mirror of
https://github.com/9fans/plan9port.git
synced 2025-01-12 11:10:07 +00:00
107 lines
1.7 KiB
C
107 lines
1.7 KiB
C
#include <u.h>
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#include <libc.h>
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#include <bio.h>
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#include <ndb.h>
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#include <ndbhf.h>
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/*
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* search for a tuple that has the given 'attr=val' and also 'rattr=x'.
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* copy 'x' into 'buf' and return the whole tuple.
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*
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* return 0 if not found.
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*/
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char*
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csgetvalue(char *netroot, char *attr, char *val, char *rattr, Ndbtuple **pp)
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{
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Ndbtuple *t, *first, *last;
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int n, linefound;
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char line[1024];
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int fd;
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int oops = 0;
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char *rv;
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if(pp)
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*pp = nil;
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rv = nil;
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if(netroot)
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snprint(line, sizeof(line), "%s/cs", netroot);
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else
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strcpy(line, "/net/cs");
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fd = open(line, ORDWR);
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if(fd < 0)
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return 0;
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seek(fd, 0, 0);
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snprint(line, sizeof(line), "!%s=%s %s=*", attr, val, rattr);
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if(write(fd, line, strlen(line)) < 0){
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close(fd);
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return 0;
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}
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seek(fd, 0, 0);
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first = last = 0;
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linefound = 0;
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for(;;){
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n = read(fd, line, sizeof(line)-2);
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if(n <= 0)
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break;
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line[n] = '\n';
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line[n+1] = 0;
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t = _ndbparseline(line);
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if(t == 0)
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continue;
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if(first)
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last->entry = t;
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else
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first = t;
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last = t;
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while(last->entry)
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last = last->entry;
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for(; t; t = t->entry){
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if(linefound == 0){
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if(strcmp(rattr, t->attr) == 0){
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linefound = 1;
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rv = strdup(t->val);
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}
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}
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}
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}
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close(fd);
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if(oops){
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werrstr("buffer too short");
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ndbfree(first);
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return nil;
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}
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if(pp){
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setmalloctag(first, getcallerpc(&netroot));
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*pp = first;
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} else
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ndbfree(first);
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return rv;
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}
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Ndbtuple*
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csgetval(char *netroot, char *attr, char *val, char *rattr, char *buf)
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{
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Ndbtuple *t;
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char *p;
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p = csgetvalue(netroot, attr, val, rattr, &t);
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if(p == nil){
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if(buf != nil)
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*buf = 0;
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} else {
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if(buf != nil){
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strncpy(buf, p, Ndbvlen-1);
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buf[Ndbvlen-1] = 0;
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}
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free(p);
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}
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return t;
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}
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