Add a --debug flag for DEBUG builds

If you compile with:

  DEBUG=true rake build

then all the commands get a --debug flag as an option which will make
the server dump crazy amounts of data to stderr.

Rakefile

@@ -1,8 +1,6 @@
 require 'rake_utils/debian'
 include RakeUtils::DSL
 
-DEBUG  = true
-
 ALL_SOURCES =FileList['src/*']
 SOURCES = ALL_SOURCES.select { |c| c =~ /\.c$/ }
 OBJECTS = SOURCES.pathmap( "%{^src,build}X.o" )
@@ -14,7 +12,7 @@ LIBCHECK = "/usr/lib/libcheck.a"
 
 TEST_MODULES = Dir["tests/check_*.c"].map { |n| n[12..-3] }
 
-if DEBUG
+if ENV['DEBUG']
   LDFLAGS << ["-g"]
   CCFLAGS << ["-g -DDEBUG"]
 end

src/bitset.h

@@ -5,7 +5,6 @@
 #include <string.h>
 #include <pthread.h>
 
-#include "util.h"
 
 static inline char char_with_bit_set(int num) { return 1<<(num%8); }
 

src/flexnbd.c

@@ -180,6 +180,9 @@ void read_serve_param( int c, char **ip_addr, char **ip_port, char **file, char
 		case 's':
 			*sock = optarg;
 			break;
+		case 'd':
+			set_debug(1);
+			break;
 		default:
 			exit_err( serve_help_text );
 			break;
@@ -206,6 +209,9 @@ void read_readwrite_param( int c, char **ip_addr, char **ip_port, char **from, c
 		case 'S':
 			*size = optarg;
 			break;
+		case 'd':
+			set_debug(1);
+			break;
 		default:
 			exit_err( read_help_text );
 			break;
@@ -222,6 +228,9 @@ void read_sock_param( int c, char **sock, char *help_text )
 		case 's':
 			*sock = optarg;
 			break;
+		case 'd':
+			set_debug(1);
+			break;
 		default:
 			exit_err( help_text );
 			break;
@@ -249,6 +258,9 @@ void read_mirror_param( int c, char **sock, char **ip_addr, char **ip_port )
 		case 'p':
 			*ip_port = optarg;
 			break;
+		case 'd':
+			set_debug(1);
+			break;
 		default:
 			exit_err( mirror_help_text );
 			break;
@@ -500,6 +512,7 @@ int main(int argc, char** argv)
 {
 	signal(SIGPIPE, SIG_IGN); /* calls to splice() unhelpfully throw this */
 	error_init();
+	set_debug(0);
 
 	if (argc < 2) {
 		exit_err( help_help_text );

src/options.h

@@ -32,12 +32,24 @@
 #define GETOPT_FROM GETOPT_ARG( OPT_FROM, 'F' )
 #define GETOPT_SIZE GETOPT_ARG( OPT_SIZE, 'S' )
 
+#ifdef DEBUG
+#  define OPT_DEBUG "debug"
+#  define GETOPT_DEBUG GETOPT_FLAG( OPT_DEBUG, 'd' )
+#  define DEBUG_LINE \
+  "\t--" OPT_DEBUG ",-d\tOutput debug information.\n"
+#else
+#  define GETOPT_DEBUG {0}
+#  define DEBUG_LINE ""
+#endif
+
+
 static struct option serve_options[] = {
 	GETOPT_HELP,
 	GETOPT_ADDR,
 	GETOPT_PORT,
 	GETOPT_FILE,
 	GETOPT_SOCK,
+	GETOPT_DEBUG,
 	{0}
 };
 static char serve_short_options[] = "hl:p:f:s:";
@@ -48,7 +60,8 @@ static char serve_help_text[] =
 	"\t--" OPT_ADDR ",-l <ADDR>\tThe address to serve on.\n"
 	"\t--" OPT_PORT ",-p <PORT>\tThe port to serve on.\n"
 	"\t--" OPT_FILE ",-f <FILE>\tThe file to serve.\n"
-	"\t--" OPT_SOCK ",-s <SOCK>\tPath to the control socket to open.\n";
+	"\t--" OPT_SOCK ",-s <SOCK>\tPath to the control socket to open.\n"
+	DEBUG_LINE;
 
 static struct option read_options[] = {
 	GETOPT_HELP,
@@ -56,6 +69,7 @@ static struct option read_options[] = {
 	GETOPT_PORT,
 	GETOPT_FROM,
 	GETOPT_SIZE,
+	GETOPT_DEBUG,
 	{0}
 };
 static char read_short_options[] = "hl:p:F:S:";
@@ -66,7 +80,8 @@ static char read_help_text[] =
 	"\t--" OPT_ADDR ",-l <ADDR>\tThe address to read from.\n"
 	"\t--" OPT_PORT ",-p <PORT>\tThe port to read from.\n"
 	"\t--" OPT_FROM ",-F <OFFSET>\tByte offset to read from.\n"
-	"\t--" OPT_SIZE ",-S <SIZE>\tBytes to read.\n";
+	"\t--" OPT_SIZE ",-S <SIZE>\tBytes to read.\n"
+	DEBUG_LINE;
 
 
 static struct option *write_options = read_options;
@@ -78,11 +93,13 @@ static char write_help_text[] =
 	"\t--" OPT_ADDR ",-l <ADDR>\tThe address to write to.\n"
 	"\t--" OPT_PORT ",-p <PORT>\tThe port to write to.\n"
 	"\t--" OPT_FROM ",-F <OFFSET>\tByte offset to write from.\n"
-	"\t--" OPT_SIZE ",-S <SIZE>\tBytes to write.\n";
+	"\t--" OPT_SIZE ",-S <SIZE>\tBytes to write.\n"
+	DEBUG_LINE;
 
 struct option acl_options[] = {
 	GETOPT_HELP,
 	GETOPT_SOCK,
+	GETOPT_DEBUG,
 	{0}
 };
 static char acl_short_options[] = "hs:";
@@ -90,13 +107,15 @@ static char acl_help_text[] =
 	"Usage: flexnbd " CMD_ACL " <options> [<acl address>+]\n\n"
 	"Set the access control list for a server with control socket SOCK.\n\n"
 	"\t--" OPT_HELP ",-h\tThis text.\n"
-	"\t--" OPT_SOCK ",-s <SOCK>\tPath to the control socket.\n";
+	"\t--" OPT_SOCK ",-s <SOCK>\tPath to the control socket.\n"
+	DEBUG_LINE;
 
 struct option mirror_options[] = {
 	GETOPT_HELP,
 	GETOPT_SOCK,
 	GETOPT_ADDR,
 	GETOPT_PORT,
+	GETOPT_DEBUG,
 	{0}
 };
 static char mirror_short_options[] = "hs:l:p:";
@@ -106,12 +125,14 @@ static char mirror_help_text[] =
 	"\t--" OPT_HELP ",-h\tThis text.\n"
 	"\t--" OPT_SOCK ",-s <SOCK>\tPath to the control socket.\n"
 	"\t--" OPT_ADDR ",-l <ADDR>\tThe address to mirror to.\n"
-	"\t--" OPT_PORT ",-p <PORT>\tThe port to mirror to.\n";
+	"\t--" OPT_PORT ",-p <PORT>\tThe port to mirror to.\n"
+	DEBUG_LINE;
 
 
 struct option status_options[] = {
 	GETOPT_HELP,
 	GETOPT_SOCK,
+	GETOPT_DEBUG,
 	{0}
 };
 static char status_short_options[] = "hs:";
@@ -119,7 +140,8 @@ static char status_help_text[] =
 	"Usage: flexnbd " CMD_STATUS " <options>\n\n"
 	"Get the status for a server with control socket SOCK.\n\n"
 	"\t--" OPT_HELP ",-h\tThis text.\n"
-	"\t--" OPT_SOCK ",-s <SOCK>\tPath to the control socket.\n";
+	"\t--" OPT_SOCK ",-s <SOCK>\tPath to the control socket.\n"
+	DEBUG_LINE;
 
 static char help_help_text[] =
 	"Usage: flexnbd <cmd> [cmd options]\n\n"

src/util.c

@@ -10,6 +10,7 @@
 #include "util.h"
 
 static pthread_t main_thread;
+static int global_debug;
 
 void error_init()
 {
@@ -59,3 +60,23 @@ void* xmalloc(size_t size)
 	return p;
 }
 
+
+void set_debug(int value) {
+	global_debug = value;
+}
+
+#ifdef DEBUG
+#  include <sys/times.h>
+#  include <stdarg.h>
+
+void debug(const char *msg, ...) {
+  va_list argp;
+
+	if ( global_debug ) {
+    fprintf(stderr, "%08x %4d: ", (int) pthread_self(), (int) clock() );
+    fprintf(stderr, msg, argp);
+    fprintf(stderr, "\n");
+	}
+}
+#endif
+

src/util.h

@@ -12,12 +12,9 @@ void* xrealloc(void* ptr, size_t size);
 
 void* xmalloc(size_t size);
 
-#ifndef DEBUG
-#  define debug(msg, ...)
-#else
-#  include <sys/times.h>
-#  define debug(msg, ...) fprintf(stderr, "%08x %4d: " msg "\n" , \
-     (int) pthread_self(), (int) clock(), ##__VA_ARGS__)
+void set_debug(int value);
+#ifdef DEBUG
+void debug(const char*msg, ...);
 #endif
 
 #define CLIENT_ERROR(msg, ...) \