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sd-daemon: simplify sd_pid_notify_with_fds

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Coverity was complaining that CMSG_NXTHDR is used without
checking the return value. In this case it cannot fail, but
it is a good excuse to simplify the function a bit.

CID #1261726.
This commit is contained in:
Zbigniew Jędrzejewski-Szmek 2015-03-13 21:22:05 -05:00
parent 24bfda116c
commit 64144440a5
1 changed files with 27 additions and 34 deletions
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61
src/libsystemd/sd-daemon/sd-daemon.c
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@ -350,12 +350,10 @@ _public_ int sd_pid_notify_with_fds(pid_t pid, int unset_environment, const char
.msg_iovlen = 1,
.msg_name = &sockaddr,
};
struct cmsghdr *control;
_cleanup_close_ int fd = -1;
struct cmsghdr *cmsg = NULL;
const char *e;
size_t controllen_without_ucred = 0;
bool try_without_ucred = false;
bool have_pid;
int r;
if (!state) {
@ -394,42 +392,37 @@ _public_ int sd_pid_notify_with_fds(pid_t pid, int unset_environment, const char
if (msghdr.msg_namelen > sizeof(struct sockaddr_un))
msghdr.msg_namelen = sizeof(struct sockaddr_un);
control = alloca(CMSG_SPACE(sizeof(struct ucred)) + CMSG_SPACE(sizeof(int) * n_fds));
have_pid = pid != 0 && pid != getpid();
if (n_fds > 0) {
msghdr.msg_control = control;
msghdr.msg_controllen = CMSG_LEN(sizeof(int) * n_fds);
if (n_fds > 0 || have_pid) {
msghdr.msg_controllen = CMSG_SPACE(sizeof(int) * n_fds) +
CMSG_SPACE(sizeof(struct ucred) * have_pid);
msghdr.msg_control = alloca(msghdr.msg_controllen);
cmsg = CMSG_FIRSTHDR(&msghdr);
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SCM_RIGHTS;
cmsg->cmsg_len = CMSG_LEN(sizeof(int) * n_fds);
if (n_fds > 0) {
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SCM_RIGHTS;
cmsg->cmsg_len = CMSG_LEN(sizeof(int) * n_fds);
memcpy(CMSG_DATA(cmsg), fds, sizeof(int) * n_fds);
}
memcpy(CMSG_DATA(cmsg), fds, sizeof(int) * n_fds);
if (pid != 0 && pid != getpid()) {
struct ucred *ucred;
if (have_pid)
assert_se(cmsg = CMSG_NXTHDR(&msghdr, cmsg));
}
try_without_ucred = true;
controllen_without_ucred = msghdr.msg_controllen;
if (have_pid) {
struct ucred *ucred;
msghdr.msg_control = control;
msghdr.msg_controllen += CMSG_LEN(sizeof(struct ucred));
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SCM_CREDENTIALS;
cmsg->cmsg_len = CMSG_LEN(sizeof(struct ucred));
if (cmsg)
cmsg = CMSG_NXTHDR(&msghdr, cmsg);
else
cmsg = CMSG_FIRSTHDR(&msghdr);
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SCM_CREDENTIALS;
cmsg->cmsg_len = CMSG_LEN(sizeof(struct ucred));
ucred = (struct ucred*) CMSG_DATA(cmsg);
ucred->pid = pid;
ucred->uid = getuid();
ucred->gid = getgid();
ucred = (struct ucred*) CMSG_DATA(cmsg);
ucred->pid = pid;
ucred->uid = getuid();
ucred->gid = getgid();
}
}
/* First try with fake ucred data, as requested */
@ -439,10 +432,10 @@ _public_ int sd_pid_notify_with_fds(pid_t pid, int unset_environment, const char
}
/* If that failed, try with our own ucred instead */
if (try_without_ucred) {
if (controllen_without_ucred <= 0)
if (have_pid) {
msghdr.msg_controllen -= CMSG_SPACE(sizeof(struct ucred));
if (msghdr.msg_controllen == 0)
msghdr.msg_control = NULL;
msghdr.msg_controllen = controllen_without_ucred;
if (sendmsg(fd, &msghdr, MSG_NOSIGNAL) >= 0) {
r = 1;