ref: fa82522b69ea663dd2ac48018de4415c96bd734f
dir: /sys/src/libndb/csgetval.c/
#include <u.h> #include <libc.h> #include <bio.h> #include <ndb.h> #include <ndbhf.h> /* * search for a tuple that has the given 'attr=val' and also 'rattr=x'. * copy 'x' into 'buf' and return the whole tuple. * * return 0 if not found. */ char* csgetvalue(char *netroot, char *attr, char *val, char *rattr, Ndbtuple **pp) { Ndbtuple *t, *first, *last; int n, linefound; char line[1024]; int fd; int oops = 0; char *rv; if(pp) *pp = nil; rv = nil; if(netroot) snprint(line, sizeof(line), "%s/cs", netroot); else strcpy(line, "/net/cs"); fd = open(line, ORDWR); if(fd < 0) return 0; seek(fd, 0, 0); snprint(line, sizeof(line), "!%s=%s %s=*", attr, val, rattr); if(write(fd, line, strlen(line)) < 0){ close(fd); return 0; } seek(fd, 0, 0); first = last = 0; linefound = 0; for(;;){ n = read(fd, line, sizeof(line)-2); if(n <= 0) break; line[n] = '\n'; line[n+1] = 0; t = _ndbparseline(line); if(t == 0) continue; if(first) last->entry = t; else first = t; last = t; while(last->entry) last = last->entry; for(; t; t = t->entry){ if(linefound == 0){ if(strcmp(rattr, t->attr) == 0){ linefound = 1; rv = strdup(t->val); } } } } close(fd); if(oops){ werrstr("buffer too short"); ndbfree(first); return nil; } if(pp){ setmalloctag(first, getcallerpc(&netroot)); *pp = first; } else ndbfree(first); return rv; } Ndbtuple* csgetval(char *netroot, char *attr, char *val, char *rattr, char *buf) { Ndbtuple *t; char *p; p = csgetvalue(netroot, attr, val, rattr, &t); if(p == nil){ if(buf != nil) *buf = 0; } else { if(buf != nil){ strncpy(buf, p, Ndbvlen-1); buf[Ndbvlen-1] = 0; } free(p); } ndbsetmalloctag(t, getcallerpc(&netroot)); return t; }