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Diffstat (limited to 'libbb')
-rw-r--r--libbb/uuencode.c125
1 files changed, 100 insertions, 25 deletions
diff --git a/libbb/uuencode.c b/libbb/uuencode.c
index 03e708f..23e2123 100644
--- a/libbb/uuencode.c
+++ b/libbb/uuencode.c
@@ -73,23 +73,23 @@ void FAST_FUNC bb_uuencode(char *p, const void *src, int length, const char *tbl
}
/*
- * Decode base64 encoded stream.
- * Can stop on EOF, specified char, or on uuencode-style "====" line:
- * flags argument controls it.
+ * Decode base64 encoded string. Stops on '\0'.
+ *
+ * Returns: pointer to the undecoded part of source.
+ * If points to '\0', then the source was fully decoded.
+ * (*dst): advanced past the last written byte.
*/
-void FAST_FUNC read_base64(FILE *src_stream, FILE *dst_stream, int flags)
+const char* FAST_FUNC decode_base64(char **pp_dst, const char *src)
{
-/* Note that EOF _can_ be passed as exit_char too */
-#define exit_char ((int)(signed char)flags)
-#define uu_style_end (flags & BASE64_FLAG_UU_STOP)
-
- int term_count = 0;
+ char *dst = *pp_dst;
+ const char *src_tail;
while (1) {
unsigned char translated[4];
int count = 0;
/* Process one group of 4 chars */
+ src_tail = src;
while (count < 4) {
char *table_ptr;
int ch;
@@ -101,11 +101,20 @@ void FAST_FUNC read_base64(FILE *src_stream, FILE *dst_stream, int flags)
* "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=\n"
*/
do {
- ch = fgetc(src_stream);
- if (ch == exit_char && count == 0)
- return;
- if (ch == EOF)
- bb_error_msg_and_die("truncated base64 input");
+ ch = *src;
+ if (ch == '\0') {
+ if (count == 0) {
+ /* Example:
+ * If we decode "QUJD <NUL>", we want
+ * to return ptr to NUL, not to ' ',
+ * because we did fully decode
+ * the string (to "ABC").
+ */
+ src_tail = src;
+ }
+ goto ret;
+ }
+ src++;
table_ptr = strchr(bb_uuenc_tbl_base64, ch);
//TODO: add BASE64_FLAG_foo to die on bad char?
//Note that then we may need to still allow '\r' (for mail processing)
@@ -114,21 +123,15 @@ void FAST_FUNC read_base64(FILE *src_stream, FILE *dst_stream, int flags)
/* Convert encoded character to decimal */
ch = table_ptr - bb_uuenc_tbl_base64;
- if (ch == 65 /* '\n' */) {
- /* Terminating "====" line? */
- if (uu_style_end && term_count == 4)
- return; /* yes */
- term_count = 0;
+ if (ch == 65) { /* '\n' */
continue;
}
/* ch is 64 if char was '=', otherwise 0..63 */
translated[count] = ch & 63; /* 64 -> 0 */
- if (ch == 64) {
- term_count++;
+ if (ch == 64) { /* '=' */
break;
}
count++;
- term_count = 0;
}
/* Merge 6 bit chars to 8 bit.
@@ -136,10 +139,82 @@ void FAST_FUNC read_base64(FILE *src_stream, FILE *dst_stream, int flags)
* "eQ==" -> "y", not "y NUL NUL"
*/
if (count > 1)
- fputc(translated[0] << 2 | translated[1] >> 4, dst_stream);
+ *dst++ = translated[0] << 2 | translated[1] >> 4;
if (count > 2)
- fputc(translated[1] << 4 | translated[2] >> 2, dst_stream);
+ *dst++ = translated[1] << 4 | translated[2] >> 2;
if (count > 3)
- fputc(translated[2] << 6 | translated[3], dst_stream);
+ *dst++ = translated[2] << 6 | translated[3];
} /* while (1) */
+ ret:
+ *pp_dst = dst;
+ return src_tail;
+}
+
+/*
+ * Decode base64 encoded stream.
+ * Can stop on EOF, specified char, or on uuencode-style "====" line:
+ * flags argument controls it.
+ */
+void FAST_FUNC read_base64(FILE *src_stream, FILE *dst_stream, int flags)
+{
+/* Note that EOF _can_ be passed as exit_char too */
+#define exit_char ((int)(signed char)flags)
+#define uu_style_end (flags & BASE64_FLAG_UU_STOP)
+
+ /* uuencoded files have 61 byte lines. Use 64 byte buffer
+ * to process line at a time.
+ */
+ enum { BUFFER_SIZE = 64 };
+
+ char in_buf[BUFFER_SIZE + 2];
+ char out_buf[BUFFER_SIZE / 4 * 3 + 2];
+ char *out_tail;
+ const char *in_tail;
+ int term_seen = 0;
+ int in_count = 0;
+
+ while (1) {
+ while (in_count < BUFFER_SIZE) {
+ int ch = fgetc(src_stream);
+ if (ch == exit_char) {
+ if (in_count == 0)
+ return;
+ term_seen = 1;
+ break;
+ }
+ if (ch == EOF) {
+ term_seen = 1;
+ break;
+ }
+ /* Prevent "====" line to be split: stop if we see '\n'.
+ * We can also skip other whitespace and skirt the problem
+ * of files with NULs by stopping on any control char or space:
+ */
+ if (ch <= ' ')
+ break;
+ in_buf[in_count++] = ch;
+ }
+ in_buf[in_count] = '\0';
+
+ /* Did we encounter "====" line? */
+ if (uu_style_end && strcmp(in_buf, "====") == 0)
+ return;
+
+ out_tail = out_buf;
+ in_tail = decode_base64(&out_tail, in_buf);
+
+ fwrite(out_buf, (out_tail - out_buf), 1, dst_stream);
+
+ if (term_seen) {
+ /* Did we consume ALL characters? */
+ if (*in_tail == '\0')
+ return;
+ /* No */
+ bb_error_msg_and_die("truncated base64 input");
+ }
+
+ /* It was partial decode */
+ in_count = strlen(in_tail);
+ memmove(in_buf, in_tail, in_count);
+ }
}