source: MondoRescue/branches/2.2.9/mindi-busybox/coreutils/dd.c@ 2859

/* vi: set sw=4 ts=4: */
/*
 * Mini dd implementation for busybox
 *
 *
 * Copyright (C) 2000,2001  Matt Kraai
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */

#include "libbb.h"

/* This is a NOEXEC applet. Be very careful! */


enum {
    ifd = STDIN_FILENO,
    ofd = STDOUT_FILENO,
};

static const struct suffix_mult dd_suffixes[] = {
    { "c", 1 },
    { "w", 2 },
    { "b", 512 },
    { "kD", 1000 },
    { "k", 1024 },
    { "K", 1024 },  /* compat with coreutils dd */
    { "MD", 1000000 },
    { "M", 1048576 },
    { "GD", 1000000000 },
    { "G", 1073741824 },
    { "", 0 }
};

struct globals {
    off_t out_full, out_part, in_full, in_part;
#if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
    unsigned long long total_bytes;
    unsigned long long begin_time_us;
#endif
} FIX_ALIASING;
#define G (*(struct globals*)&bb_common_bufsiz1)
#define INIT_G() do { \
    /* we have to zero it out because of NOEXEC */ \
    memset(&G, 0, sizeof(G)); \
} while (0)


static void dd_output_status(int UNUSED_PARAM cur_signal)
{
#if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
    double seconds;
    unsigned long long bytes_sec;
    unsigned long long now_us = monotonic_us(); /* before fprintf */
#endif

    /* Deliberately using %u, not %d */
    fprintf(stderr, "%"OFF_FMT"u+%"OFF_FMT"u records in\n"
            "%"OFF_FMT"u+%"OFF_FMT"u records out\n",
            G.in_full, G.in_part,
            G.out_full, G.out_part);

#if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
    fprintf(stderr, "%llu bytes (%sB) copied, ",
            G.total_bytes,
            /* show fractional digit, use suffixes */
            make_human_readable_str(G.total_bytes, 1, 0)
    );
    /* Corner cases:
     * ./busybox dd </dev/null >/dev/null
     * ./busybox dd bs=1M count=2000 </dev/zero >/dev/null
     * (echo DONE) | ./busybox dd >/dev/null
     * (sleep 1; echo DONE) | ./busybox dd >/dev/null
     */
    seconds = (now_us - G.begin_time_us) / 1000000.0;
    bytes_sec = G.total_bytes / seconds;
    fprintf(stderr, "%f seconds, %sB/s\n",
            seconds,
            /* show fractional digit, use suffixes */
            make_human_readable_str(bytes_sec, 1, 0)
    );
#endif
}

static ssize_t full_write_or_warn(const void *buf, size_t len,
    const char *const filename)
{
    ssize_t n = full_write(ofd, buf, len);
    if (n < 0)
        bb_perror_msg("writing '%s'", filename);
    return n;
}

static bool write_and_stats(const void *buf, size_t len, size_t obs,
    const char *filename)
{
    ssize_t n = full_write_or_warn(buf, len, filename);
    if (n < 0)
        return 1;
    if ((size_t)n == obs)
        G.out_full++;
    else if (n) /* > 0 */
        G.out_part++;
#if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
    G.total_bytes += n;
#endif
    return 0;
}

#if ENABLE_LFS
# define XATOU_SFX xatoull_sfx
#else
# define XATOU_SFX xatoul_sfx
#endif

int dd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int dd_main(int argc UNUSED_PARAM, char **argv)
{
    enum {
        /* Must be in the same order as OP_conv_XXX! */
        /* (see "flags |= (1 << what)" below) */
        FLAG_NOTRUNC = 1 << 0,
        FLAG_SYNC    = 1 << 1,
        FLAG_NOERROR = 1 << 2,
        FLAG_FSYNC   = 1 << 3,
        /* end of conv flags */
        FLAG_TWOBUFS = 1 << 4,
        FLAG_COUNT   = 1 << 5,
    };
    static const char keywords[] ALIGN1 =
        "bs\0""count\0""seek\0""skip\0""if\0""of\0"
#if ENABLE_FEATURE_DD_IBS_OBS
        "ibs\0""obs\0""conv\0"
#endif
        ;
#if ENABLE_FEATURE_DD_IBS_OBS
    static const char conv_words[] ALIGN1 =
        "notrunc\0""sync\0""noerror\0""fsync\0";
#endif
    enum {
        OP_bs = 0,
        OP_count,
        OP_seek,
        OP_skip,
        OP_if,
        OP_of,
#if ENABLE_FEATURE_DD_IBS_OBS
        OP_ibs,
        OP_obs,
        OP_conv,
        /* Must be in the same order as FLAG_XXX! */
        OP_conv_notrunc = 0,
        OP_conv_sync,
        OP_conv_noerror,
        OP_conv_fsync,
    /* Unimplemented conv=XXX: */
    //nocreat       do not create the output file
    //excl          fail if the output file already exists
    //fdatasync     physically write output file data before finishing
    //swab          swap every pair of input bytes
    //lcase         change upper case to lower case
    //ucase         change lower case to upper case
    //block         pad newline-terminated records with spaces to cbs-size
    //unblock       replace trailing spaces in cbs-size records with newline
    //ascii         from EBCDIC to ASCII
    //ebcdic        from ASCII to EBCDIC
    //ibm           from ASCII to alternate EBCDIC
#endif
    };
    int exitcode = EXIT_FAILURE;
    size_t ibs = 512, obs = 512;
    ssize_t n, w;
    char *ibuf, *obuf;
    /* And these are all zeroed at once! */
    struct {
        int flags;
        size_t oc;
        off_t count;
        off_t seek, skip;
        const char *infile, *outfile;
    } Z;
#define flags   (Z.flags  )
#define oc      (Z.oc     )
#define count   (Z.count  )
#define seek    (Z.seek   )
#define skip    (Z.skip   )
#define infile  (Z.infile )
#define outfile (Z.outfile)

    memset(&Z, 0, sizeof(Z));
    INIT_G();
    //fflush_all(); - is this needed because of NOEXEC?

    for (n = 1; argv[n]; n++) {
        int what;
        char *val;
        char *arg = argv[n];

#if ENABLE_DESKTOP
        /* "dd --". NB: coreutils 6.9 will complain if they see
         * more than one of them. We wouldn't. */
        if (arg[0] == '-' && arg[1] == '-' && arg[2] == '\0')
            continue;
#endif
        val = strchr(arg, '=');
        if (val == NULL)
            bb_show_usage();
        *val = '\0';
        what = index_in_strings(keywords, arg);
        if (what < 0)
            bb_show_usage();
        /* *val = '='; - to preserve ps listing? */
        val++;
#if ENABLE_FEATURE_DD_IBS_OBS
        if (what == OP_ibs) {
            /* Must fit into positive ssize_t */
            ibs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, dd_suffixes);
            /*continue;*/
        }
        if (what == OP_obs) {
            obs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, dd_suffixes);
            /*continue;*/
        }
        if (what == OP_conv) {
            while (1) {
                /* find ',', replace them with NUL so we can use val for
                 * index_in_strings() without copying.
                 * We rely on val being non-null, else strchr would fault.
                 */
                arg = strchr(val, ',');
                if (arg)
                    *arg = '\0';
                what = index_in_strings(conv_words, val);
                if (what < 0)
                    bb_error_msg_and_die(bb_msg_invalid_arg, val, "conv");
                flags |= (1 << what);
                if (!arg) /* no ',' left, so this was the last specifier */
                    break;
                /* *arg = ','; - to preserve ps listing? */
                val = arg + 1; /* skip this keyword and ',' */
            }
            continue; /* we trashed 'what', can't fall through */
        }
#endif
        if (what == OP_bs) {
            ibs = obs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, dd_suffixes);
            /*continue;*/
        }
        /* These can be large: */
        if (what == OP_count) {
            flags |= FLAG_COUNT;
            count = XATOU_SFX(val, dd_suffixes);
            /*continue;*/
        }
        if (what == OP_seek) {
            seek = XATOU_SFX(val, dd_suffixes);
            /*continue;*/
        }
        if (what == OP_skip) {
            skip = XATOU_SFX(val, dd_suffixes);
            /*continue;*/
        }
        if (what == OP_if) {
            infile = val;
            /*continue;*/
        }
        if (what == OP_of) {
            outfile = val;
            /*continue;*/
        }
    } /* end of "for (argv[n])" */

//XXX:FIXME for huge ibs or obs, malloc'ing them isn't the brightest idea ever
    ibuf = obuf = xmalloc(ibs);
    if (ibs != obs) {
        flags |= FLAG_TWOBUFS;
        obuf = xmalloc(obs);
    }

#if ENABLE_FEATURE_DD_SIGNAL_HANDLING
    signal_SA_RESTART_empty_mask(SIGUSR1, dd_output_status);
#endif
#if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
    G.begin_time_us = monotonic_us();
#endif

    if (infile != NULL)
        xmove_fd(xopen(infile, O_RDONLY), ifd);
    else {
        infile = bb_msg_standard_input;
    }
    if (outfile != NULL) {
        int oflag = O_WRONLY | O_CREAT;

        if (!seek && !(flags & FLAG_NOTRUNC))
            oflag |= O_TRUNC;

        xmove_fd(xopen(outfile, oflag), ofd);

        if (seek && !(flags & FLAG_NOTRUNC)) {
            if (ftruncate(ofd, seek * obs) < 0) {
                struct stat st;

                if (fstat(ofd, &st) < 0
                 || S_ISREG(st.st_mode)
                 || S_ISDIR(st.st_mode)
                ) {
                    goto die_outfile;
                }
            }
        }
    } else {
        outfile = bb_msg_standard_output;
    }
    if (skip) {
        if (lseek(ifd, skip * ibs, SEEK_CUR) < 0) {
            while (skip-- > 0) {
                n = safe_read(ifd, ibuf, ibs);
                if (n < 0)
                    goto die_infile;
                if (n == 0)
                    break;
            }
        }
    }
    if (seek) {
        if (lseek(ofd, seek * obs, SEEK_CUR) < 0)
            goto die_outfile;
    }

    while (!(flags & FLAG_COUNT) || (G.in_full + G.in_part != count)) {
        n = safe_read(ifd, ibuf, ibs);
        if (n == 0)
            break;
        if (n < 0) {
            /* "Bad block" */
            if (!(flags & FLAG_NOERROR))
                goto die_infile;
            bb_simple_perror_msg(infile);
            /* GNU dd with conv=noerror skips over bad blocks */
            xlseek(ifd, ibs, SEEK_CUR);
            /* conv=noerror,sync writes NULs,
             * conv=noerror just ignores input bad blocks */
            n = 0;
        }
        if ((size_t)n == ibs)
            G.in_full++;
        else {
            G.in_part++;
            if (flags & FLAG_SYNC) {
                memset(ibuf + n, 0, ibs - n);
                n = ibs;
            }
        }
        if (flags & FLAG_TWOBUFS) {
            char *tmp = ibuf;
            while (n) {
                size_t d = obs - oc;

                if (d > (size_t)n)
                    d = n;
                memcpy(obuf + oc, tmp, d);
                n -= d;
                tmp += d;
                oc += d;
                if (oc == obs) {
                    if (write_and_stats(obuf, obs, obs, outfile))
                        goto out_status;
                    oc = 0;
                }
            }
        } else if (write_and_stats(ibuf, n, obs, outfile))
            goto out_status;

        if (flags & FLAG_FSYNC) {
            if (fsync(ofd) < 0)
                goto die_outfile;
        }
    }

    if (ENABLE_FEATURE_DD_IBS_OBS && oc) {
        w = full_write_or_warn(obuf, oc, outfile);
        if (w < 0) goto out_status;
        if (w > 0) G.out_part++;
    }
    if (close(ifd) < 0) {
 die_infile:
        bb_simple_perror_msg_and_die(infile);
    }

    if (close(ofd) < 0) {
 die_outfile:
        bb_simple_perror_msg_and_die(outfile);
    }

    exitcode = EXIT_SUCCESS;
 out_status:
    dd_output_status(0);

    return exitcode;
}