source: MondoRescue/branches/stable/mindi-busybox/coreutils/dd.c

/* 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 tarball for details.
 */

#include <signal.h>  /* For FEATURE_DD_SIGNAL_HANDLING */
#include "libbb.h"

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


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 },
    { }
};

struct globals {
    off_t out_full, out_part, in_full, in_part;
};
#define G (*(struct globals*)&bb_common_bufsiz1)
/* We have to zero it out because of NOEXEC */
#define INIT_G() memset(&G, 0, sizeof(G))


static void dd_output_status(int ATTRIBUTE_UNUSED cur_signal)
{
    /* 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);
}

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

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

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

int dd_main(int argc, char **argv);
int dd_main(int argc, char **argv)
{
    enum {
        FLAG_SYNC    = 1 << 0,
        FLAG_NOERROR = 1 << 1,
        FLAG_NOTRUNC = 1 << 2,
        FLAG_TWOBUFS = 1 << 3,
        FLAG_COUNT   = 1 << 4,
    };
    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""notrunc\0""sync\0""noerror\0"
#endif
        ;
    enum {
        OP_bs = 1,
        OP_count,
        OP_seek,
        OP_skip,
        OP_if,
        OP_of,
#if ENABLE_FEATURE_DD_IBS_OBS
        OP_ibs,
        OP_obs,
        OP_conv,
        OP_conv_notrunc,
        OP_conv_sync,
        OP_conv_noerror,
#endif
    };
    size_t ibs = 512, obs = 512;
    ssize_t n, w;
    char *ibuf, *obuf;
    /* And these are all zeroed at once! */
    struct {
        int flags;
        int ifd, ofd;
        size_t oc;
        off_t count;
        off_t seek, skip;
        const char *infile, *outfile;
#if ENABLE_FEATURE_DD_SIGNAL_HANDLING
        struct sigaction sigact;
#endif
    } Z;
#define flags   (Z.flags  )
#define ifd     (Z.ifd    )
#define ofd     (Z.ofd    )
#define oc      (Z.oc     )
#define count   (Z.count  )
#define seek    (Z.seek   )
#define skip    (Z.skip   )
#define infile  (Z.infile )
#define outfile (Z.outfile)
#define sigact  (Z.sigact )

    memset(&Z, 0, sizeof(Z));
    INIT_G();

#if ENABLE_FEATURE_DD_SIGNAL_HANDLING
    sigact.sa_handler = dd_output_status;
    sigact.sa_flags = SA_RESTART;
    sigemptyset(&sigact.sa_mask);
    sigaction(SIGUSR1, &sigact, NULL);
#endif

    for (n = 1; n < argc; n++) {
        smalluint key_len;
        smalluint what;
        char *key;
        char *arg = argv[n];

//XXX:FIXME: we reject plain "dd --" This would cost ~20 bytes, so..
//if (*arg == '-' && *++arg == '-' && !*++arg) continue;
        key = strstr(arg, "=");
        if (key == NULL)
            bb_show_usage();
        key_len = key - arg + 1;
        key = xstrndup(arg, key_len);
        what = index_in_strings(keywords, key) + 1;
        if (ENABLE_FEATURE_CLEAN_UP)
            free(key);
        if (what == 0)
            bb_show_usage();
        arg += key_len;
        /* Must fit into positive ssize_t */
#if ENABLE_FEATURE_DD_IBS_OBS
            if (what == OP_ibs) {
                ibs = xatoul_range_sfx(arg, 1, ((size_t)-1L)/2, dd_suffixes);
                continue;
            }
            if (what == OP_obs) {
                obs = xatoul_range_sfx(arg, 1, ((size_t)-1L)/2, dd_suffixes);
                continue;
            }
            if (what == OP_conv) {
                while (1) {
                    /* find ',', replace them with nil so we can use arg for
                     * index_in_strings() without copying.
                     * We rely on arg being non-null, else strchr would fault.
                     */
                    key = strchr(arg, ',');
                    if (key)
                        *key = '\0';
                    what = index_in_strings(keywords, arg) + 1;
                    if (what < OP_conv_notrunc)
                        bb_error_msg_and_die(bb_msg_invalid_arg, arg, "conv");
                    if (what == OP_conv_notrunc)
                        flags |= FLAG_NOTRUNC;
                    if (what == OP_conv_sync)
                        flags |= FLAG_SYNC;
                    if (what == OP_conv_noerror)
                        flags |= FLAG_NOERROR;
                    if (!key) /* no ',' left, so this was the last specifier */
                        break;
                    arg = key + 1; /* skip this keyword and ',' */
                }
                continue;
            }
#endif
        if (what == OP_bs) {
            ibs = obs = xatoul_range_sfx(arg, 1, ((size_t)-1L)/2, dd_suffixes);
            continue;
        }
        /* These can be large: */
        if (what == OP_count) {
            flags |= FLAG_COUNT;
            count = XATOU_SFX(arg, dd_suffixes);
            continue;
        }
        if (what == OP_seek) {
            seek = XATOU_SFX(arg, dd_suffixes);
            continue;
        }
        if (what == OP_skip) {
            skip = XATOU_SFX(arg, dd_suffixes);
            continue;
        }
        if (what == OP_if) {
            infile = arg;
            continue;
        }
        if (what == OP_of)
            outfile = arg;
    }
//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 (infile != NULL)
        ifd = xopen(infile, O_RDONLY);
    else {
        /* ifd = STDIN_FILENO; - it's zero and it's already there */
        infile = bb_msg_standard_input;
    }
    if (outfile != NULL) {
        int oflag = O_WRONLY | O_CREAT;

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

        ofd = xopen(outfile, oflag);

        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 {
        ofd = STDOUT_FILENO;
        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)) {
        if (flags & FLAG_NOERROR) /* Pre-zero the buffer if conv=noerror */
            memset(ibuf, 0, ibs);
        n = safe_read(ifd, ibuf, ibs);
        if (n == 0)
            break;
        if (n < 0) {
            if (flags & FLAG_NOERROR) {
                n = ibs;
                bb_perror_msg("%s", infile);
            } else
                goto die_infile;
        }
        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 > n)
                    d = n;
                memcpy(obuf + oc, tmp, d);
                n -= d;
                tmp += d;
                oc += d;
                if (oc == obs) {
                    if (write_and_stats(ofd, obuf, obs, obs, outfile))
                        goto out_status;
                    oc = 0;
                }
            }
        } else if (write_and_stats(ofd, ibuf, n, obs, outfile))
            goto out_status;
    }

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

    if (close(ofd) < 0) {
 die_outfile:
        bb_perror_msg_and_die("%s", outfile);
    }
 out_status:
    dd_output_status(0);

    return EXIT_SUCCESS;
}