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Make the signal handling code use safe_read() and unify ifchd and sockd

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signals code.
This commit is contained in:
Nicholas J. Kain
2014-04-15 20:55:13 -04:00
parent baa394af9a
commit e526adce19
5 changed files with 70 additions and 121 deletions
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55
src/ifchd.c
View File

@@ -35,13 +35,11 @@
#include <sys/time.h> #include <sys/time.h>
#include <sys/types.h> #include <sys/types.h>
#include <sys/epoll.h> #include <sys/epoll.h>
#include <sys/signalfd.h>
#include <sys/prctl.h> #include <sys/prctl.h>
#include <sys/stat.h> #include <sys/stat.h>
#include <fcntl.h> #include <fcntl.h>
#include <signal.h> #include <signal.h>
#include <errno.h> #include <errno.h>
#include <getopt.h>
#include "nk/log.h" #include "nk/log.h"
#include "nk/privilege.h" #include "nk/privilege.h"
#include "nk/signals.h" #include "nk/signals.h"
@@ -256,51 +254,6 @@ void perform_wins(const char *str, size_t len)
(void)len; (void)len;
} }
static void setup_signals_ifch(void)
{
sigset_t mask;
sigemptyset(&mask);
sigaddset(&mask, SIGUSR1);
sigaddset(&mask, SIGUSR2);
sigaddset(&mask, SIGTSTP);
sigaddset(&mask, SIGTTIN);
sigaddset(&mask, SIGCHLD);
sigaddset(&mask, SIGHUP);
sigaddset(&mask, SIGINT);
sigaddset(&mask, SIGTERM);
if (sigprocmask(SIG_BLOCK, &mask, NULL) < 0)
suicide("sigprocmask failed");
signalFd = signalfd(-1, &mask, SFD_NONBLOCK);
if (signalFd < 0)
suicide("signalfd failed");
}
static void signal_dispatch(void)
{
int t;
size_t off = 0;
struct signalfd_siginfo si = {0};
again:
t = read(signalFd, (char *)&si + off, sizeof si - off);
if (t < 0) {
if (t == EAGAIN || t == EWOULDBLOCK || t == EINTR)
goto again;
else
suicide("signalfd read error");
}
if (off + (unsigned)t < sizeof si)
off += t;
switch (si.ssi_signo) {
case SIGINT:
case SIGTERM:
case SIGHUP:
exit(EXIT_SUCCESS);
break;
default:
break;
}
}
static void inform_execute(char c) static void inform_execute(char c)
{ {
ssize_t r = safe_write(ifchSock[1], &c, sizeof c); ssize_t r = safe_write(ifchSock[1], &c, sizeof c);
@@ -366,7 +319,7 @@ static void do_ifch_work(void)
if (fd == ifchSock[1]) if (fd == ifchSock[1])
process_client_socket(); process_client_socket();
else if (fd == signalFd) else if (fd == signalFd)
signal_dispatch(); signal_dispatch_subprocess(signalFd, "ifch");
else else
suicide("ifch: unexpected fd while performing epoll"); suicide("ifch: unexpected fd while performing epoll");
} }
@@ -376,9 +329,11 @@ static void do_ifch_work(void)
void ifch_main(void) void ifch_main(void)
{ {
prctl(PR_SET_NAME, "ndhc: ifch"); prctl(PR_SET_NAME, "ndhc: ifch");
prctl(PR_SET_PDEATHSIG, SIGHUP); if (prctl(PR_SET_PDEATHSIG, SIGHUP) < 0)
suicide("%s: (%s) prctl(PR_SET_PDEATHSIG) failed: %s",
client_config.interface, __func__, strerror(errno));
umask(077); umask(077);
setup_signals_ifch(); signalFd = setup_signals_subprocess();
// If we are requested to update resolv.conf, preopen the fd before // If we are requested to update resolv.conf, preopen the fd before
// we drop root privileges, making sure that if we create // we drop root privileges, making sure that if we create

32
src/ndhc.c
View File

@@ -184,26 +184,21 @@ static void setup_signals_ndhc(void)
static void signal_dispatch(void) static void signal_dispatch(void)
{ {
int t;
size_t off = 0;
struct signalfd_siginfo si = {0}; struct signalfd_siginfo si = {0};
again: ssize_t r = safe_read(cs.signalFd, (char *)&si, sizeof si);
t = read(cs.signalFd, (char *)&si + off, sizeof si - off); if (r < 0) {
if (t < 0) { log_error("%s: ndhc: error reading from signalfd: %s",
if (t == EAGAIN || t == EWOULDBLOCK || t == EINTR) client_config.interface, strerror(errno));
goto again; return;
else }
suicide("signalfd read error"); if ((size_t)r < sizeof si) {
log_error("%s: ndhc: short read from signalfd: %zd < %zu",
client_config.interface, r, sizeof si);
return;
} }
if (off + (unsigned)t < sizeof si)
off += t;
switch (si.ssi_signo) { switch (si.ssi_signo) {
case SIGUSR1: case SIGUSR1: force_renew_action(&cs); break;
force_renew_action(&cs); case SIGUSR2: force_release_action(&cs); break;
break;
case SIGUSR2:
force_release_action(&cs);
break;
case SIGCHLD: case SIGCHLD:
suicide("ndhc-master: Subprocess terminated unexpectedly. Exiting."); suicide("ndhc-master: Subprocess terminated unexpectedly. Exiting.");
break; break;
@@ -211,8 +206,7 @@ static void signal_dispatch(void)
log_line("Received SIGTERM. Exiting gracefully."); log_line("Received SIGTERM. Exiting gracefully.");
exit(EXIT_SUCCESS); exit(EXIT_SUCCESS);
break; break;
default: default: break;
break;
} }
} }

56
src/sockd.c
View File

@@ -36,7 +36,6 @@
#include <fcntl.h> #include <fcntl.h>
#include <assert.h> #include <assert.h>
#include <sys/socket.h> #include <sys/socket.h>
#include <sys/signalfd.h>
#include <sys/epoll.h> #include <sys/epoll.h>
#include <sys/types.h> #include <sys/types.h>
#include <sys/stat.h> #include <sys/stat.h>
@@ -434,53 +433,6 @@ static int create_arp_basic_socket(bool *using_bpf)
return fd; return fd;
} }
// XXX: Can share with ifch
static void setup_signals_sockd(void)
{
sigset_t mask;
sigemptyset(&mask);
sigaddset(&mask, SIGUSR1);
sigaddset(&mask, SIGUSR2);
sigaddset(&mask, SIGTSTP);
sigaddset(&mask, SIGTTIN);
sigaddset(&mask, SIGCHLD);
sigaddset(&mask, SIGHUP);
sigaddset(&mask, SIGINT);
sigaddset(&mask, SIGTERM);
if (sigprocmask(SIG_BLOCK, &mask, NULL) < 0)
suicide("sigprocmask failed");
signalFd = signalfd(-1, &mask, SFD_NONBLOCK);
if (signalFd < 0)
suicide("signalfd failed");
}
// XXX: Can share with ifch
static void signal_dispatch(void)
{
int t;
size_t off = 0;
struct signalfd_siginfo si = {0};
again:
t = read(signalFd, (char *)&si + off, sizeof si - off);
if (t < 0) {
if (t == EAGAIN || t == EWOULDBLOCK || t == EINTR)
goto again;
else
suicide("signalfd read error");
}
if (off + (unsigned)t < sizeof si)
off += t;
switch (si.ssi_signo) {
case SIGINT:
case SIGTERM:
case SIGHUP:
exit(EXIT_SUCCESS);
break;
default:
break;
}
}
static void xfer_fd(int fd, char cmd) static void xfer_fd(int fd, char cmd)
{ {
char control[sizeof(struct cmsghdr) + 10]; char control[sizeof(struct cmsghdr) + 10];
@@ -607,7 +559,7 @@ static void do_sockd_work(void)
if (fd == sockdSock[1]) if (fd == sockdSock[1])
process_client_socket(); process_client_socket();
else if (fd == signalFd) else if (fd == signalFd)
signal_dispatch(); signal_dispatch_subprocess(signalFd, "sockd");
else else
suicide("sockd: unexpected fd while performing epoll"); suicide("sockd: unexpected fd while performing epoll");
} }
@@ -617,9 +569,11 @@ static void do_sockd_work(void)
void sockd_main(void) void sockd_main(void)
{ {
prctl(PR_SET_NAME, "ndhc: sockd"); prctl(PR_SET_NAME, "ndhc: sockd");
prctl(PR_SET_PDEATHSIG, SIGHUP); if (prctl(PR_SET_PDEATHSIG, SIGHUP) < 0)
suicide("%s: (%s) prctl(PR_SET_PDEATHSIG) failed: %s",
client_config.interface, __func__, strerror(errno));
umask(077); umask(077);
setup_signals_sockd(); signalFd = setup_signals_subprocess();
nk_set_chroot(chroot_dir); nk_set_chroot(chroot_dir);
memset(chroot_dir, 0, sizeof chroot_dir); memset(chroot_dir, 0, sizeof chroot_dir);
unsigned char keepcaps[] = { CAP_NET_BIND_SERVICE, CAP_NET_BROADCAST, unsigned char keepcaps[] = { CAP_NET_BIND_SERVICE, CAP_NET_BROADCAST,

44
src/sys.c
View File

@@ -26,12 +26,16 @@
* POSSIBILITY OF SUCH DAMAGE. * POSSIBILITY OF SUCH DAMAGE.
*/ */
#include <unistd.h>
#include <stdlib.h>
#include <string.h> #include <string.h>
#include <errno.h> #include <errno.h>
#include <signal.h>
#include <sys/epoll.h> #include <sys/epoll.h>
#include <sys/signalfd.h> #include <sys/signalfd.h>
#include "nk/log.h" #include "nk/log.h"
#include "nk/io.h"
#include "ndhc.h"
#include "sys.h" #include "sys.h"
void epoll_add(int epfd, int fd) void epoll_add(int epfd, int fd)
@@ -55,3 +59,41 @@ void epoll_del(int epfd, int fd)
if (r < 0) if (r < 0)
suicide("epoll_del failed %s", strerror(errno)); suicide("epoll_del failed %s", strerror(errno));
} }
int setup_signals_subprocess(void)
{
sigset_t mask;
sigemptyset(&mask);
sigaddset(&mask, SIGHUP);
sigaddset(&mask, SIGINT);
sigaddset(&mask, SIGTERM);
if (sigprocmask(SIG_BLOCK, &mask, NULL) < 0)
suicide("sigprocmask failed");
int sfd = signalfd(-1, &mask, SFD_NONBLOCK);
if (sfd < 0)
suicide("signalfd failed");
return sfd;
}
void signal_dispatch_subprocess(int sfd, const char *pname)
{
struct signalfd_siginfo si = {0};
ssize_t r = safe_read(sfd, (char *)&si, sizeof si);
if (r < 0) {
log_error("%s: %s: error reading from signalfd: %s",
client_config.interface, pname, strerror(errno));
return;
}
if ((size_t)r < sizeof si) {
log_error("%s: %s: short read from signalfd: %zd < %zu",
client_config.interface, pname, r, sizeof si);
return;
}
switch (si.ssi_signo) {
case SIGINT:
case SIGTERM:
case SIGHUP: exit(EXIT_SUCCESS); break;
default: break;
}
}

4
src/sys.h
View File

@@ -46,4 +46,8 @@ static inline size_t min_size_t(size_t a, size_t b)
void epoll_add(int epfd, int fd); void epoll_add(int epfd, int fd);
void epoll_del(int epfd, int fd); void epoll_del(int epfd, int fd);
int setup_signals_subprocess(void);
void signal_dispatch_subprocess(int sfd, const char *pname);
#endif /* SYS_H_ */ #endif /* SYS_H_ */