r332: open() the device upon connecting after a fork(), so that the partition table...

[nbd.git] / nbd-client.c

diff --git a/nbd-client.c b/nbd-client.c
index f4836c5..4df2281 100644 (file)
--- a/nbd-client.c
+++ b/nbd-client.c
@@ -28,6 +28,7 @@
 #include <syslog.h>
 #include <stdlib.h>
 #include <sys/mount.h>
+#include <errno.h>
 
 #ifndef __GNUC__
 #error I need GCC to work
@@ -37,20 +38,50 @@
 #define MY_NAME "nbd_client"
 #include "cliserv.h"
 
-int opennet(char *name, int port) {
+int check_conn(char* devname, int do_print) {
+       char buf[256];
+       int fd;
+       int len;
+       if(!strncmp(devname, "/dev/", 5)) {
+               devname+=5;
+       }
+       snprintf(buf, 256, "/sys/block/%s/pid", devname);
+       if((fd=open(buf, O_RDONLY))<0) {
+               if(errno==ENOENT) {
+                       return 1;
+               } else {
+                       return 2;
+               }
+       }
+       len=read(fd, buf, 256);
+       buf[len-1]='\0';
+       if(do_print) printf("%s\n", buf);
+       return 0;
+}
+
+int opennet(char *name, int port, int sdp) {
        int sock;
        struct sockaddr_in xaddrin;
        int xaddrinlen = sizeof(xaddrin);
        struct hostent *hostn;
+       int af;
 
        hostn = gethostbyname(name);
        if (!hostn)
                err("Gethostname failed: %h\n");
 
-       if ((sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0)
+       af = AF_INET;
+       if(sdp) {
+#ifdef WITH_SDP
+               af = AF_INET_SDP;
+#else
+               err("Can't do SDP: I was not compiled with SDP support!");
+#endif
+       }
+       if ((sock = socket(af, SOCK_STREAM, IPPROTO_TCP)) < 0)
                err("Socket failed: %m");
 
-       xaddrin.sin_family = AF_INET;
+       xaddrin.sin_family = af;
        xaddrin.sin_port = htons(port);
        xaddrin.sin_addr.s_addr = *((int *) hostn->h_addr);
        if ((connect(sock, (struct sockaddr *) &xaddrin, xaddrinlen) < 0))
@@ -140,6 +171,16 @@ void setsizes(int nbd, u64 size64, int blocksize, u32 flags) {
                err("Unable to set read-only attribute for device");
 }
 
+void set_timeout(int nbd, int timeout) {
+#ifdef NBD_SET_TIMEOUT
+       if (timeout) {
+               if (ioctl(nbd, NBD_SET_TIMEOUT, (unsigned long)timeout) < 0)
+                       err("Ioctl NBD_SET_TIMEOUT failed: %m\n");
+               fprintf(stderr, "timeout=%d\n", timeout);
+       }
+#endif
+}
+
 void finish_sock(int sock, int nbd, int swap) {
        if (ioctl(nbd, NBD_SET_SOCK, sock) < 0)
                err("Ioctl NBD_SET_SOCK failed: %m\n");
@@ -160,6 +201,8 @@ int main(int argc, char *argv[]) {
        char *hostname, *nbddev;
        int swap=0;
        int cont=0;
+       int timeout=0;
+       int sdp=0;
        u64 size64;
        u32 flags;
 
@@ -168,8 +211,9 @@ int main(int argc, char *argv[]) {
        if (argc < 3) {
        errmsg:
                fprintf(stderr, "nbd-client version %s\n", PACKAGE_VERSION);
-               fprintf(stderr, "Usage: nbd-client [bs=blocksize] host port nbd_device [-swap] [-persist]\n");
+               fprintf(stderr, "Usage: nbd-client [bs=blocksize] [timeout=sec] host port nbd_device [-swap] [-persist]\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");
@@ -200,12 +244,20 @@ int main(int argc, char *argv[]) {
                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 */
        }
 
+       if (strncmp(argv[0], "timeout=", 8)==0) {
+               timeout=atoi(argv[0]+8);
+               ++argv; --argc; /* skip timeout */
+       }
+       
        if (argc==0) goto errmsg;
        hostname=argv[0];
        ++argv; --argc; /* skip hostname */
@@ -215,41 +267,54 @@ int main(int argc, char *argv[]) {
        ++argv; --argc; /* skip port */
 
        if (argc==0) goto errmsg;
-       sock = opennet(hostname, port);
        nbddev = argv[0];
        nbd = open(nbddev, O_RDWR);
        if (nbd < 0)
          err("Can not open NBD: %m");
        ++argv; --argc; /* skip device */
 
-       if (argc>2) goto errmsg;
-       if (argc!=0) {
+       if (argc>3) goto errmsg;
+       if (argc) {
                if(strncmp(argv[0], "-swap", 5)==0) {
                        swap=1;
                        ++argv;--argc;
                }
        }
-       if (argc!=0) {
+       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) goto errmsg;
+       sock = opennet(hostname, port, sdp);
        argv=NULL; argc=0; /* don't use it later suddenly */
 
        negotiate(sock, &size64, &flags);
        setsizes(nbd, size64, blocksize, flags);
+       set_timeout(nbd, timeout);
        finish_sock(sock, nbd, swap);
 
        /* Go daemon */
        
        chdir("/");
+       do {
 #ifndef NOFORK
-       if (fork())
-               exit(0);
+               if (fork()) {
+                       while(check_conn(nbddev, 0)) {
+                               sleep(1);
+                       }
+                       open(nbddev, O_RDONLY);
+                       exit(0);
+               }
 #endif
 
-       do {
                if (ioctl(nbd, NBD_DO_IT) < 0) {
                        fprintf(stderr, "Kernel call returned: %m");
                        if(errno==EBADR) {
@@ -263,7 +328,7 @@ int main(int argc, char *argv[]) {
 
                                        fprintf(stderr, " Reconnecting\n");
                                        close(sock); close(nbd);
-                                       sock = opennet(hostname, port);
+                                       sock = opennet(hostname, port, sdp);
                                        nbd = open(nbddev, O_RDWR);
                                        negotiate(sock, &new_size, &new_flags);
                                        if (size64 != new_size) {
@@ -272,6 +337,7 @@ int main(int argc, char *argv[]) {
                                        setsizes(nbd, size64, blocksize,
                                                                new_flags);
 
+                                       set_timeout(nbd, timeout);
                                        finish_sock(sock,nbd,swap);
                                }
                        }