util: command: Extract common parts of FD closing to virCommandMassClose

Extract the lookup of used FDs and their setup to virCommandMassClose
rather than duplicate it in the two functions we have for using
different modes of FD closing.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>

src/util/vircommand.c

@@ -520,16 +520,12 @@ virCommandMassCloseGetFDs(virBitmap *fds)
 }
 
 static int
-virCommandMassCloseFrom(virCommand *cmd,
-                        int childin,
-                        int childout,
-                        int childerr)
+virCommandMassCloseFrom(virBitmap *keep)
 {
     g_autoptr(virBitmap) fds = NULL;
     int openmax = sysconf(_SC_OPEN_MAX);
-    int lastfd = -1;
+    int lastfd = virBitmapLastSetBit(keep);
     int fd = -1;
-    size_t i;
 
     /* In general, it is not safe to call malloc() between fork() and exec()
      * because the child might have forked at the worst possible time, i.e.
@@ -551,24 +547,14 @@ virCommandMassCloseFrom(virCommand *cmd,
     if (virCommandMassCloseGetFDs(fds) < 0)
         return -1;
 
-    lastfd = MAX(lastfd, childin);
-    lastfd = MAX(lastfd, childout);
-    lastfd = MAX(lastfd, childerr);
-
-    for (i = 0; i < cmd->npassfd; i++)
-        lastfd = MAX(lastfd, cmd->passfd[i].fd);
-
     fd = virBitmapNextSetBit(fds, 2);
     for (; fd >= 0 && fd <= lastfd; fd = virBitmapNextSetBit(fds, fd)) {
-        if (fd == childin || fd == childout || fd == childerr)
+        int tmpfd = fd;
+
+        if (virBitmapIsBitSet(keep, fd))
             continue;
-        if (!virCommandFDIsSet(cmd, fd)) {
-            int tmpfd = fd;
-            VIR_MASS_CLOSE(tmpfd);
-        } else if (virSetInherit(fd, true) < 0) {
-            virReportSystemError(errno, _("failed to preserve fd %1$d"), fd);
-            return -1;
-        }
+
+        VIR_MASS_CLOSE(tmpfd);
     }
 
     if (virCloseFrom(lastfd + 1) < 0) {
@@ -588,33 +574,13 @@ virCommandMassCloseFrom(virCommand *cmd,
 
 
 static int
-virCommandMassCloseRange(virCommand *cmd,
-                         int childin,
-                         int childout,
-                         int childerr)
+virCommandMassCloseRange(virBitmap *keep)
 {
-    g_autoptr(virBitmap) fds = virBitmapNew(0);
     ssize_t first;
     ssize_t last;
-    size_t i;
-
-    virBitmapSetBitExpand(fds, childin);
-    virBitmapSetBitExpand(fds, childout);
-    virBitmapSetBitExpand(fds, childerr);
-
-    for (i = 0; i < cmd->npassfd; i++) {
-        int fd = cmd->passfd[i].fd;
-
-        virBitmapSetBitExpand(fds, fd);
-
-        if (virSetInherit(fd, true) < 0) {
-            virReportSystemError(errno, _("failed to preserve fd %1$d"), fd);
-            return -1;
-        }
-    }
 
     first = 2;
-    while ((last = virBitmapNextSetBit(fds, first)) >= 0) {
+    while ((last = virBitmapNextSetBit(keep, first)) >= 0) {
         if (first + 1 == last) {
             first = last;
             continue;
@@ -642,17 +608,44 @@ virCommandMassCloseRange(virCommand *cmd,
 }
 
 
-
+/**
+ * virCommandMassClose:
+ * @cmd: command structure
+ * @childin: fd passed to child as stdin
+ * @childout: fd passed to child as stdout
+ * @childerr: fd passed to child as stderr
+ *
+ * Prepares FDs to be passed to the child process spawned by @cmd and closes
+ * every other FD.
+ */
 static int
 virCommandMassClose(virCommand *cmd,
                     int childin,
                     int childout,
                     int childerr)
 {
-    if (virCloseRangeIsSupported())
-        return virCommandMassCloseRange(cmd, childin, childout, childerr);
+    g_autoptr(virBitmap) fds = virBitmapNew(0);
+    size_t i;
 
-    return virCommandMassCloseFrom(cmd, childin, childout, childerr);
+    virBitmapSetBitExpand(fds, childin);
+    virBitmapSetBitExpand(fds, childout);
+    virBitmapSetBitExpand(fds, childerr);
+
+    for (i = 0; i < cmd->npassfd; i++) {
+        int fd = cmd->passfd[i].fd;
+
+        virBitmapSetBitExpand(fds, fd);
+
+        if (virSetInherit(fd, true) < 0) {
+            virReportSystemError(errno, _("failed to preserve fd %1$d"), fd);
+            return -1;
+        }
+    }
+
+    if (virCloseRangeIsSupported())
+        return virCommandMassCloseRange(fds);
+
+    return virCommandMassCloseFrom(fds);
 }