c30a5b137
Rafał Miłecki
2016-02-01
Subject
dd: support iflag=skip_bytes
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coreutils/dd.c+51 -27
| @@ -55,7 +55,7 @@ | |
| //usage:#define dd_trivial_usage | |
| //usage: "[if=FILE] [of=FILE] " IF_FEATURE_DD_IBS_OBS("[ibs=N] [obs=N] ") "[bs=N] [count=N] [skip=N]\n" | |
| - | //usage: " [seek=N]" IF_FEATURE_DD_IBS_OBS(" [conv=notrunc|noerror|sync|fsync]") |
| + | //usage: " [seek=N]" IF_FEATURE_DD_IBS_OBS(" [conv=notrunc|noerror|sync|fsync] [iflag=skip_bytes]") |
| //usage:#define dd_full_usage "\n\n" | |
| //usage: "Copy a file with converting and formatting\n" | |
| //usage: "\n if=FILE Read from FILE instead of stdin" | |
| @@ -76,6 +76,7 @@ | |
| //usage: "\n conv=sync Pad blocks with zeros" | |
| //usage: "\n conv=fsync Physically write data out before finishing" | |
| //usage: "\n conv=swab Swap every pair of bytes" | |
| + | //usage: "\n iflag=skip_bytes skip=N is in bytes" |
| //usage: ) | |
| //usage: IF_FEATURE_DD_STATUS( | |
| //usage: "\n status=noxfer Suppress rate output" | |
| @@ -122,11 +123,15 @@ enum { | |
| FLAG_FSYNC = (1 << 3) * ENABLE_FEATURE_DD_IBS_OBS, | |
| FLAG_SWAB = (1 << 4) * ENABLE_FEATURE_DD_IBS_OBS, | |
| /* end of conv flags */ | |
| - | FLAG_TWOBUFS = (1 << 5) * ENABLE_FEATURE_DD_IBS_OBS, |
| - | FLAG_COUNT = 1 << 6, |
| - | FLAG_STATUS = 1 << 7, |
| - | FLAG_STATUS_NONE = 1 << 7, |
| - | FLAG_STATUS_NOXFER = 1 << 8, |
| + | /* start of input flags */ |
| + | FLAG_IFLAG_SHIFT = 5, |
| + | FLAG_SKIP_BYTES = (1 << 5) * ENABLE_FEATURE_DD_IBS_OBS, |
| + | /* end of input flags */ |
| + | FLAG_TWOBUFS = (1 << 6) * ENABLE_FEATURE_DD_IBS_OBS, |
| + | FLAG_COUNT = 1 << 7, |
| + | FLAG_STATUS = 1 << 8, |
| + | FLAG_STATUS_NONE = 1 << 9, |
| + | FLAG_STATUS_NOXFER = 1 << 10, |
| }; | |
| static void dd_output_status(int UNUSED_PARAM cur_signal) | |
| @@ -203,18 +208,47 @@ static bool write_and_stats(const void *buf, size_t len, size_t obs, | |
| # define XATOU_SFX xatoul_sfx | |
| #endif | |
| + | #if ENABLE_FEATURE_DD_IBS_OBS |
| + | static int parse_comma_flags(char *val, const char *words, const char *error_in) |
| + | { |
| + | int flags = 0; |
| + | while (1) { |
| + | int n; |
| + | char *arg; |
| + | /* 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'; |
| + | n = index_in_strings(words, val); |
| + | if (n < 0) |
| + | bb_error_msg_and_die(bb_msg_invalid_arg_to, val, error_in); |
| + | flags |= (1 << n); |
| + | if (!arg) /* no ',' left, so this was the last specifier */ |
| + | break; |
| + | *arg = ','; /* to preserve ps listing */ |
| + | val = arg + 1; /* skip this keyword and ',' */ |
| + | } |
| + | return flags; |
| + | } |
| + | #endif |
| + | |
| int dd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; | |
| int dd_main(int argc UNUSED_PARAM, char **argv) | |
| { | |
| static const char keywords[] ALIGN1 = | |
| "bs\0""count\0""seek\0""skip\0""if\0""of\0"IF_FEATURE_DD_STATUS("status\0") | |
| #if ENABLE_FEATURE_DD_IBS_OBS | |
| - | "ibs\0""obs\0""conv\0" |
| + | "ibs\0""obs\0""conv\0""iflag\0" |
| #endif | |
| ; | |
| #if ENABLE_FEATURE_DD_IBS_OBS | |
| static const char conv_words[] ALIGN1 = | |
| "notrunc\0""sync\0""noerror\0""fsync\0""swab\0"; | |
| + | static const char iflag_words[] ALIGN1 = |
| + | "skip_bytes\0"; |
| #endif | |
| #if ENABLE_FEATURE_DD_STATUS | |
| static const char status_words[] ALIGN1 = | |
| @@ -232,6 +266,7 @@ int dd_main(int argc UNUSED_PARAM, char **argv) | |
| OP_ibs, | |
| OP_obs, | |
| OP_conv, | |
| + | OP_iflag, |
| /* Must be in the same order as FLAG_XXX! */ | |
| OP_conv_notrunc = 0, | |
| OP_conv_sync, | |
| @@ -251,6 +286,7 @@ int dd_main(int argc UNUSED_PARAM, char **argv) | |
| //ibm from ASCII to alternate EBCDIC | |
| /* Partially implemented: */ | |
| //swab swap every pair of input bytes: will abort on non-even reads | |
| + | OP_iflag_skip_bytes, |
| #endif | |
| }; | |
| smallint exitcode = EXIT_FAILURE; | |
| @@ -315,24 +351,11 @@ int dd_main(int argc UNUSED_PARAM, char **argv) | |
| /*continue;*/ | |
| } | |
| if (what == OP_conv) { | |
| - | while (1) { |
| - | int n; |
| - | /* 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'; |
| - | n = index_in_strings(conv_words, val); |
| - | if (n < 0) |
| - | bb_error_msg_and_die(bb_msg_invalid_arg_to, val, "conv"); |
| - | G.flags |= (1 << n); |
| - | if (!arg) /* no ',' left, so this was the last specifier */ |
| - | break; |
| - | /* *arg = ','; - to preserve ps listing? */ |
| - | val = arg + 1; /* skip this keyword and ',' */ |
| - | } |
| + | G.flags |= parse_comma_flags(val, conv_words, "conv"); |
| + | /*continue;*/ |
| + | } |
| + | if (what == OP_iflag) { |
| + | G.flags |= parse_comma_flags(val, iflag_words, "iflag") << FLAG_IFLAG_SHIFT; |
| /*continue;*/ | |
| } | |
| #endif | |
| @@ -421,9 +444,10 @@ int dd_main(int argc UNUSED_PARAM, char **argv) | |
| outfile = bb_msg_standard_output; | |
| } | |
| if (skip) { | |
| - | if (lseek(ifd, skip * ibs, SEEK_CUR) < 0) { |
| + | size_t blocksz = (G.flags & FLAG_SKIP_BYTES) ? 1 : ibs; |
| + | if (lseek(ifd, skip * blocksz, SEEK_CUR) < 0) { |
| do { | |
| - | ssize_t n = safe_read(ifd, ibuf, ibs); |
| + | ssize_t n = safe_read(ifd, ibuf, blocksz); |
| if (n < 0) | |
| goto die_infile; | |
| if (n == 0) | |
docs/posix_conformance.txt+1 -0
| @@ -178,6 +178,7 @@ dd POSIX options: | |
| conv=noerror | yes | | | |
| conv=notrunc | yes | | | |
| conv=sync | yes | | | |
| + | iflag=skip_bytes| yes | | |
| dd Busybox specific options: | |
| conv=fsync | |