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With current pthread implementations, a mutex initialization will

Browse source 
allocate a memory block. sscanf calls __svfscanf which in turn calls
fread, fread triggers mutex initialization but the mutex is not
destroyed in sscanf, this leads to memory leak. To avoid the memory
leak and performance issue, we create a none MT-safe version of fread:
__fread, and instead let __svfscanf call __fread.

PR: threads/90392
Patch submitted by: dhartmei
MFC after: 7 days
This commit is contained in:
David Xu 2005-12-16 02:50:53 +00:00
parent 74a96f4337
commit 3b52e4d1b7
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=153467
3 changed files with 19 additions and 9 deletions
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23
lib/libc/stdio/fread.c
View file

@ -47,11 +47,23 @@ __FBSDID("$FreeBSD$");
#include "local.h"
#include "libc_private.h"
/*
* MT-safe version
*/
size_t
fread(buf, size, count, fp)
void * __restrict buf;
size_t size, count;
FILE * __restrict fp;
fread(void * __restrict buf, size_t size, size_t count, FILE * __restrict fp)
{
int ret;
FLOCKFILE(fp);
ret = __fread(buf, size, count, fp);
FUNLOCKFILE(fp);
return (ret);
}
size_t
__fread(void * __restrict buf, size_t size, size_t count, FILE * __restrict fp)
{
size_t resid;
char *p;
@ -65,7 +77,6 @@ fread(buf, size, count, fp)
*/
if ((resid = count * size) == 0)
return (0);
FLOCKFILE(fp);
ORIENT(fp, -1);
if (fp->_r < 0)
fp->_r = 0;
@ -79,13 +90,11 @@ fread(buf, size, count, fp)
resid -= r;
if (__srefill(fp)) {
/* no more input: return partial result */
FUNLOCKFILE(fp);
return ((total - resid) / size);
}
}
(void)memcpy((void *)p, (void *)fp->_p, resid);
fp->_r -= resid;
fp->_p += resid;
FUNLOCKFILE(fp);
return (count);
}

3
lib/libc/stdio/local.h
View file

@ -78,7 +78,8 @@ extern int __vfscanf(FILE *, const char *, __va_list);
extern int __vfwprintf(FILE *, const wchar_t *, __va_list);
extern int __vfwscanf(FILE * __restrict, const wchar_t * __restrict,
__va_list);
extern size_t __fread(void * __restrict buf, size_t size, size_t count,
FILE * __restrict fp);
extern int __sdidinit;

2
lib/libc/stdio/vfscanf.c
View file

@ -412,7 +412,7 @@ again: c = *fmt++;
}
nread += sum;
} else {
size_t r = fread((void *)va_arg(ap, char *), 1,
size_t r = __fread((void *)va_arg(ap, char *), 1,
width, fp);
if (r == 0)