sys/src/libc/9sys/dial.c

   1 #include <u.h>
   2 #include <libc.h>
   3
   4 typedef struct DS DS;
   5
   6 static int      call(char*, char*, char*, DS*);
   7 static int      csdial(DS*);
   8 static void     _dial_string_parse(char*, DS*);
   9
  10 enum
  11 {
  12         Maxstring       = 128,
  13         Maxpath         = 256,
  14 };
  15
  16 struct DS {
  17         /* dist string */
  18         char    buf[Maxstring];
  19         char    *netdir;
  20         char    *proto;
  21         char    *rem;
  22
  23         /* other args */
  24         char    *local;
  25         char    *dir;
  26         int     *cfdp;
  27 };
  28
  29
  30 /*
  31  *  the dialstring is of the form '[/net/]proto!dest'
  32  */
  33 int
  34 dial(char *dest, char *local, char *dir, int *cfdp)
  35 {
  36         DS ds;
  37         int rv;
  38         char err[ERRMAX];
  39
  40         ds.local = local;
  41         ds.dir = dir;
  42         ds.cfdp = cfdp;
  43
  44         _dial_string_parse(dest, &ds);
  45         if(ds.netdir)
  46                 return csdial(&ds);
  47
  48         ds.netdir = "/net";
  49         rv = csdial(&ds);
  50         if(rv >= 0)
  51                 return rv;
  52         *err = 0;
  53         errstr(err, sizeof err);
  54         if(strcmp(err, "interrupted") == 0 || strstr(err, "refused") != nil){
  55                 errstr(err, sizeof err);
  56                 return rv;
  57         }
  58
  59         ds.netdir = "/net.alt";
  60         rv = csdial(&ds);
  61         if(rv >= 0)
  62                 return rv;
  63         errstr(err, sizeof err);
  64         if(strstr(err, "translate") == nil && strstr(err, "does not exist") == nil)
  65                 errstr(err, sizeof err);
  66         return rv;
  67 }
  68
  69 static int
  70 csdial(DS *ds)
  71 {
  72         int n, fd, rv;
  73         char *rem, *loc, buf[Maxstring], clone[Maxpath], err[ERRMAX];
  74
  75         /*
  76          *  open connection server
  77          */
  78         snprint(buf, sizeof(buf), "%s/cs", ds->netdir);
  79         fd = open(buf, ORDWR);
  80         if(fd < 0){
  81                 /* no connection server, don't translate */
  82                 snprint(clone, sizeof(clone), "%s/%s/clone", ds->netdir, ds->proto);
  83                 return call(clone, ds->rem, ds->local, ds);
  84         }
  85
  86         /*
  87          *  ask connection server to translate
  88          */
  89         snprint(buf, sizeof(buf), "%s!%s", ds->proto, ds->rem);
  90         if(write(fd, buf, strlen(buf)) < 0){
  91                 close(fd);
  92                 return -1;
  93         }
  94
  95         /*
  96          *  loop through each address from the connection server till
  97          *  we get one that works.
  98          */
  99         rv = -1;
 100         *err = 0;
 101         seek(fd, 0, 0);
 102         while((n = read(fd, buf, sizeof(buf) - 1)) > 0){
 103                 buf[n] = 0;
 104                 rem = strchr(buf, ' ');
 105                 if(rem == nil)
 106                         continue;
 107                 *rem++ = 0;
 108                 loc = strchr(rem, ' ');
 109                 if(loc != nil)
 110                         *loc++ = 0;
 111                 rv = call(buf, rem, ds->local!=nil? ds->local: loc, ds);
 112                 if(rv >= 0)
 113                         break;
 114                 errstr(err, sizeof err);
 115                 if(strcmp(err, "interrupted") == 0)
 116                         break;
 117                 if(strstr(err, "does not exist") != nil)
 118                         errstr(err, sizeof err);        /* get previous error back */
 119         }
 120         close(fd);
 121
 122         /* restore errstr if any */
 123         if(rv < 0 && *err)
 124                 errstr(err, sizeof err);
 125
 126         return rv;
 127 }
 128
 129 static int
 130 call(char *clone, char *remote, char *local, DS *ds)
 131 {
 132         int fd, cfd, n;
 133         char cname[Maxpath], name[Maxpath], data[Maxpath], *p;
 134
 135         /* because cs is in a different name space, replace the mount point */
 136         if(*clone == '/' || *clone == '#'){
 137                 p = strchr(clone+1, '/');
 138                 if(p == nil)
 139                         p = clone;
 140                 else
 141                         p++;
 142         } else
 143                 p = clone;
 144         snprint(cname, sizeof cname, "%s/%s", ds->netdir, p);
 145
 146         cfd = open(cname, ORDWR);
 147         if(cfd < 0)
 148                 return -1;
 149
 150         /* get directory name */
 151         n = read(cfd, name, sizeof(name)-1);
 152         if(n < 0){
 153                 close(cfd);
 154                 return -1;
 155         }
 156         name[n] = 0;
 157         for(p = name; *p == ' '; p++)
 158                 ;
 159         snprint(name, sizeof(name), "%ld", strtoul(p, 0, 0));
 160         p = strrchr(cname, '/');
 161         *p = 0;
 162         if(ds->dir)
 163                 snprint(ds->dir, NETPATHLEN, "%s/%s", cname, name);
 164         snprint(data, sizeof(data), "%s/%s/data", cname, name);
 165
 166         /* connect */
 167         if(local != nil)
 168                 snprint(name, sizeof(name), "connect %s %s", remote, local);
 169         else
 170                 snprint(name, sizeof(name), "connect %s", remote);
 171         if(write(cfd, name, strlen(name)) < 0){
 172                 close(cfd);
 173                 return -1;
 174         }
 175
 176         /* open data connection */
 177         fd = open(data, ORDWR);
 178         if(fd < 0){
 179                 close(cfd);
 180                 return -1;
 181         }
 182         if(ds->cfdp)
 183                 *ds->cfdp = cfd;
 184         else
 185                 close(cfd);
 186         return fd;
 187 }
 188
 189 /*
 190  *  parse a dial string
 191  */
 192 static void
 193 _dial_string_parse(char *str, DS *ds)
 194 {
 195         char *p, *p2;
 196
 197         strncpy(ds->buf, str, Maxstring);
 198         ds->buf[Maxstring-1] = 0;
 199
 200         p = strchr(ds->buf, '!');
 201         if(p == 0) {
 202                 ds->netdir = 0;
 203                 ds->proto = "net";
 204                 ds->rem = ds->buf;
 205         } else {
 206                 p2 = ds->buf;
 207                 if(*p2 == '#'){
 208                         p2 = strchr(p2, '/');
 209                         if(p2 == nil || p2 > p)
 210                                 p2 = ds->buf;
 211                 }
 212                 if(*p2 != '/'){
 213                         ds->netdir = 0;
 214                         ds->proto = ds->buf;
 215                 } else {
 216                         for(p2 = p; *p2 != '/'; p2--)
 217                                 ;
 218                         *p2++ = 0;
 219                         ds->netdir = ds->buf;
 220                         ds->proto = p2;
 221                 }
 222                 *p = 0;
 223                 ds->rem = p + 1;
 224         }
 225 }