nfs-utils: move check for active knfsd to helper function

[nfs-utils.git] / utils / nfsd / nfssvc.c

diff --git a/utils/nfsd/nfssvc.c b/utils/nfsd/nfssvc.c
index 0a7546a3c6f53544f65b65a564dc16a4f7308577..7ecaea9e76cc26eee99037a9897794ceafbe4017 100644 (file)
--- a/utils/nfsd/nfssvc.c
+++ b/utils/nfsd/nfssvc.c
@@ -24,28 +24,51 @@
 #define NFSD_VERS_FILE    "/proc/fs/nfsd/versions"
 #define NFSD_THREAD_FILE  "/proc/fs/nfsd/threads"
 
+/*
+ * declaring a common static scratch buffer here keeps us from having to
+ * continually thrash the stack. The value of 128 bytes here is really just a
+ * SWAG and can be increased if necessary. It ought to be enough for the
+ * routines below however.
+ */
+char buf[128];
+
+/*
+ * Are there already sockets configured? If not, then it is safe to try to
+ * open some and pass them through.
+ *
+ * Note: If the user explicitly asked for 'udp', then we should probably check
+ * if that is open, and should open it if not. However we don't yet. All
+ * sockets have to be opened when the first daemon is started.
+ */
+int
+nfssvc_inuse(void)
+{
+       int fd, n;
+
+       fd = open(NFSD_PORTS_FILE, O_RDONLY);
+
+       /* problem opening file, assume that nothing is configured */
+       if (fd < 0)
+               return 0;
+
+       n = read(fd, buf, sizeof(buf));
+       close(fd);
+
+       xlog(D_GENERAL, "knfsd is currently %s", (n > 0) ? "up" : "down");
+
+       return (n > 0);
+}
+
 static void
 nfssvc_setfds(int port, unsigned int ctlbits, char *haddr)
 {
-       int fd, n, on=1;
-       char buf[BUFSIZ];
+       int fd, on=1;
        int udpfd = -1, tcpfd = -1;
        struct sockaddr_in sin;
 
-       fd = open(NFSD_PORTS_FILE, O_RDONLY);
-       if (fd < 0)
-               return;
-       n = read(fd, buf, BUFSIZ);
-       close(fd);
-       if (n != 0)
+       if (nfssvc_inuse())
                return;
-       /* there are no ports currently open, so it is safe to
-        * try to open some and pass them through.
-        * Note: If the user explicitly asked for 'udp', then
-        * we should probably check if that is open, and should
-        * open it if not.  However we don't yet.  All sockets
-        * have to be opened when the first daemon is started.
-        */
+
        fd = open(NFSD_PORTS_FILE, O_WRONLY);
        if (fd < 0)
                return;
@@ -91,7 +114,7 @@ nfssvc_setfds(int port, unsigned int ctlbits, char *haddr)
                }
        }
        if (udpfd >= 0) {
-               snprintf(buf, BUFSIZ,"%d\n", udpfd); 
+               snprintf(buf, sizeof(buf), "%d\n", udpfd); 
                if (write(fd, buf, strlen(buf)) != strlen(buf)) {
                        xlog(L_ERROR, 
                               "writing fds to kernel failed: errno %d (%m)", 
@@ -103,7 +126,7 @@ nfssvc_setfds(int port, unsigned int ctlbits, char *haddr)
        if (tcpfd >= 0) {
                if (fd < 0)
                        fd = open(NFSD_PORTS_FILE, O_WRONLY);
-               snprintf(buf, BUFSIZ,"%d\n", tcpfd); 
+               snprintf(buf, sizeof(buf), "%d\n", tcpfd); 
                if (write(fd, buf, strlen(buf)) != strlen(buf)) {
                        xlog(L_ERROR, 
                               "writing fds to kernel failed: errno %d (%m)", 
@@ -118,7 +141,7 @@ static void
 nfssvc_versbits(unsigned int ctlbits, int minorvers4)
 {
        int fd, n, off;
-       char buf[BUFSIZ], *ptr;
+       char *ptr;
 
        ptr = buf;
        off = 0;
@@ -128,17 +151,17 @@ nfssvc_versbits(unsigned int ctlbits, int minorvers4)
 
        for (n = NFSD_MINVERS; n <= NFSD_MAXVERS; n++) {
                if (NFSCTL_VERISSET(ctlbits, n))
-                   off += snprintf(ptr+off, BUFSIZ - off, "+%d ", n);
+                   off += snprintf(ptr+off, sizeof(buf) - off, "+%d ", n);
                else
-                   off += snprintf(ptr+off, BUFSIZ - off, "-%d ", n);
+                   off += snprintf(ptr+off, sizeof(buf) - off, "-%d ", n);
        }
        n = minorvers4 >= 0 ? minorvers4 : -minorvers4;
        if (n >= NFSD_MINMINORVERS4 && n <= NFSD_MAXMINORVERS4)
-                   off += snprintf(ptr+off, BUFSIZ - off, "%c4.%d",
+                   off += snprintf(ptr+off, sizeof(buf) - off, "%c4.%d",
                                    minorvers4 > 0 ? '+' : '-',
                                    n);
        xlog(D_GENERAL, "Writing version string to kernel: %s", buf);
-       snprintf(ptr+off, BUFSIZ - off, "\n");
+       snprintf(ptr+off, sizeof(buf) - off, "\n");
        if (write(fd, buf, strlen(buf)) != strlen(buf))
                xlog(L_ERROR, "Setting version failed: errno %d (%m)", errno);
 
@@ -168,9 +191,8 @@ nfssvc(int port, int nrservs, unsigned int versbits, int minorvers4,
                 * Just write the number in.
                 * Cannot handle port number yet, but does anyone care?
                 */
-               char buf[20];
                int n;
-               snprintf(buf, 20,"%d\n", nrservs);
+               snprintf(buf, sizeof(buf), "%d\n", nrservs);
                n = write(fd, buf, strlen(buf));
                close(fd);
                if (n != strlen(buf))