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plumber: fix EOF detection on writes to rules file (#257)

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Instead of checking Fcall.data==nil, check Fcall.count==0.
The former check always fails after `gcc -O2` optimizations
(gcc version 8.3.0).

Also fix an out-of-bound read detected by valgrind:
```
==31162== Invalid read of size 1
==31162==    at 0x11005E: morerules (rules.c:739)
==31162==    by 0x110254: writerules (rules.c:775)
==31162==    by 0x10D2FE: fsyswrite (fsys.c:848)
==31162==    by 0x10C304: fsysproc (fsys.c:248)
==31162==    by 0x112E8C: threadstart (thread.c:96)
==31162==    by 0x4A682BF: ??? (in /usr/lib/libc-2.29.so)
==31162==  Address 0x4ea984a is 0 bytes after a block of size 250 alloc'd
==31162==    at 0x483AD7B: realloc (vg_replace_malloc.c:826)
==31162==    by 0x1196F3: p9realloc (malloc.c:53)
==31162==    by 0x10BDFD: erealloc (plumber.c:124)
==31162==    by 0x10FCD9: concat (rules.c:642)
==31162==    by 0x10FCD9: concat (rules.c:635)
==31162==    by 0x110230: writerules (rules.c:773)
==31162==    by 0x10D2FE: fsyswrite (fsys.c:848)
==31162==    by 0x10C304: fsysproc (fsys.c:248)
==31162==    by 0x112E8C: threadstart (thread.c:96)
==31162==    by 0x4A682BF: ??? (in /usr/lib/libc-2.29.so)
```

Fixes #256
This commit is contained in:
Fazlul Shahriar 2019-09-19 13:08:54 -04:00 committed by Dan Cross
parent 7d827b5cca
commit b9424f640a
1 changed files with 3 additions and 3 deletions
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6
src/cmd/plumb/rules.c
View file

@ -736,8 +736,8 @@ morerules(uchar *text, int done)
*/
endofrule = nil;
for(s=text; *s!='\0'; s++)
if(*s=='\n' && *++s=='\n')
endofrule = s+1;
if(*s=='\n' && *(s+1)=='\n')
endofrule = s+2;
if(endofrule == nil)
return text;
input->end = endofrule;
@ -772,7 +772,7 @@ writerules(char *s, int n)
tmp = stringof(s, n);
text = (uchar*)concat((char*)text, tmp);
free(tmp);
text = morerules(text, s==nil);
text = morerules(text, n==0);
}
if(s == nil){
free(text);