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nss-myhostname: use _cleanup_ and split function into two

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The triply nested loop is just too much. Let's split out the
middle loop's body, so the whole thing is easier to read. Also
modernize the style a bit, using structure initialization to
avoid memset and such.
This commit is contained in:
Zbigniew Jędrzejewski-Szmek 2013-03-30 10:46:04 -04:00
parent 7a22620612
commit d73c3269cd
1 changed files with 145 additions and 151 deletions
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296
src/nss-myhostname/netlink.c
View File

@ -35,174 +35,168 @@
#include <stdlib.h>
#include "ifconf.h"
#include "macro.h"
#include "util.h"
#define SEQ 4711
static int read_reply(int fd, struct address **list, unsigned *n_list) {
ssize_t bytes;
struct cmsghdr *cmsg;
struct ucred *ucred;
struct nlmsghdr *p;
uint8_t cred_buffer[CMSG_SPACE(sizeof(struct ucred))];
struct {
struct nlmsghdr hdr;
struct ifaddrmsg ifaddrmsg;
uint8_t payload[16*1024];
} resp;
struct iovec iov = {
.iov_base = &resp,
.iov_len = sizeof(resp),
};
struct msghdr msg = {
.msg_name = NULL,
.msg_namelen = 0,
.msg_iov = &iov,
.msg_iovlen = 1,
.msg_control = cred_buffer,
.msg_controllen = sizeof(cred_buffer),
.msg_flags = 0,
};
assert(fd >= 0);
assert(list);
bytes = recvmsg(fd, &msg, 0);
if (bytes < 0)
return -errno;
cmsg = CMSG_FIRSTHDR(&msg);
if (!cmsg || cmsg->cmsg_type != SCM_CREDENTIALS)
return -EIO;
ucred = (struct ucred*) CMSG_DATA(cmsg);
if (ucred->uid != 0 || ucred->pid != 0)
return 0;
for (p = &resp.hdr; bytes > 0; p = NLMSG_NEXT(p, bytes)) {
struct ifaddrmsg *ifaddrmsg;
struct rtattr *a;
size_t l;
void *local = NULL, *address = NULL;
if (!NLMSG_OK(p, (size_t) bytes))
return -EIO;
if (p->nlmsg_seq != SEQ)
continue;
if (p->nlmsg_type == NLMSG_DONE)
return 1;
if (p->nlmsg_type == NLMSG_ERROR) {
struct nlmsgerr *nlmsgerr;
nlmsgerr = NLMSG_DATA(p);
return -nlmsgerr->error;
}
if (p->nlmsg_type != RTM_NEWADDR)
continue;
ifaddrmsg = NLMSG_DATA(p);
if (ifaddrmsg->ifa_family != AF_INET &&
ifaddrmsg->ifa_family != AF_INET6)
continue;
if (ifaddrmsg->ifa_scope == RT_SCOPE_HOST ||
ifaddrmsg->ifa_scope == RT_SCOPE_NOWHERE)
continue;
if (ifaddrmsg->ifa_flags & IFA_F_DEPRECATED)
continue;
l = NLMSG_PAYLOAD(p, sizeof(struct ifaddrmsg));
a = IFA_RTA(ifaddrmsg);
while (RTA_OK(a, l)) {
if (a->rta_type == IFA_ADDRESS)
address = RTA_DATA(a);
else if (a->rta_type == IFA_LOCAL)
local = RTA_DATA(a);
a = RTA_NEXT(a, l);
}
if (local)
address = local;
if (!address)
continue;
*list = realloc(*list, (*n_list+1) * sizeof(struct address));
if (!*list)
return -ENOMEM;
(*list)[*n_list].family = ifaddrmsg->ifa_family;
(*list)[*n_list].scope = ifaddrmsg->ifa_scope;
memcpy((*list)[*n_list].address,
address, ifaddrmsg->ifa_family == AF_INET ? 4 : 16);
(*list)[*n_list].ifindex = ifaddrmsg->ifa_index;
(*n_list)++;
}
return 0;
}
int ifconf_acquire_addresses(struct address **_list, unsigned *_n_list) {
struct {
struct nlmsghdr hdr;
struct rtgenmsg gen;
} req;
struct rtgenmsg *gen;
int fd, r, on = 1;
uint32_t seq = 4711;
} req = { {
.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtgenmsg)),
.nlmsg_type = RTM_GETADDR,
.nlmsg_flags = NLM_F_REQUEST|NLM_F_DUMP|NLM_F_ACK,
.nlmsg_seq = SEQ,
.nlmsg_pid = 0,
}, {
.rtgen_family = AF_UNSPEC,
}
};
int r, on = 1;
struct address *list = NULL;
unsigned n_list = 0;
int _cleanup_close_ fd;
fd = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
if (fd < 0)
return -errno;
if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)) < 0) {
r = -errno;
goto finish;
}
if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)) < 0)
return -errno;
memset(&req, 0, sizeof(req));
req.hdr.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtgenmsg));
req.hdr.nlmsg_type = RTM_GETADDR;
req.hdr.nlmsg_flags = NLM_F_REQUEST|NLM_F_DUMP|NLM_F_ACK;
req.hdr.nlmsg_seq = seq;
req.hdr.nlmsg_pid = 0;
if (send(fd, &req, req.hdr.nlmsg_len, 0) < 0)
return -errno;
gen = NLMSG_DATA(&req.hdr);
gen->rtgen_family = AF_UNSPEC;
while((r = read_reply(fd, &list, &n_list)) == 0)
;
if (send(fd, &req, req.hdr.nlmsg_len, 0) < 0) {
r = -errno;
goto finish;
}
for (;;) {
ssize_t bytes;
struct msghdr msg;
struct cmsghdr *cmsg;
struct ucred *ucred;
struct iovec iov;
struct nlmsghdr *p;
uint8_t cred_buffer[CMSG_SPACE(sizeof(struct ucred))];
struct {
struct nlmsghdr hdr;
struct ifaddrmsg ifaddrmsg;
uint8_t payload[16*1024];
} resp;
memset(&iov, 0, sizeof(iov));
iov.iov_base = &resp;
iov.iov_len = sizeof(resp);
memset(&msg, 0, sizeof(msg));
msg.msg_name = NULL;
msg.msg_namelen = 0;
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
msg.msg_control = cred_buffer;
msg.msg_controllen = sizeof(cred_buffer);
msg.msg_flags = 0;
bytes = recvmsg(fd, &msg, 0);
if (bytes < 0) {
r = -errno;
goto finish;
}
cmsg = CMSG_FIRSTHDR(&msg);
if (!cmsg || cmsg->cmsg_type != SCM_CREDENTIALS) {
r = -EIO;
goto finish;
}
ucred = (struct ucred*) CMSG_DATA(cmsg);
if (ucred->uid != 0 || ucred->pid != 0)
continue;
for (p = &resp.hdr; bytes > 0; p = NLMSG_NEXT(p, bytes)) {
struct ifaddrmsg *ifaddrmsg;
struct rtattr *a;
size_t l;
void *local = NULL, *address = NULL;
if (!NLMSG_OK(p, (size_t) bytes)) {
r = -EIO;
goto finish;
}
if (p->nlmsg_seq != seq)
continue;
if (p->nlmsg_type == NLMSG_DONE) {
r = 0;
goto finish;
}
if (p->nlmsg_type == NLMSG_ERROR) {
struct nlmsgerr *nlmsgerr;
nlmsgerr = NLMSG_DATA(p);
r = -nlmsgerr->error;
goto finish;
}
if (p->nlmsg_type != RTM_NEWADDR)
continue;
ifaddrmsg = NLMSG_DATA(p);
if (ifaddrmsg->ifa_family != AF_INET &&
ifaddrmsg->ifa_family != AF_INET6)
continue;
if (ifaddrmsg->ifa_scope == RT_SCOPE_HOST ||
ifaddrmsg->ifa_scope == RT_SCOPE_NOWHERE)
continue;
if (ifaddrmsg->ifa_flags & IFA_F_DEPRECATED)
continue;
l = NLMSG_PAYLOAD(p, sizeof(struct ifaddrmsg));
a = IFA_RTA(ifaddrmsg);
while (RTA_OK(a, l)) {
if (a->rta_type == IFA_ADDRESS)
address = RTA_DATA(a);
else if (a->rta_type == IFA_LOCAL)
local = RTA_DATA(a);
a = RTA_NEXT(a, l);
}
if (local)
address = local;
if (!address)
continue;
list = realloc(list, (n_list+1) * sizeof(struct address));
if (!list) {
r = -ENOMEM;
goto finish;
}
list[n_list].family = ifaddrmsg->ifa_family;
list[n_list].scope = ifaddrmsg->ifa_scope;
memcpy(list[n_list].address, address, ifaddrmsg->ifa_family == AF_INET ? 4 : 16);
list[n_list].ifindex = ifaddrmsg->ifa_index;
n_list++;
}
}
finish:
close(fd);
if (r < 0)
if (r < 0) {
free(list);
else {
qsort(list, n_list, sizeof(struct address), address_compare);
*_list = list;
*_n_list = n_list;
return r;
}
return r;
assert(n_list == 0 || list);
qsort(list, n_list, sizeof(struct address), address_compare);
*_list = list;
*_n_list = n_list;
return 0;
}