hush/coreutils/uudecode.c

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/* vi: set sw=4 ts=4: */
/*
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* Copyright 2003, Glenn McGrath
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*
* Based on specification from
* http://www.opengroup.org/onlinepubs/007904975/utilities/uuencode.html
*
* Bugs: the spec doesn't mention anything about "`\n`\n" prior to the
* "end" line
*/
#include "libbb.h"
static void read_stduu(FILE *src_stream, FILE *dst_stream)
{
char *line;
while ((line = xmalloc_fgetline(src_stream)) != NULL) {
int encoded_len, str_len;
char *line_ptr, *dst;
if (strcmp(line, "end") == 0) {
return; /* the only non-error exit */
}
line_ptr = line;
while (*line_ptr) {
*line_ptr = (*line_ptr - 0x20) & 0x3f;
line_ptr++;
}
str_len = line_ptr - line;
encoded_len = line[0] * 4 / 3;
/* Check that line is not too short. (we tolerate
* overly _long_ line to accomodate possible extra '`').
* Empty line case is also caught here. */
if (str_len <= encoded_len) {
break; /* go to bb_error_msg_and_die("short file"); */
}
if (encoded_len <= 0) {
/* Ignore the "`\n" line, why is it even in the encode file ? */
free(line);
continue;
}
if (encoded_len > 60) {
bb_error_msg_and_die("line too long");
}
dst = line;
line_ptr = line + 1;
do {
/* Merge four 6 bit chars to three 8 bit chars */
*dst++ = line_ptr[0] << 2 | line_ptr[1] >> 4;
encoded_len--;
if (encoded_len == 0) {
break;
}
*dst++ = line_ptr[1] << 4 | line_ptr[2] >> 2;
encoded_len--;
if (encoded_len == 0) {
break;
}
*dst++ = line_ptr[2] << 6 | line_ptr[3];
line_ptr += 4;
encoded_len -= 2;
} while (encoded_len > 0);
fwrite(line, 1, dst - line, dst_stream);
free(line);
}
bb_error_msg_and_die("short file");
}
static void read_base64(FILE *src_stream, FILE *dst_stream)
{
int term_count = 1;
while (1) {
char translated[4];
int count = 0;
while (count < 4) {
char *table_ptr;
int ch;
/* Get next _valid_ character.
* global vector bb_uuenc_tbl_base64[] contains this string:
* "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=\n"
*/
do {
ch = fgetc(src_stream);
if (ch == EOF) {
bb_error_msg_and_die("short file");
}
table_ptr = strchr(bb_uuenc_tbl_base64, ch);
} while (table_ptr == NULL);
/* Convert encoded character to decimal */
ch = table_ptr - bb_uuenc_tbl_base64;
if (*table_ptr == '=') {
if (term_count == 0) {
translated[count] = '\0';
break;
}
term_count++;
} else if (*table_ptr == '\n') {
/* Check for terminating line */
if (term_count == 5) {
return;
}
term_count = 1;
continue;
} else {
translated[count] = ch;
count++;
term_count = 0;
}
}
/* Merge 6 bit chars to 8 bit */
if (count > 1) {
fputc(translated[0] << 2 | translated[1] >> 4, dst_stream);
}
if (count > 2) {
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fputc(translated[1] << 4 | translated[2] >> 2, dst_stream);
}
if (count > 3) {
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fputc(translated[2] << 6 | translated[3], dst_stream);
}
}
}
int uudecode_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int uudecode_main(int argc UNUSED_PARAM, char **argv)
{
FILE *src_stream;
char *outname = NULL;
char *line;
opt_complementary = "?1"; /* 1 argument max */
getopt32(argv, "o:", &outname);
argv += optind;
if (!*argv)
*--argv = (char*)"-";
src_stream = xfopen_stdin(*argv);
/* Search for the start of the encoding */
while ((line = xmalloc_fgetline(src_stream)) != NULL) {
void (*decode_fn_ptr)(FILE *src, FILE *dst);
char *line_ptr;
FILE *dst_stream;
int mode;
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if (strncmp(line, "begin-base64 ", 13) == 0) {
line_ptr = line + 13;
decode_fn_ptr = read_base64;
} else if (strncmp(line, "begin ", 6) == 0) {
line_ptr = line + 6;
decode_fn_ptr = read_stduu;
} else {
free(line);
continue;
}
/* begin line found. decode and exit */
mode = bb_strtou(line_ptr, NULL, 8);
if (outname == NULL) {
outname = strchr(line_ptr, ' ');
if ((outname == NULL) || (*outname == '\0')) {
break;
}
outname++;
}
dst_stream = stdout;
if (NOT_LONE_DASH(outname)) {
dst_stream = xfopen_for_write(outname);
fchmod(fileno(dst_stream), mode & (S_IRWXU | S_IRWXG | S_IRWXO));
}
free(line);
decode_fn_ptr(src_stream, dst_stream);
/* fclose_if_not_stdin(src_stream); - redundant */
return EXIT_SUCCESS;
}
bb_error_msg_and_die("no 'begin' line");
}
/* Test script.
Put this into an empty dir with busybox binary, an run.
#!/bin/sh
test -x busybox || { echo "No ./busybox?"; exit; }
ln -sf busybox uudecode
ln -sf busybox uuencode
>A_null
echo -n A >A
echo -n AB >AB
echo -n ABC >ABC
echo -n ABCD >ABCD
echo -n ABCDE >ABCDE
echo -n ABCDEF >ABCDEF
cat busybox >A_bbox
for f in A*; do
echo uuencode $f
./uuencode $f <$f >u_$f
./uuencode -m $f <$f >m_$f
done
mkdir unpk_u unpk_m 2>/dev/null
for f in u_*; do
./uudecode <$f -o unpk_u/${f:2}
diff -a ${f:2} unpk_u/${f:2} >/dev/null 2>&1
echo uudecode $f: $?
done
for f in m_*; do
./uudecode <$f -o unpk_m/${f:2}
diff -a ${f:2} unpk_m/${f:2} >/dev/null 2>&1
echo uudecode $f: $?
done
*/