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- /*
- * dial - connect to a service (threaded parallel version)
- */
- #include <u.h>
- #include <libc.h>
- #include <ctype.h>
- #include <fcall.h>
- #include <thread.h>
- #include <9p.h>
- typedef struct Conn Conn;
- typedef struct Dest Dest;
- typedef struct DS DS;
- typedef struct Kidargs Kidargs;
- typedef struct Restup Restup;
- enum
- {
- Noblock,
- Block,
- Defstksize = 8192,
- Maxstring = 128,
- Maxpath = 256,
- Maxcsreply = 64*80, /* this is probably overly generous */
- /*
- * this should be a plausible slight overestimate for non-interactive
- * use even if it's ridiculously long for interactive use.
- */
- Maxconnms = 2*60*1000, /* 2 minutes */
- };
- struct DS {
- /* dial string */
- char buf[Maxstring];
- char *netdir;
- char *proto;
- char *rem;
- /* other args */
- char *local;
- char *dir;
- int *cfdp;
- };
- struct Conn {
- int cfd;
- char dir[NETPATHLEN+1];
- };
- struct Dest {
- DS *ds;
- Channel *reschan; /* all callprocs send results on this */
- int nkid;
- int kidthrids[64]; /* one per addr; ought to be enough */
- int windfd;
- char err[ERRMAX];
- long oalarm;
- int naddrs;
- char *nextaddr;
- char addrlist[Maxcsreply];
- };
- struct Kidargs { /* arguments to callproc */
- Dest *dp;
- int thridsme;
- char *clone;
- char *dest;
- };
- struct Restup { /* result tuple from callproc */
- int dfd;
- int cfd;
- char *err;
- char *conndir;
- };
- static int call(char*, char*, Dest*, Conn*);
- static int call1(char*, char*, Dest*, Conn*);
- static int csdial(DS*);
- static void _dial_string_parse(char*, DS*);
- /*
- * the dialstring is of the form '[/net/]proto!dest'
- */
- static int
- dialimpl(char *dest, char *local, char *dir, int *cfdp)
- {
- DS ds;
- int rv;
- char err[ERRMAX], alterr[ERRMAX];
- ds.local = local;
- ds.dir = dir;
- ds.cfdp = cfdp;
- _dial_string_parse(dest, &ds);
- if(ds.netdir)
- return csdial(&ds);
- ds.netdir = "/net";
- rv = csdial(&ds);
- if(rv >= 0)
- return rv;
- err[0] = '\0';
- errstr(err, sizeof err);
- if(strstr(err, "refused") != 0){
- werrstr("%s", err);
- return rv;
- }
- ds.netdir = "/net.alt";
- rv = csdial(&ds);
- if(rv >= 0)
- return rv;
- alterr[0] = 0;
- errstr(alterr, sizeof alterr);
- if(strstr(alterr, "translate") || strstr(alterr, "does not exist"))
- werrstr("%s", err);
- else
- werrstr("%s", alterr);
- return rv;
- }
- /*
- * the thread library can't cope with rfork(RFMEM|RFPROC),
- * so it must override _dial with this version of dial.
- */
- int (*_dial)(char *, char *, char *, int *) = dialimpl;
- int
- dial(char *dest, char *local, char *dir, int *cfdp)
- {
- return (*_dial)(dest, local, dir, cfdp);
- }
- static void
- freedest(Dest *dp)
- {
- if (dp) {
- if (dp->oalarm >= 0)
- alarm(dp->oalarm);
- free(dp);
- }
- }
- static void
- closeopenfd(int *fdp)
- {
- if (*fdp >= 0) {
- close(*fdp);
- *fdp = -1;
- }
- }
- static int
- parsecs(Dest *dp, char **clonep, char **destp)
- {
- char *dest, *p;
- dest = strchr(dp->nextaddr, ' ');
- if(dest == nil)
- return -1;
- *dest++ = '\0';
- p = strchr(dest, '\n');
- if(p == nil)
- return -1;
- *p++ = '\0';
- *clonep = dp->nextaddr;
- *destp = dest;
- dp->nextaddr = p; /* advance to next line */
- return 0;
- }
- static void
- pickuperr(char *besterr)
- {
- char err[ERRMAX];
- err[0] = '\0';
- errstr(err, ERRMAX);
- if(strstr(err, "does not exist") == 0)
- strcpy(besterr, err);
- }
- static int
- catcher(void *, char *s)
- {
- return strstr(s, "alarm") != nil;
- }
- static void
- callproc(void *p)
- {
- int dfd;
- char besterr[ERRMAX];
- Conn lconn;
- Conn *conn;
- Kidargs *args;
- Restup *tup;
- threadnotify(catcher, 1); /* avoid atnotify callbacks in parent */
- conn = &lconn;
- memset(conn, 0, sizeof *conn);
- *besterr = '\0';
- args = (Kidargs *)p;
- dfd = call(args->clone, args->dest, args->dp, conn);
- if(dfd < 0)
- pickuperr(besterr);
- tup = (Restup *)emalloc9p(sizeof *tup);
- *tup = (Restup){dfd, conn->cfd, nil, nil};
- if (dfd >= 0)
- tup->conndir = strdup(conn->dir);
- else
- tup->err = strdup(besterr);
- sendp(args->dp->reschan, tup);
- args->dp->kidthrids[args->thridsme] = -1;
- free(args);
- threadexits(besterr); /* better be no atexit callbacks */
- }
- /* interrupt all of our still-live kids */
- static void
- intrcallprocs(Dest *dp)
- {
- int i;
- for (i = 0; i < nelem(dp->kidthrids); i++)
- if (dp->kidthrids[i] >= 0)
- threadint(dp->kidthrids[i]);
- }
- static int
- recvresults(Dest *dp, int block)
- {
- DS *ds;
- Restup *tup;
- for (; dp->nkid > 0; dp->nkid--) {
- if (block)
- tup = recvp(dp->reschan);
- else
- tup = nbrecvp(dp->reschan);
- if (tup == nil)
- break;
- if (tup->dfd >= 0) /* connected? */
- if (dp->windfd < 0) { /* first connection? */
- ds = dp->ds;
- dp->windfd = tup->dfd;
- if (ds->cfdp)
- *ds->cfdp = tup->cfd;
- if (ds->dir) {
- strncpy(ds->dir, tup->conndir,
- NETPATHLEN);
- ds->dir[NETPATHLEN] = '\0';
- }
- intrcallprocs(dp);
- } else {
- close(tup->dfd);
- close(tup->cfd);
- }
- else if (dp->err[0] == '\0' && tup->err) {
- strncpy(dp->err, tup->err, ERRMAX - 1);
- dp->err[ERRMAX - 1] = '\0';
- }
- free(tup->conndir);
- free(tup->err);
- free(tup);
- }
- return dp->windfd;
- }
- /*
- * try all addresses in parallel and take the first one that answers;
- * this helps when systems have ip v4 and v6 addresses but are
- * only reachable from here on one (or some) of them.
- */
- static int
- dialmulti(Dest *dp)
- {
- int kidme;
- char *clone, *dest;
- Kidargs *argp;
- dp->reschan = chancreate(sizeof(void *), 0);
- dp->err[0] = '\0';
- dp->nkid = 0;
- dp->windfd = -1;
- /* if too many addresses for dp->kidthrids, ignore the last few */
- while(dp->windfd < 0 && dp->nkid < nelem(dp->kidthrids) &&
- *dp->nextaddr != '\0' && parsecs(dp, &clone, &dest) >= 0) {
- kidme = dp->nkid++;
- argp = (Kidargs *)emalloc9p(sizeof *argp);
- *argp = (Kidargs){dp, kidme, clone, dest};
- dp->kidthrids[kidme] = proccreate(callproc, argp, Defstksize);
- if (dp->kidthrids[kidme] < 0)
- --dp->nkid;
- }
- recvresults(dp, Block);
- assert(dp->nkid == 0);
- chanclose(dp->reschan);
- chanfree(dp->reschan);
- if(dp->windfd < 0 && dp->err[0])
- werrstr("%s", dp->err);
- return dp->windfd;
- }
- /* call a single address and pass back cfd & conn dir after */
- static int
- call1(char *clone, char *rem, Dest *dp, Conn *conn)
- {
- int dfd;
- DS *ds;
- ds = dp->ds;
- dfd = call(clone, rem, dp, conn);
- if (dfd < 0)
- return dfd;
- if (ds->cfdp)
- *ds->cfdp = conn->cfd;
- if (ds->dir) {
- strncpy(ds->dir, conn->dir, NETPATHLEN);
- ds->dir[NETPATHLEN] = '\0';
- }
- return dfd;
- }
- static int
- csdial(DS *ds)
- {
- int n, fd, dfd, addrs, bleft;
- char c;
- char *addrp, *clone2, *dest;
- char buf[Maxstring], clone[Maxpath], besterr[ERRMAX];
- Conn lconn;
- Conn *conn;
- Dest *dp;
- dp = mallocz(sizeof *dp, 1);
- if(dp == nil)
- return -1;
- conn = &lconn;
- memset(conn, 0, sizeof *conn);
- dp->ds = ds;
- if (ds->cfdp)
- *ds->cfdp = -1;
- if (ds->dir)
- ds->dir[0] = '\0';
- dp->oalarm = alarm(0);
- /*
- * open connection server
- */
- snprint(buf, sizeof(buf), "%s/cs", ds->netdir);
- fd = open(buf, ORDWR);
- if(fd < 0){
- /* no connection server, don't translate */
- snprint(clone, sizeof(clone), "%s/%s/clone", ds->netdir, ds->proto);
- dfd = call1(clone, ds->rem, dp, conn);
- freedest(dp);
- return dfd;
- }
- /*
- * ask connection server to translate
- */
- snprint(buf, sizeof(buf), "%s!%s", ds->proto, ds->rem);
- if(write(fd, buf, strlen(buf)) < 0){
- close(fd);
- freedest(dp);
- return -1;
- }
- /*
- * read all addresses from the connection server.
- */
- seek(fd, 0, 0);
- addrs = 0;
- addrp = dp->nextaddr = dp->addrlist;
- bleft = sizeof dp->addrlist - 2; /* 2 is room for \n\0 */
- while(bleft > 0 && (n = read(fd, addrp, bleft)) > 0) {
- if (addrp[n-1] != '\n')
- addrp[n++] = '\n';
- addrs++;
- addrp += n;
- bleft -= n;
- }
- /*
- * if we haven't read all of cs's output, assume the last line might
- * have been truncated and ignore it. we really don't expect this
- * to happen.
- */
- if (addrs > 0 && bleft <= 0 && read(fd, &c, 1) == 1)
- addrs--;
- close(fd);
- *besterr = 0;
- dfd = -1; /* pessimistic default */
- dp->naddrs = addrs;
- if (addrs == 0)
- werrstr("no address to dial");
- else if (addrs == 1) {
- /* common case: dial one address without forking */
- if (parsecs(dp, &clone2, &dest) >= 0 &&
- (dfd = call1(clone2, dest, dp, conn)) < 0) {
- pickuperr(besterr);
- werrstr("%s", besterr);
- }
- } else
- dfd = dialmulti(dp);
- freedest(dp);
- return dfd;
- }
- /* returns dfd, stores cfd through cfdp */
- static int
- call(char *clone, char *dest, Dest *dp, Conn *conn)
- {
- int fd, cfd, n, calleralarm, oalarm;
- char cname[Maxpath], name[Maxpath], data[Maxpath], *p;
- DS *ds;
- /* because cs is in a different name space, replace the mount point */
- if(*clone == '/'){
- p = strchr(clone+1, '/');
- if(p == nil)
- p = clone;
- else
- p++;
- } else
- p = clone;
- ds = dp->ds;
- snprint(cname, sizeof cname, "%s/%s", ds->netdir, p);
- conn->cfd = cfd = open(cname, ORDWR);
- if(cfd < 0)
- return -1;
- /* get directory name */
- n = read(cfd, name, sizeof(name)-1);
- if(n < 0){
- closeopenfd(&conn->cfd);
- return -1;
- }
- name[n] = 0;
- for(p = name; *p == ' '; p++)
- ;
- snprint(name, sizeof(name), "%ld", strtoul(p, 0, 0));
- p = strrchr(cname, '/');
- *p = 0;
- if(ds->dir)
- snprint(conn->dir, NETPATHLEN, "%s/%s", cname, name);
- snprint(data, sizeof(data), "%s/%s/data", cname, name);
- /* should be no alarm pending now; re-instate caller's alarm, if any */
- calleralarm = dp->oalarm > 0;
- if (calleralarm)
- alarm(dp->oalarm);
- else if (dp->naddrs > 1) /* in a sub-process? */
- alarm(Maxconnms);
- /* connect */
- if(ds->local)
- snprint(name, sizeof(name), "connect %s %s", dest, ds->local);
- else
- snprint(name, sizeof(name), "connect %s", dest);
- if(write(cfd, name, strlen(name)) < 0){
- closeopenfd(&conn->cfd);
- return -1;
- }
- oalarm = alarm(0); /* don't let alarm interrupt critical section */
- if (calleralarm)
- dp->oalarm = oalarm; /* time has passed, so update user's */
- /* open data connection */
- fd = open(data, ORDWR);
- if(fd < 0){
- closeopenfd(&conn->cfd);
- alarm(dp->oalarm);
- return -1;
- }
- if(ds->cfdp == nil)
- closeopenfd(&conn->cfd);
- alarm(calleralarm? dp->oalarm: 0);
- return fd;
- }
- /*
- * assume p points at first '!' in dial string. st is start of dial string.
- * there could be subdirs of the conn dirs (e.g., ssh/0) that must count as
- * part of the proto string, so skip numeric components.
- * returns pointer to delimiter after right-most non-numeric component.
- */
- static char *
- backoverchans(char *st, char *p)
- {
- char *sl;
- for (sl = p; --p >= st && isascii(*p) && isdigit(*p); sl = p) {
- while (--p >= st && isascii(*p) && isdigit(*p))
- ;
- if (p < st || *p != '/')
- break; /* "net.alt2" or ran off start */
- while (p > st && p[-1] == '/') /* skip runs of slashes */
- p--;
- }
- return sl;
- }
- /*
- * parse a dial string
- */
- static void
- _dial_string_parse(char *str, DS *ds)
- {
- char *p, *p2;
- strncpy(ds->buf, str, Maxstring);
- ds->buf[Maxstring-1] = 0;
- p = strchr(ds->buf, '!');
- if(p == 0) {
- ds->netdir = 0;
- ds->proto = "net";
- ds->rem = ds->buf;
- } else {
- if(*ds->buf != '/' && *ds->buf != '#'){
- ds->netdir = 0;
- ds->proto = ds->buf;
- } else {
- p2 = backoverchans(ds->buf, p);
- /* back over last component of netdir (proto) */
- while (--p2 > ds->buf && *p2 != '/')
- ;
- *p2++ = 0;
- ds->netdir = ds->buf;
- ds->proto = p2;
- }
- *p = 0;
- ds->rem = p + 1;
- }
- }
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