On Sat, Oct 31, 2015 at 07:21:18PM +0000, Sami Kerola wrote:
> Check if a file path and descriptor are indeed the same file. This function
> is needed for TACTOU avoidance.
>
> Signed-off-by: Sami Kerola <kerolasa@xxxxxx>
> ---
> include/fileutils.h | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/include/fileutils.h b/include/fileutils.h
> index be6d1f7..55df1a7 100644
> --- a/include/fileutils.h
> +++ b/include/fileutils.h
> @@ -4,6 +4,7 @@
> #include <stdio.h>
> #include <fcntl.h>
> #include <unistd.h>
> +#include <sys/stat.h>
>
> #include "c.h"
>
> @@ -25,6 +26,19 @@ static inline FILE *xfmkstemp(char **tmpname, const char *dir, const char *prefi
> return ret;
> }
>
> +static inline int is_same_inode(const int fd, const char *path)
> +{
> + struct stat f, p;
> +
> + if (fstat(fd, &f) < 0)
> + return 0;
> + if (stat(path, &p) < 0)
> + return 0;
> + if (f.st_dev != p.st_dev || f.st_ino != p.st_ino)
> + return 0;
> + return 1;
> +}
Maybe don't call fstat() here and use
static inline int is_same_inode(struct stat st, const char *path)
than you reduce stat() calls on many places...
Karel
--
Karel Zak <kzak@xxxxxxxxxx>
http://karelzak.blogspot.com
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