WIP

src/liblwevent/000_TopHeader.h

@@ -9,6 +9,8 @@
 #define HEADER_liblwevent
 
 /* standard includes, or includes needed for type declarations */
+#include <signal.h> /* for 400_signalfd.h */
+#include <stdint.h> /* for 400_signalfd.h */
 
 /* options for text editors
 kate: replace-trailing-space-save true; space-indent true; tab-width 4;

src/liblwevent/000_TopSource.c

@@ -13,6 +13,7 @@
 #include <string.h>
 #include <unistd.h>
 #include <sys/epoll.h>
+#include <sys/syscall.h> /* for 400_signalfd.c */
 
 /* options for text editors
 kate: replace-trailing-space-save true; space-indent true; tab-width 4;

src/liblwevent/300_fdevent.c

@@ -8,17 +8,18 @@
 
 
 /* _lwevent_activate()
- *  Activates the event `ev'. Called when creating a new event in lwevent_new() or when reactivating
- *  an event in lwevent_reactivate(). Calls epoll_ctl(EPOLL_CTL_ADD).
+ *  Activates the event `ev'. Called with EPOLL_CTL_ADD in `op' when creating a new event in 
+ *  lwevent_new() or when reactivating an event in lwevent_reactivate(). Called with EPOLL_CTL_MOD
+ *  in lwevent_set_events(). Calls epoll_ctl(), returning -1 on permanent failure.
  */
-static int _lwevent_activate(struct lwevent* ev)
+static int _lwevent_activate(int op, struct lwevent* ev)
 {
     struct epoll_event ee;
 
     ee.events = ev->events;
     ee.data.ptr = ev;
 
-    return TEMP_FAILURE_RETRY( epoll_ctl(lwevent_epoll_fd, EPOLL_CTL_ADD, ev->fd, &ee) );
+    return TEMP_FAILURE_RETRY( epoll_ctl(lwevent_epoll_fd, op, ev->fd, &ee) );
 }
 
 
@@ -38,7 +39,7 @@ struct lwevent* lwevent_new(int fd, int events, lwevent_callback callback)
     ev->events = events;
     ev->callback = callback;
 
-    if(_lwevent_activate(ev)) {
+    if(_lwevent_activate(EPOLL_CTL_ADD, ev)) {
         free(ev);
         return 0;
     }
@@ -79,7 +80,7 @@ int lwevent_deactivate(struct lwevent* ev)
  */
 int lwevent_reactivate(struct lwevent* ev)
 {
-    return _lwevent_activate(ev);
+    return _lwevent_activate(EPOLL_CTL_ADD, ev);
 }
 
 

src/liblwevent/300_fdevent.h

@@ -28,14 +28,13 @@ retrieve associated values.
 
 */
 struct lwevent
-#ifndef DOXYGEN
-;
-#else
+#ifdef DOXYGEN
 {
     /*! \brief Dummy variable for doxygen */
     int dummy;
-};
+}
 #endif
+;
 
 
 

src/liblwevent/350_fdparams.c

@@ -0,0 +1,93 @@
+/* liblwevent/src/liblwevent/300_fdparams.c
+ *
+ *  (c)2007, Laurence Withers, <l@lwithers.me.uk>.
+ *  Released under the GNU GPLv2. See file COPYING or
+ *  http://www.gnu.org/copyleft/gpl.html for details.
+*/
+
+
+
+/* lwevent_get_*()
+ *  Functions for retrieving attributes stored in a struct lwevent.
+ */
+int lwevent_get_fd(const struct lwevent* ev) 
+{
+    return ev->fd;
+}
+
+int lwevent_get_events(const struct lwevent* ev) 
+{
+    return ev->events;
+}
+
+lwevent_callback lwevent_get_callback(const struct lwevent* ev) 
+{
+    return ev->callback;
+}
+
+void* lwevent_get_user(const struct lwevent* ev) 
+{
+    return ev->user;
+}
+
+lwevent_dtor lwevent_get_dtor(const struct lwevent* ev) 
+{
+    return ev->dtor;
+}
+
+int lwevent_get_autodestroy(const struct lwevent* ev) 
+{
+    return ev->autodestroy;
+}
+
+
+
+/* lwevent_set_events()
+ *  Calls epoll_ctl(EPOLL_CTL_MOD) to change the events associated with the object `ev'. Does not
+ *  perform the call if the new events match the current events. If `old_events' is not null, stores
+ *  the existing events before changing. Returns -1 if epoll_ctl fails.
+ */
+int lwevent_set_events(struct lwevent* ev, int events, int* old_events)
+{
+    if(old_events) *old_events = ev->events;
+    if(events == ev->events) return 0; /* don't call epoll_ctl() if no change */
+
+    return _lwevent_activate(EPOLL_CTL_MOD, ev);
+}
+    
+
+
+/* lwevent_set_*()
+ *  Changes attributes associated with `ev', possibly storing the old value.
+ */
+void lwevent_set_callback(struct lwevent* ev, lwevent_callback callback,
+    lwevent_callback* old_callback) 
+{
+    if(old_callback) *old_callback = ev->callback;
+    ev->callback = callback;
+}
+
+void lwevent_set_user(struct lwevent* ev, void* user, void** old_user) 
+{
+    if(old_user) *old_user = ev->user;
+    ev->user = user;
+}
+    
+void lwevent_set_dtor(struct lwevent* ev, lwevent_dtor dtor, lwevent_dtor* old_dtor)
+{
+    if(old_dtor) *old_dtor = ev->dtor;
+    ev->dtor = dtor;
+}
+
+void lwevent_set_autodestroy(struct lwevent* ev, int autodestroy, int* old_autodestroy)
+{
+    if(old_autodestroy) *old_autodestroy = ev->autodestroy;
+    ev->autodestroy = autodestroy;
+}    
+
+
+
+/* options for text editors
+kate: replace-trailing-space-save true; space-indent true; tab-width 4;
+vim: expandtab:ts=4:sw=4
+*/

src/liblwevent/350_fdparams.h

@@ -1,4 +1,4 @@
-/* liblwevent/src/liblwevent/300_fdevent.h
+/* liblwevent/src/liblwevent/300_fdparams.h
  *
  *  (c)2007, Laurence Withers, <l@lwithers.me.uk>.
  *  Released under the GNU GPLv2. See file COPYING or
@@ -29,15 +29,6 @@ typedef void (*lwevent_dtor)(struct lwevent* ev);
 
 
 
-/*! \brief Flag: autodestroy object if \c EPOLLERR is received. */
-extern const int LWEVENT_AUTODESTROY_ERR;
-/*! \brief Flag: autodestroy object if \c EPOLLRDHUP is received. */
-extern const int LWEVENT_AUTODESTROY_RDHUP;
-/*! \brief Flag: autodestroy object if \c EPOLLHUP is received. */
-extern const int LWEVENT_AUTODESTROY_WRHUP;
-
-
-
 /*! \brief Retrieve file descriptor associated with object. */
 int lwevent_get_fd(const struct lwevent* ev) __attribute__((nonnull, warn_unused_result));
 
@@ -145,7 +136,9 @@ void lwevent_set_dtor(struct lwevent* ev, lwevent_dtor dtor, lwevent_dtor* old_d
 \param[out] old_autodestroy Previous bitmask stored here. May be 0.
 
 The autodestroy functionality causes the event object \a ev to be automatically passed to
-lwevent_free() if any specified event occurs. You may pass ~0 to autodestroy on any error event.
+lwevent_free() if any specified event occurs. You may pass ~0 to autodestroy on any event. See
+\c epoll_ctl(2) for a list of valid event flags (non-authoritative list: \c EPOLLIN, \c EPOLLOUT,
+\c EPOLLRDHUP, \c EPOLLPRI, \c EPOLLERR, \c EPOLLHUP).
 
 */
 void lwevent_set_autodestroy(struct lwevent* ev, int autodestroy, int* old_autodestroy)

src/liblwevent/400_signalfd.c

@@ -0,0 +1,145 @@
+/* liblwevent/src/liblwevent/400_signalfd.c
+ *
+ *  (c)2007, Laurence Withers, <l@lwithers.me.uk>.
+ *  Released under the GNU GPLv2. See file COPYING or
+ *  http://www.gnu.org/copyleft/gpl.html for details.
+*/
+
+
+
+int signalfd(int fd, const sigset_t* mask)
+{
+    size_t sz;
+    sz = sizeof(sigset_t);
+    return syscall(__NR_signalfd, fd, mask, sz);
+}
+
+
+
+struct lwevent_signal {
+    sigset_t mask;
+    lwevent_signalcb callback;
+    struct lwevent* ev;
+};
+
+
+
+static void _lwevent_signalfd_callback(struct lwevent* ev, int revents)
+{
+    (void)revents;
+    struct signalfd_siginfo ssi;
+    struct lwevent_signal* si;
+
+    si = lwevent_get_user(ev);
+
+    while(1) {
+        if(TEMP_FAILURE_RETRY( read(lwevent_get_fd(ev), &ssi, sizeof(ssi)) ) == -1) {
+            if(errno == EAGAIN) return;
+            /* TODO: now what??? */
+        }
+
+        si->callback(&ssi);
+    }
+}
+
+struct lwevent_signal* lwevent_signalfd(const sigset_t* mask, lwevent_signalcb callback)
+{
+    struct lwevent_signal* si;
+    int fd;
+
+    si = malloc(sizeof(struct lwevent_signal));
+    if(!si) return 0;
+    memset(si, 0, sizeof(struct lwevent_signal));
+
+    si->mask = *mask;
+    sigdelset(&si->mask, SIGBUS);
+    sigdelset(&si->mask, SIGFPE);
+    sigdelset(&si->mask, SIGILL);
+    sigdelset(&si->mask, SIGSEGV);
+    si->callback = callback;
+
+    fd = signalfd(-1, &si->mask);
+    if(fd == -1) {
+        free(si);
+        return 0;
+    }
+
+    /* TODO: make non-blocking */
+
+    si->ev = lwevent_new(fd, EPOLLIN, _lwevent_signalfd_callback);
+    if(!si->ev) {
+        close(fd);
+        free(si);
+        return 0;
+    }
+
+    lwevent_set_user(si->ev, si, 0);
+    return si;
+}
+
+
+
+void lwevent_signalfd_getsigs(const struct lwevent_signal* si, sigset_t* mask)
+{
+    *mask = si->mask;
+}
+
+    
+
+lwevent_signalcb lwevent_signalfd_getcb(const struct lwevent_signal* si)
+{
+    return si->callback;
+}    
+
+
+
+int lwevent_signalfd_setsigs(struct lwevent_signal* si, const sigset_t* mask, sigset_t* old_mask)
+{
+    sigset_t mnew;
+
+    if(old_mask) *old_mask = si->mask;
+
+    mnew = *mask;
+    sigdelset(&mnew, SIGBUS);
+    sigdelset(&mnew, SIGFPE);
+    sigdelset(&mnew, SIGILL);
+    sigdelset(&mnew, SIGSEGV);
+
+    if(signalfd(lwevent_get_fd(si->ev), &mnew)) return -1;
+    si->mask = mnew;
+    return 0;
+}
+
+
+
+void lwevent_signalfd_setcb(struct lwevent_signal* si, lwevent_signalcb callback, 
+    lwevent_signalcb* old_callback)
+{
+    if(old_callback) *old_callback = si->callback;
+    si->callback = callback;
+}
+
+
+
+void lwevent_signalfd_close(struct lwevent_signal* si)
+{
+    if(!si) return;
+
+    lwevent_free(si->ev);
+    free(si);
+}
+
+
+
+struct lwevent_signal* lwevent_signalfd_default(void) 
+{
+    /* TODO */
+    return lwevent_signalfd(...);
+}
+
+
+
+/* options for text editors
+kate: replace-trailing-space-save true; space-indent true; tab-width 4;
+vim: expandtab:ts=4:sw=4
+*/

src/liblwevent/400_signalfd.h

@@ -0,0 +1,188 @@
+/* liblwevent/src/liblwevent/400_signalfd.h
+ *
+ *  (c)2007, Laurence Withers, <l@lwithers.me.uk>.
+ *  Released under the GNU GPLv2. See file COPYING or
+ *  http://www.gnu.org/copyleft/gpl.html for details.
+*/
+
+
+
+/*! \defgroup signalfd Signals through file descriptor
+
+This module provides an interface to \c signalfd(2), a system call which provides an alternative
+signal delivery mechanism: certain signals can be read from a file descriptor queue.
+
+\todo Currently, the \c signalfd(2) interface is very new (in fact, the manpage has not yet been
+    released and must be pieced together from http://lkml.org/lkml/2007/9/27/88). Furthermore, it
+    is not yet implemented in \a glibc. Until that occurs, a function call wrapper for the system
+    call is provided in this library. Eventually this will be removed in favour of the authoritative
+    \a glibc interface.
+
+*/
+/*!@{*/
+
+
+
+/*! \brief Signal info structure.
+
+This is the structure that is returned from a \c read(2) of a signalfd.
+
+\todo Eventually, this will be folded into glibc. At that time, this structure definition will have
+    to be removed and the code updated to use the new stuff.
+
+*/
+struct signalfd_siginfo {
+    uint32_t  ssi_signo;       /*!< si_signo */
+    int32_t   ssi_err;         /*!< si_errno */
+    int32_t   ssi_code;        /*!< si_code */
+    uint32_t  ssi_pid;         /*!< si_pid */
+    uint32_t  ssi_uid;         /*!< si_uid */
+    int32_t   ssi_fd;          /*!< si_fd */
+    uint32_t  ssi_tid;         /*!< si_tid */
+    uint32_t  ssi_band;        /*!< si_band */
+    uint32_t  ssi_overrun;     /*!< si_overrun */
+    uint32_t  ssi_trapno;      /*!< si_trapno */
+    int32_t   ssi_status;      /*!< si_status */
+    int32_t   ssi_svint;       /*!< si_int */
+    uint64_t  ssi_svptr;       /*!< si_ptr */
+    uint64_t  ssi_utime;       /*!< si_utime */
+    uint64_t  ssi_stime;       /*!< si_stime */
+    uint64_t  ssi_addr;        /*!< si_addr */
+    uint8_t   ssi_pad[48];     /*!< Pad size to 128 bytes (allow space for additional fields in the future) */
+};
+
+
+
+/*! \brief System call wrapper for \c signalfd(2).
+
+\param fd File descriptor to modify (pass -1 to create a new file descriptor).
+\param mask Signal mask. Any signals set in \a mask will be delivered through \a fd (but see below).
+\retval 0 on success.
+\retval -1 on error (and see \a errno).
+
+System call wrapper function for \c signalfd(2). Any signals turned on in \a mask will be delivered
+through the file descriptor \a fd. However, these signals should also be masked from the process
+using \c sigprocmask(2), since otherwise the two delivery mechanisms will race.
+
+Passing -1 in \a fd causes a new file descriptor to be allocated. It can be polled, closed and read
+normally. It will return struct signalfd_siginfo objects when read. Passing an existing signalfd
+file descriptor in \a fd will allow the \a mask to be modified.
+
+\todo Eventually, this system call wrapper function will be removed in favour of \a glibc's
+    authoritative version.
+
+*/
+int signalfd(int fd, const sigset_t* mask);
+
+
+
+/*! \brief Event-driven signal receiver object.
+
+This object implements an event-driven signal receiver based on \c signalfd(2). The object contains
+details such as the callback function for each received signal.
+
+*/
+struct lwevent_signal
+#ifdef DOXYGEN
+{
+    /*! \brief Dummy variable for doxygen; this structure is really opaque. */
+    int dummy;
+}
+#endif
+;
+
+
+
+/*! \brief Pointer to signal callback function. */
+typedef void (*lwevent_signalcb)(const struct signalfd_siginfo* ssi);
+
+
+
+/*! \brief Create and register event-driven signal receiver object.
+
+\param mask Set of signals to catch.
+\param callback Callback for received signals.
+\returns Pointer to new receiver object.
+\retval 0 on error (and see \a errno).
+
+Creates a signal receiver file descriptor using \c signalfd(2), and requests that the signals in
+\a mask are received through it. Also calls \c sigprocmask(2) to block the signals in \a mask, and
+ensure the delivery mechanisms do not race.
+
+This function will silently ignore attempts to receive \c SIGKILL, \c SIGSTOP, \c SIGBUS, \c SIGFPE,
+\c SIGILL and \c SIGSEGV even if they are set in \a mask. Such signals either cannot be redirected
+or would cause serious misbehaviour if they were not received immediately through the normal
+mechanism.
+
+*/
+struct lwevent_signal* lwevent_signalfd(const sigset_t* mask, lwevent_signalcb callback)
+    __attribute__((malloc,nonnull,warn_unused_result));
+
+
+
+/*! \brief Retrieve signal receiver's signal set. */
+void lwevent_signalfd_getsigs(const struct lwevent_signal* si, sigset_t* mask)
+    __attribute__((nonnull));
+
+/*! \brief Retrieve signal receiver's callback function. */
+lwevent_signalcb lwevent_signalfd_getcb(const struct lwevent_signal* si)
+    __attribute__((nonnull));
+
+
+
+/*! \brief Modify signal receiver's signal set.
+
+\param si Signal receiver object.
+\param mask The new mask to enact.
+\param oldmask The old mask. May be 0.
+\retval 0 on success.
+\retval -1 on error (and see \a errno).
+
+Changes the set of signals being received by \a si to those set in \a mask. See lwevent_signalfd()
+for a discussion of the full behaviour of the receiver. The application may retrieve the previous
+mask by passing a pointer to a signal set in \a oldmask.
+
+*/
+int lwevent_signalfd_setsigs(struct lwevent_signal* si, const sigset_t* mask, sigset_t* oldmask)
+    __attribute__((nonnull,warn_unused_result));
+
+
+
+/*! \brief Modiy signal receiver's callback function. */
+void lwevent_signalfd_setcb(struct lwevent_signal* si, lwevent_signalcb callback,
+    lwevent_signalcb* old_callback) __attribute__((nonnull));
+
+
+
+/*! \brief Close signal receiver.
+
+\param si Signal receiver object. May be 0.
+
+Closes a signal receiver object, unblocking the signals it blocked with \c sigprocmask(2). If \a si
+is null, this is a no-op.
+
+*/
+void lwevent_signalfd_close(struct lwevent_signal* si);
+
+
+
+/*! \brief Set up a default signal receiver.
+
+\returns Pointer to new receiver object.
+\retval 0 on error (and see \a errno).
+
+Sets up a default signal receiver object. This object will catch \c SIGINT and \c SIGTERM and set
+the lwevent_loop_exit flag to non-zero. Other signals are left for the normal delivery mechanism.
+
+*/
+struct lwevent_signal* lwevent_signalfd_default(void) __attribute__((malloc,warn_unused_result));
+
+
+
+/*!@}*/
+
+
+/* options for text editors
+kate: replace-trailing-space-save true; space-indent true; tab-width 4;
+vim: expandtab:ts=4:sw=4:syntax=c.doxygen
+*/