/* vi: set sw=4 ts=4: */
/*
 * chattr.c             - Change file attributes on an ext2 file system
 *
 * Copyright (C) 1993, 1994  Remy Card <card@masi.ibp.fr>
 *                           Laboratoire MASI, Institut Blaise Pascal
 *                           Universite Pierre et Marie Curie (Paris VI)
 *
 * This file can be redistributed under the terms of the GNU General
 * Public License
 */
//config:config CHATTR
//config:       bool "chattr (3.8 kb)"
//config:       default y
//config:       help
//config:       chattr changes the file attributes on a second extended file system.

//applet:IF_CHATTR(APPLET_NOEXEC(chattr, chattr, BB_DIR_BIN, BB_SUID_DROP, chattr))

//kbuild:lib-$(CONFIG_CHATTR) += chattr.o e2fs_lib.o

//usage:#define chattr_trivial_usage
//usage:       "[-R] [-v VERSION] [-p PROJID] [-+=AacDdijsStTu] FILE..."
//usage:#define chattr_full_usage "\n\n"
//usage:       "Change ext2 file attributes\n"
//usage:     "\n        -R      Recurse"
//usage:     "\n        -v NUM  Set version/generation number"
//usage:     "\n        -p NUM  Set project number"
//-V, -f accepted but ignored
//usage:     "\nModifiers:"
//usage:     "\n        -,+,=   Remove/add/set attributes"
//usage:     "\nAttributes:"
//usage:     "\n        A       No atime"
//usage:     "\n        a       Append only"
//usage:     "\n        C       No copy-on-write"
//usage:     "\n        c       Compressed"
//usage:     "\n        D       Synchronous dir updates"
//usage:     "\n        d       Don't backup with dump"
//usage:     "\n        E       Encrypted"
//usage:     "\n        e       File uses extents"
//usage:     "\n        F       Case-insensitive dir"
//usage:     "\n        I       Indexed dir"
//usage:     "\n        i       Immutable"
//usage:     "\n        j       Write data to journal first"
//usage:     "\n        N       File is stored in inode"
//usage:     "\n        P       Hierarchical project ID dir"
//usage:     "\n        S       Synchronous file updates"
//usage:     "\n        s       Zero storage when deleted"
//usage:     "\n        T       Top of dir hierarchy"
//usage:     "\n        t       Don't tail-merge with other files"
//usage:     "\n        u       Allow undelete"
//usage:     "\n        V       Verity"

#include "libbb.h"
#include "e2fs_lib.h"

#define OPT_ADD      (1 << 0)
#define OPT_REM      (1 << 1)
#define OPT_SET      (1 << 2)
#define OPT_SET_VER  (1 << 3)
#define OPT_SET_PROJ (1 << 4)

struct globals {
        unsigned version;
        unsigned af;
        unsigned rf;
        int flags;
        uint32_t projid;
        smallint recursive;
};

static unsigned long get_flag(char c)
{
        const char *fp = strchr(e2attr_flags_sname_chattr, c);
        if (fp)
                return e2attr_flags_value_chattr[fp - e2attr_flags_sname_chattr];
        bb_show_usage();
}

static char** decode_arg(char **argv, struct globals *gp)
{
        unsigned *fl;
        const char *arg = *argv;
        char opt = *arg;

        fl = &gp->af;
        if (opt == '-') {
                /* gp->flags |= OPT_REM; - WRONG, it can be an option */
                /* testcase: chattr =ae -R FILE should not complain "= is incompatible with - and +" */
                /* (and should not read flags, with =FLAGS they can be just set directly) */
                fl = &gp->rf;
        } else if (opt == '+') {
                gp->flags |= OPT_ADD;
        } else { /* if (opt == '=') */
                gp->flags |= OPT_SET;
        }

        while (*++arg) {
                if (opt == '-') {
//e2fsprogs-1.43.1 accepts:
// "-RRR", "-RRRv VER" and even "-ARRRva VER" and "-vvv V1 V2 V3"
// but not "-vVER".
// IOW: options are parsed as part of "remove attrs" strings,
// if "v" is seen, next argv[] is VER, even if more opts/attrs follow in this argv[]!
                        if (*arg == 'R') {
                                gp->recursive = 1;
                                continue;
                        }
                        if (*arg == 'V') {
                                /*"verbose and print program version" (nop for now) */;
                                continue;
                        }
                        if (*arg == 'f') {
                                /*"suppress most error messages" (nop) */;
                                continue;
                        }
                        if (*arg == 'v') {
                                if (!*++argv)
                                        bb_show_usage();
                                gp->version = xatou(*argv);
                                gp->flags |= OPT_SET_VER;
                                continue;
                        }
                        if (*arg == 'p') {
                                if (!*++argv)
                                        bb_show_usage();
                                gp->projid = xatou32(*argv);
                                gp->flags |= OPT_SET_PROJ;
                                continue;
                        }
                        /* not a known option, try as an attribute */
                        gp->flags |= OPT_REM;
                }
                *fl |= get_flag(*arg); /* aborts on bad flag letter */
        }

        return argv;
}

static void change_attributes(const char *name, struct globals *gp);

static int FAST_FUNC chattr_dir_proc(const char *dir_name, struct dirent *de, void *gp)
{
//TODO: use de->d_type (if it's not DT_UNKNOWN) to skip !(REG || DIR || LNK) entries without lstat?

        char *path = concat_subpath_file(dir_name, de->d_name);
        /* path is NULL if de->d_name is "." or "..", else... */
        if (path) {
                change_attributes(path, gp);
                free(path);
        }
        return 0;
}

static void change_attributes(const char *name, struct globals *gp)
{
        unsigned fsflags;
        int fd;
        struct stat st;

        if (lstat(name, &st) != 0) {
                bb_perror_msg("can't stat '%s'", name);
                return;
        }

        /* Don't try to open device files, fifos etc.  We probably
         * ought to display an error if the file was explicitly given
         * on the command line (whether or not recursive was
         * requested).  */
        if (!S_ISREG(st.st_mode) && !S_ISLNK(st.st_mode) && !S_ISDIR(st.st_mode))
                return;

        /* There is no way to run needed ioctls on a symlink.
         * open(O_PATH | O_NOFOLLOW) _can_ be used to get a fd referring to the symlink,
         * but ioctls fail on such a fd (tried on 4.12.0 kernel).
         * e2fsprogs-1.46.2 uses open(O_NOFOLLOW), it fails on symlinks.
         */
        fd = open_or_warn(name, O_RDONLY | O_NONBLOCK | O_NOCTTY | O_NOFOLLOW);
        if (fd >= 0) {
                int r;

                if (gp->flags & OPT_SET_VER) {
                        r = ioctl(fd, EXT2_IOC_SETVERSION, &gp->version);
                        if (r != 0)
                                bb_perror_msg("setting %s on %s", "version", name);
                }

                if (gp->flags & OPT_SET_PROJ) {
                        struct ext2_fsxattr fsxattr;
                        r = ioctl(fd, EXT2_IOC_FSGETXATTR, &fsxattr);
                        /* note: ^^^ may fail in 32-bit userspace on 64-bit kernel (seen on 4.12.0) */
                        if (r != 0) {
                                bb_perror_msg("getting %s on %s", "project ID", name);
                        } else {
                                fsxattr.fsx_projid = gp->projid;
                                r = ioctl(fd, EXT2_IOC_FSSETXATTR, &fsxattr);
                                if (r != 0)
                                        bb_perror_msg("setting %s on %s", "project ID", name);
                        }
                }

                if (gp->flags & OPT_SET) {
                        fsflags = gp->af;
                } else {
                        r = ioctl(fd, EXT2_IOC_GETFLAGS, &fsflags);
                        if (r != 0) {
                                bb_perror_msg("getting %s on %s", "flags", name);
                                goto skip_setflags;
                        }
                        /*if (gp->flags & OPT_REM) - not needed, rf is zero otherwise */
                                fsflags &= ~gp->rf;
                        /*if (gp->flags & OPT_ADD) - not needed, af is zero otherwise */
                                fsflags |= gp->af;
// What is this? And why it's not done for SET case?
                        if (!S_ISDIR(st.st_mode))
                                fsflags &= ~EXT2_DIRSYNC_FL;
                }
                r = ioctl(fd, EXT2_IOC_SETFLAGS, &fsflags);
                if (r != 0)
                        bb_perror_msg("setting %s on %s", "flags", name);
 skip_setflags:
                close(fd);
        }

        if (gp->recursive && S_ISDIR(st.st_mode))
                iterate_on_dir(name, chattr_dir_proc, gp);
}

int chattr_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int chattr_main(int argc UNUSED_PARAM, char **argv)
{
        struct globals g;

        memset(&g, 0, sizeof(g));

        /* parse the args */
        for (;;) {
                char *arg = *++argv;
                if (!arg)
                        bb_show_usage();
                if (arg[0] != '-' && arg[0] != '+' && arg[0] != '=')
                        break;

                argv = decode_arg(argv, &g);
        }
        /* note: on loop exit, remaining argv[] is never empty */

        /* run sanity checks on all the arguments given us */
        if ((g.flags & OPT_SET) && (g.flags & (OPT_ADD|OPT_REM)))
                bb_simple_error_msg_and_die("= is incompatible with - and +");
        if (g.rf & g.af)
                bb_simple_error_msg_and_die("can't set and unset a flag");
        if (!g.flags)
                bb_simple_error_msg_and_die("must use -v, -p, =, - or +");

        /* now run chattr on all the files passed to us */
        do change_attributes(*argv, &g); while (*++argv);

        return EXIT_SUCCESS;
}