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src/dd.c
2 573 строки
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Paul Eggert
dd: revert previous patch
20 июн 2026, 23:30
20 июн 2026, 23:30
79b4925
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/* dd -- convert a file while copying it. Copyright (C) 1985-2026 Free Software Foundation, Inc. This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <https://www.gnu.org/licenses/>. */ /* Written by Paul Rubin, David MacKenzie, and Stuart Kemp. */ #include <config.h> #include <sys/types.h> #include <signal.h> #include "system.h" #include "alignalloc.h" #include "close-stream.h" #include "fd-reopen.h" #include "gethrxtime.h" #include "human.h" #include "ioblksize.h" #include "long-options.h" #include "quote.h" #include "xstrtol.h" #include "xtime.h" /* The official name of this program (e.g., no 'g' prefix). */ #define PROGRAM_NAME "dd" #define AUTHORS \ proper_name ("Paul Rubin"), \ proper_name ("David MacKenzie"), \ proper_name ("Stuart Kemp") /* NonStop circa 2011 lacks SA_RESETHAND; see Bug#9076. */ #ifndef SA_RESETHAND # define SA_RESETHAND 0 #endif #ifndef SIGINFO # define SIGINFO SIGUSR1 #endif /* This may belong in GNULIB's fcntl module instead. Define O_CIO to 0 if it is not supported by this OS. */ #ifndef O_CIO # define O_CIO 0 #endif /* On AIX 5.1 and AIX 5.2, O_NOCACHE is defined via <fcntl.h> and would interfere with our use of that name, below. */ #undef O_NOCACHE #define output_char(c) \ do \ { \ obuf[oc++] = (c); \ if (oc >= output_blocksize) \ write_output (); \ } \ while (0) /* Default input and output blocksize. */ #define DEFAULT_BLOCKSIZE 512 /* Conversions bit masks. */ enum { C_ASCII = 01, C_EBCDIC = 02, C_IBM = 04, C_BLOCK = 010, C_UNBLOCK = 020, C_LCASE = 040, C_UCASE = 0100, C_SWAB = 0200, C_NOERROR = 0400, C_NOTRUNC = 01000, C_SYNC = 02000, /* Use separate input and output buffers, and combine partial input blocks. */ C_TWOBUFS = 04000, C_NOCREAT = 010000, C_EXCL = 020000, C_FDATASYNC = 040000, C_FSYNC = 0100000, C_SPARSE = 0200000 }; /* Status levels. */ enum { STATUS_NONE = 1, STATUS_NOXFER = 2, STATUS_DEFAULT = 3, STATUS_PROGRESS = 4 }; /* The name of the input file, or NULL for the standard input. */ static char const *input_file = NULL; /* The name of the output file, or NULL for the standard output. */ static char const *output_file = NULL; /* The page size on this host. */ static idx_t page_size; /* The number of bytes in which atomic reads are done. */ static idx_t input_blocksize = 0; /* The number of bytes in which atomic writes are done. */ static idx_t output_blocksize = 0; /* Conversion buffer size, in bytes. 0 prevents conversions. */ static idx_t conversion_blocksize = 0; /* Skip this many records of 'input_blocksize' bytes before input. */ static intmax_t skip_records = 0; /* Skip this many bytes before input in addition of 'skip_records' records. */ static idx_t skip_bytes = 0; /* Skip this many records of 'output_blocksize' bytes before output. */ static intmax_t seek_records = 0; /* Skip this many bytes in addition to 'seek_records' records before output. */ static intmax_t seek_bytes = 0; /* Whether the final output was done with a seek (rather than a write). */ static bool final_op_was_seek; /* Copy only this many records. The default is effectively infinity. */ static intmax_t max_records = INTMAX_MAX; /* Copy this many bytes in addition to 'max_records' records. */ static idx_t max_bytes = 0; /* Bit vector of conversions to apply. */ static int conversions_mask = 0; /* Open flags for the input and output files. */ static int input_flags = 0; static int output_flags = 0; /* Status flags for what is printed to stderr. */ static int status_level = STATUS_DEFAULT; /* If nonzero, filter characters through the translation table. */ static bool translation_needed = false; /* Number of partial blocks written. */ static intmax_t w_partial = 0; /* Number of full blocks written. */ static intmax_t w_full = 0; /* Number of partial blocks read. */ static intmax_t r_partial = 0; /* Number of full blocks read. */ static intmax_t r_full = 0; /* Number of bytes written. */ static intmax_t w_bytes = 0; /* Last-reported number of bytes written, or negative if never reported. */ static intmax_t reported_w_bytes = -1; /* Time that dd started. */ static xtime_t start_time; /* Next time to report periodic progress. */ static xtime_t next_time; /* If positive, the number of bytes output in the current progress line. */ static int progress_len; /* True if input is seekable. */ static bool input_seekable; /* Error number corresponding to initial attempt to lseek input. If ESPIPE, do not issue any more diagnostics about it. */ static int input_seek_errno; /* File offset of the input, in bytes, or -1 if it overflowed. */ static off_t input_offset; /* True if a partial read should be diagnosed. */ static bool warn_partial_read; /* Records truncated by conv=block. */ static intmax_t r_truncate = 0; /* Output representation of newline and space characters. They change if we're converting to EBCDIC. */ static char newline_character = '\n'; static char space_character = ' '; /* I/O buffers. */ static char *ibuf; static char *obuf; /* Current index into 'obuf'. */ static idx_t oc = 0; /* Index into current line, for 'conv=block' and 'conv=unblock'. */ static idx_t col = 0; /* The set of signals that are caught. */ static sigset_t caught_signals; /* If nonzero, the value of the pending fatal signal. */ static sig_atomic_t volatile interrupt_signal; /* A count of the number of pending info signals that have been received. */ static sig_atomic_t volatile info_signal_count; /* Whether to discard cache for input or output. */ static bool i_nocache, o_nocache; /* Whether to instruct the kernel to discard the complete file. */ static bool i_nocache_eof, o_nocache_eof; /* Function used for read (to handle iflag=fullblock parameter). */ static ssize_t (*iread_fnc) (int fd, char *buf, idx_t size); /* A longest symbol in the struct symbol_values tables below. */ #define LONGEST_SYMBOL "count_bytes" /* A symbol and the corresponding integer value. */ struct symbol_value { char symbol[sizeof LONGEST_SYMBOL]; int value; }; /* Conversion symbols, for conv="...". */ static struct symbol_value const conversions[] = { {"ascii", C_ASCII | C_UNBLOCK | C_TWOBUFS}, /* EBCDIC to ASCII. */ {"ebcdic", C_EBCDIC | C_BLOCK | C_TWOBUFS}, /* ASCII to EBCDIC. */ {"ibm", C_IBM | C_BLOCK | C_TWOBUFS}, /* Different ASCII to EBCDIC. */ {"block", C_BLOCK | C_TWOBUFS}, /* Variable to fixed length records. */ {"unblock", C_UNBLOCK | C_TWOBUFS}, /* Fixed to variable length records. */ {"lcase", C_LCASE | C_TWOBUFS}, /* Translate upper to lower case. */ {"ucase", C_UCASE | C_TWOBUFS}, /* Translate lower to upper case. */ {"sparse", C_SPARSE}, /* Try to sparsely write output. */ {"swab", C_SWAB | C_TWOBUFS}, /* Swap bytes of input. */ {"noerror", C_NOERROR}, /* Ignore i/o errors. */ {"nocreat", C_NOCREAT}, /* Do not create output file. */ {"excl", C_EXCL}, /* Fail if the output file already exists. */ {"notrunc", C_NOTRUNC}, /* Do not truncate output file. */ {"sync", C_SYNC}, /* Pad input records to ibs with NULs. */ {"fdatasync", C_FDATASYNC}, /* Synchronize output data before finishing. */ {"fsync", C_FSYNC}, /* Also synchronize output metadata. */ {"", 0} }; #define FFS_MASK(x) ((x) ^ ((x) & ((x) - 1))) enum { /* Compute a value that's bitwise disjoint from the union of all O_ values. */ v = ~(0 | O_APPEND | O_BINARY | O_CIO | O_DIRECT | O_DIRECTORY | O_DSYNC | O_EXCL | O_NOATIME | O_NOCTTY | O_NOFOLLOW | O_NOLINKS | O_NONBLOCK | O_SYNC | O_TEXT ), /* Use its lowest bits for private flags. */ O_FULLBLOCK = FFS_MASK (v), v2 = v ^ O_FULLBLOCK, O_NOCACHE = FFS_MASK (v2), v3 = v2 ^ O_NOCACHE, O_COUNT_BYTES = FFS_MASK (v3), v4 = v3 ^ O_COUNT_BYTES, O_SKIP_BYTES = FFS_MASK (v4), v5 = v4 ^ O_SKIP_BYTES, O_SEEK_BYTES = FFS_MASK (v5) }; /* Ensure that we got something. */ static_assert (O_FULLBLOCK != 0); static_assert (O_NOCACHE != 0); static_assert (O_COUNT_BYTES != 0); static_assert (O_SKIP_BYTES != 0); static_assert (O_SEEK_BYTES != 0); #define MULTIPLE_BITS_SET(i) (((i) & ((i) - 1)) != 0) /* Ensure that this is a single-bit value. */ static_assert ( ! MULTIPLE_BITS_SET (O_FULLBLOCK)); static_assert ( ! MULTIPLE_BITS_SET (O_NOCACHE)); static_assert ( ! MULTIPLE_BITS_SET (O_COUNT_BYTES)); static_assert ( ! MULTIPLE_BITS_SET (O_SKIP_BYTES)); static_assert ( ! MULTIPLE_BITS_SET (O_SEEK_BYTES)); /* Flags, for iflag="..." and oflag="...". */ static struct symbol_value const flags[] = { {"append", O_APPEND}, {"binary", O_BINARY}, {"cio", O_CIO}, {"direct", O_DIRECT}, {"directory", O_DIRECTORY}, {"dsync", O_DSYNC}, {"noatime", O_NOATIME}, {"nocache", O_NOCACHE}, /* Discard cache. */ {"noctty", O_NOCTTY}, {"nofollow", HAVE_WORKING_O_NOFOLLOW ? O_NOFOLLOW : 0}, {"nolinks", O_NOLINKS}, {"nonblock", O_NONBLOCK}, {"sync", O_SYNC}, {"text", O_TEXT}, {"fullblock", O_FULLBLOCK}, /* Accumulate full blocks from input. */ {"count_bytes", O_COUNT_BYTES}, {"skip_bytes", O_SKIP_BYTES}, {"seek_bytes", O_SEEK_BYTES}, {"", 0} }; /* Status, for status="...". */ static struct symbol_value const statuses[] = { {"none", STATUS_NONE}, {"noxfer", STATUS_NOXFER}, {"progress", STATUS_PROGRESS}, {"", 0} }; /* Translation table formed by applying successive transformations. */ static unsigned char trans_table[256]; /* Standard translation tables, taken from POSIX 1003.1-2013. Beware of imitations; there are lots of ASCII<->EBCDIC tables floating around the net, perhaps valid for some applications but not correct here. */ static char const ascii_to_ebcdic[] = { '\000', '\001', '\002', '\003', '\067', '\055', '\056', '\057', '\026', '\005', '\045', '\013', '\014', '\015', '\016', '\017', '\020', '\021', '\022', '\023', '\074', '\075', '\062', '\046', '\030', '\031', '\077', '\047', '\034', '\035', '\036', '\037', '\100', '\132', '\177', '\173', '\133', '\154', '\120', '\175', '\115', '\135', '\134', '\116', '\153', '\140', '\113', '\141', '\360', '\361', '\362', '\363', '\364', '\365', '\366', '\367', '\370', '\371', '\172', '\136', '\114', '\176', '\156', '\157', '\174', '\301', '\302', '\303', '\304', '\305', '\306', '\307', '\310', '\311', '\321', '\322', '\323', '\324', '\325', '\326', '\327', '\330', '\331', '\342', '\343', '\344', '\345', '\346', '\347', '\350', '\351', '\255', '\340', '\275', '\232', '\155', '\171', '\201', '\202', '\203', '\204', '\205', '\206', '\207', '\210', '\211', '\221', '\222', '\223', '\224', '\225', '\226', '\227', '\230', '\231', '\242', '\243', '\244', '\245', '\246', '\247', '\250', '\251', '\300', '\117', '\320', '\137', '\007', '\040', '\041', '\042', '\043', '\044', '\025', '\006', '\027', '\050', '\051', '\052', '\053', '\054', '\011', '\012', '\033', '\060', '\061', '\032', '\063', '\064', '\065', '\066', '\010', '\070', '\071', '\072', '\073', '\004', '\024', '\076', '\341', '\101', '\102', '\103', '\104', '\105', '\106', '\107', '\110', '\111', '\121', '\122', '\123', '\124', '\125', '\126', '\127', '\130', '\131', '\142', '\143', '\144', '\145', '\146', '\147', '\150', '\151', '\160', '\161', '\162', '\163', '\164', '\165', '\166', '\167', '\170', '\200', '\212', '\213', '\214', '\215', '\216', '\217', '\220', '\152', '\233', '\234', '\235', '\236', '\237', '\240', '\252', '\253', '\254', '\112', '\256', '\257', '\260', '\261', '\262', '\263', '\264', '\265', '\266', '\267', '\270', '\271', '\272', '\273', '\274', '\241', '\276', '\277', '\312', '\313', '\314', '\315', '\316', '\317', '\332', '\333', '\334', '\335', '\336', '\337', '\352', '\353', '\354', '\355', '\356', '\357', '\372', '\373', '\374', '\375', '\376', '\377' }; static char const ascii_to_ibm[] = { '\000', '\001', '\002', '\003', '\067', '\055', '\056', '\057', '\026', '\005', '\045', '\013', '\014', '\015', '\016', '\017', '\020', '\021', '\022', '\023', '\074', '\075', '\062', '\046', '\030', '\031', '\077', '\047', '\034', '\035', '\036', '\037', '\100', '\132', '\177', '\173', '\133', '\154', '\120', '\175', '\115', '\135', '\134', '\116', '\153', '\140', '\113', '\141', '\360', '\361', '\362', '\363', '\364', '\365', '\366', '\367', '\370', '\371', '\172', '\136', '\114', '\176', '\156', '\157', '\174', '\301', '\302', '\303', '\304', '\305', '\306', '\307', '\310', '\311', '\321', '\322', '\323', '\324', '\325', '\326', '\327', '\330', '\331', '\342', '\343', '\344', '\345', '\346', '\347', '\350', '\351', '\255', '\340', '\275', '\137', '\155', '\171', '\201', '\202', '\203', '\204', '\205', '\206', '\207', '\210', '\211', '\221', '\222', '\223', '\224', '\225', '\226', '\227', '\230', '\231', '\242', '\243', '\244', '\245', '\246', '\247', '\250', '\251', '\300', '\117', '\320', '\241', '\007', '\040', '\041', '\042', '\043', '\044', '\025', '\006', '\027', '\050', '\051', '\052', '\053', '\054', '\011', '\012', '\033', '\060', '\061', '\032', '\063', '\064', '\065', '\066', '\010', '\070', '\071', '\072', '\073', '\004', '\024', '\076', '\341', '\101', '\102', '\103', '\104', '\105', '\106', '\107', '\110', '\111', '\121', '\122', '\123', '\124', '\125', '\126', '\127', '\130', '\131', '\142', '\143', '\144', '\145', '\146', '\147', '\150', '\151', '\160', '\161', '\162', '\163', '\164', '\165', '\166', '\167', '\170', '\200', '\212', '\213', '\214', '\215', '\216', '\217', '\220', '\232', '\233', '\234', '\235', '\236', '\237', '\240', '\252', '\253', '\254', '\255', '\256', '\257', '\260', '\261', '\262', '\263', '\264', '\265', '\266', '\267', '\270', '\271', '\272', '\273', '\274', '\275', '\276', '\277', '\312', '\313', '\314', '\315', '\316', '\317', '\332', '\333', '\334', '\335', '\336', '\337', '\352', '\353', '\354', '\355', '\356', '\357', '\372', '\373', '\374', '\375', '\376', '\377' }; static char const ebcdic_to_ascii[] = { '\000', '\001', '\002', '\003', '\234', '\011', '\206', '\177', '\227', '\215', '\216', '\013', '\014', '\015', '\016', '\017', '\020', '\021', '\022', '\023', '\235', '\205', '\010', '\207', '\030', '\031', '\222', '\217', '\034', '\035', '\036', '\037', '\200', '\201', '\202', '\203', '\204', '\012', '\027', '\033', '\210', '\211', '\212', '\213', '\214', '\005', '\006', '\007', '\220', '\221', '\026', '\223', '\224', '\225', '\226', '\004', '\230', '\231', '\232', '\233', '\024', '\025', '\236', '\032', '\040', '\240', '\241', '\242', '\243', '\244', '\245', '\246', '\247', '\250', '\325', '\056', '\074', '\050', '\053', '\174', '\046', '\251', '\252', '\253', '\254', '\255', '\256', '\257', '\260', '\261', '\041', '\044', '\052', '\051', '\073', '\176', '\055', '\057', '\262', '\263', '\264', '\265', '\266', '\267', '\270', '\271', '\313', '\054', '\045', '\137', '\076', '\077', '\272', '\273', '\274', '\275', '\276', '\277', '\300', '\301', '\302', '\140', '\072', '\043', '\100', '\047', '\075', '\042', '\303', '\141', '\142', '\143', '\144', '\145', '\146', '\147', '\150', '\151', '\304', '\305', '\306', '\307', '\310', '\311', '\312', '\152', '\153', '\154', '\155', '\156', '\157', '\160', '\161', '\162', '\136', '\314', '\315', '\316', '\317', '\320', '\321', '\345', '\163', '\164', '\165', '\166', '\167', '\170', '\171', '\172', '\322', '\323', '\324', '\133', '\326', '\327', '\330', '\331', '\332', '\333', '\334', '\335', '\336', '\337', '\340', '\341', '\342', '\343', '\344', '\135', '\346', '\347', '\173', '\101', '\102', '\103', '\104', '\105', '\106', '\107', '\110', '\111', '\350', '\351', '\352', '\353', '\354', '\355', '\175', '\112', '\113', '\114', '\115', '\116', '\117', '\120', '\121', '\122', '\356', '\357', '\360', '\361', '\362', '\363', '\134', '\237', '\123', '\124', '\125', '\126', '\127', '\130', '\131', '\132', '\364', '\365', '\366', '\367', '\370', '\371', '\060', '\061', '\062', '\063', '\064', '\065', '\066', '\067', '\070', '\071', '\372', '\373', '\374', '\375', '\376', '\377' }; /* True if we need to close the standard output *stream*. */ static bool close_stdout_required = true; /* The only reason to close the standard output *stream* is if parse_long_options fails (as it does for --help or --version). In any other case, dd uses only the STDOUT_FILENO file descriptor, and the "cleanup" function calls "close (STDOUT_FILENO)". Closing the file descriptor and then letting the usual atexit-run close_stdout function call "fclose (stdout)" would result in a harmless failure of the close syscall (with errno EBADF). This function serves solely to avoid the unnecessary close_stdout call, once parse_long_options has succeeded. Meanwhile, we guarantee that the standard error stream is flushed, by inlining the last half of close_stdout as needed. */ static void maybe_close_stdout (void) { if (close_stdout_required) close_stdout (); else if (close_stream (stderr) != 0) _exit (EXIT_FAILURE); } /* Like the 'error' function but handle any pending newline, and do not exit. */ ATTRIBUTE_FORMAT ((__printf__, 2, 3)) static void diagnose (int errnum, char const *fmt, ...) { if (0 < progress_len) { fputc ('\n', stderr); progress_len = 0; } va_list ap; va_start (ap, fmt); verror (0, errnum, fmt, ap); va_end (ap); } void usage (int status) { if (status != EXIT_SUCCESS) emit_try_help (); else { printf (_("\ Usage: %s [OPERAND]...\n\ or: %s OPTION\n\ "), program_name, program_name); fputs (_("\ Copy a file, converting and formatting according to the operands.\n\ \n\ "), stdout); oputs (_("\ bs=BYTES read and write up to BYTES bytes at a time (default: 512);\n\ overrides ibs and obs\n\ ")); oputs (_("\ cbs=BYTES convert BYTES bytes at a time\n\ ")); oputs (_("\ conv=CONVS convert the file as per the comma separated symbol list\n\ ")); oputs (_("\ count=N copy only N input blocks\n\ ")); oputs (_("\ ibs=BYTES read up to BYTES bytes at a time (default: 512)\n\ ")); oputs (_("\ if=FILE read from FILE instead of standard input\n\ ")); oputs (_("\ iflag=FLAGS read as per the comma separated symbol list\n\ ")); oputs (_("\ obs=BYTES write BYTES bytes at a time (default: 512)\n\ ")); oputs (_("\ of=FILE write to FILE instead of standard output\n\ ")); oputs (_("\ oflag=FLAGS write as per the comma separated symbol list\n\ ")); oputs (_("\ seek=N (or oseek=N) skip N obs sized output blocks\n\ ")); oputs (_("\ skip=N (or iseek=N) skip N ibs sized input blocks\n\ ")); oputs (_("\ status=LEVEL The LEVEL of information to print to standard error;\n\ 'none' suppresses everything but error messages,\n\ 'noxfer' suppresses the final transfer statistics,\n\ 'progress' shows periodic transfer statistics\n\ ")); fputs (_("\ \n\ N and BYTES may be followed by the following multiplicative suffixes:\n\ c=1, w=2, b=512, kB=1000, K=1024, MB=1000*1000, M=1024*1024, xM=M,\n\ GB=1000*1000*1000, G=1024*1024*1024, and so on for T, P, E, Z, Y, R, Q.\n\ Binary prefixes can be used, too: KiB=K, MiB=M, and so on.\n\ If N ends in 'B', it counts bytes not blocks.\n\ \n\ Each CONV symbol may be:\n\ \n\ "), stdout); fputs (_("\ ascii from EBCDIC to ASCII\n\ ebcdic from ASCII to EBCDIC\n\ ibm from ASCII to alternate EBCDIC\n\ block pad newline-terminated records with spaces to cbs-size\n\ unblock replace trailing spaces in cbs-size records with newline\n\ lcase change upper case to lower case\n\ ucase change lower case to upper case\n\ sparse try to seek rather than write all-NUL output blocks\n\ swab swap every pair of input bytes\n\ sync pad every input block with NULs to ibs-size; when used\n\ with block or unblock, pad with spaces rather than NULs\n\ "), stdout); fputs (_("\ excl fail if the output file already exists\n\ nocreat do not create the output file\n\ notrunc do not truncate the output file\n\ noerror continue after read errors\n\ fdatasync physically write output file data before finishing\n\ fsync likewise, but also write metadata\n\ "), stdout); fputs (_("\ \n\ Each FLAG symbol may be:\n\ \n\ append append mode (makes sense only for output; conv=notrunc suggested)\n\ "), stdout); if (O_CIO) fputs (_(" cio use concurrent I/O for data\n"), stdout); if (O_DIRECT) fputs (_(" direct use direct I/O for data\n"), stdout); fputs (_(" directory fail unless a directory\n"), stdout); if (O_DSYNC) fputs (_(" dsync use synchronized I/O for data\n"), stdout); if (O_SYNC) fputs (_(" sync likewise, but also for metadata\n"), stdout); fputs (_(" fullblock accumulate full blocks of input (iflag only)\n"), stdout); if (O_NONBLOCK) fputs (_(" nonblock use non-blocking I/O\n"), stdout); if (O_NOATIME) fputs (_(" noatime do not update access time\n"), stdout); #if HAVE_POSIX_FADVISE if (O_NOCACHE) fputs (_(" nocache Request to drop cache. See also oflag=sync\n"), stdout); #endif if (O_NOCTTY) fputs (_(" noctty do not assign controlling terminal from file\n"), stdout); if (HAVE_WORKING_O_NOFOLLOW) fputs (_(" nofollow do not follow symlinks\n"), stdout); if (O_NOLINKS) fputs (_(" nolinks fail if multiply-linked\n"), stdout); if (O_BINARY) fputs (_(" binary use binary I/O for data\n"), stdout); if (O_TEXT) fputs (_(" text use text I/O for data\n"), stdout); { printf (_("\ \n\ Sending a %s signal to a running 'dd' process makes it\n\ print I/O statistics to standard error and then resume copying.\n\ \n\ Options are:\n\ \n\ "), SIGINFO == SIGUSR1 ? "USR1" : "INFO"); } oputs (HELP_OPTION_DESCRIPTION); oputs (VERSION_OPTION_DESCRIPTION); emit_ancillary_info (PROGRAM_NAME); } exit (status); } /* Common options to use when displaying sizes and rates. */ enum { human_opts = (human_autoscale | human_round_to_nearest | human_space_before_unit | human_SI | human_B) }; /* Ensure input buffer IBUF is allocated. */ static void alloc_ibuf (void) { if (ibuf) return; bool extra_byte_for_swab = !!(conversions_mask & C_SWAB); ibuf = alignalloc (page_size, input_blocksize + extra_byte_for_swab); if (!ibuf) { char hbuf[LONGEST_HUMAN_READABLE + 1]; error (EXIT_FAILURE, 0, _("memory exhausted by input buffer of size %td bytes (%s)"), input_blocksize, human_readable (input_blocksize, hbuf, human_opts | human_base_1024, 1, 1)); } } /* Ensure output buffer OBUF is allocated/initialized. */ static void alloc_obuf (void) { if (obuf) return; if (conversions_mask & C_TWOBUFS) { obuf = alignalloc (page_size, output_blocksize); if (!obuf) { char hbuf[LONGEST_HUMAN_READABLE + 1]; error (EXIT_FAILURE, 0, _("memory exhausted by output buffer of size %td" " bytes (%s)"), output_blocksize, human_readable (output_blocksize, hbuf, human_opts | human_base_1024, 1, 1)); } } else { alloc_ibuf (); obuf = ibuf; } } static void translate_charset (char const *new_trans) { for (int i = 0; i < 256; i++) trans_table[i] = new_trans[trans_table[i]]; translation_needed = true; } /* Return true if I has more than one bit set. I must be nonnegative. */ static inline bool multiple_bits_set (int i) { return MULTIPLE_BITS_SET (i); } static bool abbreviation_lacks_prefix (char const *message) { return message[strlen (message) - 2] == ' '; } /* Print transfer statistics. */ static void print_xfer_stats (xtime_t progress_time) { xtime_t now = progress_time ? progress_time : gethrxtime (); static char const slash_s[] = "/s"; char hbuf[3][LONGEST_HUMAN_READABLE + sizeof slash_s]; double delta_s; char const *bytes_per_second; char const *si = human_readable (w_bytes, hbuf[0], human_opts, 1, 1); char const *iec = human_readable (w_bytes, hbuf[1], human_opts | human_base_1024, 1, 1); /* Use integer arithmetic to compute the transfer rate, since that makes it easy to use SI abbreviations. */ char *bpsbuf = hbuf[2]; int bpsbufsize = sizeof hbuf[2]; if (start_time < now) { double XTIME_PRECISIONe0 = XTIME_PRECISION; xtime_t delta_xtime = now - start_time; delta_s = delta_xtime / XTIME_PRECISIONe0; bytes_per_second = human_readable (w_bytes, bpsbuf, human_opts, XTIME_PRECISION, delta_xtime); strcat (bytes_per_second - bpsbuf + bpsbuf, slash_s); } else { delta_s = 0; snprintf (bpsbuf, bpsbufsize, "%s B/s", _("Infinity")); bytes_per_second = bpsbuf; } if (progress_time) fputc ('\r', stderr); /* Use full seconds when printing progress, since the progress report is output once per second and there is little point displaying any subsecond jitter. Use default precision with %g otherwise, as this provides more-useful output then. With long transfers %g can generate a number with an exponent; that is OK. */ char delta_s_buf[24]; snprintf (delta_s_buf, sizeof delta_s_buf, progress_time ? "%.0f s" : "%g s", delta_s); int stats_len = (abbreviation_lacks_prefix (si) ? fprintf (stderr, ngettext ("%jd byte copied, %s, %s", "%jd bytes copied, %s, %s", select_plural (w_bytes)), w_bytes, delta_s_buf, bytes_per_second) : abbreviation_lacks_prefix (iec) ? fprintf (stderr, _("%jd bytes (%s) copied, %s, %s"), w_bytes, si, delta_s_buf, bytes_per_second) : fprintf (stderr, _("%jd bytes (%s, %s) copied, %s, %s"), w_bytes, si, iec, delta_s_buf, bytes_per_second)); if (progress_time) { /* Erase any trailing junk on the output line by outputting spaces. In theory this could glitch the display because the formatted translation of a line describing a larger file could consume fewer screen columns than the strlen difference from the previously formatted translation. In practice this does not seem to be a problem. */ if (0 <= stats_len && stats_len < progress_len) fprintf (stderr, "%*s", progress_len - stats_len, ""); progress_len = stats_len; } else fputc ('\n', stderr); reported_w_bytes = w_bytes; } static void print_stats (void) { if (status_level == STATUS_NONE) return; if (0 < progress_len) { fputc ('\n', stderr); progress_len = 0; } fprintf (stderr, _("%jd+%jd records in\n" "%jd+%jd records out\n"), r_full, r_partial, w_full, w_partial); if (r_truncate != 0) fprintf (stderr, ngettext ("%jd truncated record\n", "%jd truncated records\n", select_plural (r_truncate)), r_truncate); if (status_level == STATUS_NOXFER) return; print_xfer_stats (0); } /* An ordinary signal was received; arrange for the program to exit. */ static void interrupt_handler (int sig) { if (! SA_RESETHAND) signal (sig, SIG_DFL); interrupt_signal = sig; } /* An info signal was received; arrange for the program to print status. */ static void siginfo_handler (MAYBE_UNUSED int sig) { info_signal_count++; } /* Install the signal handlers. */ static void install_signal_handlers (void) { bool catch_siginfo = ! (SIGINFO == SIGUSR1 && getenv ("POSIXLY_CORRECT")); struct sigaction act; sigemptyset (&caught_signals); if (catch_siginfo) sigaddset (&caught_signals, SIGINFO); sigaction (SIGINT, NULL, &act); if (act.sa_handler != SIG_IGN) sigaddset (&caught_signals, SIGINT); act.sa_mask = caught_signals; if (sigismember (&caught_signals, SIGINFO)) { act.sa_handler = siginfo_handler; /* Note we don't use SA_RESTART here and instead handle EINTR explicitly in iftruncate etc. to avoid blocking on uncommitted read/write calls. */ act.sa_flags = 0; sigaction (SIGINFO, &act, NULL); } if (sigismember (&caught_signals, SIGINT)) { act.sa_handler = interrupt_handler; act.sa_flags = SA_NODEFER | SA_RESETHAND; sigaction (SIGINT, &act, NULL); } } /* Close FD. Return 0 if successful, -1 (setting errno) otherwise. If close fails with errno == EINTR, POSIX says the file descriptor is in an unspecified state, so keep trying to close FD but do not consider EBADF to be an error. Do not process signals. This all differs somewhat from functions like ifdatasync and ifsync. */ static int iclose (int fd) { if (close (fd) != 0) do if (errno != EINTR) return -1; while (close (fd) != 0 && errno != EBADF); return 0; } static int synchronize_output (void); static void cleanup (void) { if (!interrupt_signal) { int sync_status = synchronize_output (); if (sync_status) exit (sync_status); } if (iclose (STDIN_FILENO) != 0) error (EXIT_FAILURE, errno, _("closing input file %s"), quoteaf (input_file)); /* Don't remove this call to close, even though close_stdout closes standard output. This close is necessary when cleanup is called as a consequence of signal handling. */ if (iclose (STDOUT_FILENO) != 0) error (EXIT_FAILURE, errno, _("closing output file %s"), quoteaf (output_file)); } /* Process any pending signals. If signals are caught, this function should be called periodically. Ideally there should never be an unbounded amount of time when signals are not being processed. */ static void process_signals (void) { while (interrupt_signal || info_signal_count) { int interrupt; int infos; sigset_t oldset; sigprocmask (SIG_BLOCK, &caught_signals, &oldset); /* Reload interrupt_signal and info_signal_count, in case a new signal was handled before sigprocmask took effect. */ interrupt = interrupt_signal; infos = info_signal_count; if (infos) info_signal_count = infos - 1; sigprocmask (SIG_SETMASK, &oldset, NULL); if (interrupt) cleanup (); print_stats (); if (interrupt) raise (interrupt); } } static void finish_up (void) { /* Process signals first, so that cleanup is called at most once. */ process_signals (); cleanup (); print_stats (); } static void quit (int code) { finish_up (); exit (code); } /* Return LEN rounded down to a multiple of IO_BUFSIZE (to minimize calls to the expensive posix_fadvise (,POSIX_FADV_DONTNEED), while storing the remainder internally per FD. Pass LEN == 0 to get the current remainder. */ static off_t cache_round (int fd, off_t len) { static off_t i_pending, o_pending; off_t *pending = (fd == STDIN_FILENO ? &i_pending : &o_pending); if (len) { intmax_t c_pending; if (ckd_add (&c_pending, *pending, len)) c_pending = INTMAX_MAX; *pending = c_pending % IO_BUFSIZE; if (c_pending > *pending) len = c_pending - *pending; else len = 0; } else len = *pending; return len; } /* Discard the cache from the current offset of either STDIN_FILENO or STDOUT_FILENO. Return true on success. Return false on failure, with errno set. */ static bool invalidate_cache (int fd, off_t len) { int adv_ret = -1; off_t offset; bool nocache_eof = (fd == STDIN_FILENO ? i_nocache_eof : o_nocache_eof); /* Minimize syscalls. */ off_t clen = cache_round (fd, len); if (len && !clen) return true; /* Don't advise this time. */ else if (! len && ! clen && ! nocache_eof) return true; off_t pending = len ? cache_round (fd, 0) : 0; if (fd == STDIN_FILENO) { if (input_seekable) offset = input_offset; else { offset = -1; errno = ESPIPE; } } else { static off_t output_offset = -2; if (output_offset != -1) { if (output_offset < 0) output_offset = lseek (fd, 0, SEEK_CUR); else if (len) output_offset += clen + pending; } offset = output_offset; } if (0 <= offset) { if (! len && clen && nocache_eof) { pending = clen; clen = 0; } /* Note we're being careful here to only invalidate what we've read, so as not to dump any read ahead cache. Note also the kernel is conservative and only invalidates full pages in the specified range. */ #if HAVE_POSIX_FADVISE offset = offset - clen - pending; /* ensure full page specified when invalidating to eof. */ if (clen == 0) offset -= offset % page_size; adv_ret = posix_fadvise (fd, offset, clen, POSIX_FADV_DONTNEED); errno = adv_ret; #else errno = ENOTSUP; #endif } return adv_ret == 0; } /* Read from FD into the buffer BUF of size SIZE, processing any signals that arrive before bytes are read. Return the number of bytes read if successful, -1 (setting errno) on failure. */ static ssize_t iread (int fd, char *buf, idx_t size) { ssize_t nread; static ssize_t prev_nread; do { process_signals (); nread = read (fd, buf, size); /* Ignore final read error with iflag=direct as that returns EINVAL due to the non aligned file offset. */ if (nread == -1 && errno == EINVAL && 0 < prev_nread && prev_nread < size && (input_flags & O_DIRECT)) { errno = 0; nread = 0; } } while (nread < 0 && errno == EINTR); /* Short read may be due to received signal. */ if (0 < nread && nread < size) process_signals (); if (0 < nread && warn_partial_read) { if (0 < prev_nread && prev_nread < size) { idx_t prev = prev_nread; if (status_level != STATUS_NONE) diagnose (0, ngettext (("warning: partial read (%td byte); " "suggest iflag=fullblock"), ("warning: partial read (%td bytes); " "suggest iflag=fullblock"), select_plural (prev)), prev); warn_partial_read = false; } } prev_nread = nread; return nread; } /* Wrapper around iread function to accumulate full blocks. */ static ssize_t iread_fullblock (int fd, char *buf, idx_t size) { ssize_t nread = 0; while (0 < size) { ssize_t ncurr = iread (fd, buf, size); if (ncurr < 0) return ncurr; if (ncurr == 0) break; nread += ncurr; buf += ncurr; size -= ncurr; } return nread; } /* Write to FD the buffer BUF of size SIZE, processing any signals that arrive. Return the number of bytes written, setting errno if this is less than SIZE. Keep trying if there are partial writes. */ static idx_t iwrite (int fd, char const *buf, idx_t size) { idx_t total_written = 0; if ((output_flags & O_DIRECT) && size < output_blocksize) { int old_flags = fcntl (STDOUT_FILENO, F_GETFL); if (fcntl (STDOUT_FILENO, F_SETFL, old_flags & ~O_DIRECT) != 0 && status_level != STATUS_NONE) diagnose (errno, _("failed to turn off O_DIRECT: %s"), quotef (output_file)); /* Since we have just turned off O_DIRECT for the final write, we try to preserve some of its semantics. */ /* Call invalidate_cache to setup the appropriate offsets for subsequent calls. */ o_nocache_eof = true; invalidate_cache (STDOUT_FILENO, 0); /* Attempt to ensure that the final block is committed to stable storage as quickly as possible. */ conversions_mask |= C_FSYNC; /* After the subsequent fsync we'll call invalidate_cache to attempt to clear all data from the page cache. */ } while (total_written < size) { ssize_t nwritten = 0; process_signals (); /* Perform a seek for a NUL block if sparse output is enabled. */ final_op_was_seek = false; if ((conversions_mask & C_SPARSE) && is_nul (buf, size)) { if (lseek (fd, size, SEEK_CUR) < 0) { conversions_mask &= ~C_SPARSE; /* Don't warn about the advisory sparse request. */ } else { final_op_was_seek = true; nwritten = size; } } if (!nwritten) nwritten = write (fd, buf + total_written, size - total_written); if (nwritten < 0) { if (errno != EINTR) break; } else if (nwritten == 0) { /* Some buggy drivers return 0 when one tries to write beyond a device's end. (Example: Linux kernel 1.2.13 on /dev/fd0.) Set errno to ENOSPC so they get a sensible diagnostic. */ errno = ENOSPC; break; } else total_written += nwritten; } if (o_nocache && total_written) invalidate_cache (fd, total_written); return total_written; } /* Write, then empty, the output buffer 'obuf'. */ static void write_output (void) { idx_t nwritten = iwrite (STDOUT_FILENO, obuf, output_blocksize); w_bytes += nwritten; if (nwritten != output_blocksize) { diagnose (errno, _("writing to %s"), quoteaf (output_file)); if (nwritten != 0) w_partial++; quit (EXIT_FAILURE); } else w_full++; oc = 0; } /* Restart on EINTR from fdatasync. */ static int ifdatasync (int fd) { int ret; do { process_signals (); ret = fdatasync (fd); } while (ret < 0 && errno == EINTR); return ret; } /* Restart on EINTR from fd_reopen. */ static int ifd_reopen (int desired_fd, char const *file, int flag, mode_t mode) { int ret; do { process_signals (); ret = fd_reopen (desired_fd, file, flag, mode); } while (ret < 0 && errno == EINTR); return ret; } /* Restart on EINTR from fstat. */ static int ifstat (int fd, struct stat *st) { int ret; do { process_signals (); ret = fstat (fd, st); } while (ret < 0 && errno == EINTR); return ret; } /* Restart on EINTR from fsync. */ static int ifsync (int fd) { int ret; do { process_signals (); ret = fsync (fd); } while (ret < 0 && errno == EINTR); return ret; } /* Restart on EINTR from ftruncate. */ static int iftruncate (int fd, off_t length) { int ret; do { process_signals (); ret = ftruncate (fd, length); } while (ret < 0 && errno == EINTR); return ret; } /* Return true if STR is of the form "PATTERN" or "PATTERNDELIM...". */ ATTRIBUTE_PURE static bool operand_matches (char const *str, char const *pattern, char delim) { while (*pattern) if (*str++ != *pattern++) return false; return !*str || *str == delim; } /* Interpret one "conv=..." or similar operand STR according to the symbols in TABLE, returning the flags specified. If the operand cannot be parsed, use ERROR_MSGID to generate a diagnostic. */ static int parse_symbols (char const *str, struct symbol_value const *table, bool exclusive, char const *error_msgid) { int value = 0; while (true) { char const *strcomma = strchr (str, ','); struct symbol_value const *entry; for (entry = table; ! (operand_matches (str, entry->symbol, ',') && entry->value); entry++) { if (! entry->symbol[0]) { idx_t slen = strcomma ? strcomma - str : strlen (str); diagnose (0, "%s: %s", _(error_msgid), quotearg_n_style_mem (0, locale_quoting_style, str, slen)); usage (EXIT_FAILURE); } } if (exclusive) value = entry->value; else value |= entry->value; if (!strcomma) break; str = strcomma + 1; } return value; } /* Return the value of STR, interpreted as a non-negative decimal integer, optionally multiplied by various values. Set *INVALID to an appropriate error value and return INTMAX_MAX if it is an overflow, an indeterminate value if some other error occurred. */ static intmax_t parse_integer (char const *str, strtol_error *invalid) { /* Call xstrtoumax, not xstrtoimax, since we don't want to allow strings like " -0". Initialize N to an indeterminate value; calling code should not rely on this function returning 0 when *INVALID represents a non-overflow error. */ int indeterminate = 0; static char const suffixes[] = "bcEGkKMPQRTwYZ0"; intmax_t result = 1; bool overflow = false; bool warn_zero_multiplier = false; strtol_error e; while (true) { uintmax_t n = indeterminate; char *suffix; e = xstrtoumax (str, &suffix, 10, &n, suffixes); if ((e & ~LONGINT_OVERFLOW) == LONGINT_INVALID_SUFFIX_CHAR && *suffix == 'B' && str < suffix && suffix[-1] != 'B') { suffix++; if (!*suffix) e &= ~LONGINT_INVALID_SUFFIX_CHAR; } bool multiply = ((e & ~LONGINT_OVERFLOW) == LONGINT_INVALID_SUFFIX_CHAR && *suffix == 'x'); if (multiply) e &= ~LONGINT_INVALID_SUFFIX_CHAR; if ((e & ~LONGINT_OVERFLOW) != LONGINT_OK) { if (! (e & LONGINT_OVERFLOW) && n <= INTMAX_MAX) { *invalid = e; return indeterminate; } e = LONGINT_OVERFLOW; } if (n == 0) result = 0; else if (result != 0) { intmax_t product; if ((e & LONGINT_OVERFLOW) || overflow || ckd_mul (&product, result, n)) overflow = true; else result = product; } if (multiply && STRPREFIX (str, "0x")) warn_zero_multiplier = true; if (! multiply) break; str = suffix + 1; } if (result == 0) { if (warn_zero_multiplier) diagnose (0, _("warning: %s is a zero multiplier; " "use %s if that is intended"), quote_n (0, "0x"), quote_n (1, "00x")); e = LONGINT_OK; } else if (overflow) { e = LONGINT_OVERFLOW; result = INTMAX_MAX; } *invalid = e; return result; } /* OPERAND is of the form "X=...". Return true if X is NAME. */ ATTRIBUTE_PURE static bool operand_is (char const *operand, char const *name) { return operand_matches (operand, name, '='); } static void scanargs (int argc, char *const *argv) { idx_t blocksize = 0; intmax_t count = INTMAX_MAX; intmax_t skip = 0; intmax_t seek = 0; bool count_B = false, skip_B = false, seek_B = false; for (int i = optind; i < argc; i++) { char const *name = argv[i]; char const *val = strchr (name, '='); if (val == NULL) { diagnose (0, _("unrecognized operand %s"), quoteaf (name)); usage (EXIT_FAILURE); } val++; if (operand_is (name, "if")) input_file = val; else if (operand_is (name, "of")) output_file = val; else if (operand_is (name, "conv")) conversions_mask |= parse_symbols (val, conversions, false, N_("invalid conversion")); else if (operand_is (name, "iflag")) input_flags |= parse_symbols (val, flags, false, N_("invalid input flag")); else if (operand_is (name, "oflag")) output_flags |= parse_symbols (val, flags, false, N_("invalid output flag")); else if (operand_is (name, "status")) status_level = parse_symbols (val, statuses, true, N_("invalid status level")); else { strtol_error invalid = LONGINT_OK; intmax_t n = parse_integer (val, &invalid); bool has_B = !!strchr (val, 'B'); intmax_t n_min = 0; intmax_t n_max = INTMAX_MAX; idx_t *converted_idx = NULL; /* Maximum blocksize. Keep it smaller than IDX_MAX, so that it fits into blocksize vars even if 1 is added for conv=swab. Do not exceed SSIZE_MAX, for the benefit of system calls like "read". And do not exceed OFF_T_MAX, for the benefit of the large-offset seek code. */ idx_t max_blocksize = MIN (IDX_MAX - 1, MIN (SSIZE_MAX, OFF_T_MAX)); if (operand_is (name, "ibs")) { n_min = 1; n_max = max_blocksize; converted_idx = &input_blocksize; } else if (operand_is (name, "obs")) { n_min = 1; n_max = max_blocksize; converted_idx = &output_blocksize; } else if (operand_is (name, "bs")) { n_min = 1; n_max = max_blocksize; converted_idx = &blocksize; } else if (operand_is (name, "cbs")) { n_min = 1; n_max = MIN (SIZE_MAX, IDX_MAX); converted_idx = &conversion_blocksize; } else if (operand_is (name, "skip") || operand_is (name, "iseek")) { skip = n; skip_B = has_B; } else if (operand_is (name + (*name == 'o'), "seek")) { seek = n; seek_B = has_B; } else if (operand_is (name, "count")) { count = n; count_B = has_B; } else { diagnose (0, _("unrecognized operand %s"), quoteaf (name)); usage (EXIT_FAILURE); } if (n < n_min) invalid = LONGINT_INVALID; else if (n_max < n) invalid = LONGINT_OVERFLOW; if (invalid != LONGINT_OK) error (EXIT_FAILURE, invalid == LONGINT_OVERFLOW ? EOVERFLOW : 0, "%s: %s", _("invalid number"), quoteaf (val)); else if (converted_idx) *converted_idx = n; } } if (blocksize) input_blocksize = output_blocksize = blocksize; else { /* POSIX says dd aggregates partial reads into output_blocksize if bs= is not specified. */ conversions_mask |= C_TWOBUFS; } if (input_blocksize == 0) input_blocksize = DEFAULT_BLOCKSIZE; if (output_blocksize == 0) output_blocksize = DEFAULT_BLOCKSIZE; if (conversion_blocksize == 0) conversions_mask &= ~(C_BLOCK | C_UNBLOCK); if (input_flags & (O_DSYNC | O_SYNC)) input_flags |= O_RSYNC; if (output_flags & O_FULLBLOCK) { diagnose (0, "%s: %s", _("invalid output flag"), quote ("fullblock")); usage (EXIT_FAILURE); } if (skip_B) input_flags |= O_SKIP_BYTES; if (input_flags & O_SKIP_BYTES && skip != 0) { skip_records = skip / input_blocksize; skip_bytes = skip % input_blocksize; } else if (skip != 0) skip_records = skip; if (count_B) input_flags |= O_COUNT_BYTES; if (input_flags & O_COUNT_BYTES && count != INTMAX_MAX) { max_records = count / input_blocksize; max_bytes = count % input_blocksize; } else if (count != INTMAX_MAX) max_records = count; if (seek_B) output_flags |= O_SEEK_BYTES; if (output_flags & O_SEEK_BYTES && seek != 0) { seek_records = seek / output_blocksize; seek_bytes = seek % output_blocksize; } else if (seek != 0) seek_records = seek; /* Warn about partial reads if bs=SIZE is given and iflag=fullblock is not, and if counting or skipping bytes or using direct I/O. This helps to avoid confusion with miscounts, and to avoid issues with direct I/O on GNU/Linux. */ warn_partial_read = (! (conversions_mask & C_TWOBUFS) && ! (input_flags & O_FULLBLOCK) && (skip_records || (0 < max_records && max_records < INTMAX_MAX) || (input_flags | output_flags) & O_DIRECT)); iread_fnc = ((input_flags & O_FULLBLOCK) ? iread_fullblock : iread); input_flags &= ~O_FULLBLOCK; if (multiple_bits_set (conversions_mask & (C_ASCII | C_EBCDIC | C_IBM))) error (EXIT_FAILURE, 0, _("cannot combine any two of {ascii,ebcdic,ibm}")); if (multiple_bits_set (conversions_mask & (C_BLOCK | C_UNBLOCK))) error (EXIT_FAILURE, 0, _("cannot combine block and unblock")); if (multiple_bits_set (conversions_mask & (C_LCASE | C_UCASE))) error (EXIT_FAILURE, 0, _("cannot combine lcase and ucase")); if (multiple_bits_set (conversions_mask & (C_EXCL | C_NOCREAT))) error (EXIT_FAILURE, 0, _("cannot combine excl and nocreat")); if (multiple_bits_set (input_flags & (O_DIRECT | O_NOCACHE)) || multiple_bits_set (output_flags & (O_DIRECT | O_NOCACHE))) error (EXIT_FAILURE, 0, _("cannot combine direct and nocache")); if (input_flags & O_NOCACHE) { i_nocache = true; i_nocache_eof = (max_records == 0 && max_bytes == 0); input_flags &= ~O_NOCACHE; } if (output_flags & O_NOCACHE) { o_nocache = true; o_nocache_eof = (max_records == 0 && max_bytes == 0); output_flags &= ~O_NOCACHE; } } /* Fix up translation table. */ static void apply_translations (void) { if (conversions_mask & C_ASCII) translate_charset (ebcdic_to_ascii); if (conversions_mask & C_UCASE) { for (int i = 0; i < 256; i++) trans_table[i] = toupper (trans_table[i]); translation_needed = true; } else if (conversions_mask & C_LCASE) { for (int i = 0; i < 256; i++) trans_table[i] = tolower (trans_table[i]); translation_needed = true; } if (conversions_mask & C_EBCDIC) { translate_charset (ascii_to_ebcdic); newline_character = ascii_to_ebcdic['\n']; space_character = ascii_to_ebcdic[' ']; } else if (conversions_mask & C_IBM) { translate_charset (ascii_to_ibm); newline_character = ascii_to_ibm['\n']; space_character = ascii_to_ibm[' ']; } } /* Apply the character-set translations specified by the user to the NREAD bytes in BUF. */ static void translate_buffer (char *buf, idx_t nread) { char *cp = buf; for (idx_t i = nread; i; i--, cp++) *cp = trans_table[to_uchar (*cp)]; } /* Swap *NREAD bytes in BUF, which should have room for an extra byte after the end because the swapping is not in-place. If *SAVED_BYTE is nonnegative, also swap that initial byte from the previous call. Save the last byte into into *SAVED_BYTE if needed to make the resulting *NREAD even, and set *SAVED_BYTE to -1 otherwise. Return the buffer's adjusted start, either BUF or BUF + 1. */ static char * swab_buffer (char *buf, idx_t *nread, int *saved_byte) { if (*nread == 0) return buf; /* Update *SAVED_BYTE, and set PREV_SAVED to its old value. */ int prev_saved = *saved_byte; if ((prev_saved < 0) == (*nread & 1)) { unsigned char c = buf[--*nread]; *saved_byte = c; } else *saved_byte = -1; /* Do the byte-swapping by moving every other byte two positions toward the end, working from the end of the buffer toward the beginning. This way we move only half the data. */ for (idx_t i = *nread; 1 < i; i -= 2) buf[i] = buf[i - 2]; if (prev_saved < 0) return buf + 1; buf[1] = prev_saved; ++*nread; return buf; } /* Add OFFSET to the input offset, setting the overflow flag if necessary. */ static void advance_input_offset (intmax_t offset) { if (0 <= input_offset && ckd_add (&input_offset, input_offset, offset)) input_offset = -1; } /* Throw away RECORDS blocks of BLOCKSIZE bytes plus BYTES bytes on file descriptor FDESC, which is open with read permission for FILE. Store up to BLOCKSIZE bytes of the data at a time in IBUF or OBUF, if necessary. RECORDS or BYTES must be nonzero. If FDESC is STDIN_FILENO, advance the input offset. Return the number of records remaining, i.e., that were not skipped because EOF was reached. If FDESC is STDOUT_FILENO, on return, BYTES is the remaining bytes in addition to the remaining records. */ static intmax_t skip (int fdesc, char const *file, intmax_t records, idx_t blocksize, idx_t *bytes) { /* Try lseek and if an error indicates it was an inappropriate operation -- or if the file offset is not representable as an off_t -- fall back on using read. */ errno = 0; off_t offset; if (! ckd_mul (&offset, records, blocksize) && ! ckd_add (&offset, offset, *bytes) && 0 <= lseek (fdesc, offset, SEEK_CUR)) { if (fdesc == STDIN_FILENO) { struct stat st; if (ifstat (STDIN_FILENO, &st) != 0) error (EXIT_FAILURE, errno, _("cannot fstat %s"), quoteaf (file)); if (usable_st_size (&st) && 0 < st.st_size && 0 <= input_offset && st.st_size - input_offset < offset) { /* When skipping past EOF, return the number of _full_ blocks * that are not skipped, and set offset to EOF, so the caller * can determine the requested skip was not satisfied. */ records = ( offset - st.st_size ) / blocksize; offset = st.st_size - input_offset; } else records = 0; advance_input_offset (offset); } else { records = 0; *bytes = 0; } return records; } else { int lseek_errno = errno; /* The seek request may have failed above if it was too big (> device size, > max file size, etc.) Or it may not have been done at all (> OFF_T_MAX). Therefore try to seek to the end of the file, to avoid redundant reading. */ if (lseek (fdesc, 0, SEEK_END) >= 0) { /* File is seekable, and we're at the end of it, and size <= OFF_T_MAX. So there's no point using read to advance. */ if (!lseek_errno) { /* The original seek was not attempted as offset > OFF_T_MAX. We should error for write as can't get to the desired location, even if OFF_T_MAX < max file size. For read we're not going to read any data anyway, so we should error for consistency. It would be nice to not error for /dev/{zero,null} for any offset, but that's not a significant issue. */ lseek_errno = EOVERFLOW; } diagnose (lseek_errno, gettext (fdesc == STDIN_FILENO ? N_("%s: cannot skip") : N_("%s: cannot seek")), quotef (file)); /* If the file has a specific size and we've asked to skip/seek beyond the max allowable, then quit. */ quit (EXIT_FAILURE); } /* else file_size && offset > OFF_T_MAX or file ! seekable */ char *buf; if (fdesc == STDIN_FILENO) { alloc_ibuf (); buf = ibuf; } else { alloc_obuf (); buf = obuf; } do { ssize_t nread = iread_fnc (fdesc, buf, records ? blocksize : *bytes); if (nread < 0) { if (fdesc == STDIN_FILENO) { diagnose (errno, _("error reading %s"), quoteaf (file)); if (conversions_mask & C_NOERROR) print_stats (); } else diagnose (lseek_errno, _("%s: cannot seek"), quotef (file)); quit (EXIT_FAILURE); } else if (nread == 0) break; else if (fdesc == STDIN_FILENO) advance_input_offset (nread); if (records != 0) records--; else *bytes = 0; } while (records || *bytes); return records; } } /* Advance the input by NBYTES if possible, after a read error. The input file offset may or may not have advanced after the failed read; adjust it to point just after the bad record regardless. Return true if successful, or if the input is already known to not be seekable. */ static bool advance_input_after_read_error (idx_t nbytes) { if (! input_seekable) { if (input_seek_errno == ESPIPE) return true; errno = input_seek_errno; } else { off_t offset; advance_input_offset (nbytes); if (input_offset < 0) { diagnose (0, _("offset overflow while reading file %s"), quoteaf (input_file)); return false; } offset = lseek (STDIN_FILENO, 0, SEEK_CUR); if (0 <= offset) { off_t diff; if (offset == input_offset) return true; diff = input_offset - offset; if (! (0 <= diff && diff <= nbytes) && status_level != STATUS_NONE) diagnose (0, _("warning: invalid file offset after failed read")); if (0 <= lseek (STDIN_FILENO, diff, SEEK_CUR)) return true; if (errno == 0) diagnose (0, _("cannot work around kernel bug after all")); } } diagnose (errno, _("%s: cannot seek"), quotef (input_file)); return false; } /* Copy NREAD bytes of BUF, with no conversions. */ static void copy_simple (char const *buf, idx_t nread) { char const *start = buf; /* First uncopied char in BUF. */ do { idx_t nfree = MIN (nread, output_blocksize - oc); memcpy (obuf + oc, start, nfree); nread -= nfree; /* Update the number of bytes left to copy. */ start += nfree; oc += nfree; if (oc >= output_blocksize) write_output (); } while (nread != 0); } /* Copy NREAD bytes of BUF, doing conv=block (pad newline-terminated records to 'conversion_blocksize', replacing the newline with trailing spaces). */ static void copy_with_block (char const *buf, idx_t nread) { for (idx_t i = nread; i; i--, buf++) { if (*buf == newline_character) { if (col < conversion_blocksize) { for (idx_t j = col; j < conversion_blocksize; j++) output_char (space_character); } col = 0; } else { if (col == conversion_blocksize) r_truncate++; else if (col < conversion_blocksize) output_char (*buf); col++; } } } /* Copy NREAD bytes of BUF, doing conv=unblock (replace trailing spaces in 'conversion_blocksize'-sized records with a newline). */ static void copy_with_unblock (char const *buf, idx_t nread) { static idx_t pending_spaces = 0; for (idx_t i = 0; i < nread; i++) { char c = buf[i]; if (col++ >= conversion_blocksize) { col = pending_spaces = 0; /* Wipe out any pending spaces. */ i--; /* Push the char back; get it later. */ output_char (newline_character); } else if (c == space_character) pending_spaces++; else { /* 'c' is the character after a run of spaces that were not at the end of the conversion buffer. Output them. */ while (pending_spaces) { output_char (space_character); --pending_spaces; } output_char (c); } } } /* Set the file descriptor flags for FD that correspond to the nonzero bits in ADD_FLAGS. The file's name is NAME. */ static void set_fd_flags (int fd, int add_flags, char const *name) { /* Ignore file creation flags that are no-ops on file descriptors. */ add_flags &= ~ (O_NOCTTY | O_NOFOLLOW); if (add_flags) { int old_flags = fcntl (fd, F_GETFL); int new_flags = old_flags | add_flags; bool ok = true; if (old_flags < 0) ok = false; else if (old_flags != new_flags) { if (new_flags & (O_DIRECTORY | O_NOLINKS)) { /* NEW_FLAGS contains at least one file creation flag that requires some checking of the open file descriptor. */ struct stat st; if (ifstat (fd, &st) != 0) ok = false; else if ((new_flags & O_DIRECTORY) && ! S_ISDIR (st.st_mode)) { errno = ENOTDIR; ok = false; } else if ((new_flags & O_NOLINKS) && 1 < st.st_nlink) { errno = EMLINK; ok = false; } new_flags &= ~ (O_DIRECTORY | O_NOLINKS); } if (ok && old_flags != new_flags && fcntl (fd, F_SETFL, new_flags) == -1) ok = false; } if (!ok) error (EXIT_FAILURE, errno, _("setting flags for %s"), quoteaf (name)); } } /* The main loop. */ static int dd_copy (void) { char *bufstart; /* Input buffer. */ ssize_t nread; /* Bytes read in the current block. */ /* If nonzero, then the previously read block was partial and PARTREAD was its size. */ idx_t partread = 0; int exit_status = EXIT_SUCCESS; idx_t n_bytes_read; if (skip_records != 0 || skip_bytes != 0) { intmax_t us_bytes; bool us_bytes_overflow = (ckd_mul (&us_bytes, skip_records, input_blocksize) || ckd_add (&us_bytes, skip_bytes, us_bytes)); off_t input_offset0 = input_offset; intmax_t us_blocks = skip (STDIN_FILENO, input_file, skip_records, input_blocksize, &skip_bytes); /* POSIX doesn't say what to do when dd detects it has been asked to skip past EOF, so I assume it's non-fatal. There are 3 reasons why there might be unskipped blocks/bytes: 1. file is too small 2. pipe has not enough data 3. partial reads */ if ((us_blocks || (0 <= input_offset && (us_bytes_overflow || us_bytes != input_offset - input_offset0))) && status_level != STATUS_NONE) { diagnose (0, _("%s: cannot skip to specified offset"), quotef (input_file)); } } if (seek_records != 0 || seek_bytes != 0) { idx_t bytes = seek_bytes; intmax_t write_records = skip (STDOUT_FILENO, output_file, seek_records, output_blocksize, &bytes); if (write_records != 0 || bytes != 0) { memset (obuf, 0, write_records ? output_blocksize : bytes); do { idx_t size = write_records ? output_blocksize : bytes; if (iwrite (STDOUT_FILENO, obuf, size) != size) { diagnose (errno, _("writing to %s"), quoteaf (output_file)); quit (EXIT_FAILURE); } if (write_records != 0) write_records--; else bytes = 0; } while (write_records || bytes); } } if (max_records == 0 && max_bytes == 0) return exit_status; alloc_ibuf (); alloc_obuf (); int saved_byte = -1; while (true) { if (status_level == STATUS_PROGRESS) { xtime_t progress_time = gethrxtime (); if (next_time <= progress_time) { print_xfer_stats (progress_time); next_time += XTIME_PRECISION; } } if (r_partial + r_full >= max_records + !!max_bytes) break; /* Zero the buffer before reading, so that if we get a read error, whatever data we are able to read is followed by zeros. This minimizes data loss. */ if ((conversions_mask & C_SYNC) && (conversions_mask & C_NOERROR)) memset (ibuf, (conversions_mask & (C_BLOCK | C_UNBLOCK)) ? ' ' : '\0', input_blocksize); if (r_partial + r_full >= max_records) nread = iread_fnc (STDIN_FILENO, ibuf, max_bytes); else nread = iread_fnc (STDIN_FILENO, ibuf, input_blocksize); if (nread > 0) { advance_input_offset (nread); if (i_nocache) invalidate_cache (STDIN_FILENO, nread); } else if (nread == 0) { i_nocache_eof |= i_nocache; o_nocache_eof |= o_nocache && ! (conversions_mask & C_NOTRUNC); break; /* EOF. */ } else { if (!(conversions_mask & C_NOERROR) || status_level != STATUS_NONE) diagnose (errno, _("error reading %s"), quoteaf (input_file)); if (conversions_mask & C_NOERROR) { print_stats (); idx_t bad_portion = input_blocksize - partread; /* We already know this data is not cached, but call this so that correct offsets are maintained. */ invalidate_cache (STDIN_FILENO, bad_portion); /* Seek past the bad block if possible. */ if (!advance_input_after_read_error (bad_portion)) { exit_status = EXIT_FAILURE; /* Suppress duplicate diagnostics. */ input_seekable = false; input_seek_errno = ESPIPE; } if ((conversions_mask & C_SYNC) && !partread) /* Replace the missing input with null bytes and proceed normally. */ nread = 0; else continue; } else { /* Write any partial block. */ exit_status = EXIT_FAILURE; break; } } n_bytes_read = nread; if (n_bytes_read < input_blocksize) { r_partial++; partread = n_bytes_read; if (conversions_mask & C_SYNC) { if (!(conversions_mask & C_NOERROR)) /* If C_NOERROR, we zeroed the block before reading. */ memset (ibuf + n_bytes_read, (conversions_mask & (C_BLOCK | C_UNBLOCK)) ? ' ' : '\0', input_blocksize - n_bytes_read); n_bytes_read = input_blocksize; } } else { r_full++; partread = 0; } if (ibuf == obuf) /* If not C_TWOBUFS. */ { idx_t nwritten = iwrite (STDOUT_FILENO, obuf, n_bytes_read); w_bytes += nwritten; if (nwritten != n_bytes_read) { diagnose (errno, _("error writing %s"), quoteaf (output_file)); if (nwritten != 0) w_partial++; return EXIT_FAILURE; } else if (n_bytes_read == input_blocksize) w_full++; else w_partial++; continue; } /* Do any translations on the whole buffer at once. */ if (translation_needed) translate_buffer (ibuf, n_bytes_read); if (conversions_mask & C_SWAB) bufstart = swab_buffer (ibuf, &n_bytes_read, &saved_byte); else bufstart = ibuf; if (conversions_mask & C_BLOCK) copy_with_block (bufstart, n_bytes_read); else if (conversions_mask & C_UNBLOCK) copy_with_unblock (bufstart, n_bytes_read); else copy_simple (bufstart, n_bytes_read); } /* If we have a char left as a result of conv=swab, output it. */ if (0 <= saved_byte) { char saved_char = saved_byte; if (conversions_mask & C_BLOCK) copy_with_block (&saved_char, 1); else if (conversions_mask & C_UNBLOCK) copy_with_unblock (&saved_char, 1); else output_char (saved_char); } if ((conversions_mask & C_BLOCK) && col > 0) { /* If the final input line didn't end with a '\n', pad the output block to 'conversion_blocksize' chars. */ for (idx_t i = col; i < conversion_blocksize; i++) output_char (space_character); } if (col && (conversions_mask & C_UNBLOCK)) { /* If there was any output, add a final '\n'. */ output_char (newline_character); } /* Write out the last block. */ if (oc != 0) { idx_t nwritten = iwrite (STDOUT_FILENO, obuf, oc); w_bytes += nwritten; if (nwritten != 0) w_partial++; if (nwritten != oc) { diagnose (errno, _("error writing %s"), quoteaf (output_file)); return EXIT_FAILURE; } } /* If the last write was converted to a seek, then for a regular file or shared memory object, ftruncate to extend the size. */ if (final_op_was_seek) { struct stat stdout_stat; if (ifstat (STDOUT_FILENO, &stdout_stat) != 0) { diagnose (errno, _("cannot fstat %s"), quoteaf (output_file)); return EXIT_FAILURE; } if (S_ISREG (stdout_stat.st_mode) || S_TYPEISSHM (&stdout_stat)) { off_t output_offset = lseek (STDOUT_FILENO, 0, SEEK_CUR); if (0 <= output_offset && stdout_stat.st_size < output_offset) { if (iftruncate (STDOUT_FILENO, output_offset) != 0) { diagnose (errno, _("failed to truncate to %jd bytes" " in output file %s"), (intmax_t) {output_offset}, quoteaf (output_file)); return EXIT_FAILURE; } } } } /* fdatasync/fsync can take a long time, so issue a final progress indication now if progress has been made since the previous indication. */ if (conversions_mask & (C_FDATASYNC | C_FSYNC) && status_level == STATUS_PROGRESS && 0 <= reported_w_bytes && reported_w_bytes < w_bytes) print_xfer_stats (0); return exit_status; } /* Synchronize output according to conversions_mask. Do this even if w_bytes is zero, as fsync and fdatasync flush out write requests from other processes too. Clear bits in conversions_mask so that synchronization is done only once. Return zero if successful, an exit status otherwise. */ static int synchronize_output (void) { int exit_status = 0; int mask = conversions_mask; conversions_mask &= ~ (C_FDATASYNC | C_FSYNC); if ((mask & C_FDATASYNC) && ifdatasync (STDOUT_FILENO) != 0) { if (errno != ENOSYS && errno != EINVAL) { diagnose (errno, _("fdatasync failed for %s"), quoteaf (output_file)); exit_status = EXIT_FAILURE; } mask |= C_FSYNC; } if ((mask & C_FSYNC) && ifsync (STDOUT_FILENO) != 0) { diagnose (errno, _("fsync failed for %s"), quoteaf (output_file)); return EXIT_FAILURE; } return exit_status; } int main (int argc, char **argv) { off_t offset; install_signal_handlers (); initialize_main (&argc, &argv); set_program_name (argv[0]); setlocale (LC_ALL, ""); bindtextdomain (PACKAGE, LOCALEDIR); textdomain (PACKAGE); /* Arrange to close stdout if parse_long_options exits. */ atexit (maybe_close_stdout); page_size = getpagesize (); parse_gnu_standard_options_only (argc, argv, PROGRAM_NAME, PACKAGE, Version, true, usage, AUTHORS, (char const *) NULL); close_stdout_required = false; /* Initialize translation table to identity translation. */ for (int i = 0; i < 256; i++) trans_table[i] = i; /* Decode arguments. */ scanargs (argc, argv); apply_translations (); if (input_file == NULL) { input_file = _("standard input"); set_fd_flags (STDIN_FILENO, input_flags, input_file); } else { if (ifd_reopen (STDIN_FILENO, input_file, O_RDONLY | input_flags, 0) < 0) error (EXIT_FAILURE, errno, _("failed to open %s"), quoteaf (input_file)); } offset = lseek (STDIN_FILENO, 0, SEEK_CUR); input_seekable = (0 <= offset); input_offset = MAX (0, offset); input_seek_errno = errno; if (output_file == NULL) { output_file = _("standard output"); set_fd_flags (STDOUT_FILENO, output_flags, output_file); } else { mode_t perms = MODE_RW_UGO; int opts = (output_flags | (conversions_mask & C_NOCREAT ? 0 : O_CREAT) | (conversions_mask & C_EXCL ? O_EXCL : 0) | (seek_records || (conversions_mask & C_NOTRUNC) ? 0 : O_TRUNC)); off_t size; if ((ckd_mul (&size, seek_records, output_blocksize) || ckd_add (&size, seek_bytes, size)) && !(conversions_mask & C_NOTRUNC)) error (EXIT_FAILURE, 0, _("offset too large: " "cannot truncate to a length of seek=%jd" " (%td-byte) blocks"), seek_records, output_blocksize); /* Open the output file with *read* access only if we might need to read to satisfy a 'seek=' request. If we can't read the file, go ahead with write-only access; it might work. */ if ((! seek_records || ifd_reopen (STDOUT_FILENO, output_file, O_RDWR | opts, perms) < 0) && (ifd_reopen (STDOUT_FILENO, output_file, O_WRONLY | opts, perms) < 0)) error (EXIT_FAILURE, errno, _("failed to open %s"), quoteaf (output_file)); if (seek_records != 0 && !(conversions_mask & C_NOTRUNC)) { if (iftruncate (STDOUT_FILENO, size) != 0) { /* Complain only when ftruncate fails on a regular file, a directory, or a shared memory object, as POSIX 1003.1-2004 specifies ftruncate's behavior only for these file types. For example, do not complain when Linux kernel 2.4 ftruncate fails on /dev/fd0. */ int ftruncate_errno = errno; struct stat stdout_stat; if (ifstat (STDOUT_FILENO, &stdout_stat) != 0) error (EXIT_FAILURE, errno, _("cannot fstat %s"), quoteaf (output_file)); else if (S_ISREG (stdout_stat.st_mode) || S_ISDIR (stdout_stat.st_mode) || S_TYPEISSHM (&stdout_stat)) { intmax_t isize = size; error (EXIT_FAILURE, ftruncate_errno, _("failed to truncate to %jd bytes" " in output file %s"), isize, quoteaf (output_file)); } } } } start_time = gethrxtime (); next_time = start_time + XTIME_PRECISION; int copy_status = dd_copy (); int sync_status = synchronize_output (); int exit_status = copy_status | sync_status; if (max_records == 0 && max_bytes == 0) { /* Special case to invalidate cache to end of file. */ if (i_nocache && !invalidate_cache (STDIN_FILENO, 0)) { diagnose (errno, _("failed to discard cache for: %s"), quotef (input_file)); exit_status = EXIT_FAILURE; } if (o_nocache && !invalidate_cache (STDOUT_FILENO, 0)) { diagnose (errno, _("failed to discard cache for: %s"), quotef (output_file)); exit_status = EXIT_FAILURE; } } else { /* Invalidate any pending region or to EOF if appropriate. */ if (i_nocache || i_nocache_eof) invalidate_cache (STDIN_FILENO, 0); if (o_nocache || o_nocache_eof) invalidate_cache (STDOUT_FILENO, 0); } finish_up (); main_exit (exit_status); }