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util-net: Make send/recv fds carry fd flags in message

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The flags are only one bit in the kernel (close-on-exec, all the rest are not per-fd, but per-file),
but for simplicity I save it in a char field.

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
This commit is contained in:
Pavel Emelyanov 2012-04-10 18:36:13 +04:00
parent e8cdf57f40
commit 30224abcb6
4 changed files with 32 additions and 15 deletions
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11
include/util-net.h
View File

@ -25,22 +25,23 @@ struct scm_fdset {
struct msghdr hdr;
struct iovec iov;
char msg_buf[CR_SCM_MSG_SIZE];
int msg; /* We are to send at least one byte */
char msg[CR_SCM_MAX_FD];
};
extern int send_fds(int sock, struct sockaddr_un *saddr, int saddr_len, int *fds, int nr_fds);
extern int recv_fds(int sock, int *fds, int nr_fds);
extern int send_fds(int sock, struct sockaddr_un *saddr, int saddr_len,
int *fds, int nr_fds, bool with_flags);
extern int recv_fds(int sock, int *fds, int nr_fds, char *flags);
static inline int send_fd(int sock, struct sockaddr_un *saddr, int saddr_len, int fd)
{
return send_fds(sock, saddr, saddr_len, &fd, 1);
return send_fds(sock, saddr, saddr_len, &fd, 1, false);
}
static inline int recv_fd(int sock)
{
int fd, ret;
ret = recv_fds(sock, &fd, 1);
ret = recv_fds(sock, &fd, 1, NULL);
if (ret)
return -1;

2
parasite-syscall.c
View File

@ -583,7 +583,7 @@ int parasite_drain_fds_seized(struct parasite_ctl *ctl, int *fds, int *lfds, int
goto err;
}
ret = recv_fds(sock, lfds, nr_fds);
ret = recv_fds(sock, lfds, nr_fds, NULL);
if (ret) {
pr_err("Can't retrieve FDs from socket\n");
goto err;

2
parasite.c
View File

@ -373,7 +373,7 @@ static int drain_fds(struct parasite_drain_fd *args)
int ret;
ret = send_fds(tsock, &args->saddr, args->sun_len,
args->fds, args->nr_fds);
args->fds, args->nr_fds, false);
if (ret) {
sys_write_msg("send_fds failed\n");
SET_PARASITE_RET(st, ret);

32
util-net.c
View File

@ -20,17 +20,16 @@ static void scm_fdset_init_chunk(struct scm_fdset *fdset, int nr_fds)
cmsg->cmsg_len = fdset->hdr.msg_controllen;
}
static int *scm_fdset_init(struct scm_fdset *fdset, struct sockaddr_un *saddr, int saddr_len)
static int *scm_fdset_init(struct scm_fdset *fdset, struct sockaddr_un *saddr,
int saddr_len, bool with_flags)
{
struct cmsghdr *cmsg;
BUILD_BUG_ON(CR_SCM_MAX_FD > SCM_MAX_FD);
BUILD_BUG_ON(sizeof(fdset->msg_buf) < (CMSG_SPACE(sizeof(int) * CR_SCM_MAX_FD)));
fdset->msg = '*';
fdset->iov.iov_base = &fdset->msg;
fdset->iov.iov_len = sizeof(fdset->msg);
fdset->iov.iov_len = with_flags ? sizeof(fdset->msg) : 1;
fdset->hdr.msg_iov = &fdset->iov;
fdset->hdr.msg_iovlen = 1;
@ -48,18 +47,33 @@ static int *scm_fdset_init(struct scm_fdset *fdset, struct sockaddr_un *saddr, i
return (int *)CMSG_DATA(cmsg);
}
int send_fds(int sock, struct sockaddr_un *saddr, int len, int *fds, int nr_fds)
int send_fds(int sock, struct sockaddr_un *saddr, int len,
int *fds, int nr_fds, bool with_flags)
{
struct scm_fdset fdset;
int *cmsg_data;
int i, min_fd, ret;
cmsg_data = scm_fdset_init(&fdset, saddr, len);
cmsg_data = scm_fdset_init(&fdset, saddr, len, with_flags);
for (i = 0; i < nr_fds; i += min_fd) {
min_fd = min(CR_SCM_MAX_FD, nr_fds - i);
scm_fdset_init_chunk(&fdset, min_fd);
builtin_memcpy(cmsg_data, &fds[i], sizeof(int) * min_fd);
if (with_flags) {
int j;
for (j = 0; j < min_fd; j++) {
int flags;
flags = sys_fcntl(fds[i + j], F_GETFD, 0);
if (flags < 0)
return -1;
fdset.msg[j] = (char)flags;
}
}
ret = sys_sendmsg(sock, &fdset.hdr, 0);
if (ret <= 0)
return ret ? : -1;
@ -68,7 +82,7 @@ int send_fds(int sock, struct sockaddr_un *saddr, int len, int *fds, int nr_fds)
return 0;
}
int recv_fds(int sock, int *fds, int nr_fds)
int recv_fds(int sock, int *fds, int nr_fds, char *flags)
{
struct scm_fdset fdset;
struct cmsghdr *cmsg;
@ -76,7 +90,7 @@ int recv_fds(int sock, int *fds, int nr_fds)
int ret;
int i, min_fd;
cmsg_data = scm_fdset_init(&fdset, NULL, 0);
cmsg_data = scm_fdset_init(&fdset, NULL, 0, flags != NULL);
for (i = 0; i < nr_fds; i += min_fd) {
min_fd = min(CR_SCM_MAX_FD, nr_fds - i);
scm_fdset_init_chunk(&fdset, min_fd);
@ -104,6 +118,8 @@ int recv_fds(int sock, int *fds, int nr_fds)
if (unlikely(min_fd <= 0))
return -1;
builtin_memcpy(&fds[i], cmsg_data, sizeof(int) * min_fd);
if (flags)
builtin_memcpy(flags, fdset.msg, sizeof(char) * min_fd);
}
return 0;