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libc: improve dial error handling

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when dial is called with a generic dialstring, it will try
/net and /net.alt in sequence. error out if the /net dial
gets interrupted and do not continue dialing /net.alt.

reduce stack usage by using the swaping nature of errstr()
instead of keeping two error string buffers on the stack.
This commit is contained in:
cinap_lenrek 2014-11-07 08:10:19 +01:00
parent a0e001a234
commit 958d698bf8
1 changed files with 12 additions and 17 deletions
Download patch file Download diff file Expand all files Collapse all files

29
sys/src/libc/9sys/dial.c
View file

@ -35,7 +35,7 @@ dial(char *dest, char *local, char *dir, int *cfdp)
{ {
DS ds; DS ds;
int rv; int rv;
char err[ERRMAX], alterr[ERRMAX]; char err[ERRMAX];
ds.local = local; ds.local = local;
ds.dir = dir; ds.dir = dir;
@ -49,23 +49,20 @@ dial(char *dest, char *local, char *dir, int *cfdp)
rv = csdial(&ds); rv = csdial(&ds);
if(rv >= 0) if(rv >= 0)
return rv; return rv;
err[0] = '\0'; *err = 0;
errstr(err, sizeof err); errstr(err, sizeof err);
if(strstr(err, "refused") != 0){ if(strcmp(err, "interrupted") == 0 || strstr(err, "refused") != nil){
werrstr("%s", err); errstr(err, sizeof err);
return rv; return rv;
} }
ds.netdir = "/net.alt"; ds.netdir = "/net.alt";
rv = csdial(&ds); rv = csdial(&ds);
if(rv >= 0) if(rv >= 0)
return rv; return rv;
errstr(err, sizeof err);
alterr[0] = 0; if(strstr(err, "translate") == nil && strstr(err, "does not exist") == nil)
errstr(alterr, sizeof alterr); errstr(err, sizeof err);
if(strstr(alterr, "translate") || strstr(alterr, "does not exist"))
werrstr("%s", err);
else
werrstr("%s", alterr);
return rv; return rv;
} }
@ -73,7 +70,7 @@ static int
csdial(DS *ds) csdial(DS *ds)
{ {
int n, fd, rv; int n, fd, rv;
char *p, buf[Maxstring], clone[Maxpath], err[ERRMAX], besterr[ERRMAX]; char *p, buf[Maxstring], clone[Maxpath], err[ERRMAX];
/* /*
* open connection server * open connection server
@ -101,7 +98,6 @@ csdial(DS *ds)
*/ */
rv = -1; rv = -1;
*err = 0; *err = 0;
*besterr = 0;
seek(fd, 0, 0); seek(fd, 0, 0);
while((n = read(fd, buf, sizeof(buf) - 1)) > 0){ while((n = read(fd, buf, sizeof(buf) - 1)) > 0){
buf[n] = 0; buf[n] = 0;
@ -112,18 +108,17 @@ csdial(DS *ds)
rv = call(buf, p, ds); rv = call(buf, p, ds);
if(rv >= 0) if(rv >= 0)
break; break;
*err = 0;
errstr(err, sizeof err); errstr(err, sizeof err);
if(strcmp(err, "interrupted") == 0) if(strcmp(err, "interrupted") == 0)
break; break;
if(strstr(err, "does not exist") == 0) if(strstr(err, "does not exist") != nil)
strcpy(besterr, err); errstr(err, sizeof err); /* get previous error back */
} }
close(fd); close(fd);
/* restore errstr if any */ /* restore errstr if any */
if(rv < 0 && *err) if(rv < 0 && *err)
errstr(*besterr ? besterr : err, sizeof err); errstr(err, sizeof err);
return rv; return rv;
} }