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/*
* Unix implementation of open_for_write_would_lose_data().
*/
#include <sys/types.h>
#include <sys/stat.h>
#include "putty.h"
bool open_for_write_would_lose_data(const Filename *fn)
{
struct stat st;
if (stat(fn->path, &st) < 0) {
/*
* If the file doesn't even exist, we obviously want to return
* false. If we failed to stat it for any other reason,
* ignoring the precise error code and returning false still
* doesn't seem too unreasonable, because then we'll try to
* open the file for writing and report _that_ error, which is
* likely to be more to the point.
*/
return false;
}
/*
* OK, something exists at this pathname and we've found out
* something about it. But an open-for-write will only
* destructively truncate it if it's a regular file with nonzero
* size. If it's empty, or some other kind of special thing like a
* character device (e.g. /dev/tty) or a named pipe, then opening
* it for write is already non-destructive and it's pointless and
* annoying to warn about it just because the same file can be
* opened for reading. (Indeed, if it's a named pipe, opening it
* for reading actually _causes inconvenience_ in its own right,
* even before the question of whether it gives misleading
* information.)
*/
if (S_ISREG(st.st_mode) && st.st_size > 0) {
return true;
}
return false;
}
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