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Use ioctl(FIONREAD) to determine how many bytes are readable in the socket

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and make sure we dont try to read mor than that.
This commit is contained in:
Ronnie Sahlberg
2011-04-03 07:22:05 +10:00
parent 4979b7346f
commit 376f60fc06
1 changed files with 30 additions and 3 deletions
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lib/socket.c
+30 -3
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@@ -212,6 +212,16 @@ iscsi_read_from_socket(struct iscsi_context *iscsi)
{ {
struct iscsi_in_pdu *in; struct iscsi_in_pdu *in;
ssize_t data_size, count; ssize_t data_size, count;
int socket_count = 0;
if (ioctl(iscsi->fd, FIONREAD, &socket_count) != 0) {
iscsi_set_error(iscsi, "Socket failure. Socket FIONREAD failed");
return -1;
}
if (socket_count == 0) {
iscsi_set_error(iscsi, "Socket failure. Socket is readable but no bytes available in FIONREAD");
return -1;
}
if (iscsi->incoming == NULL) { if (iscsi->incoming == NULL) {
iscsi->incoming = malloc(sizeof(struct iscsi_in_pdu)); iscsi->incoming = malloc(sizeof(struct iscsi_in_pdu));
@@ -225,7 +235,14 @@ iscsi_read_from_socket(struct iscsi_context *iscsi)
/* first we must read the header, including any digests */ /* first we must read the header, including any digests */
if (in->hdr_pos < ISCSI_HEADER_SIZE) { if (in->hdr_pos < ISCSI_HEADER_SIZE) {
count = read(iscsi->fd, &in->hdr[in->hdr_pos], ISCSI_HEADER_SIZE - in->hdr_pos); /* try to only read the header, and make sure we don't
* read more than is available in the socket;
*/
count = ISCSI_HEADER_SIZE - in->hdr_pos;
if (socket_count < count) {
count = socket_count;
}
count = read(iscsi->fd, &in->hdr[in->hdr_pos], count);
if (count < 0) { if (count < 0) {
if (errno == EINTR) { if (errno == EINTR) {
return 0; return 0;
@@ -237,7 +254,8 @@ iscsi_read_from_socket(struct iscsi_context *iscsi)
if (count == 0) { if (count == 0) {
return 0; return 0;
} }
in->hdr_pos += count; in->hdr_pos += count;
socket_count -= count;
} }
if (in->hdr_pos < ISCSI_HEADER_SIZE) { if (in->hdr_pos < ISCSI_HEADER_SIZE) {
@@ -255,7 +273,15 @@ iscsi_read_from_socket(struct iscsi_context *iscsi)
} }
} }
count = read(iscsi->fd, &in->data[in->data_pos], data_size - in->data_pos); /* No more data right now */
if (socket_count == 0) {
return 0;
}
count = data_size - in->data_pos;
if (count > socket_count) {
count = socket_count;
}
count = read(iscsi->fd, &in->data[in->data_pos], count);
if (count < 0) { if (count < 0) {
if (errno == EINTR) { if (errno == EINTR) {
return 0; return 0;
@@ -268,6 +294,7 @@ iscsi_read_from_socket(struct iscsi_context *iscsi)
return 0; return 0;
} }
in->data_pos += count; in->data_pos += count;
socket_count -= count;
} }
if (in->data_pos < data_size) { if (in->data_pos < data_size) {