a directory is an error, so must always stat the file.
         */
        while ((f = *argv++) != NULL) {
                if (info) {
                        info = 0;
                        fprintf(stderr, "Currently removing: %s\n", f);
                }

                /* Assume if can't stat the file, can't unlink it. */
                if (lstat(f, &sb)) {
                        if (Wflag) {
#ifdef S_IFWHT
                                sb.st_mode = S_IFWHT|S_IWUSR|S_IRUSR;
#endif
                        } else {
                                if (!fflag || errno != ENOENT) {
                                        warn("%s", f);
                                        eval = 1;
                                }
                                continue;
                        }
                } else if (Wflag) {
                        warnx("%s: %s", f, strerror(EEXIST));
                        eval = 1;
                        continue;
                }

                if (S_ISDIR(sb.st_mode) && !dflag) {
                        warnx("%s: is a directory", f);
                        eval = 1;
                        continue;
                }
                if (!fflag && !S_ISWHT(sb.st_mode) && !check(f, f, &sb))
                        continue;
                rval = 0;
#ifdef _ST_FLAGS_PRESENT_
                if (!uid && !S_ISWHT(sb.st_mode) &&
                    (sb.st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
                    !(sb.st_flags & (SF_APPEND|SF_IMMUTABLE)))
                        rval = lchflags(f, sb.st_flags & ~(UF_APPEND|UF_IMMUTABLE));
#endif
                if (rval == 0) {
#ifdef S_IFWHT
                        if (S_ISWHT(sb.st_mode))
                                rval = undelete(f);
                        else
#endif
                        if (S_ISDIR(sb.st_mode))
                                rval = rmdir(f);
                        else {
                                if (Pflag)
                                        if (!rm_overwrite(f, &sb))
                                                continue;
                                rval = unlink(f);
                        }
                }
                if (rval && (!fflag || errno != ENOENT)) {
                        warn("%s", f);
                        eval = 1;
                }
                if (vflag && rval == 0)
                        printf("%s\n", f);
        }
}

/*
 * rm_overwrite --
 *      Overwrite the file 3 times with varying bit patterns.
 *
 * XXX
 * This is a cheap way to *really* delete files.  Note that only regular
 * files are deleted, directories (and therefore names) will remain.
 * Also, this assumes a fixed-block filesystem (like FFS, or a V7 or a
 * System V filesystem).  In a logging filesystem, you'll have to have
 * kernel support.
 */
static int 
rm_overwrite(const char *file, struct stat *sbp)
{
        struct stat sb;
        struct statfs fsb;
        off_t len;
        int bsize, fd, wlen;
        char *buf = NULL;

        fd = -1;
        if (sbp == NULL) {
                if (lstat(file, &sb))
                        goto err;
                sbp = &sb;
        }
        if (!S_ISREG(sbp->st_mode)) {
                warnx("%s: cannot overwrite a non-regular file", file);
                return (1);
        }
        if (sbp->st_nlink > 1) {
                warnx("%s (inode %ju): not overwritten due to multiple links",
                      file, (uintmax_t)sbp->st_ino);
                return (0);
        }
        if ((fd = open(file, O_WRONLY, 0)) == -1)
                goto err;
        if (fstatfs(fd, &fsb) == -1)
                goto err;
        bsize = MAX(fsb.f_iosize, 1024);
        if ((buf = malloc(bsize)) == NULL)
                err(1, "%s malloc failed", file);

#define PASS(byte) {                                                    \
        memset(buf, byte, bsize);                                       \
        for (len = sbp->st_size; len > 0; len -= wlen) {                \
                wlen = len < bsize ? len : bsize;                       \
                if (write(fd, buf, wlen) != wlen)                       \
                        goto err;                                       \
        }                                                               \
}
        PASS(0xff);
        if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
                goto err;
        PASS(0x00);
        if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
                goto err;
        PASS(0xff);
        if (!fsync(fd) && !close(fd)) {
                free(buf);
                return (1);
        }

err:    eval = 1;
        if (buf)
                free(buf);
        if (fd != -1)
                close(fd);
        warn("%s", file);
        return (0);
}


static int
check(const char *path, const char *name, struct stat *sp)
{
        static int perm_answer = -1;
        struct choice {
                int ch;
                const char *str;
                int res;
                int perm;
        } *choice, choices[] = {
                { 'y', "yes"   , 1, 0 },
                { 'n', "no"    , 0, 0 },
                { 'a', "always", 1, 1 },
                { 'v', "never" , 0, 1 },
                { 0, NULL, 0, 0 }
        };
        char modep[15], *flagsp = NULL;

        if (perm_answer != -1)
                return (perm_answer);

        /* Check -i first. */
        if (iflag)
                fprintf(stderr, "remove %s? ", path);
        else {
                /*
                 * If it's not a symbolic link and it's unwritable and we're
                 * talking to a terminal, ask.  Symbolic links are excluded
                 * because their permissions are meaningless.  Check stdin_ok
                 * first because we may not have stat'ed the file.
                 * Also skip this check if the -P option was specified because
                 * we will not be able to overwrite file contents and will
                 * barf later.
                 */
                if (!stdin_ok || S_ISLNK(sp->st_mode) || Pflag ||
                    (!access(name, W_OK)
#ifdef _ST_FLAGS_PRESENT_
                    && !(sp->st_flags & (SF_APPEND|SF_IMMUTABLE)) &&
                    (!(sp->st_flags & (UF_APPEND|UF_IMMUTABLE)) || !uid)
#endif
                    ))
                        return (1);
                strmode(sp->st_mode, modep);
#ifdef _ST_FLAGS_PRESENT_
                if ((flagsp = fflagstostr(sp->st_flags)) == NULL)
                        err(1, NULL);
#endif
                fprintf(stderr, "override %s%s%s/%s %s%sfor %s? ",
                    modep + 1, modep[9] == ' ' ? "" : " ",
                    user_from_uid(sp->st_uid, 0),
                    group_from_gid(sp->st_gid, 0),
                    *flagsp ? flagsp : "", *flagsp ? " " : "",
                    path);
                free(flagsp);
        }
        fflush(stderr);

        for (;;) {
                size_t len;
                char *answer;

                answer = fgetln(stdin, &len);
                /* clearerr(stdin); */
                if (answer == NULL)
                        return (0);
                if (answer[len - 1] == '\n')
                        len--;
                if (len == 0)
                        continue;

                for (choice = choices; choice->str != NULL; choice++) {
                        if (len == 1 && choice->ch == answer[0])
                                goto valid_choice;
                        if (strncasecmp(answer, choice->str, len) == 0)
                                goto valid_choice;
                }

                fprintf(stderr, "invalid answer, try again (y/n/a/v): ");
        }

valid_choice:
        if (choice->perm)
                perm_answer = choice->res;
        return (choice->res);
}

static int
check2(char **argv)
{
        struct stat st;
        int first;
        int ch;
        int fcount = 0;
        int dcount = 0;
        int i;
        const char *dname = NULL;

        for (i = 0; argv[i]; ++i) {
                if (lstat(argv[i], &st) == 0) {
                        if (S_ISDIR(st.st_mode)) {
                                ++dcount;
                                dname = argv[i];    /* only used if 1 dir */
                        } else {
                                ++fcount;
                        }
                }
        }
        first = 0;
        while (first != 'n' && first != 'N' && first != 'y' && first != 'Y') {
                if (dcount && rflag) {
                        fprintf(stderr, "recursively remove");
                        if (dcount == 1)
                                fprintf(stderr, " %s", dname);
                        else
                                fprintf(stderr, " %d dirs", dcount);
                        if (fcount == 1)
                                fprintf(stderr, " and 1 file");
                        else if (fcount > 1)
                                fprintf(stderr, " and %d files", fcount);
                } else if (dcount + fcount > 3) {
                        fprintf(stderr, "remove %d files", dcount + fcount);
                } else {
                        return(1);
                }
                fprintf(stderr, "? ");
                fflush(stderr);

                first = ch = getchar();
                while (ch != '\n' && ch != EOF)
                        ch = getchar();
                if (ch == EOF)
                        break;
        }
        return (first == 'y' || first == 'Y');
}

#define ISDOT(a)        ((a)[0] == '.' && (!(a)[1] || ((a)[1] == '.' && !(a)[2])))
static void
checkdot(char **argv)
{
        char *p, **save, **t;
        int complained;

        complained = 0;
        for (t = argv; *t;) {
                if ((p = strrchr(*t, '/')) != NULL)
                        ++p;
                else
                        p = *t;
                if (ISDOT(p)) {
                        if (!complained++)
                                warnx("\".\" and \"..\" may not be removed");
                        eval = 1;
                        for (save = t; (t[0] = t[1]) != NULL; ++t)
                                continue;
                        t = save;
                } else
                        ++t;
        }
}

static void
usage(void)
{

        fprintf(stderr, "%s\n%s\n",
            "usage: rm [-f | -i] [-dIPRrvWx] file ...",
            "       unlink file");
        exit(EX_USAGE);
}

#ifdef SIGINFO
static void
siginfo(int notused __unused)
{
        info = 1;
}
#endif