Hi Alex,
On 9/23/20 4:54 PM, Alejandro Colomar wrote:
> These variables are either of an unsigned integer type per POSIX;
> or of an integer type per POSIX, that Linux defines as an unsigned integer type.
>
> Print them with 'uintmax_t' instead of 'intmax_t' to avoid
> big positive numbers being printed as negative numbers.
>
> Bug report:
> From: Konstantin Bukin @ 2020-09-13 15:04 UTC
> To: mtk.manpages; +Cc: Konstantin Bukin, linux-man
>
> inode numbers are expected to be positive. Casting them to a signed type
> may result in printing negative values. E.g. running example program on
> the following file:
>
> $ ls -li test.txt
> 9280843260537405888 -r--r--r-- 1 kbukin hardware 300 Jul 21 06:36 test.txt
>
> resutls in the following output:
>
> $ ./example test.txt
> ID of containing device: [0,480]
> File type: regular file
> I-node number: -9165900813172145728
> Mode: 100444 (octal)
> Link count: 1
> Ownership: UID=2743 GID=30
> Preferred I/O block size: 32768 bytes
> File size: 300 bytes
> Blocks allocated: 8
> Last status change: Tue Jul 21 06:36:50 2020
> Last file access: Sat Sep 12 14:13:38 2020
> Last file modification: Tue Jul 21 06:36:50 2020
>
> Such erroneous reporting happens for inode values greater than maximum
> value which can be stored in signed long. Casting does not seem to be
> necessary here. Printing inode as unsigned long fixes the issue.
>
> Reported-by: Konstantin Bukin <kbukin@xxxxxxxxx>
> Signed-off-by: Alejandro Colomar <colomar.6.4.3@xxxxxxxxx>
Thanks! Patch applied.
Cheers,
Michael
> ---
>
> Hi Michael,
>
> I wrote a patch similar to Konstantin's patch,
> but using `uintmax_t` as we discussed.
> I further fixed a few more cases of incorrect casts.
> I found all of those related to `struct stat`'s members,
> but there may be more incorrect casts out there.
>
> Cheers,
>
> Alex
>
> man2/ioctl_ns.2 | 8 ++++----
> man2/stat.2 | 8 ++++----
> 2 files changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/man2/ioctl_ns.2 b/man2/ioctl_ns.2
> index b83db74e0..87b5168a7 100644
> --- a/man2/ioctl_ns.2
> +++ b/man2/ioctl_ns.2
> @@ -317,10 +317,10 @@ main(int argc, char *argv[])
> exit(EXIT_FAILURE);
> }
> printf("Device/Inode of owning user namespace is: "
> - "[%jx,%jx] / %jd\en",
> + "[%jx,%jx] / %ju\en",
> (uintmax_t) major(sb.st_dev),
> (uintmax_t) minor(sb.st_dev),
> - (intmax_t) sb.st_ino);
> + (uintmax_t) sb.st_ino);
>
> close(userns_fd);
> }
> @@ -347,10 +347,10 @@ main(int argc, char *argv[])
> perror("fstat\-parentns");
> exit(EXIT_FAILURE);
> }
> - printf("Device/Inode of parent namespace is: [%jx,%jx] / %jd\en",
> + printf("Device/Inode of parent namespace is: [%jx,%jx] / %ju\en",
> (uintmax_t) major(sb.st_dev),
> (uintmax_t) minor(sb.st_dev),
> - (intmax_t) sb.st_ino);
> + (uintmax_t) sb.st_ino);
>
> close(parent_fd);
> }
> diff --git a/man2/stat.2 b/man2/stat.2
> index f71cc3831..13a1f37f7 100644
> --- a/man2/stat.2
> +++ b/man2/stat.2
> @@ -682,14 +682,14 @@ main(int argc, char *argv[])
> default: printf("unknown?\en"); break;
> }
>
> - printf("I\-node number: %jd\en", (intmax_t) sb.st_ino);
> + printf("I\-node number: %ju\en", (uintmax_t) sb.st_ino);
>
> printf("Mode: %jo (octal)\en",
> (uintmax_t) sb.st_mode);
>
> - printf("Link count: %jd\en", (intmax_t) sb.st_nlink);
> - printf("Ownership: UID=%jd GID=%jd\en",
> - (intmax_t) sb.st_uid, (intmax_t) sb.st_gid);
> + printf("Link count: %ju\en", (uintmax_t) sb.st_nlink);
> + printf("Ownership: UID=%ju GID=%ju\en",
> + (uintmax_t) sb.st_uid, (uintmax_t) sb.st_gid);
>
> printf("Preferred I/O block size: %jd bytes\en",
> (intmax_t) sb.st_blksize);
>
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
