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fincore: Handle large files on 32 bit without LFS 

If util-linux is installed on a system without large file support,
an out of memory issue can occur while processing a file which is
2 GB in size:

$ ./configure --disable-largefile && make

$ dd if=/dev/zero of=2gb-file seek=2147483646 count=1 bs=1
$ fincore 2gb-file
(endless loop)
fincore: failed to do mmap: 2gb-file: Cannot allocate memory

Even though iterating with "len" seems counter-intuitive, it fixes
this issue. The variable len is only in the last iteration not a
multiplication of pagesize -- which is the requirement for mmap.

Signed-off-by: Tobias Stoeckmann <tobias@stoeckmann.org>
This commit is contained in:
Tobias Stoeckmann 2018-02-25 20:27:59 +01:00 committed by Karel Zak
parent ea62c15276
commit fcfe1a5cde
1 changed files with 2 additions and 3 deletions
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5
misc-utils/fincore.c
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@ -194,12 +194,11 @@ static int fincore_fd (struct fincore_control *ctl,
off_t *count_incore)
{
size_t window_size = N_PAGES_IN_WINDOW * ctl->pagesize;
off_t file_offset;
off_t file_offset, len;
int rc = 0;
int warned_once = 0;
for (file_offset = 0; file_offset < file_size; file_offset += window_size) {
off_t len;
for (file_offset = 0; file_offset < file_size; file_offset += len) {
void *window = NULL;
len = file_size - file_offset;