X-Git-Url: https://mattmccutchen.net/rsync/rsync.git/blobdiff_plain/e4c598c830234fe3def0bae6ba45ca54071a9ee5..907e6a32a00ace7cf1e96f9c9132f83f4a208430:/rsync.c diff --git a/rsync.c b/rsync.c index a3f9b950..3d45d01b 100644 --- a/rsync.c +++ b/rsync.c @@ -133,42 +133,53 @@ void setup_iconv(void) # endif } -/* Move any bytes in the overflow space to the start. This avoids any issue - * with a multibyte sequence that needs to span the end of the buffer. */ -static void wrap_overflow(xbuf *out, int siz) -{ - if (DEBUG_GTE(IO, 4)) - rprintf(FINFO, "[%s] wrap-bytes moved: %d (iconvbufs)\n", who_am_i(), siz); - memcpy(out->buf, out->buf + out->size, siz); -} - -/* This function converts the characters in the "in" xbuf into characters - * in the "out" xbuf. The "len" of the "in" xbuf is used starting from its - * "pos". The "size" of the "out" xbuf restricts how many characters can be - * stored, starting at its "pos+len" position. Note that the last byte of - * the buffer is never used, which reserves space for a terminating '\0'. - * If ICB_CIRCULAR_OUT is set, the output data can wrap around to the start, - * and the buf IS ASSUMED TO HAVE AN EXTRA 4 BYTES OF OVERFLOW SPACE at the - * end (the buffer will also not be expanded if it is already allocated). +/* This function converts the chars in the "in" xbuf into characters in the + * "out" xbuf. The ".len" chars of the "in" xbuf is used starting from its + * ".pos". The ".size" of the "out" xbuf restricts how many characters can + * be stored, starting at its ".pos+.len" position. Note that the last byte + * of the "out" xbuf is not used, which reserves space for a trailing '\0' + * (though it is up to the caller to store a trailing '\0', as needed). + * * We return a 0 on success or a -1 on error. An error also sets errno to * E2BIG, EILSEQ, or EINVAL (see below); otherwise errno will be set to 0. - * The "in" xbuf is altered to update "pos" and "len". The "out" xbuf has - * data appended, and its "len" incremented. If ICB_EXPAND_OUT is set in - * "flags", the "out" xbuf will also be allocated if empty, and expanded if - * too small (so E2BIG will not be returned). If ICB_INCLUDE_BAD is set in - * "flags", any badly-encoded chars are included verbatim in the "out" xbuf, - * so EILSEQ will not be returned. Likewise for ICB_INCLUDE_INCOMPLETE with - * respect to an incomplete multi-byte char at the end, which ensures that - * EINVAL is not returned. If ICB_INIT is set, the iconv() conversion state - * is initialized prior to processing the characters. */ + * The "in" xbuf is altered to update ".pos" and ".len". The "out" xbuf has + * data appended, and its ".len" incremented (see below for a ".size" note). + * + * If ICB_CIRCULAR_OUT is set in "flags", the chars going into the "out" xbuf + * can wrap around to the start, and the xbuf may have its ".size" reduced + * (presumably by 1 byte) if the iconv code doesn't have space to store a + * multi-byte character at the physical end of the ".buf" (though no reducing + * happens if ".pos" is < 1, since there is no room to wrap around). + * + * If ICB_EXPAND_OUT is set in "flags", the "out" xbuf will be allocated if + * empty, and (as long as ICB_CIRCULAR_OUT is not set) expanded if too small. + * This prevents the return of E2BIG (except for a circular xbuf). + * + * If ICB_INCLUDE_BAD is set in "flags", any badly-encoded chars are included + * verbatim in the "out" xbuf, so EILSEQ will not be returned. + * + * If ICB_INCLUDE_INCOMPLETE is set in "flags", any incomplete multi-byte + * chars are included, which ensures that EINVAL is not returned. + * + * If ICB_INIT is set, the iconv() conversion state is initialized prior to + * processing the characters. */ int iconvbufs(iconv_t ic, xbuf *in, xbuf *out, int flags) { ICONV_CONST char *ibuf; size_t icnt, ocnt, opos; char *obuf; - if (!out->size && flags & ICB_EXPAND_OUT) - alloc_xbuf(out, 1024); + if (!out->size && flags & ICB_EXPAND_OUT) { + size_t siz = ROUND_UP_1024(in->len * 2); + alloc_xbuf(out, siz); + } else if (out->len+1 >= out->size) { + /* There is no room to even start storing data. */ + if (!(flags & ICB_EXPAND_OUT) || flags & ICB_CIRCULAR_OUT) { + errno = E2BIG; + return -1; + } + realloc_xbuf(out, out->size + ROUND_UP_1024(in->len * 2)); + } if (flags & ICB_INIT) iconv(ic, NULL, 0, NULL, 0); @@ -180,12 +191,13 @@ int iconvbufs(iconv_t ic, xbuf *in, xbuf *out, int flags) if (flags & ICB_CIRCULAR_OUT) { if (opos >= out->size) { opos -= out->size; + /* We know that out->pos is not 0 due to the "no room" check + * above, so this can't go "negative". */ ocnt = out->pos - opos - 1; } else { - /* We only make use of the 4 bytes of overflow buffer - * if there is room to move the bytes to the start of - * the circular buffer. */ - ocnt = out->size - opos + MIN((ssize_t)out->pos - 1, 4); + /* Allow the use of all bytes to the physical end of the buffer + * unless pos is 0, in which case we reserve our trailing '\0'. */ + ocnt = out->size - opos - (out->pos ? 0 : 1); } } else ocnt = out->size - opos - 1; @@ -201,22 +213,32 @@ int iconvbufs(iconv_t ic, xbuf *in, xbuf *out, int flags) } else if (errno == EILSEQ) { if (!(flags & ICB_INCLUDE_BAD)) goto finish; - } else { + } else if (errno == E2BIG) { + size_t siz; opos = obuf - out->buf; - if (flags & ICB_CIRCULAR_OUT && opos > out->size) { - wrap_overflow(out, opos -= out->size); - obuf = out->buf + opos; - if ((ocnt = out->pos - opos - 1) > 0) - continue; + if (flags & ICB_CIRCULAR_OUT && out->pos > 1 && opos > out->pos) { + /* We are in a divided circular buffer at the physical + * end with room to wrap to the start. If iconv() refused + * to use one or more trailing bytes in the buffer, we + * set the size to ignore the unused bytes. */ + if (opos < out->size) + reduce_iobuf_size(out, opos); + obuf = out->buf; + ocnt = out->pos - 1; + continue; } if (!(flags & ICB_EXPAND_OUT) || flags & ICB_CIRCULAR_OUT) { errno = E2BIG; goto finish; } - realloc_xbuf(out, out->size + 1024); + siz = ROUND_UP_1024(in->len * 2); + realloc_xbuf(out, out->size + siz); obuf = out->buf + opos; - ocnt += 1024; + ocnt += siz; continue; + } else { + rsyserr(FERROR, errno, "unexpected error from iconv()"); + exit_cleanup(RERR_UNSUPPORTED); } *obuf++ = *ibuf++; ocnt--, icnt--; @@ -227,12 +249,8 @@ int iconvbufs(iconv_t ic, xbuf *in, xbuf *out, int flags) finish: opos = obuf - out->buf; - if (flags & ICB_CIRCULAR_OUT) { - if (opos > out->size) - wrap_overflow(out, opos - out->size); - else if (opos < out->pos) - opos += out->size; - } + if (flags & ICB_CIRCULAR_OUT && opos < out->pos) + opos += out->size; out->len = opos - out->pos; in->len = icnt;