138 lines
3.4 KiB
C
138 lines
3.4 KiB
C
/* xxd.c - hexdump.
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*
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* Copyright 2015 The Android Open Source Project
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*
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* No obvious standard, output looks like:
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* 0000000: 4c69 6e75 7820 7665 7273 696f 6e20 332e Linux version 3.
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USE_XXD(NEWTOY(xxd, ">1c#<1>4096=16l#g#<1=2prs#[!rs]", TOYFLAG_USR|TOYFLAG_BIN))
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config XXD
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bool "xxd"
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default y
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help
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usage: xxd [-c n] [-g n] [-l n] [-p] [-r] [-s n] [file]
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Hexdump a file to stdout. If no file is listed, copy from stdin.
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Filename "-" is a synonym for stdin.
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-c n Show n bytes per line (default 16).
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-g n Group bytes by adding a ' ' every n bytes (default 2).
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-l n Limit of n bytes before stopping (default is no limit).
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-p Plain hexdump (30 bytes/line, no grouping).
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-r Reverse operation: turn a hexdump into a binary file.
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-s n Skip to offset n.
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*/
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#define FOR_xxd
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#include "toys.h"
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GLOBALS(
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long s;
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long g;
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long l;
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long c;
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)
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static void do_xxd(int fd, char *name)
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{
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long long pos = 0;
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long long limit = TT.l;
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int i, len, space;
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if (toys.optflags&FLAG_s) {
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xlseek(fd, TT.s, SEEK_SET);
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pos = TT.s;
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if (limit) limit += TT.s;
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}
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while (0<(len = readall(fd, toybuf,
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(limit && limit-pos<TT.c)?limit-pos:TT.c))) {
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if (!(toys.optflags&FLAG_p)) printf("%08llx: ", pos);
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pos += len;
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space = 2*TT.c+TT.c/TT.g+1;
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for (i=0; i<len;) {
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space -= printf("%02x", toybuf[i]);
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if (!(++i%TT.g)) {
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putchar(' ');
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space--;
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}
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}
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if (!(toys.optflags&FLAG_p)) {
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printf("%*s", space, "");
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for (i=0; i<len; i++)
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putchar((toybuf[i]>=' ' && toybuf[i]<='~') ? toybuf[i] : '.');
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}
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putchar('\n');
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}
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if (len<0) perror_exit("read");
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}
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static int dehex(char ch)
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{
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if (ch >= '0' && ch <= '9') return ch - '0';
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if (ch >= 'a' && ch <= 'f') return ch - 'a' + 10;
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if (ch >= 'A' && ch <= 'F') return ch - 'a' + 10;
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return (ch == '\n') ? -2 : -1;
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}
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static void do_xxd_reverse(int fd, char *name)
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{
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FILE *fp = xfdopen(fd, "r");
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while (!feof(fp)) {
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int col = 0;
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int tmp;
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// Each line of a non-plain hexdump starts with an offset/address.
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if (!(toys.optflags&FLAG_p)) {
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long long pos;
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if (fscanf(fp, "%llx: ", &pos) == 1) {
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if (fseek(stdout, pos, SEEK_SET) != 0) {
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// TODO: just write out zeros if non-seekable?
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perror_exit("%s: seek failed", name);
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}
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}
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}
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// A plain hexdump can have as many bytes per line as you like,
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// but a non-plain hexdump assumes garbage after it's seen the
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// specified number of bytes.
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while (toys.optflags&FLAG_p || col < TT.c) {
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int n1, n2;
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// If we're at EOF or EOL or we read some non-hex...
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if ((n1 = n2 = dehex(fgetc(fp))) < 0 || (n2 = dehex(fgetc(fp))) < 0) {
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// If we're at EOL, start on that line.
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if (n1 == -2 || n2 == -2) continue;
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// Otherwise, skip to the next line.
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break;
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}
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fputc((n1 << 4) | (n2 & 0xf), stdout);
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col++;
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// Is there any grouping going on? Ignore a single space.
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tmp = fgetc(fp);
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if (tmp != ' ') ungetc(tmp, fp);
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}
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// Skip anything else on this line (such as the ASCII dump).
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while ((tmp = fgetc(fp)) != EOF && tmp != '\n')
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;
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}
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if (ferror(fp)) perror_msg_raw(name);
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fclose(fp);
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}
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void xxd_main(void)
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{
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// Plain style is 30 bytes/line, no grouping.
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if (toys.optflags&FLAG_p) TT.c = TT.g = 30;
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loopfiles(toys.optargs, toys.optflags&FLAG_r ? do_xxd_reverse : do_xxd);
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}
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