MonetDB: Oct2014 - Protect against zero element size.

[Sjoerd Mullender]

Changeset: 5e2d1b6a9dce for MonetDB
URL: http://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=5e2d1b6a9dce
Modified Files:
        common/stream/stream.c
Branch: Oct2014
Log Message:

Protect against zero element size.


diffs (102 lines):

diff --git a/common/stream/stream.c b/common/stream/stream.c
--- a/common/stream/stream.c
+++ b/common/stream/stream.c
@@ -571,7 +571,7 @@ file_read(stream *s, void *buf, size_t e
                return -1;
        }
 
-       if (!feof(fp)) {
+       if (elmsize && cnt && !feof(fp)) {
                if (ferror(fp) ||
                    ((rc = fread(buf, elmsize, cnt, fp)) == 0 &&
                     ferror(fp))) {
@@ -775,7 +775,7 @@ stream_gzread(stream *s, void *buf, size
                return -1;
        }
 
-       if (!gzeof(fp)) {
+       if (size && !gzeof(fp)) {
                size = gzread(fp, buf, size);
                if (gzerror(fp, &err) != NULL && err < 0) {
                        s->errnr = MNSTR_READ_ERROR;
@@ -997,6 +997,8 @@ stream_bzread(stream *s, void *buf, size
                s->errnr = MNSTR_READ_ERROR;
                return -1;
        }
+       if (size == 0)
+               return 0;
        size = BZ2_bzRead(&err, bzp->b, buf, size);
        if (err == BZ_STREAM_END) {
                /* end of stream, but not necessarily end of file: get
@@ -1444,20 +1446,23 @@ static ssize_t
 curl_read(stream *s, void *buf, size_t elmsize, size_t cnt)
 {
        struct curl_data *c = (struct curl_data *) s->stream_data.p;
-       size_t size;
+       size_t size = cnt * elmsize;
 
        if (c == NULL) {
                s->errnr = MNSTR_READ_ERROR;
                return -1;
        }
 
+       if (size == 0)
+               return 0;
        if (c->usesize - c->offset >= elmsize || !c->running) {
                /* there is at least one element's worth of data
                 * available, or we have reached the end: return as
                 * much as we have, but no more than requested */
-               if (cnt * elmsize > c->usesize - c->offset)
+               if (size > c->usesize - c->offset) {
                        cnt = (c->usesize - c->offset) / elmsize;
-               size = cnt * elmsize;
+                       size = cnt * elmsize;
+               }
                memcpy(buf, c->buffer + c->offset, size);
                c->offset += size;
                if (c->offset == c->usesize)
@@ -1639,6 +1644,8 @@ socket_read(stream *s, void *buf, size_t
        if (s->errnr || size == 0)
                return -1;
 
+       if (size == 0)
+               return 0;
        do {
                errno = 0;
 #ifdef NATIVE_WIN32
@@ -1904,6 +1911,8 @@ udp_read(stream *s, void *buf, size_t el
        if (s->errnr || udp == NULL)
                return -1;
 
+       if (size == 0)
+               return 0;
        errno = 0;
        if ((res = recvfrom(udp->s, buf,
 #ifdef NATIVE_WIN32
@@ -2249,6 +2258,8 @@ ic_read(stream *s, void *buf, size_t elm
        inbytesleft = ic->buflen;
        outbuf = (char *) buf;
        outbytesleft = elmsize * cnt;
+       if (outbytesleft == 0)
+               return 0;
        while (outbytesleft > 0 && !ic->eof) {
                if (ic->buflen == sizeof(ic->buffer)) {
                        /* ridiculously long multibyte sequence, return error */
@@ -2554,7 +2565,7 @@ buffer_read(stream *s, void *buf, size_t
 
        b = (buffer *) s->stream_data.p;
        assert(b);
-       if (b && b->pos + size <= b->len) {
+       if (size && b && b->pos + size <= b->len) {
                memcpy(buf, b->buf + b->pos, size);
                b->pos += size;
                return (ssize_t) (size / elmsize);
@@ -2940,7 +2951,7 @@ bs_read(stream *ss, void *buf, size_t el
         * empty read */
        if (todo > 0 && cnt == 0)
                s->nr = 0;
-       return (ssize_t) (cnt / elmsize);
+       return (ssize_t) (elmsize > 0 ? cnt / elmsize : 0);
 }
 
 static void
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