If a file is larger than 4 GB on a 32 bit system with large file
support (default), it can happen that not all pages are properly
processed. This happens due to an int truncation (off_t vs size_t).
You can reproduce this on 32 bit with these commands:
$ dd if=/dev/zero of=4gb-file seek=4294967295 count=1 bs=1
$ fincore 4gb-file
fincore: failed to do mmap: 4gb-file: Invalid argument
If a file is larger than 4 GB, the first few pages of a file won't
be properly processed. "len" will be smaller than window_size,
but the for-loop iterates "window_size" bytes, skipping some pages.
Signed-off-by: Tobias Stoeckmann <tobias@xxxxxxxxxxxxxx>
---
misc-utils/fincore.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/misc-utils/fincore.c b/misc-utils/fincore.c
index 4641408f8..ab11594cc 100644
--- a/misc-utils/fincore.c
+++ b/misc-utils/fincore.c
@@ -199,11 +199,11 @@ static int fincore_fd (struct fincore_control *ctl,
int warned_once = 0;
for (file_offset = 0; file_offset < file_size; file_offset += window_size) {
- size_t len;
+ off_t len;
void *window = NULL;
len = file_size - file_offset;
- if (len >= window_size)
+ if (len >= (off_t) window_size)
len = window_size;
window = mmap(window, len, PROT_NONE, MAP_PRIVATE, fd, file_offset);
--
2.16.2
--
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