From: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
To: Eric DeCosta via GitGitGadget <gitgitgadget@gmail.com>
Cc: git@vger.kernel.org, Eric Sunshine <sunshine@sunshineco.com>,
Glen Choo <chooglen@google.com>,
Johannes Schindelin <Johannes.Schindelin@gmx.de>,
Taylor Blau <me@ttaylorr.com>,
Eric DeCosta <edecosta@mathworks.com>
Subject: Re: [PATCH v4 2/6] fsmonitor: determine if filesystem is local or remote
Date: Mon, 12 Dec 2022 11:24:27 +0100 [thread overview]
Message-ID: <221212.86lenc6h2l.gmgdl@evledraar.gmail.com> (raw)
In-Reply-To: <e53fc07754094aa5ba8080ec7761869c6429a8af.1669230044.git.gitgitgadget@gmail.com>
On Wed, Nov 23 2022, Eric DeCosta via GitGitGadget wrote:
> From: Eric DeCosta <edecosta@mathworks.com>
>
> Compare the given path to the mounted filesystems. Find the mount that is
> the longest prefix of the path (if any) and determine if that mount is on a
> local or remote filesystem.
>
> Signed-off-by: Eric DeCosta <edecosta@mathworks.com>
> ---
> compat/fsmonitor/fsm-path-utils-linux.c | 186 ++++++++++++++++++++++++
> 1 file changed, 186 insertions(+)
> create mode 100644 compat/fsmonitor/fsm-path-utils-linux.c
>
> diff --git a/compat/fsmonitor/fsm-path-utils-linux.c b/compat/fsmonitor/fsm-path-utils-linux.c
> new file mode 100644
> index 00000000000..d3281422ebc
> --- /dev/null
> +++ b/compat/fsmonitor/fsm-path-utils-linux.c
> @@ -0,0 +1,186 @@
> +#include "fsmonitor.h"
> +#include "fsmonitor-path-utils.h"
> +#include <errno.h>
> +#include <mntent.h>
> +#include <sys/mount.h>
> +#include <sys/vfs.h>
> +#include <sys/statvfs.h>
> +
> +static int is_remote_fs(const char* path) {
> + struct statfs fs;
> +
> + if (statfs(path, &fs)) {
> + error_errno(_("statfs('%s') failed"), path);
> + return -1;
> + }
Nit: Drop the braces and do:
if (statfs(...) == -1)
return error_errno(...)
> + switch (fs.f_type) {
> + case 0x61636673: /* ACFS */
> + case 0x5346414F: /* AFS */
> + case 0x00C36400: /* CEPH */
> + case 0xFF534D42: /* CIFS */
> + case 0x73757245: /* CODA */
> + case 0x19830326: /* FHGFS */
> + case 0x1161970: /* GFS */
> + case 0x47504653: /* GPFS */
> + case 0x013111A8: /* IBRIX */
> + case 0x6B414653: /* KAFS */
> + case 0x0BD00BD0: /* LUSTRE */
> + case 0x564C: /* NCP */
> + case 0x6969: /* NFS */
> + case 0x6E667364: /* NFSD */
> + case 0x7461636f: /* OCFS2 */
> + case 0xAAD7AAEA: /* PANFS */
> + case 0x517B: /* SMB */
> + case 0xBEEFDEAD: /* SNFS */
> + case 0xFE534D42: /* SMB2 */
> + case 0xBACBACBC: /* VMHGFS */
> + case 0xA501FCF5: /* VXFS */
So, before we'd compare against the name, but to avoid the GPLv3
copy/pasting we're now comparing against the fs.f_type.
If we are hardcoding them, our usual convention is to lower-case
hexdigits, so 0xbacbacbc not 0xBACBACBC.
But at least my statfs() manpage documents the named defines in
linux/magic.h for most of these. Why not use those?
> + return 1;
> + default:
> + break;
You could just "return 0" here, and...
> + }
> +
> + return 0;
...drop this "return 0".
> +}
> +
> +static int find_mount(const char *path, const struct statvfs *fs,
> + struct mntent *ent)
Misindentation.
> +{
> + const char *const mounts = "/proc/mounts";
> + const char *rp = real_pathdup(path, 1);
> + struct mntent *ment = NULL;
> + struct statvfs mntfs;
> + FILE *fp;
> + int found = 0;
> + int dlen, plen, flen = 0;
> +
> + ent->mnt_fsname = NULL;
> + ent->mnt_dir = NULL;
> + ent->mnt_type = NULL;
> +
> + fp = setmntent(mounts, "r");
> + if (!fp) {
> + error_errno(_("setmntent('%s') failed"), mounts);
> + return -1;
Ditto "return error_errno()"
> + }
> +
> + plen = strlen(rp);
Let's make "plen", "dlen" and "flen" a "size_t", not "int"
> +
> + /* read all the mount information and compare to path */
> + while ((ment = getmntent(fp)) != NULL) {
Drop the "!= NULL"
> + if (statvfs(ment->mnt_dir, &mntfs)) {
> + switch (errno) {
> + case EPERM:
> + case ESRCH:
> + case EACCES:
> + continue;
> + default:
> + error_errno(_("statvfs('%s') failed"), ment->mnt_dir);
> + endmntent(fp);
Shouldn't we check the endmntent() error too? Now, from the manpage the
interface is funny, and always returns 1.
But since this is linux-specific code it seems safe enough to go with it
& glibc assumptions and:
errno = 0;
endmntent(fp);
if (errno)
return error_errno(....);
I.e. it'll just call fclose(), which might set errno() on failure.
Maybe it's not worth it...
> + if (statvfs(path, &fs))
> + return error_errno(_("statvfs('%s') failed"), path);
Here you do use that "return error_errno(...)" pattern...", yay!
> +
> +
> + if (find_mount(path, &fs, &ment) < 0) {
> + free(ment.mnt_fsname);
> + free(ment.mnt_dir);
> + free(ment.mnt_type);
> + return -1;
> + }
> +
> + trace_printf_key(&trace_fsmonitor,
> + "statvfs('%s') [flags 0x%08lx] '%s' '%s'",
> + path, fs.f_flag, ment.mnt_type, ment.mnt_fsname);
> +
> + fs_info->is_remote = is_remote_fs(ment.mnt_dir);
> + fs_info->typename = ment.mnt_fsname;
> + free(ment.mnt_dir);
> + free(ment.mnt_type);
If you're going to \n\n-seperate this and the trace_printf_key() above I
think moving the second free() here to that "block" would make sense,
sinec here is the last time we use mnt_dir, but the last time we used
mnt_type was in the trace_printf_key().
But...
> +
> + if (fs_info->is_remote < 0) {
> + free(ment.mnt_fsname);
...aren't you NULL init-ing these, why not just for all of these:
goto error;
Then....
> + return -1;
> + }
> +
> + trace_printf_key(&trace_fsmonitor,
> + "'%s' is_remote: %d",
> + path, fs_info->is_remote);
> +
> + return 0;
Have this be:
int ret = -1; /* earlier */
ret = 0;
cleanup:
free(...);
free(...);
return ret;
> +}
> +
> +int fsmonitor__is_fs_remote(const char *path)
> +{
> + struct fs_info fs;
> +
> + if (fsmonitor__get_fs_info(path, &fs))
> + return -1;
> +
> + free(fs.typename);
This will segfault if you take the part through fsmonitor__get_fs_info()
where we don't have the fs.typename yet, i.e. if statfs() fails.
There's the trivial NULL-init way to work around it, but I think this
suggests a leaky abstraction. If we fail to get the fs info, then the
function itself should have free'd that, shouldn't it?
> +/*
> + * No-op for now.
> + */
> +char *fsmonitor__resolve_alias(const char *path,
> + const struct alias_info *info)
Ditto misindentatione
next prev parent reply other threads:[~2022-12-12 10:47 UTC|newest]
Thread overview: 89+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-09 14:37 [PATCH 00/12] fsmonitor: Implement fsmonitor for Linux Eric DeCosta via GitGitGadget
2022-10-09 14:37 ` [PATCH 01/12] fsmonitor: refactor filesystem checks to common interface Eric DeCosta via GitGitGadget
2022-10-18 12:29 ` Ævar Arnfjörð Bjarmason
2022-10-09 14:37 ` [PATCH 02/12] fsmonitor: relocate socket file if .git directory is remote Eric DeCosta via GitGitGadget
2022-10-09 14:37 ` [PATCH 03/12] fsmonitor: avoid socket location check if using hook Eric DeCosta via GitGitGadget
2022-10-09 14:37 ` [PATCH 04/12] fsmonitor: deal with synthetic firmlinks on macOS Eric DeCosta via GitGitGadget
2022-10-09 14:37 ` [PATCH 05/12] fsmonitor: check for compatability before communicating with fsmonitor Eric DeCosta via GitGitGadget
2022-10-09 14:37 ` [PATCH 06/12] fsmonitor: add documentation for allowRemote and socketDir options Eric DeCosta via GitGitGadget
2022-10-09 14:37 ` [PATCH 07/12] fsmonitor: prepare to share code between Mac OS and Linux Eric DeCosta via GitGitGadget
2022-10-09 22:36 ` Junio C Hamano
2022-10-10 16:23 ` Jeff Hostetler
2022-10-09 14:37 ` [PATCH 08/12] fsmonitor: determine if filesystem is local or remote Eric DeCosta via GitGitGadget
2022-10-10 10:04 ` Ævar Arnfjörð Bjarmason
2022-10-14 19:38 ` Eric DeCosta
2022-10-09 14:37 ` [PATCH 09/12] fsmonitor: implement filesystem change listener for Linux Eric DeCosta via GitGitGadget
2022-10-09 14:37 ` [PATCH 10/12] fsmonitor: enable fsmonitor " Eric DeCosta via GitGitGadget
2022-10-09 14:37 ` [PATCH 11/12] fsmonitor: test updates Eric DeCosta via GitGitGadget
2022-10-18 12:42 ` Ævar Arnfjörð Bjarmason
2022-10-09 14:37 ` [PATCH 12/12] fsmonitor: update doc for Linux Eric DeCosta via GitGitGadget
2022-10-18 12:43 ` Ævar Arnfjörð Bjarmason
2022-10-09 22:24 ` [PATCH 00/12] fsmonitor: Implement fsmonitor " Junio C Hamano
2022-10-10 0:19 ` Eric Sunshine
2022-10-10 21:08 ` Junio C Hamano
2022-10-14 21:45 ` [PATCH v2 " Eric DeCosta via GitGitGadget
2022-10-14 21:45 ` [PATCH v2 01/12] fsmonitor: refactor filesystem checks to common interface Eric DeCosta via GitGitGadget
2022-10-14 21:45 ` [PATCH v2 02/12] fsmonitor: relocate socket file if .git directory is remote Eric DeCosta via GitGitGadget
2022-10-18 12:12 ` Ævar Arnfjörð Bjarmason
2022-10-14 21:45 ` [PATCH v2 03/12] fsmonitor: avoid socket location check if using hook Eric DeCosta via GitGitGadget
2022-10-14 21:45 ` [PATCH v2 04/12] fsmonitor: deal with synthetic firmlinks on macOS Eric DeCosta via GitGitGadget
2022-10-14 21:45 ` [PATCH v2 05/12] fsmonitor: check for compatability before communicating with fsmonitor Eric DeCosta via GitGitGadget
2022-10-14 21:45 ` [PATCH v2 06/12] fsmonitor: add documentation for allowRemote and socketDir options Eric DeCosta via GitGitGadget
2022-10-14 21:45 ` [PATCH v2 07/12] fsmonitor: prepare to share code between Mac OS and Linux Eric DeCosta via GitGitGadget
2022-10-14 23:46 ` Junio C Hamano
2022-10-17 21:30 ` Eric DeCosta
2022-10-18 6:31 ` Junio C Hamano
2022-10-14 21:45 ` [PATCH v2 08/12] fsmonitor: determine if filesystem is local or remote Eric DeCosta via GitGitGadget
2022-10-14 21:45 ` [PATCH v2 09/12] fsmonitor: implement filesystem change listener for Linux Eric DeCosta via GitGitGadget
2022-10-18 11:59 ` Ævar Arnfjörð Bjarmason
2022-10-14 21:45 ` [PATCH v2 10/12] fsmonitor: enable fsmonitor " Eric DeCosta via GitGitGadget
2022-10-14 21:45 ` [PATCH v2 11/12] fsmonitor: test updates Eric DeCosta via GitGitGadget
2022-10-14 21:45 ` [PATCH v2 12/12] fsmonitor: update doc for Linux Eric DeCosta via GitGitGadget
2022-10-14 23:32 ` [PATCH v2 00/12] fsmonitor: Implement fsmonitor " Junio C Hamano
2022-10-17 21:32 ` Eric DeCosta
2022-10-17 22:22 ` Junio C Hamano
2022-10-18 14:02 ` Johannes Schindelin
2022-10-17 22:14 ` Glen Choo
2022-10-18 4:17 ` Junio C Hamano
2022-10-18 17:03 ` Glen Choo
2022-10-18 17:11 ` Junio C Hamano
2022-10-19 1:19 ` Ævar Arnfjörð Bjarmason
2022-10-19 2:28 ` Eric Sunshine
2022-10-19 16:58 ` Junio C Hamano
2022-10-19 19:11 ` Ævar Arnfjörð Bjarmason
2022-10-19 20:14 ` Eric Sunshine
2022-10-19 1:04 ` Ævar Arnfjörð Bjarmason
2022-10-19 16:33 ` Junio C Hamano
2022-10-20 16:13 ` Junio C Hamano
2022-10-20 16:37 ` Eric Sunshine
2022-10-20 17:01 ` Junio C Hamano
2022-10-20 17:54 ` Eric Sunshine
2022-10-20 15:43 ` Junio C Hamano
2022-10-20 22:01 ` Junio C Hamano
2022-11-16 23:23 ` [PATCH v3 0/6] " Eric DeCosta via GitGitGadget
2022-11-16 23:23 ` [PATCH v3 1/6] fsmonitor: prepare to share code between Mac OS and Linux Eric DeCosta via GitGitGadget
2022-11-16 23:23 ` [PATCH v3 2/6] fsmonitor: determine if filesystem is local or remote Eric DeCosta via GitGitGadget
2022-11-16 23:23 ` [PATCH v3 3/6] fsmonitor: implement filesystem change listener for Linux Eric DeCosta via GitGitGadget
2022-11-16 23:23 ` [PATCH v3 4/6] fsmonitor: enable fsmonitor " Eric DeCosta via GitGitGadget
2022-11-16 23:23 ` [PATCH v3 5/6] fsmonitor: test updates Eric DeCosta via GitGitGadget
2022-11-16 23:23 ` [PATCH v3 6/6] fsmonitor: update doc for Linux Eric DeCosta via GitGitGadget
2022-11-16 23:27 ` [PATCH v3 0/6] fsmonitor: Implement fsmonitor " Taylor Blau
2022-11-23 19:00 ` [PATCH v4 " Eric DeCosta via GitGitGadget
2022-11-23 19:00 ` [PATCH v4 1/6] fsmonitor: prepare to share code between Mac OS and Linux Eric DeCosta via GitGitGadget
2022-11-23 19:00 ` [PATCH v4 2/6] fsmonitor: determine if filesystem is local or remote Eric DeCosta via GitGitGadget
2022-11-25 7:31 ` Junio C Hamano
2022-12-12 10:24 ` Ævar Arnfjörð Bjarmason [this message]
2022-11-23 19:00 ` [PATCH v4 3/6] fsmonitor: implement filesystem change listener for Linux Eric DeCosta via GitGitGadget
2022-12-12 10:42 ` Ævar Arnfjörð Bjarmason
2022-11-23 19:00 ` [PATCH v4 4/6] fsmonitor: enable fsmonitor " Eric DeCosta via GitGitGadget
2022-11-23 19:00 ` [PATCH v4 5/6] fsmonitor: test updates Eric DeCosta via GitGitGadget
2022-11-23 19:00 ` [PATCH v4 6/6] fsmonitor: update doc for Linux Eric DeCosta via GitGitGadget
2022-12-12 21:57 ` [PATCH v5 0/6] fsmonitor: Implement fsmonitor " Eric DeCosta via GitGitGadget
2022-12-12 21:58 ` [PATCH v5 1/6] fsmonitor: prepare to share code between Mac OS and Linux Eric DeCosta via GitGitGadget
2022-12-12 21:58 ` [PATCH v5 2/6] fsmonitor: determine if filesystem is local or remote Eric DeCosta via GitGitGadget
2022-12-12 21:58 ` [PATCH v5 3/6] fsmonitor: implement filesystem change listener for Linux Eric DeCosta via GitGitGadget
2022-12-12 21:58 ` [PATCH v5 4/6] fsmonitor: enable fsmonitor " Eric DeCosta via GitGitGadget
2022-12-12 21:58 ` [PATCH v5 5/6] fsmonitor: test updates Eric DeCosta via GitGitGadget
2022-12-12 21:58 ` [PATCH v5 6/6] fsmonitor: update doc for Linux Eric DeCosta via GitGitGadget
2023-04-12 5:42 ` [PATCH v5 0/6] fsmonitor: Implement fsmonitor " Junio C Hamano
2022-10-18 12:47 ` [PATCH 00/12] " Ævar Arnfjörð Bjarmason
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