X-Git-Url: https://git.distorted.org.uk/~mdw/rsync-backup/blobdiff_plain/f6b4ffdc7265b79b945e2350efbd9d2a94df4450..HEAD:/rfreezefs.c

diff --git a/rfreezefs.c b/rfreezefs.c
index c390c36..fa1f053 100644
--- a/rfreezefs.c
+++ b/rfreezefs.c
@@ -54,6 +54,7 @@
 #include <mLib/dstr.h>
 #include <mLib/base64.h>
 #include <mLib/fdflags.h>
+#include <mLib/macros.h>
 #include <mLib/mdwopt.h>
 #include <mLib/quis.h>
 #include <mLib/report.h>
@@ -228,7 +229,7 @@ static size_t nfs;			/* Number of descriptors */
 /*----- Cleanup -----------------------------------------------------------*/
 
 #define EOM ((char *)0)
-static void emerg(const char *msg,...)
+static void EXECL_LIKE(0) emerg(const char *msg, ...)
 {
   va_list ap;
 
@@ -251,7 +252,7 @@ static void partial_cleanup(size_t n)
   int i;
   int bad = 0;
 
-  for (i = 0; i < nfs; i++) {
+  for (i = 0; i < n; i++) {
     if (fs[i] == -1)
       emerg("not really thawing ", fsname[i], EOM);
     else if (fs[i] != -2) {
@@ -274,12 +275,12 @@ static int sigcatch[] = {
   SIGILL, SIGSEGV, SIGBUS, SIGFPE, SIGABRT
 };
 
-static void sigmumble(int sig)
+static void NORETURN sigmumble(int sig)
 {
   sigset_t ss;
 
   cleanup();
-  emerg(strsignal(sig), 0);
+  emerg(strsignal(sig), EOM);
 
   signal(sig, SIG_DFL);
   sigemptyset(&ss); sigaddset(&ss, sig);
@@ -302,17 +303,31 @@ static void help(FILE *fp)
   fputs("\n\
 Freezes a filesystem temporarily, with some measure of safety.\n\
 \n\
-The program listens for connections on a TCP port, and prints a line\n\
+The program listens for connections on a TCP port, and prints a number of\n\
+lines:\n\
+\n\
+	PORT <port>\n\
+	TOKEN FREEZE <token>\n\
+	TOKEN FROZEN <token>\n\
+	TOKEN KEEPALIVE <token>\n\
+	TOKEN THAW <token>\n\
+	TOKEN THAWED <token>\n\
+	READY\n\
 \n\
-	PORT COOKIE\n\
+to standard output.  You must connect to the <port>, using TCP, and send\n\
+the FREEZE token followed by a newline within a short period of time.  The\n\
+filesystems will then be frozen, and the FROZEN token written to the\n\
+connection.  In order to keep the file system frozen, you must keep the\n\
+connection open, and periodically echo the KEEPALIVE token to it.  To\n\
+release the filesystems, write the THAW token to the connection, followed\n\
+by a newline; the filesystem will be thawed, and the THAWED token echoed\n\
+back.  If the connection closes, or no valid message is received within a\n\
+set period of time, or the program receives one of a variety of signals or\n\
+otherwise becomes unhappy, the filesystems are thawed again.\n\
 \n\
-to standard output.  You must connect to this PORT and send the COOKIE\n\
-followed by a newline within a short period of time.  The filesystems\n\
-will then be frozen, and `OK' written to the connection.  In order to\n\
-keep the file system frozen, you must keep the connection open, and\n\
-feed data into it.  If the connection closes, or no data is received\n\
-within a set period of time, or the program receives one of a variety\n\
-of signals or otherwise becomes unhappy, the filesystems are thawed again.\n\
+The program exits with status zero if everything worked as planned, while\n\
+nonzero codes indicate failures of various kinds (see the manual); an exit\n\
+status of 112 means that thawing a filesystem failed.\n\
 \n\
 Options:\n\
 \n\
@@ -542,7 +557,7 @@ connected:
    * Hopefully this will prevent bad things happening if we have an accident.
    */
 
-  for (i = 0; i < sizeof(sigcatch)/sizeof(sigcatch[0]); i++) {
+  for (i = 0; i < N(sigcatch); i++) {
     if (signal(sigcatch[i], sigmumble) == SIG_ERR)
       die(2, "signal (%d): %s", i, strerror(errno));
   }