Improve structure

- Use getopt_long_only() to implement option parsing. This probably
  makes use of small C libraries harder, but that wasn't very much
  possible to begin with, anyway.
- Deprecate bs= and timeout= options in favour of new --block-size and
  --timeout options.
- Compartmentalize a bit more. Yes, the compiler will optimize that away
  in some cases, but what do I care, I don't need to write assembler
  code.

Documentation update to follow.

diff --git a/nbd-client.c b/nbd-client.c
index 7aceb3e..35f5d8d 100644 (file)
--- a/nbd-client.c
+++ b/nbd-client.c
@@ -34,6 +34,7 @@
 #include <sys/mount.h>
 #include <sys/mman.h>
 #include <errno.h>
 #include <sys/mount.h>
 #include <sys/mman.h>
 #include <errno.h>

+#include <getopt.h>

 
 #ifndef __GNUC__
 #error I need GCC to work
 
 #ifndef __GNUC__
 #error I need GCC to work

@@ -223,10 +224,44 @@ void finish_sock(int sock, int nbd, int swap) {
                mlockall(MCL_CURRENT | MCL_FUTURE);
 }
 
                mlockall(MCL_CURRENT | MCL_FUTURE);
 }
 

+void usage(void) {
+       fprintf(stderr, "nbd-client version %s\n", PACKAGE_VERSION);
+       fprintf(stderr, "Usage: nbd-client [bs=blocksize] [timeout=sec] host port nbd_device [-swap] [-sdp] [-persist] [-nofork]\n");
+       fprintf(stderr, "Or   : nbd-client -d nbd_device\n");
+       fprintf(stderr, "Or   : nbd-client -c nbd_device\n");
+       fprintf(stderr, "Default value for blocksize is 1024 (recommended for ethernet)\n");
+       fprintf(stderr, "Allowed values for blocksize are 512,1024,2048,4096\n"); /* will be checked in kernel :) */
+       fprintf(stderr, "Note, that kernel 2.4.2 and older ones do not work correctly with\n");
+       fprintf(stderr, "blocksizes other than 1024 without patches\n");
+}
+
+void disconnect(char* device) {
+       int nbd = open(device, O_RDWR);
+       if (nbd < 0)
+               err("Cannot open NBD: %m\nPlease ensure the 'nbd' module is loaded.");
+       printf("Disconnecting: que, ");
+       if (ioctl(nbd, NBD_CLEAR_QUE)< 0)
+               err("Ioctl failed: %m\n");
+       printf("disconnect, ");
+#ifdef NBD_DISCONNECT
+       if (ioctl(nbd, NBD_DISCONNECT)<0)
+               err("Ioctl failed: %m\n");
+       printf("sock, ");
+#else
+       fprintf(stderr, "Can't disconnect: I was not compiled with disconnect support!\n" );
+       exit(1);
+#endif
+       if (ioctl(nbd, NBD_CLEAR_SOCK)<0)
+               err("Ioctl failed: %m\n");
+       printf("done\n");
+}
+

 int main(int argc, char *argv[]) {
 int main(int argc, char *argv[]) {

-       int port, sock, nbd;
+       int port=0;
+       int sock, nbd;

        int blocksize=1024;
        int blocksize=1024;

-       char *hostname, *nbddev;
+       char *hostname=NULL;
+       char *nbddev=NULL;

        int swap=0;
        int cont=0;
        int timeout=0;
        int swap=0;
        int cont=0;
        int timeout=0;

@@ -234,105 +269,105 @@ int main(int argc, char *argv[]) {
        int nofork=0;
        u64 size64;
        u32 flags;
        int nofork=0;
        u64 size64;
        u32 flags;

-       int i;
+       int i, c;
+       int nonspecial=0;
+       struct option long_options[] = {
+               { "block-size", required_argument, NULL, 'b' },
+               { "check", required_argument, NULL, 'c' },
+               { "disconnect", required_argument, NULL, 'd' },
+               { "help", no_argument, NULL, 'h' },
+               { "nofork", no_argument, NULL, 'n' },
+               { "persist", no_argument, NULL, 'p' },
+               { "sdp", no_argument, NULL, 'S' },
+               { "swap", no_argument, NULL, 's' },
+               { "timeout", required_argument, NULL, 't' },
+       };

 
        logging();
 
 
        logging();
 

-       if (argc < 3) {
-       errmsg:
-               fprintf(stderr, "nbd-client version %s\n", PACKAGE_VERSION);
-               fprintf(stderr, "Usage: nbd-client [bs=blocksize] [timeout=sec] host port nbd_device [-swap] [-persist] [-nofork]\n");
-               fprintf(stderr, "Or   : nbd-client -d nbd_device\n");
-               fprintf(stderr, "Or   : nbd-client -c nbd_device\n");
-               fprintf(stderr, "Default value for blocksize is 1024 (recommended for ethernet)\n");
-               fprintf(stderr, "Allowed values for blocksize are 512,1024,2048,4096\n"); /* will be checked in kernel :) */
-               fprintf(stderr, "Note, that kernel 2.4.2 and older ones do not work correctly with\n");
-               fprintf(stderr, "blocksizes other than 1024 without patches\n");
-               return 1;
-       }
-
-       ++argv; --argc; /* skip programname */
-
-       if (strcmp(argv[0], "-d")==0) {
-               nbd = open(argv[1], O_RDWR);
-               if (nbd < 0)
-                       err("Cannot open NBD: %m\nPlease ensure the 'nbd' module is loaded.");
-               printf("Disconnecting: que, ");
-               if (ioctl(nbd, NBD_CLEAR_QUE)< 0)
-                       err("Ioctl failed: %m\n");
-               printf("disconnect, ");
-#ifdef NBD_DISCONNECT
-               if (ioctl(nbd, NBD_DISCONNECT)<0)
-                       err("Ioctl failed: %m\n");
-               printf("sock, ");
-#else
-               fprintf(stderr, "Can't disconnect: I was not compiled with disconnect support!\n" );
-               exit(1);
-#endif
-               if (ioctl(nbd, NBD_CLEAR_SOCK)<0)
-                       err("Ioctl failed: %m\n");
-               printf("done\n");
-               return 0;
-       }
-       if(strcmp(argv[0], "-c")==0) {
-               return check_conn(argv[1], 1);
-       }
-       
-       if (strncmp(argv[0], "bs=", 3)==0) {
-               blocksize=atoi(argv[0]+3);
-               ++argv; --argc; /* skip blocksize */
+       while((c=getopt_long_only(argc, argv, "-b:c:d:hnpSst:", long_options, NULL))>=0) {
+               switch(c) {
+               case 1:
+                       // non-option argument
+                       if(strchr(optarg, '=')) {
+                               // old-style 'bs=' or 'timeout='
+                               // argument
+                               fprintf(stderr, "WARNING: old-style command-line argument encountered. This is deprecated.\n");
+                               if(!strncmp(optarg, "bs=", 3)) {
+                                       optarg+=3;
+                                       goto blocksize;
+                               }
+                               if(!strncmp(optarg, "timeout=", 8)) {
+                                       optarg+=8;
+                                       goto timeout;
+                               }
+                               fprintf(stderr, "ERROR: unknown option %s encountered\n", optarg);
+                               exit(EXIT_FAILURE);
+                       }
+                       switch(nonspecial++) {
+                               case 0:
+                                       // host
+                                       hostname=optarg;
+                                       break;
+                               case 1:
+                                       // port
+                                       port = strtol(optarg, NULL, 0);
+                                       break;
+                               case 2:
+                                       // device
+                                       nbddev = optarg;
+                                       break;
+                               default:
+                                       fprintf(stderr, "ERROR: too many non-option arguments specified\n");
+                                       exit(EXIT_FAILURE);
+                       }
+                       break;
+               case 'b':
+                     blocksize:
+                       blocksize=(int)strtol(optarg, NULL, 0);
+                       break;
+               case 'c':
+                       check_conn(optarg, 1);
+                       exit(EXIT_SUCCESS);
+               case 'd':
+                       disconnect(optarg);
+                       exit(EXIT_SUCCESS);
+               case 'h':
+                       usage();
+                       exit(EXIT_SUCCESS);
+               case 'n':
+                       nofork=1;
+                       break;
+               case 'p':
+                       cont=1;
+                       break;
+               case 's':
+                       swap=1;
+                       break;
+               case 'S':
+                       sdp=1;
+                       break;
+               case 't':
+                     timeout:
+                       timeout=strtol(optarg, NULL, 0);
+                       break;
+               default:
+                       fprintf(stderr, "E: option eaten by 42 mice\n");
+                       exit(EXIT_FAILURE);
+               }

        }
 
        }
 

-       if (strncmp(argv[0], "timeout=", 8)==0) {
-               timeout=atoi(argv[0]+8);
-               ++argv; --argc; /* skip timeout */
+       if(!port || !hostname || !nbddev) {
+               usage();
+               exit(EXIT_FAILURE);

        }
        }

-       
-       if (argc==0) goto errmsg;
-       hostname=argv[0];
-       ++argv; --argc; /* skip hostname */
-
-       if (argc==0) goto errmsg;
-       port = atoi(argv[0]);
-       ++argv; --argc; /* skip port */

 
 

-       if (argc==0) goto errmsg;
-       nbddev = argv[0];

        nbd = open(nbddev, O_RDWR);
        if (nbd < 0)
          err("Cannot open NBD: %m\nPlease ensure the 'nbd' module is loaded.");
        ++argv; --argc; /* skip device */
 
        nbd = open(nbddev, O_RDWR);
        if (nbd < 0)
          err("Cannot open NBD: %m\nPlease ensure the 'nbd' module is loaded.");
        ++argv; --argc; /* skip device */
 

-       if (argc>4) goto errmsg;
-       for(i=0; i<4; i++) {
-               if (argc) {
-                       if(strncmp(argv[0], "-swap", 5)==0) {
-                               swap=1;
-                               ++argv;--argc;
-                       }
-               }
-               if (argc) {
-                       if(strncmp(argv[0], "-persist", 8)==0) {
-                               cont=1;
-                               ++argv;--argc;
-                       }
-               }
-               if (argc) {
-                       if(strncmp(argv[0], "-sdp", 4)==0) {
-                               sdp=1;
-                               ++argv;--argc;
-                       }
-               }
-               if (argc) {
-                       if(strncmp(argv[0], "-nofork", 7)==0) {
-                               nofork=1;
-                               ++argv;--argc;
-                       }
-               }
-       }
-       if(argc) goto errmsg;

        sock = opennet(hostname, port, sdp);
        sock = opennet(hostname, port, sdp);

-       argv=NULL; argc=0; /* don't use it later suddenly */

 
        negotiate(sock, &size64, &flags);
        setsizes(nbd, size64, blocksize, flags);
 
        negotiate(sock, &size64, &flags);
        setsizes(nbd, size64, blocksize, flags);