Minor tweak in the VG_(poll) syscall and callers: have a way to show

the error in case the poll syscall unexpectedly fails.

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13748

diff --git a/coregrind/m_gdbserver/remote-utils.c b/coregrind/m_gdbserver/remote-utils.c
index 9028288dbe17d0e698ac9966076f1ac37c97aba5..25e8f46a2068b97c4ecc6ceadb806d354f42b783 100644 (file)
--- a/coregrind/m_gdbserver/remote-utils.c
+++ b/coregrind/m_gdbserver/remote-utils.c
@@ -157,22 +157,27 @@ int poll_cond (short revents)
 
 /* Ensures we have a valid write file descriptor.
    Returns 1 if we have a valid write file descriptor,
-   0 if the write fd could not be opened. */
+   0 if the write fd is not valid/cannot be opened. */
 static
 int ensure_write_remote_desc(void)
 {
    struct vki_pollfd write_remote_desc_ok;
-   int ret;
+   SysRes ret;
    if (write_remote_desc != INVALID_DESCRIPTOR) {
       write_remote_desc_ok.fd = write_remote_desc;
       write_remote_desc_ok.events = VKI_POLLOUT;
       write_remote_desc_ok.revents = 0;
       ret = VG_(poll)(&write_remote_desc_ok, 1, 0);
-      if (ret && poll_cond(write_remote_desc_ok.revents)) {
-         dlog(1, "POLLcond %d closing write_remote_desc %d\n", 
-              write_remote_desc_ok.revents, write_remote_desc);
-         VG_(close) (write_remote_desc);
-         write_remote_desc = INVALID_DESCRIPTOR;
+      if (sr_isError(ret) 
+          || (sr_Res(ret) > 0 && poll_cond(write_remote_desc_ok.revents))) {
+        if (sr_isError(ret)) {
+          sr_perror(ret, "ensure_write_remote_desc: poll error\n");
+        } else {
+          dlog(0, "POLLcond %d closing write_remote_desc %d\n", 
+               write_remote_desc_ok.revents, write_remote_desc);
+        }
+        VG_(close) (write_remote_desc);
+        write_remote_desc = INVALID_DESCRIPTOR;
       }
    }
    if (write_remote_desc == INVALID_DESCRIPTOR) {
@@ -439,10 +444,10 @@ void error_poll_cond(void)
    counter values maintained in shared memory by vgdb. */
 int remote_desc_activity(const char *msg)
 {
-   int ret;
+   int retval;
+   SysRes ret;
    const int looking_at = shared->written_by_vgdb;
    if (shared->seen_by_valgrind == looking_at)
-   //   if (last_looked_cntr == looking_at)
       return 0;
    if (remote_desc == INVALID_DESCRIPTOR)
       return 0;
@@ -450,23 +455,30 @@ int remote_desc_activity(const char *msg)
    /* poll the remote desc */
    remote_desc_pollfdread_activity.revents = 0;
    ret = VG_(poll) (&remote_desc_pollfdread_activity, 1, 0);
-   if (ret && poll_cond(remote_desc_pollfdread_activity.revents)) {
-      dlog(1, "POLLcond %d remote_desc_pollfdread %d\n", 
-           remote_desc_pollfdread_activity.revents, remote_desc);
-      error_poll_cond();
-      ret = 2;
+   if (sr_isError(ret)
+       || (sr_Res(ret) && poll_cond(remote_desc_pollfdread_activity.revents))) {
+     if (sr_isError(ret)) {
+       sr_perror(ret, "remote_desc_activity: poll error\n");
+     } else {
+       dlog(0, "POLLcond %d remote_desc_pollfdread %d\n", 
+            remote_desc_pollfdread_activity.revents, remote_desc);
+       error_poll_cond();
+     }
+     retval = 2;
+   } else {
+     retval = sr_Res(ret);
    }
    dlog(1,
         "remote_desc_activity %s %d last_looked_cntr %d looking_at %d"
         " shared->written_by_vgdb %d shared->seen_by_valgrind %d"
-        " ret %d\n", 
+        " retval %d\n", 
         msg, remote_desc, last_looked_cntr, looking_at, 
         shared->written_by_vgdb, shared->seen_by_valgrind,
-        ret);
+        retval);
    /* if no error from poll, indicate we have "seen" up to looking_at */
-   if (ret != 2)
+   if (retval == 1)
       last_looked_cntr = looking_at;
-   return ret;
+   return retval;
 }
 
 /* Convert hex digit A to a number.  */
@@ -803,7 +815,7 @@ int readchar (int single)
    static unsigned char buf[PBUFSIZ];
    static int bufcnt = 0;
    static unsigned char *bufp;
-   int ret;
+   SysRes ret;
   
    if (bufcnt-- > 0)
       return *bufp++;
@@ -815,9 +827,13 @@ int readchar (int single)
       wait for some characters to arrive */
    remote_desc_pollfdread_activity.revents = 0;
    ret = VG_(poll)(&remote_desc_pollfdread_activity, 1, -1);
-   if (ret != 1) {
-      dlog(0, "readchar: poll got %d\n", ret);
-      return -1;
+   if (sr_isError(ret) || sr_Res(ret) != 1) {
+     if (sr_isError(ret)) {
+        sr_perror(ret, "readchar: poll error\n");
+     } else {
+        dlog(0, "readchar: poll got %d, expecting 1\n", (int)sr_Res(ret));
+     }
+     return -1;
    }
    if (single)
       bufcnt = VG_(read) (remote_desc, buf, 1);

diff --git a/coregrind/m_libcfile.c b/coregrind/m_libcfile.c
index aeca9dd8b23a751587d2b0d22f87872ed8d653d6..4f6d3d0cc001bc79b68eb63980433f2914fca72e 100644 (file)
--- a/coregrind/m_libcfile.c
+++ b/coregrind/m_libcfile.c
@@ -456,7 +456,7 @@ Bool VG_(get_startup_wd) ( HChar* buf, SizeT size )
    return True;
 }
 
-Int VG_(poll) (struct vki_pollfd *fds, Int nfds, Int timeout)
+SysRes VG_(poll) (struct vki_pollfd *fds, Int nfds, Int timeout)
 {
    SysRes res;
 #  if defined(VGO_linux)
@@ -466,7 +466,7 @@ Int VG_(poll) (struct vki_pollfd *fds, Int nfds, Int timeout)
 #  else
 #    error "Unknown OS"
 #  endif
-   return sr_isError(res) ? -1 : sr_Res(res);
+   return res;
 }
 
 

diff --git a/include/pub_tool_libcfile.h b/include/pub_tool_libcfile.h
index eed404fc7b1e64364243579f29f91da6f2be7fcc..00505fda9073cc6730860d9599b3243a363e02eb 100644 (file)
--- a/include/pub_tool_libcfile.h
+++ b/include/pub_tool_libcfile.h
@@ -89,7 +89,7 @@ extern SysRes VG_(dup2)   ( Int oldfd, Int newfd );
 extern Int    VG_(rename) ( const HChar* old_name, const HChar* new_name );
 extern Int    VG_(unlink) ( const HChar* file_name );
 
-extern Int    VG_(poll) (struct vki_pollfd *fds, Int nfds, Int timeout);
+extern SysRes VG_(poll) (struct vki_pollfd *fds, Int nfds, Int timeout);
 
 extern Int    VG_(readlink)( const HChar* path, HChar* buf, UInt bufsize );
 extern Int    VG_(getdents)( Int fd, struct vki_dirent *dirp, UInt count );