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linux(4): Improve recvmsg() readability

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To improve recvmsg() readability SCM_ handlers moved to a separate
functions.

MFC after:		2 weeks
This commit is contained in:
Dmitry Chagin 2022-05-28 23:44:02 +03:00
parent f409a7c538
commit b408788d6b
1 changed files with 95 additions and 59 deletions
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154
sys/compat/linux/linux_socket.c
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@ -1532,26 +1532,90 @@ linux_sendmmsg(struct thread *td, struct linux_sendmmsg_args *args)
return (error);
}
static int
recvmsg_scm_rights(struct thread *td, l_uint flags, socklen_t *datalen,
void **data, void **udata)
{
int i, fd, fds, *fdp;
if (flags & LINUX_MSG_CMSG_CLOEXEC) {
fds = *datalen / sizeof(int);
fdp = *data;
for (i = 0; i < fds; i++) {
fd = *fdp++;
(void)kern_fcntl(td, fd, F_SETFD, FD_CLOEXEC);
}
}
return (0);
}
static int
recvmsg_scm_creds(socklen_t *datalen, void **data, void **udata)
{
struct cmsgcred *cmcred;
struct l_ucred lu;
cmcred = *data;
lu.pid = cmcred->cmcred_pid;
lu.uid = cmcred->cmcred_uid;
lu.gid = cmcred->cmcred_gid;
memmove(*data, &lu, sizeof(lu));
*datalen = sizeof(lu);
return (0);
}
_Static_assert(sizeof(struct cmsgcred) >= sizeof(struct l_ucred),
"scm_creds sizeof l_ucred");
static int
recvmsg_scm_creds2(socklen_t *datalen, void **data, void **udata)
{
struct sockcred2 *scred;
struct l_ucred lu;
scred = *data;
lu.pid = scred->sc_pid;
lu.uid = scred->sc_uid;
lu.gid = scred->sc_gid;
memmove(*data, &lu, sizeof(lu));
*datalen = sizeof(lu);
return (0);
}
_Static_assert(sizeof(struct sockcred2) >= sizeof(struct l_ucred),
"scm_creds2 sizeof l_ucred");
static int
recvmsg_scm_timestamp(socklen_t *datalen, void **data, void **udata)
{
struct timeval *ftmvl;
l_timeval *ltv;
if (*datalen != sizeof(struct timeval))
return (EMSGSIZE);
ftmvl = *data;
ltv = malloc(sizeof(*ltv), M_LINUX, M_WAITOK);
ltv->tv_sec = ftmvl->tv_sec;
ltv->tv_usec = ftmvl->tv_usec;
*data = *udata = ltv;
*datalen = sizeof(*ltv);
return (0);
}
static int
linux_recvmsg_common(struct thread *td, l_int s, struct l_msghdr *msghdr,
l_uint flags, struct msghdr *msg)
{
struct cmsghdr *cm;
struct cmsgcred *cmcred;
struct sockcred2 *scred;
struct l_cmsghdr *linux_cmsg = NULL;
struct l_ucred linux_ucred;
socklen_t datalen, maxlen, outlen;
struct l_msghdr linux_msghdr;
struct iovec *iov, *uiov;
struct mbuf *control = NULL;
struct mbuf **controlp;
struct timeval *ftmvl;
struct sockaddr *sa;
l_timeval ltmvl;
caddr_t outbuf;
void *data;
int error, i, fd, fds, *fdp;
void *data, *udata;
int error;
error = copyin(msghdr, &linux_msghdr, sizeof(linux_msghdr));
if (error != 0)
@ -1635,69 +1699,40 @@ linux_recvmsg_common(struct thread *td, l_int s, struct l_msghdr *msghdr,
data = CMSG_DATA(cm);
datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data;
udata = NULL;
switch (cm->cmsg_type) {
case SCM_RIGHTS:
if (flags & LINUX_MSG_CMSG_CLOEXEC) {
fds = datalen / sizeof(int);
fdp = data;
for (i = 0; i < fds; i++) {
fd = *fdp++;
(void)kern_fcntl(td, fd,
F_SETFD, FD_CLOEXEC);
}
}
error = recvmsg_scm_rights(td, flags,
&datalen, &data, &udata);
break;
case SCM_CREDS:
/*
* Currently LOCAL_CREDS is never in
* effect for Linux so no need to worry
* about sockcred
*/
if (datalen != sizeof(*cmcred)) {
error = EMSGSIZE;
goto bad;
}
cmcred = (struct cmsgcred *)data;
bzero(&linux_ucred, sizeof(linux_ucred));
linux_ucred.pid = cmcred->cmcred_pid;
linux_ucred.uid = cmcred->cmcred_uid;
linux_ucred.gid = cmcred->cmcred_gid;
data = &linux_ucred;
datalen = sizeof(linux_ucred);
error = recvmsg_scm_creds(&datalen,
&data, &udata);
break;
case SCM_CREDS2:
scred = data;
bzero(&linux_ucred, sizeof(linux_ucred));
linux_ucred.pid = scred->sc_pid;
linux_ucred.uid = scred->sc_uid;
linux_ucred.gid = scred->sc_gid;
data = &linux_ucred;
datalen = sizeof(linux_ucred);
error = recvmsg_scm_creds2(&datalen,
&data, &udata);
break;
case SCM_TIMESTAMP:
if (datalen != sizeof(struct timeval)) {
error = EMSGSIZE;
goto bad;
}
ftmvl = (struct timeval *)data;
ltmvl.tv_sec = ftmvl->tv_sec;
ltmvl.tv_usec = ftmvl->tv_usec;
data = &ltmvl;
datalen = sizeof(ltmvl);
error = recvmsg_scm_timestamp(&datalen,
&data, &udata);
break;
}
if (error != 0)
goto bad;
if (outlen + LINUX_CMSG_LEN(datalen) > maxlen) {
if (outlen == 0) {
error = EMSGSIZE;
goto bad;
goto err;
} else {
linux_msghdr.msg_flags |= LINUX_MSG_CTRUNC;
m_dispose_extcontrolm(control);
free(udata, M_LINUX);
goto out;
}
}
@ -1705,18 +1740,19 @@ linux_recvmsg_common(struct thread *td, l_int s, struct l_msghdr *msghdr,
linux_cmsg->cmsg_len = LINUX_CMSG_LEN(datalen);
error = copyout(linux_cmsg, outbuf, L_CMSG_HDRSZ);
if (error == 0) {
outbuf += L_CMSG_HDRSZ;
error = copyout(data, outbuf, datalen);
if (error == 0) {
outbuf += LINUX_CMSG_ALIGN(datalen);
outlen += LINUX_CMSG_LEN(datalen);
cm = CMSG_NXTHDR(msg, cm);
}
}
err:
free(udata, M_LINUX);
if (error != 0)
goto bad;
outbuf += L_CMSG_HDRSZ;
error = copyout(data, outbuf, datalen);
if (error != 0)
goto bad;
outbuf += LINUX_CMSG_ALIGN(datalen);
outlen += LINUX_CMSG_LEN(datalen);
cm = CMSG_NXTHDR(msg, cm);
}
linux_msghdr.msg_controllen = outlen;
}