[PATCH v4 23/32] tools/xenstored: move all log-pipe handling into posix.c

[Juergen Gross <jgross@xxxxxxxx>]

All of the log-pipe handling is needed only when running as daemon.

Move it into posix.c. This requires to have a service function in the
main event loop for handling the related requests and one for setting
the fds[] array. Use a generic name for those functions, as socket
handling can be added to them later, too.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
V3:
- new patch
V4:
- rename fds to poll_fds (Julien Grall)
---
 tools/xenstored/core.c   | 69 +++++++++++-----------------------------
 tools/xenstored/core.h   | 11 ++++---
 tools/xenstored/minios.c | 14 ++++----
 tools/xenstored/posix.c  | 47 ++++++++++++++++++++++++++-
 4 files changed, 79 insertions(+), 62 deletions(-)

diff --git a/tools/xenstored/core.c b/tools/xenstored/core.c
index 7b5e1d0c0f..86ab330eaf 100644
--- a/tools/xenstored/core.c
+++ b/tools/xenstored/core.c
@@ -56,7 +56,7 @@
 
 extern xenevtchn_handle *xce_handle; /* in domain.c */
 static int xce_pollfd_idx = -1;
-static struct pollfd *fds;
+struct pollfd *poll_fds;
 static unsigned int current_array_size;
 static unsigned int nr_fds;
 static unsigned int delayed_requests;
@@ -69,8 +69,6 @@ char **orig_argv;
 LIST_HEAD(connections);
 int tracefd = -1;
 bool keep_orphans = false;
-int reopen_log_pipe[2];
-static int reopen_log_pipe0_pollfd_idx = -1;
 char *tracefile = NULL;
 static struct hashtable *nodes;
 unsigned int trace_flags = TRACE_OBJ | TRACE_IO;
@@ -145,18 +143,6 @@ void trace_destroy(const void *data, const char *type)
                trace("obj: DESTROY %s %p\n", type, data);
 }
 
-/**
- * Signal handler for SIGHUP, which requests that the trace log is reopened
- * (in the main loop).  A single byte is written to reopen_log_pipe, to awaken
- * the poll() in the main loop.
- */
-static void trigger_reopen_log(int signal __attribute__((unused)))
-{
-       char c = 'A';
-       int dummy;
-       dummy = write(reopen_log_pipe[1], &c, 1);
-}
-
 void close_log(void)
 {
        if (tracefd >= 0)
@@ -467,7 +453,7 @@ static bool conn_can_write(struct connection *conn)
 }
 
 /* This function returns index inside the array if succeed, -1 if fail */
-static int set_fd(int fd, short events)
+int set_fd(int fd, short events)
 {
        int ret;
        if (current_array_size < nr_fds + 1) {
@@ -479,18 +465,18 @@ static int set_fd(int fd, short events)
                 */
                newsize = ROUNDUP(nr_fds + 1, 8);
 
-               new_fds = realloc(fds, sizeof(struct pollfd)*newsize);
+               new_fds = realloc(poll_fds, sizeof(struct pollfd)*newsize);
                if (!new_fds)
                        goto fail;
-               fds = new_fds;
+               poll_fds = new_fds;
 
-               memset(&fds[0] + current_array_size, 0,
+               memset(&poll_fds[0] + current_array_size, 0,
                       sizeof(struct pollfd ) * (newsize-current_array_size));
                current_array_size = newsize;
        }
 
-       fds[nr_fds].fd = fd;
-       fds[nr_fds].events = events;
+       poll_fds[nr_fds].fd = fd;
+       poll_fds[nr_fds].events = events;
        ret = nr_fds;
        nr_fds++;
 
@@ -505,18 +491,16 @@ static void initialize_fds(int *p_sock_pollfd_idx, int 
*ptimeout)
        struct connection *conn;
        uint64_t msecs;
 
-       if (fds)
-               memset(fds, 0, sizeof(struct pollfd) * current_array_size);
+       if (poll_fds)
+               memset(poll_fds, 0, sizeof(struct pollfd) * current_array_size);
        nr_fds = 0;
 
        /* In case of delayed requests pause for max 1 second. */
        *ptimeout = delayed_requests ? 1000 : -1;
 
+       set_special_fds();
        if (sock != -1)
                *p_sock_pollfd_idx = set_fd(sock, POLLIN|POLLPRI);
-       if (reopen_log_pipe[0] != -1)
-               reopen_log_pipe0_pollfd_idx =
-                       set_fd(reopen_log_pipe[0], POLLIN|POLLPRI);
 
        if (xce_handle != NULL)
                xce_pollfd_idx = set_fd(xenevtchn_fd(xce_handle),
@@ -2324,12 +2308,12 @@ static bool socket_can_process(struct connection *conn, 
int mask)
        if (conn->pollfd_idx == -1)
                return false;
 
-       if (fds[conn->pollfd_idx].revents & ~(POLLIN | POLLOUT)) {
+       if (poll_fds[conn->pollfd_idx].revents & ~(POLLIN | POLLOUT)) {
                talloc_free(conn);
                return false;
        }
 
-       return (fds[conn->pollfd_idx].revents & mask);
+       return (poll_fds[conn->pollfd_idx].revents & mask);
 }
 
 static bool socket_can_write(struct connection *conn)
@@ -2897,8 +2881,6 @@ int main(int argc, char *argv[])
 
        talloc_enable_null_tracking();
 
-       init_pipe(reopen_log_pipe);
-
        /* Listen to hypervisor. */
        if (!live_update) {
                domain_init(-1);
@@ -2913,7 +2895,6 @@ int main(int argc, char *argv[])
                xprintf = trace;
 #endif
 
-       signal(SIGHUP, trigger_reopen_log);
        if (tracefile)
                tracefile = talloc_strdup(NULL, tracefile);
 
@@ -2934,43 +2915,29 @@ int main(int argc, char *argv[])
        for (;;) {
                struct connection *conn, *next;
 
-               if (poll(fds, nr_fds, timeout) < 0) {
+               if (poll(poll_fds, nr_fds, timeout) < 0) {
                        if (errno == EINTR)
                                continue;
                        barf_perror("Poll failed");
                }
 
-               if (reopen_log_pipe0_pollfd_idx != -1) {
-                       if (fds[reopen_log_pipe0_pollfd_idx].revents
-                           & ~POLLIN) {
-                               close(reopen_log_pipe[0]);
-                               close(reopen_log_pipe[1]);
-                               init_pipe(reopen_log_pipe);
-                       } else if (fds[reopen_log_pipe0_pollfd_idx].revents
-                                  & POLLIN) {
-                               char c;
-                               if (read(reopen_log_pipe[0], &c, 1) != 1)
-                                       barf_perror("read failed");
-                               reopen_log();
-                       }
-                       reopen_log_pipe0_pollfd_idx = -1;
-               }
+               handle_special_fds();
 
                if (sock_pollfd_idx != -1) {
-                       if (fds[sock_pollfd_idx].revents & ~POLLIN) {
+                       if (poll_fds[sock_pollfd_idx].revents & ~POLLIN) {
                                barf_perror("sock poll failed");
                                break;
-                       } else if (fds[sock_pollfd_idx].revents & POLLIN) {
+                       } else if (poll_fds[sock_pollfd_idx].revents & POLLIN) {
                                accept_connection(sock);
                                sock_pollfd_idx = -1;
                        }
                }
 
                if (xce_pollfd_idx != -1) {
-                       if (fds[xce_pollfd_idx].revents & ~POLLIN) {
+                       if (poll_fds[xce_pollfd_idx].revents & ~POLLIN) {
                                barf_perror("xce_handle poll failed");
                                break;
-                       } else if (fds[xce_pollfd_idx].revents & POLLIN) {
+                       } else if (poll_fds[xce_pollfd_idx].revents & POLLIN) {
                                handle_event();
                                xce_pollfd_idx = -1;
                        }
diff --git a/tools/xenstored/core.h b/tools/xenstored/core.h
index 0de2d8a26e..44c4d0f8b8 100644
--- a/tools/xenstored/core.h
+++ b/tools/xenstored/core.h
@@ -25,6 +25,7 @@
 #include <sys/types.h>
 #include <dirent.h>
 #include <fcntl.h>
+#include <poll.h>
 #include <stdbool.h>
 #include <stdint.h>
 #include <time.h>
@@ -361,6 +362,8 @@ extern int dom0_event;
 extern int priv_domid;
 extern bool keep_orphans;
 
+extern struct pollfd *poll_fds;
+
 extern unsigned int timeout_watch_event_msec;
 
 /* Get internal time in milliseconds. */
@@ -387,15 +390,15 @@ evtchn_port_t get_xenbus_evtchn(void);
 void early_init(bool live_update, bool dofork, const char *pidfile);
 void late_init(bool live_update);
 
+int set_fd(int fd, short events);
+void set_special_fds(void);
+void handle_special_fds(void);
+
 void init_sockets(void);
-extern int reopen_log_pipe[2];
 
 /* Close stdin/stdout/stderr to complete daemonize */
 void finish_daemonize(void);
 
-/* Open a pipe for signal handling */
-void init_pipe(int reopen_log_pipe[2]);
-
 #ifndef NO_SOCKETS
 extern const struct interface_funcs socket_funcs;
 #endif
diff --git a/tools/xenstored/minios.c b/tools/xenstored/minios.c
index 45bb0440be..3208169187 100644
--- a/tools/xenstored/minios.c
+++ b/tools/xenstored/minios.c
@@ -24,12 +24,6 @@ void finish_daemonize(void)
 {
 }
 
-void init_pipe(int reopen_log_pipe[2])
-{
-       reopen_log_pipe[0] = -1;
-       reopen_log_pipe[1] = -1;
-}
-
 evtchn_port_t get_xenbus_evtchn(void)
 {
        return dom0_event;
@@ -53,3 +47,11 @@ void early_init(bool live_update, bool dofork, const char 
*pidfile)
 void late_init(bool live_update)
 {
 }
+
+void set_special_fds(void)
+{
+}
+
+void handle_special_fds(void)
+{
+}
diff --git a/tools/xenstored/posix.c b/tools/xenstored/posix.c
index 97c8dcaba3..1ea8475293 100644
--- a/tools/xenstored/posix.c
+++ b/tools/xenstored/posix.c
@@ -33,6 +33,9 @@
 #include "core.h"
 #include "osdep.h"
 
+static int reopen_log_pipe0_pollfd_idx = -1;
+static int reopen_log_pipe[2];
+
 static void write_pidfile(const char *pidfile)
 {
        char buf[100];
@@ -82,6 +85,19 @@ static void daemonize(void)
        umask(0);
 }
 
+/*
+ * Signal handler for SIGHUP, which requests that the trace log is reopened
+ * (in the main loop).  A single byte is written to reopen_log_pipe, to awaken
+ * the poll() in the main loop.
+ */
+static void trigger_reopen_log(int signal __attribute__((unused)))
+{
+       char c = 'A';
+       int dummy;
+
+       dummy = write(reopen_log_pipe[1], &c, 1);
+}
+
 void finish_daemonize(void)
 {
        int devnull = open("/dev/null", O_RDWR);
@@ -93,7 +109,7 @@ void finish_daemonize(void)
        close(devnull);
 }
 
-void init_pipe(int reopen_log_pipe[2])
+static void init_pipe(void)
 {
        int flags;
        unsigned int i;
@@ -183,9 +199,38 @@ void early_init(bool live_update, bool dofork, const char 
*pidfile)
 
        /* Don't kill us with SIGPIPE. */
        signal(SIGPIPE, SIG_IGN);
+       signal(SIGHUP, trigger_reopen_log);
 
        if (!live_update)
                init_sockets();
+
+       init_pipe();
+}
+
+void set_special_fds(void)
+{
+       if (reopen_log_pipe[0] != -1)
+               reopen_log_pipe0_pollfd_idx =
+                       set_fd(reopen_log_pipe[0], POLLIN|POLLPRI);
+}
+
+void handle_special_fds(void)
+{
+       if (reopen_log_pipe0_pollfd_idx != -1) {
+               if (poll_fds[reopen_log_pipe0_pollfd_idx].revents & ~POLLIN) {
+                       close(reopen_log_pipe[0]);
+                       close(reopen_log_pipe[1]);
+                       init_pipe();
+               } else if (poll_fds[reopen_log_pipe0_pollfd_idx].revents &
+                          POLLIN) {
+                       char c;
+
+                       if (read(reopen_log_pipe[0], &c, 1) != 1)
+                               barf_perror("read failed");
+                       reopen_log();
+               }
+               reopen_log_pipe0_pollfd_idx = -1;
+       }
 }
 
 void late_init(bool live_update)
-- 
2.35.3