cpp buffer overflow on long lines

[drh]

---------- Forwarded message ---------
From: nikonsmith [email protected]
Date: Mon, Jul 20, 2015 at 10:49 PM
Subject: lcc's cpp bug
To: [email protected] [email protected]

cpp bug:

when I compile a c source file which have a line that much than 32KB, it then print `Input buffer overflow' and exit process.

for example, I write a program generate a c source file that 100KB in one line,as follow:

/* generate.c */

include <stdio.h>

int code_len = 100*1024; // 100KB c source code

int main(void) {
char *str="int a%04d=10;";
int str_len = 13;
int str_nr = code_len / str_len;
int i;
for(i=0;i<str_nr;i++) {
printf(str,i);
}
printf("\nint main(void) { return 0; }\n");
return 0;
}

$ ./generate > 100k.c

$ lcc -v 100k.c
cpp: 100k.c:1 Input buffer overflow

[rofl0r]

according to posix: http://pubs.opengroup.org/onlinepubs/009695399/basedefs/limits.h.html

<limits.h>
{LINE_MAX}
    Unless otherwise noted, the maximum length, in bytes, of a utility's input line (either standard input or another file), when the utility is described as processing text files. The length includes room for the trailing <newline>.
    Minimum Acceptable Value: {_POSIX2_LINE_MAX}

so a C file with 100KB line length is not a valid textfile (LINE_MAX is typically 4KB).