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author | Tobias Stoeckmann | 2018-02-25 20:27:18 +0100 |
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committer | Karel Zak | 2018-02-26 11:54:12 +0100 |
commit | ea62c152766ff22038630c9afdeb1df5dcc044cb (patch) | |
tree | 22322c429c1b8b33bcec32dbee675dbddd498642 /misc-utils/fincore.c | |
parent | build-sys: forgot update NEWS for v2.32-rc1 (diff) | |
download | kernel-qcow2-util-linux-ea62c152766ff22038630c9afdeb1df5dcc044cb.tar.gz kernel-qcow2-util-linux-ea62c152766ff22038630c9afdeb1df5dcc044cb.tar.xz kernel-qcow2-util-linux-ea62c152766ff22038630c9afdeb1df5dcc044cb.zip |
fincore: Handle large files correctly on 32 bit
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@stoeckmann.org>
Diffstat (limited to 'misc-utils/fincore.c')
-rw-r--r-- | misc-utils/fincore.c | 4 |
1 files 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); |