[PHP-DEV] PHP 4.0 Bug #6913 Updated: wrong use of C language, serious bug! From: Bug Database (php-dev <email protected>)
Date: 09/27/00

ID: 6913
User Update by: melchers <email protected>
Status: Open
Bug Type: Sockets related
Description: wrong use of C language, serious bug!

i don't find this line in the php-3.x series,
although socket communication is not possible
in irix: fgets() never returns as long as
the other side keeps the socket open and
php is blocked by waiting for data.
The above error can trivially fixed by writing:
int ii;
if ((ii = FP_FGETC(socketd, (FILE*)what, issock)) == EOF) {
  *buf = ii;
  ...
} else {
  *buf = ii;
  ...
}

Previous Comments:
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[2000-09-27 21:47:32] melchers <email protected>
file ext/standard/file.c contains the line:
        if ((*buf = FP_FGETC(socketd, (FILE*)what, issock)) == EOF) {
this is a _serious_ bug, since on _all_ machine architectures where the data type
 "char" defaults to unsigned, the return value of FP_FGETC() is converted to
unsigned, before it is compared to EOF. Since EOF is defined as (-1), the
comparison _never_ succedds. This makes any usage of sockets and file-I/O
on "unsigned char" architectures impossible. As far as i remember, the bug
occurs in all php versions, i.e. 3.x and 4.x.

my page for fgetc(3) says:

WARNING
     If the integer value returned by getc, getchar, or fgetc is stored into a
     character variable and then compared against the integer constant EOF,
     the comparison may never succeed, because sign-extension of a character
     on widening to integer is machine-dependent.

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Full Bug description available at: http://bugs.php.net/?id=6913 

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