bytemark/flexnbd-c
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Added working read via splice syscall.

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This commit is contained in:
Matthew Bloch
2012-05-16 03:20:09 +01:00
parent c796a526d0
commit b1aa942b3d
1 changed files with 103 additions and 10 deletions
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113
flexnbd.c
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@@ -136,11 +136,11 @@ struct mode_serve_params {
};
struct mode_readwrite_params {
int writeNotRead;
union mysockaddr connect_to;
off64_t from;
off64_t len;
int fd;
int data_fd;
int client;
};
struct client_params {
@@ -193,6 +193,30 @@ int sendfileloop(int out_fd, int in_fd, off64_t *offset, size_t count)
return 0;
}
int splice_via_pipe_loop(int fd_in, int fd_out, size_t len)
{
int pipefd[2];
size_t spliced=0;
if (pipe(pipefd) == -1)
return -1;
while (spliced < len) {
size_t r1,r2;
r1 = splice(fd_in, NULL, pipefd[1], NULL, len-spliced, 0);
if (r1 <= 0)
break;
r2 = splice(pipefd[0], NULL, fd_out, NULL, r1, 0);
if (r1 != r2)
break;
spliced += r1;
}
close(pipefd[0]);
close(pipefd[1]);
return spliced < len ? -1 : 0;
}
int client_serve_request(struct client_params* client)
{
off64_t offset;
@@ -442,14 +466,77 @@ void do_serve(struct mode_serve_params* params)
serve_accept_loop(params);
}
int socket_connect(struct sockaddr* to)
{
int fd = socket(PF_INET, SOCK_STREAM, 0);
SERVER_ERROR_ON_FAILURE(fd, "Couldn't create client socket");
SERVER_ERROR_ON_FAILURE(connect(fd, to, sizeof(*to)),
"connect failed");
return fd;
}
off64_t socket_nbd_read_hello(int fd)
{
struct nbd_init init;
SERVER_ERROR_ON_FAILURE(readloop(fd, &init, sizeof(init)),
"Couldn't read init");
if (strncmp(init.passwd, INIT_PASSWD, 8) != 0)
SERVER_ERROR("wrong passwd");
if (be64toh(init.magic) != INIT_MAGIC)
SERVER_ERROR("wrong magic (%x)", be64toh(init.magic));
return be64toh(init.size);
}
void socket_nbd_read(int fd, off64_t from, int len, int out_fd, void* out_buf)
{
struct nbd_request request;
struct nbd_reply reply;
request.magic = htobe32(REQUEST_MAGIC);
request.type = htobe32(REQUEST_READ);
((int*) request.handle)[0] = rand();
((int*) request.handle)[1] = rand();
request.from = htobe64(from);
request.len = htobe32(len);
SERVER_ERROR_ON_FAILURE(writeloop(fd, &request, sizeof(request)),
"Couldn't write request");
SERVER_ERROR_ON_FAILURE(readloop(fd, &reply, sizeof(reply)),
"Couldn't read reply");
if (be32toh(reply.magic) != REPLY_MAGIC)
SERVER_ERROR("Reply magic incorrect (%p)", reply.magic);
if (be32toh(reply.error) != 0)
SERVER_ERROR("Server replied with error %d", reply.error);
if (out_buf) {
SERVER_ERROR_ON_FAILURE(readloop(fd, out_buf, len),
"Read failed");
}
else {
SERVER_ERROR_ON_FAILURE(
splice_via_pipe_loop(fd, out_fd, len),
"Splice failed"
);
}
}
void do_read(struct mode_readwrite_params* params)
{
off64_t size;
params->client = socket_connect(&params->connect_to.generic);
size = socket_nbd_read_hello(params->client);
if (params->from < 0 || (params->from + params->len) >= size)
SERVER_ERROR("Read request %d+%d is out of range given size %d",
params->from, params->len, size);
socket_nbd_read(params->client, params->from, params->len,
params->data_fd, NULL);
close(params->client);
}
void do_write(struct mode_readwrite_params* params)
{
params->client = socket_connect(&params->connect_to.generic);
close(params->client);
}
#define IS_IP_VALID_CHAR(x) ( ((x) >= '0' && (x) <= '9' ) || \
@@ -473,8 +560,6 @@ int parse_ip_to_sockaddr(struct sockaddr* out, char* src)
temp[j] = 0;
}
debug("temp='%s'", temp);
if (temp[0] == '0' && temp[1] == '\0') {
v4->sin_family = AF_INET;
v4->sin_addr.s_addr = INADDR_ANY;
@@ -579,14 +664,20 @@ void params_readwrite(
SERVER_ERROR("No IP address supplied");
if (s_port == NULL)
SERVER_ERROR("No port number supplied");
if (s_from == NULL);
if (s_from == NULL)
SERVER_ERROR("No from supplied");
if (s_length == NULL);
if (s_length == NULL)
SERVER_ERROR("No length supplied");
if (parse_ip_to_sockaddr(&out->connect_to.generic, s_ip_address) == 0)
SERVER_ERROR("Couldn't parse connection address '%s'");
out->connect_to.v4.sin_port = atoi(s_port);
if (out->connect_to.v4.sin_port < 0 || out->connect_to.v4.sin_port > 65535)
SERVER_ERROR("Port number must be >= 0 and <= 65535");
out->connect_to.v4.sin_port = htobe16(out->connect_to.v4.sin_port);
out->from = atol(s_from);
out->len = atol(s_length);
}
@@ -605,8 +696,9 @@ void mode(char* mode, int argc, char **argv)
}
}
else if (strcmp(mode, "read") == 0 ) {
if (argc != 4) {
if (argc == 4) {
params_readwrite(&params.readwrite, argv[0], argv[1], argv[2], argv[3]);
params.readwrite.data_fd = 1;
do_read(&params.readwrite);
}
else {
@@ -614,8 +706,9 @@ void mode(char* mode, int argc, char **argv)
}
}
else if (strcmp(mode, "write") == 0 ) {
if (argc != 4) {
if (argc == 4) {
params_readwrite(&params.readwrite, argv[0], argv[1], argv[2], argv[3]);
params.readwrite.data_fd = 0;
do_write(&params.readwrite);
}
else {