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tree-wide: port more code to use send_one_fd() and receive_one_fd()

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Also, make it slightly more powerful, by accepting a flags argument, and
make it safe for handling if more than one cmsg attribute happens to be
attached.
This commit is contained in:
Lennart Poettering
2015-09-29 21:08:37 +02:00
parent 400f1a33cf
commit 3ee897d6c2
8 changed files with 47 additions and 136 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/basic/util.c
+24 -60
View File
@@ -6201,15 +6201,6 @@ int ptsname_malloc(int fd, char **ret) {
int openpt_in_namespace(pid_t pid, int flags) {
_cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
_cleanup_close_pair_ int pair[2] = { -1, -1 };
union {
struct cmsghdr cmsghdr;
uint8_t buf[CMSG_SPACE(sizeof(int))];
} control = {};
struct msghdr mh = {
.msg_control = &control,
.msg_controllen = sizeof(control),
};
struct cmsghdr *cmsg;
siginfo_t si;
pid_t child;
int r;
@@ -6243,15 +6234,7 @@ int openpt_in_namespace(pid_t pid, int flags) {
if (unlockpt(master) < 0)
_exit(EXIT_FAILURE);
cmsg = CMSG_FIRSTHDR(&mh);
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SCM_RIGHTS;
cmsg->cmsg_len = CMSG_LEN(sizeof(int));
memcpy(CMSG_DATA(cmsg), &master, sizeof(int));
mh.msg_controllen = cmsg->cmsg_len;
if (sendmsg(pair[1], &mh, MSG_NOSIGNAL) < 0)
if (send_one_fd(pair[1], master, 0) < 0)
_exit(EXIT_FAILURE);
_exit(EXIT_SUCCESS);
@@ -6265,26 +6248,7 @@ int openpt_in_namespace(pid_t pid, int flags) {
if (si.si_code != CLD_EXITED || si.si_status != EXIT_SUCCESS)
return -EIO;
if (recvmsg(pair[0], &mh, MSG_NOSIGNAL|MSG_CMSG_CLOEXEC) < 0)
return -errno;
CMSG_FOREACH(cmsg, &mh)
if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) {
int *fds;
unsigned n_fds;
fds = (int*) CMSG_DATA(cmsg);
n_fds = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int);
if (n_fds != 1) {
close_many(fds, n_fds);
return -EIO;
}
return fds[0];
}
return -EIO;
return receive_one_fd(pair[0], 0);
}
ssize_t fgetxattrat_fake(int dirfd, const char *filename, const char *attribute, void *value, size_t size, int flags) {
@@ -6884,7 +6848,7 @@ int fgetxattr_malloc(int fd, const char *name, char **value) {
}
}
int send_one_fd(int transport_fd, int fd) {
int send_one_fd(int transport_fd, int fd, int flags) {
union {
struct cmsghdr cmsghdr;
uint8_t buf[CMSG_SPACE(sizeof(int))];
@@ -6894,7 +6858,6 @@ int send_one_fd(int transport_fd, int fd) {
.msg_controllen = sizeof(control),
};
struct cmsghdr *cmsg;
ssize_t k;
assert(transport_fd >= 0);
assert(fd >= 0);
@@ -6906,14 +6869,13 @@ int send_one_fd(int transport_fd, int fd) {
memcpy(CMSG_DATA(cmsg), &fd, sizeof(int));
mh.msg_controllen = CMSG_SPACE(sizeof(int));
k = sendmsg(transport_fd, &mh, MSG_NOSIGNAL);
if (k < 0)
if (sendmsg(transport_fd, &mh, MSG_NOSIGNAL | flags) < 0)
return -errno;
return 0;
}
int receive_one_fd(int transport_fd) {
int receive_one_fd(int transport_fd, int flags) {
union {
struct cmsghdr cmsghdr;
uint8_t buf[CMSG_SPACE(sizeof(int))];
@@ -6922,33 +6884,35 @@ int receive_one_fd(int transport_fd) {
.msg_control = &control,
.msg_controllen = sizeof(control),
};
struct cmsghdr *cmsg;
ssize_t k;
struct cmsghdr *cmsg, *found = NULL;
assert(transport_fd >= 0);
/*
* Receive a single FD via @transport_fd. We don't care for the
* transport-type, but the caller must assure that no other CMSG types
* than SCM_RIGHTS is enabled. We also retrieve a single FD at most, so
* for packet-based transports, the caller must ensure to send only a
* single FD per packet.
* This is best used in combination with send_one_fd().
* Receive a single FD via @transport_fd. We don't care for
* the transport-type. We retrieve a single FD at most, so for
* packet-based transports, the caller must ensure to send
* only a single FD per packet. This is best used in
* combination with send_one_fd().
*/
k = recvmsg(transport_fd, &mh, MSG_NOSIGNAL | MSG_CMSG_CLOEXEC);
if (k < 0)
if (recvmsg(transport_fd, &mh, MSG_NOSIGNAL | MSG_CMSG_CLOEXEC | flags) < 0)
return -errno;
cmsg = CMSG_FIRSTHDR(&mh);
if (!cmsg || CMSG_NXTHDR(&mh, cmsg) ||
cmsg->cmsg_level != SOL_SOCKET ||
cmsg->cmsg_type != SCM_RIGHTS ||
cmsg->cmsg_len != CMSG_LEN(sizeof(int)) ||
*(const int *)CMSG_DATA(cmsg) < 0) {
CMSG_FOREACH(cmsg, &mh) {
if (cmsg->cmsg_level == SOL_SOCKET &&
cmsg->cmsg_type == SCM_RIGHTS &&
cmsg->cmsg_len == CMSG_LEN(sizeof(int))) {
assert(!found);
found = cmsg;
break;
}
}
if (!found) {
cmsg_close_all(&mh);
return -EIO;
}
return *(const int *)CMSG_DATA(cmsg);
return *(int*) CMSG_DATA(found);
}