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Re: [PATCH] Add me_mountroot to mount_entry for linux machines
From: |
Dave Chiluk |
Subject: |
Re: [PATCH] Add me_mountroot to mount_entry for linux machines |
Date: |
Mon, 31 Aug 2015 16:07:04 -0500 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.8.0 |
I agree with all suggestions. I'm posting a revised patch shortly.
Dave.
On 08/28/2015 07:42 PM, Pádraig Brady wrote:
> On 28/08/15 21:41, Dave Chiluk wrote:
>> Add me_mountroot to mount_entry so linux machines based on
>> /proc/self/mountinfo can distinguish between bind mounts and original
>> mounts. In reality bind mounts aren't treated any different than
>> mountroot=/ mounts by the kernel, but this is still confusing to the
>> user, and a change in behavior
>
> Thanks, I think this makes sense,
> and shouldn't introduce API issues since gnulib
> isn't released as a separate lib.
> More notes below...
>
>> More information is available here
>> https://bugs.launchpad.net/ubuntu/+source/coreutils/+bug/1432871
>> ---
>> lib/mountlist.c | 29 ++++++++++++++++++++++++++---
>> lib/mountlist.h | 2 ++
>> 2 files changed, 28 insertions(+), 3 deletions(-)
>>
>> diff --git a/lib/mountlist.c b/lib/mountlist.c
>> index 6f04f55..4e4c129 100644
>> --- a/lib/mountlist.c
>> +++ b/lib/mountlist.c
>> @@ -480,25 +480,32 @@ read_file_system_list (bool need_fs_type)
>> unsigned int devmaj, devmin;
>> int target_s, target_e, type_s, type_e, source_s, source_e;
>> char test;
>> - char *dash;
>> + char *dash, *mountroot;
>> int rc;
>>
>> rc = sscanf(line, "%*u " /* id - discarded */
>> "%*u " /* parent - discarded */
>> "%u:%u " /* dev major:minor */
>> - "%*s " /* mountroot - discarded */
>> + "%ms " /* mountroot */
>
> Better to use the mntroot_s, mntroot_e ... unescape_tab()
> mechanism used for other parsed paths.
>
>> "%n%*s%n" /* target, start and end */
>> "%c", /* more data... */
>> &devmaj, &devmin,
>> + &mountroot,
>> &target_s, &target_e,
>> &test);
>> - if (rc != 3 && rc != 5) /* 5 if %n included in count. */
>> + if (rc != 4 && rc != 6) /* 6 if %n included in count. */
>> + {
>> + free(mountroot);
>> continue;
>> + }
>>
>> /* skip optional fields, terminated by " - " */
>> dash = strstr (line + target_e, " - ");
>> if (! dash)
>> + {
>> + free(mountroot);
>> continue;
>> + }
>>
>> rc = sscanf(dash, " - "
>> "%n%*s%n " /* FS type, start and end */
>> @@ -508,7 +515,10 @@ read_file_system_list (bool need_fs_type)
>> &source_s, &source_e,
>> &test);
>> if (rc != 1 && rc != 5) /* 5 if %n included in count. */
>> + {
>> + free(mountroot);
>> continue;
>> + }
>>
>> /* manipulate the sub-strings in place. */
>> line[target_e] = '\0';
>> @@ -521,6 +531,7 @@ read_file_system_list (bool need_fs_type)
>>
>> me->me_devname = xstrdup (dash + source_s);
>> me->me_mountdir = xstrdup (line + target_s);
>> + me->me_mountroot = mountroot;
>> me->me_type = xstrdup (dash + type_s);
>> me->me_type_malloced = 1;
>> me->me_dev = makedev (devmaj, devmin);
>> @@ -566,6 +577,7 @@ read_file_system_list (bool need_fs_type)
>> me = xmalloc (sizeof *me);
>> me->me_devname = xstrdup (mnt->mnt_fsname);
>> me->me_mountdir = xstrdup (mnt->mnt_dir);
>> + me->me_mountroot = NULL;
>> me->me_type = xstrdup (mnt->mnt_type);
>> me->me_type_malloced = 1;
>> me->me_dummy = ME_DUMMY (me->me_devname, me->me_type, bind);
>> @@ -598,6 +610,7 @@ read_file_system_list (bool need_fs_type)
>> me = xmalloc (sizeof *me);
>> me->me_devname = xstrdup (fsp->f_mntfromname);
>> me->me_mountdir = xstrdup (fsp->f_mntonname);
>> + me->me_mountroot = NULL;
>> me->me_type = fs_type;
>> me->me_type_malloced = 0;
>> me->me_dummy = ME_DUMMY (me->me_devname, me->me_type);
>> @@ -624,6 +637,7 @@ read_file_system_list (bool need_fs_type)
>> me = xmalloc (sizeof *me);
>> me->me_devname = xstrdup (fsp->f_mntfromname);
>> me->me_mountdir = xstrdup (fsp->f_mntonname);
>> + me->me_mountroot = NULL;
>> me->me_type = xstrdup (fsp->f_fstypename);
>> me->me_type_malloced = 1;
>> me->me_dummy = ME_DUMMY (me->me_devname, me->me_type);
>> @@ -650,6 +664,7 @@ read_file_system_list (bool need_fs_type)
>> me = xmalloc (sizeof *me);
>> me->me_devname = xstrdup (fsd.fd_req.devname);
>> me->me_mountdir = xstrdup (fsd.fd_req.path);
>> + me->me_mountroot = NULL;
>> me->me_type = gt_names[fsd.fd_req.fstype];
>> me->me_type_malloced = 0;
>> me->me_dummy = ME_DUMMY (me->me_devname, me->me_type);
>> @@ -748,6 +763,7 @@ read_file_system_list (bool need_fs_type)
>> me->me_devname = xstrdup (fi.device_name[0] != '\0'
>> ? fi.device_name : fi.fsh_name);
>> me->me_mountdir = xstrdup (re != NULL ? re->name : fi.fsh_name);
>> + me->mountroot = NULL ;
>> me->me_type = xstrdup (fi.fsh_name);
>> me->me_type_malloced = 1;
>> me->me_dev = fi.dev;
>> @@ -797,6 +813,7 @@ read_file_system_list (bool need_fs_type)
>> me = xmalloc (sizeof *me);
>> me->me_devname = xstrdup (stats[counter].f_mntfromname);
>> me->me_mountdir = xstrdup (stats[counter].f_mntonname);
>> + me->me_mountroot = NULL;
>> me->me_type = xstrdup (FS_TYPE (stats[counter]));
>> me->me_type_malloced = 1;
>> me->me_dummy = ME_DUMMY (me->me_devname, me->me_type);
>> @@ -833,6 +850,7 @@ read_file_system_list (bool need_fs_type)
>> strcpy (me->me_devname + 5, mnt.mt_dev);
>> # endif
>> me->me_mountdir = xstrdup (mnt.mt_filsys);
>> + me->me_mountroot = NULL;
>> me->me_dev = (dev_t) -1; /* Magic; means not known yet. */
>> me->me_type = "";
>> me->me_type_malloced = 0;
>> @@ -880,6 +898,7 @@ read_file_system_list (bool need_fs_type)
>> me = xmalloc (sizeof *me);
>> me->me_devname = xstrdup ((*ent)->mt_resource);
>> me->me_mountdir = xstrdup ((*ent)->mt_directory);
>> + me->me_mountroot = NULL;
>> me->me_type = xstrdup ((*ent)->mt_fstype);
>> me->me_type_malloced = 1;
>> me->me_dummy = ME_DUMMY (me->me_devname, me->me_type);
>> @@ -942,6 +961,7 @@ read_file_system_list (bool need_fs_type)
>> me = xmalloc (sizeof *me);
>> me->me_devname = xstrdup (mnt.mnt_special);
>> me->me_mountdir = xstrdup (mnt.mnt_mountp);
>> + me->me_mountroot = NULL;
>> me->me_type = xstrdup (mnt.mnt_fstype);
>> me->me_type_malloced = 1;
>> me->me_dummy = MNT_IGNORE (&mnt) != 0;
>> @@ -1020,6 +1040,7 @@ read_file_system_list (bool need_fs_type)
>> vmp->vmt_data[VMT_OBJECT].vmt_off);
>> }
>> me->me_mountdir = xstrdup (thisent +
>> vmp->vmt_data[VMT_STUB].vmt_off);
>> + me->me_mountroot = NULL;
>> me->me_type = xstrdup (fstype_to_string (vmp->vmt_gfstype));
>> me->me_type_malloced = 1;
>> options = thisent + vmp->vmt_data[VMT_ARGS].vmt_off;
>> @@ -1063,6 +1084,7 @@ read_file_system_list (bool need_fs_type)
>> me = xmalloc (sizeof *me);
>> me->me_devname = xstrdup (dev.f_mntfromname);
>> me->me_mountdir = xstrdup (dev.f_mntonname);
>> + me->me_mountroot = NULL;
>> me->me_type = xstrdup (dev.f_fstypename);
>> me->me_type_malloced = 1;
>> me->me_dummy = ME_DUMMY (me->me_devname, me->me_type);
>> @@ -1105,6 +1127,7 @@ void free_mount_entry (struct mount_entry *me)
>> {
>> free (me->me_devname);
>> free (me->me_mountdir);
>> + free (me->me_mountroot);
>> if (me->me_type_malloced)
>> free (me->me_type);
>> free (me);
>> diff --git a/lib/mountlist.h b/lib/mountlist.h
>> index 735776b..38a4ccf 100644
>> --- a/lib/mountlist.h
>> +++ b/lib/mountlist.h
>> @@ -27,6 +27,8 @@ struct mount_entry
>> {
>> char *me_devname; /* Device node name, including "/dev/". */
>> char *me_mountdir; /* Mount point directory name. */
>> + char *me_mountroot; /* Directory on filesystem of device used */
>> + /* as root for the mount*/
>
> s/mount/(bind) mount. /
>
>> char *me_type; /* "nfs", "4.2", etc. */
>> dev_t me_dev; /* Device number of me_mountdir. */
>> unsigned int me_dummy : 1; /* Nonzero for dummy file systems. */
>>
>
> thanks,
> Pádraig
>