[PATCH] shell: Remove not functioning fdisk mount/unmount command
Gedare Bloom
gedare at rtems.org
Fri Oct 9 15:37:10 UTC 2020
Excellent analysis. I would like Chris to weigh in, but the rationale
to remove instead of try to fix makes sense because it is basically an
undocumented shell API.
On Fri, Oct 9, 2020 at 7:38 AM Frank Kuehndel
<frank.kuehndel at embedded-brains.de> wrote:
>
> The shell has an 'fdisk' command which has sub-commands 'mount' and 'unmount'.
> These two sub-commands have a bug which causes them to be not able
> to mount anything. This proposed patch removes the buggy file
> cpukit/libblock/src/bdpart-mount.c and the mount/unmount commands
> from 'fdisk' as bug fix. The 'fdisk' command itself is not removed.
> The reasons for removing the sub-commands (instead of fixing the issue) are:
>
> 1) The bug has been introduced on 2010-May-31 with commit
> 29e92b090c8bc35745aa5c89231ce806bcb11e57. Since ten years no one
> can use this feature, nor has anybody complained about it.
>
> 2) Besides of the 'fdisk' 'mount' sub-command, the shell has the
> usual 'mount' and 'unmount' commands which can serve as
> substitutes.
>
> 3) There are additional minor issues (see further down) which needed to
> be addressed when the file will be kept.
>
> What follows below is the precise bug description.
>
> The bug is in function rtems_bdpart_mount() which is only be used
> by the 'fdisk' shell command to mount all partitions of a disk with a
> single command:
>
> > fdisk DISK_NAME mount
> > mounts the file system of each partition of the disk
> >
> > fdisk DISK_NAME unmount
> > unmounts the file system of each partition of the disk
>
> The whole command does not work because in file
> cpukit/libblock/src/bdpart-mount.c line 103 specifies the file system type
> of each partition to be "msdos". Yet, "msdos" does not exist. The name
> must be "dosfs".
>
> Beside of this fundamental problem, there are more issues with the code
> in bdpart-mount.c:
>
> 1) The function returns RTEMS_SUCCESSFUL despite the mount always fails.
>
> 2) The reason for errors is not written to the terminal.
>
> 3) The directory '/mnt' is created but not deleted later on (failure or not).
>
> 3) There is no documentation about this special 'fdisk' feature in the
> RTEMS Shell Guide ('fdisk' is mentioned but its documentation is a
> bit short):
> https://docs.rtems.org/branches/master/shell/
> file_and_directory.html#fdisk-format-disk
>
> 4) Only "msdos" formatted partitions can be mounted and all partitions
> are mounted read-only. This is hard coded and cannot be changed by
> options. Moreover, there is no information about this to the user of
> the shell (i.e. using 'fdisk' mount requires insider knowledge).
>
> How to reproduce:
>
> 1) For testing, I use the 'testsuites/samples/fileio.exe' sample with qemu:
>
> > cd rtems
> > env QEMU_AUDIO_DRV="none" qemu-system-arm -net none -nographic \
> > -M realview-pbx-a9 -m 256M -kernel \
> > build/arm/realview_pbx_a9_qemu/testsuites/samples/fileio.exe
>
> 2) Type any key to stop the timer and enter the sample tool.
> Type 's' to enter the shell, login as 'root' with the password
> shown in the terminal.
>
> 3) Type the following shell commands (they create a RAM disk,
> partition it, register it, format it and try to mount it):
>
> > mkrd
> > fdisk /dev/rda fat32 16 write mbr
> > fdisk /dev/rda register
> > mkdos /dev/rda1
> > fdisk /dev/rda mount
>
> 4) The last line above is the command which fails - without an error
> message. There exists a '/mnt' directory but no '/mnt/rda1' directory
> as it should be:
>
> > ls -la /mnt
>
> 5) If you change line 103 of 'cpukit/libblock/src/bdpart-mount.c'
> from "msdos" to "dosfs", compile and build the executable and
> re-run the above test, '/mnt/rda1' exists (but the file system
> is mounted read-only).
>
> Close #4131
> ---
> cpukit/Makefile.am | 1 -
> cpukit/include/rtems/bdpart.h | 35 +-----
> cpukit/libblock/src/bdpart-mount.c | 184 -----------------------------
> cpukit/libmisc/shell/fdisk.c | 36 +-----
> spec/build/cpukit/librtemscpu.yml | 1 -
> 5 files changed, 7 insertions(+), 250 deletions(-)
> delete mode 100644 cpukit/libblock/src/bdpart-mount.c
>
> diff --git a/cpukit/Makefile.am b/cpukit/Makefile.am
> index 1f9124e175..bdd8ebef33 100644
> --- a/cpukit/Makefile.am
> +++ b/cpukit/Makefile.am
> @@ -44,7 +44,6 @@ librtemscpu_a_SOURCES += dtc/libfdt/fdt_wip.c
> librtemscpu_a_SOURCES += libblock/src/bdbuf.c
> librtemscpu_a_SOURCES += libblock/src/bdpart-create.c
> librtemscpu_a_SOURCES += libblock/src/bdpart-dump.c
> -librtemscpu_a_SOURCES += libblock/src/bdpart-mount.c
> librtemscpu_a_SOURCES += libblock/src/bdpart-read.c
> librtemscpu_a_SOURCES += libblock/src/bdpart-register.c
> librtemscpu_a_SOURCES += libblock/src/bdpart-sort.c
> diff --git a/cpukit/include/rtems/bdpart.h b/cpukit/include/rtems/bdpart.h
> index 8886c3614d..dde716e146 100644
> --- a/cpukit/include/rtems/bdpart.h
> +++ b/cpukit/include/rtems/bdpart.h
> @@ -7,10 +7,10 @@
> */
>
> /*
> - * Copyright (c) 2009-2012 embedded brains GmbH. All rights reserved.
> + * Copyright (c) 2009-2012, 2020 embedded brains GmbH. All rights reserved.
> *
> * embedded brains GmbH
> - * Obere Lagerstr. 30
> + * Dornierstr. 4
> * 82178 Puchheim
> * Germany
> * <rtems at embedded-brains.de>
> @@ -302,37 +302,6 @@ rtems_status_code rtems_bdpart_unregister(
> size_t count
> );
>
> -/**
> - * @brief Mounts all supported file systems inside the logical disks derived
> - * from the partitions of the physical disk device with name @a disk_name.
> - *
> - * For each partition in the partition table @a partitions with @a count
> - * partitions it will be checked if it contains a supported file system. In
> - * this case a mount point derived from the disk name will be created in the
> - * mount base path @a mount_base. The file system will be mounted there. The
> - * partition number equals the partition table index plus one. The mount point
> - * name for each partition will be the concatenation of the mount base path,
> - * the disk device file name and the parition number.
> - *
> - * @see rtems_bdpart_read().
> - */
> -rtems_status_code rtems_bdpart_mount(
> - const char *disk_name,
> - const rtems_bdpart_partition *partitions,
> - size_t count,
> - const char *mount_base
> -);
> -
> -/**
> - * @brief Unmounts all file systems mounted with rtems_bdpart_mount().
> - */
> -rtems_status_code rtems_bdpart_unmount(
> - const char *disk_name,
> - const rtems_bdpart_partition *partitions,
> - size_t count,
> - const char *mount_base
> -);
> -
> /**
> * @brief Prints the partition table @a partitions with @a count partitions to
> * standard output.
> diff --git a/cpukit/libblock/src/bdpart-mount.c b/cpukit/libblock/src/bdpart-mount.c
> deleted file mode 100644
> index cfc08ead30..0000000000
> --- a/cpukit/libblock/src/bdpart-mount.c
> +++ /dev/null
> @@ -1,184 +0,0 @@
> -/**
> - * @file
> - *
> - * @ingroup rtems_bdpart
> - *
> - * @brief Block Device Partition Management
> - */
> -
> -/*
> - * Copyright (c) 2009, 2010
> - * embedded brains GmbH
> - * Obere Lagerstr. 30
> - * D-82178 Puchheim
> - * Germany
> - * <rtems at embedded-brains.de>
> - *
> - * The license and distribution terms for this file may be
> - * found in the file LICENSE in this distribution or at
> - * http://www.rtems.org/license/LICENSE.
> - */
> -
> -#ifdef HAVE_CONFIG_H
> -#include "config.h"
> -#endif
> -
> -#include <stdio.h>
> -#include <stdlib.h>
> -#include <string.h>
> -
> -#include <rtems.h>
> -#include <rtems/bdpart.h>
> -#include <rtems/libio.h>
> -
> -rtems_status_code rtems_bdpart_mount(
> - const char *disk_name,
> - const rtems_bdpart_partition *pt RTEMS_UNUSED,
> - size_t count,
> - const char *mount_base
> -)
> -{
> - rtems_status_code esc = RTEMS_SUCCESSFUL;
> - const char *disk_file_name = strrchr( disk_name, '/');
> - char *logical_disk_name = NULL;
> - char *logical_disk_marker = NULL;
> - char *mount_point = NULL;
> - char *mount_marker = NULL;
> - size_t disk_file_name_size = 0;
> - size_t disk_name_size = strlen( disk_name);
> - size_t mount_base_size = strlen( mount_base);
> - size_t i = 0;
> -
> - /* Create logical disk name base */
> - logical_disk_name = malloc( disk_name_size + RTEMS_BDPART_NUMBER_SIZE);
> - if (logical_disk_name == NULL) {
> - return RTEMS_NO_MEMORY;
> - }
> - strncpy( logical_disk_name, disk_name, disk_name_size);
> -
> - /* Get disk file name */
> - if (disk_file_name != NULL) {
> - disk_file_name += 1;
> - disk_file_name_size = strlen( disk_file_name);
> - } else {
> - disk_file_name = disk_name;
> - disk_file_name_size = disk_name_size;
> - }
> -
> - /* Create mount point base */
> - mount_point = malloc( mount_base_size + 1 + disk_file_name_size + RTEMS_BDPART_NUMBER_SIZE);
> - if (mount_point == NULL) {
> - esc = RTEMS_NO_MEMORY;
> - goto cleanup;
> - }
> - strncpy( mount_point, mount_base, mount_base_size);
> - mount_point [mount_base_size] = '/';
> - strncpy( mount_point + mount_base_size + 1, disk_file_name, disk_file_name_size);
> -
> - /* Markers */
> - logical_disk_marker = logical_disk_name + disk_name_size;
> - mount_marker = mount_point + mount_base_size + 1 + disk_file_name_size;
> -
> - /* Mount supported file systems for each partition */
> - for (i = 0; i < count; ++i) {
> - /* Create logical disk name */
> - int rv = snprintf( logical_disk_marker, RTEMS_BDPART_NUMBER_SIZE, "%zu", i + 1);
> - if (rv >= RTEMS_BDPART_NUMBER_SIZE) {
> - esc = RTEMS_INVALID_NAME;
> - goto cleanup;
> - }
> -
> - /* Create mount point */
> - strncpy( mount_marker, logical_disk_marker, RTEMS_BDPART_NUMBER_SIZE);
> - rv = rtems_mkdir( mount_point, S_IRWXU | S_IRWXG | S_IRWXO);
> - if (rv != 0) {
> - esc = RTEMS_IO_ERROR;
> - goto cleanup;
> - }
> -
> - /* Mount */
> - rv = mount(
> - logical_disk_name,
> - mount_point,
> - "msdos",
> - 0,
> - NULL
> - );
> - if (rv != 0) {
> - rmdir( mount_point);
> - }
> - }
> -
> -cleanup:
> -
> - free( logical_disk_name);
> - free( mount_point);
> -
> - return esc;
> -}
> -
> -rtems_status_code rtems_bdpart_unmount(
> - const char *disk_name,
> - const rtems_bdpart_partition *pt RTEMS_UNUSED,
> - size_t count,
> - const char *mount_base
> -)
> -{
> - rtems_status_code esc = RTEMS_SUCCESSFUL;
> - const char *disk_file_name = strrchr( disk_name, '/');
> - char *mount_point = NULL;
> - char *mount_marker = NULL;
> - size_t disk_file_name_size = 0;
> - size_t disk_name_size = strlen( disk_name);
> - size_t mount_base_size = strlen( mount_base);
> - size_t i = 0;
> -
> - /* Get disk file name */
> - if (disk_file_name != NULL) {
> - disk_file_name += 1;
> - disk_file_name_size = strlen( disk_file_name);
> - } else {
> - disk_file_name = disk_name;
> - disk_file_name_size = disk_name_size;
> - }
> -
> - /* Create mount point base */
> - mount_point = malloc( mount_base_size + 1 + disk_file_name_size + RTEMS_BDPART_NUMBER_SIZE);
> - if (mount_point == NULL) {
> - esc = RTEMS_NO_MEMORY;
> - goto cleanup;
> - }
> - strncpy( mount_point, mount_base, mount_base_size);
> - mount_point [mount_base_size] = '/';
> - strncpy( mount_point + mount_base_size + 1, disk_file_name, disk_file_name_size);
> -
> - /* Marker */
> - mount_marker = mount_point + mount_base_size + 1 + disk_file_name_size;
> -
> - /* Mount supported file systems for each partition */
> - for (i = 0; i < count; ++i) {
> - /* Create mount point */
> - int rv = snprintf( mount_marker, RTEMS_BDPART_NUMBER_SIZE, "%zu", i + 1);
> - if (rv >= RTEMS_BDPART_NUMBER_SIZE) {
> - esc = RTEMS_INVALID_NAME;
> - goto cleanup;
> - }
> -
> - /* Unmount */
> - rv = unmount( mount_point);
> - if (rv == 0) {
> - /* Remove mount point */
> - rv = rmdir( mount_point);
> - if (rv != 0) {
> - esc = RTEMS_IO_ERROR;
> - goto cleanup;
> - }
> - }
> - }
> -
> -cleanup:
> -
> - free( mount_point);
> -
> - return esc;
> -}
> diff --git a/cpukit/libmisc/shell/fdisk.c b/cpukit/libmisc/shell/fdisk.c
> index d071e4fbba..c244922492 100644
> --- a/cpukit/libmisc/shell/fdisk.c
> +++ b/cpukit/libmisc/shell/fdisk.c
> @@ -5,10 +5,10 @@
> */
>
> /*
> - * Copyright (c) 2009
> + * Copyright (c) 2009, 2020
> * embedded brains GmbH
> - * Obere Lagerstr. 30
> - * D-82178 Puchheim
> + * Dornierstr. 4
> + * 82178 Puchheim
> * Germany
> * <rtems at embedded-brains.de>
> *
> @@ -61,13 +61,8 @@ static const char rtems_bdpart_shell_usage [] =
> "\tcreates a logical disk for each partition of the disk\n"
> "\n"
> "fdisk DISK_NAME unregister\n"
> - "\tdeletes the logical disks associated with the partitions of the disk\n"
> - "\n"
> - "fdisk DISK_NAME mount\n"
> - "\tmounts the file system of each partition of the disk\n"
> - "\n"
> - "fdisk DISK_NAME unmount\n"
> - "\tunmounts the file system of each partition of the disk\n"
> + "\tdeletes the logical disks associated with the partitions\n"
> + "\tof the disk\n"
> "\n"
> "option values:\n"
> "\tDISK_NAME: absolute path to disk device like '/dev/hda'\n"
> @@ -84,14 +79,11 @@ static int rtems_bdpart_shell_main( int argc, char **argv)
> unsigned dist [RTEMS_BDPART_PARTITION_NUMBER_HINT];
> size_t count = RTEMS_BDPART_PARTITION_NUMBER_HINT;
> const char *disk_name = NULL;
> - const char *mount_base = "/mnt";
> bool do_create = false;
> bool do_read = false;
> bool do_write = false;
> bool do_register = false;
> bool do_unregister = false;
> - bool do_mount = false;
> - bool do_unmount = false;
> bool do_dump = false;
>
> if (argc < 2) {
> @@ -112,12 +104,6 @@ static int rtems_bdpart_shell_main( int argc, char **argv)
> } else if (strcmp( argv [2], "unregister") == 0) {
> do_read = true;
> do_unregister = true;
> - } else if (strcmp( argv [2], "mount") == 0) {
> - do_read = true;
> - do_mount = true;
> - } else if (strcmp( argv [2], "unmount") == 0) {
> - do_read = true;
> - do_unmount = true;
> } else {
> RTEMS_BDPART_SHELL_ERROR( "unexpected option: %s", argv [2]);
> }
> @@ -250,18 +236,6 @@ static int rtems_bdpart_shell_main( int argc, char **argv)
> RTEMS_BDPART_SHELL_ERROR_SC( sc, "cannot unregister partitions of '%s'", disk_name);
> }
>
> - if (do_mount) {
> - /* Mount partitions */
> - sc = rtems_bdpart_mount( disk_name, pt, count, mount_base);
> - RTEMS_BDPART_SHELL_ERROR_SC( sc, "cannot mount partitions of '%s' to '%s'", disk_name, mount_base);
> - }
> -
> - if (do_unmount) {
> - /* Unmount partitions */
> - sc = rtems_bdpart_unmount( disk_name, pt, count, mount_base);
> - RTEMS_BDPART_SHELL_ERROR_SC( sc, "cannot unmount partitions of '%s'", disk_name);
> - }
> -
> if (do_dump) {
> /* Dump partitions */
> rtems_bdpart_dump( pt, count);
> diff --git a/spec/build/cpukit/librtemscpu.yml b/spec/build/cpukit/librtemscpu.yml
> index fe440de738..d039bd6267 100644
> --- a/spec/build/cpukit/librtemscpu.yml
> +++ b/spec/build/cpukit/librtemscpu.yml
> @@ -539,7 +539,6 @@ source:
> - cpukit/libblock/src/bdbuf.c
> - cpukit/libblock/src/bdpart-create.c
> - cpukit/libblock/src/bdpart-dump.c
> -- cpukit/libblock/src/bdpart-mount.c
> - cpukit/libblock/src/bdpart-read.c
> - cpukit/libblock/src/bdpart-register.c
> - cpukit/libblock/src/bdpart-sort.c
> --
> 2.26.2
>
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