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Improve libzfs api for zfs diff and add JSON support #18299

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141 changes: 138 additions & 3 deletions cmd/zfs/zfs_main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -413,7 +413,7 @@ get_usage(zfs_help_t idx)
case HELP_RELEASE:
return (gettext("\trelease [-r] <tag> <snapshot> ...\n"));
case HELP_DIFF:
return (gettext("\tdiff [-FHth] <snapshot> "
return (gettext("\tdiff [-FHthj] <snapshot> "
"[snapshot|filesystem]\n"));
case HELP_BOOKMARK:
return (gettext("\tbookmark <snapshot|bookmark> "
Expand Down Expand Up @@ -8064,6 +8064,128 @@ find_command_idx(const char *command, int *idx)
return (1);
}

typedef struct diff_json_cbdata {
boolean_t timestamped;
} diff_json_cbdata_t;

/*
* Populate the "changes" sub-object of a diff JSON entry with the specific
* attributes that changed: rename destination path, nlink {from,to},
* mode {from,to}, and ctime {from,to}. The object is omitted entirely when
* there is nothing to report.
*/
static void
diff_json_add_changes(nvlist_t *nvl, zfs_diff_entry_t *entry,
boolean_t timestamped)
{
if (!timestamped && entry->de_type != ZFS_DIFF_RENAMED &&
entry->de_nlink_from == 0 && entry->de_mode_from == 0)
return;

nvlist_t *changes = fnvlist_alloc();

if (entry->de_type == ZFS_DIFF_RENAMED)
fnvlist_add_string(changes, "path", entry->de_path);
if (entry->de_nlink_from != 0) {
nvlist_t *nlink = fnvlist_alloc();
fnvlist_add_uint64(nlink, "from", entry->de_nlink_from);
fnvlist_add_uint64(nlink, "to", entry->de_nlink);
fnvlist_add_nvlist(changes, "nlink", nlink);
fnvlist_free(nlink);
}
if (entry->de_mode_from != 0) {
nvlist_t *mode = fnvlist_alloc();
fnvlist_add_uint64(mode, "from", entry->de_mode_from);
fnvlist_add_uint64(mode, "to", entry->de_mode);
fnvlist_add_nvlist(changes, "mode", mode);
fnvlist_free(mode);
}
if (timestamped) {
nvlist_t *ctime = fnvlist_alloc();
if (entry->de_ctime_from[0] || entry->de_ctime_from[1])
fnvlist_add_uint64_array(ctime, "from",
entry->de_ctime_from, 2);
if (entry->de_ctime_to[0] || entry->de_ctime_to[1])
fnvlist_add_uint64_array(ctime, "to",
entry->de_ctime_to, 2);
fnvlist_add_nvlist(changes, "ctime", ctime);
fnvlist_free(ctime);
}

fnvlist_add_nvlist(nvl, "changes", changes);
fnvlist_free(changes);
}

static int
diff_json_callback(zfs_diff_entry_t *entry, void *arg)
{
diff_json_cbdata_t *cbd = arg;
nvlist_t *nvl;
const char *type_str;
const char *file_type;
mode_t m = (mode_t)entry->de_mode;

switch (entry->de_type) {
case ZFS_DIFF_ADDED:
type_str = "added";
break;
case ZFS_DIFF_REMOVED:
type_str = "removed";
break;
case ZFS_DIFF_MODIFIED:
type_str = "modified";
break;
case ZFS_DIFF_RENAMED:
type_str = "renamed";
break;
default:
type_str = "unknown";
break;
}

if (S_ISREG(m))
file_type = "regular";
else if (S_ISDIR(m))
file_type = "directory";
else if (S_ISLNK(m))
file_type = "symlink";
else if (S_ISBLK(m))
file_type = "block";
else if (S_ISCHR(m))
file_type = "char";
else if (S_ISFIFO(m))
file_type = "fifo";
else if (S_ISSOCK(m))
file_type = "socket";
#ifdef S_IFDOOR
else if ((m & S_IFMT) == S_IFDOOR)
file_type = "door";
#endif
#ifdef S_IFPORT
else if ((m & S_IFMT) == S_IFPORT)
file_type = "port";
#endif
else
file_type = "unknown";

nvl = fnvlist_alloc();
fnvlist_add_string(nvl, "change_type", type_str);
fnvlist_add_string(nvl, "mountpoint", entry->de_mntpt);
fnvlist_add_uint64(nvl, "inode", entry->de_inode);
fnvlist_add_uint64(nvl, "gen", entry->de_gen);
fnvlist_add_string(nvl, "file_type", file_type);
fnvlist_add_string(nvl, "path",
entry->de_type == ZFS_DIFF_RENAMED ?
entry->de_path2 : entry->de_path);

diff_json_add_changes(nvl, entry, cbd->timestamped);

(void) nvlist_print_json(stdout, nvl);
(void) fputc('\n', stdout);
fnvlist_free(nvl);
return (0);
}

static int
zfs_do_diff(int argc, char **argv)
{
Expand All @@ -8075,8 +8197,9 @@ zfs_do_diff(int argc, char **argv)
int err = 0;
int c;
struct sigaction sa;
boolean_t json = B_FALSE;

while ((c = getopt(argc, argv, "FHth")) != -1) {
while ((c = getopt(argc, argv, "FHthj")) != -1) {
switch (c) {
case 'F':
flags |= ZFS_DIFF_CLASSIFY;
Expand All @@ -8090,6 +8213,9 @@ zfs_do_diff(int argc, char **argv)
case 'h':
flags |= ZFS_DIFF_NO_MANGLE;
break;
case 'j':
json = B_TRUE;
break;
default:
(void) fprintf(stderr,
gettext("invalid option '%c'\n"), optopt);
Expand Down Expand Up @@ -8146,7 +8272,16 @@ zfs_do_diff(int argc, char **argv)
goto out;
}

err = zfs_show_diffs(zhp, STDOUT_FILENO, fromsnap, tosnap, flags);
if (json) {
diff_json_cbdata_t cbd = { 0 };
cbd.timestamped = (flags & ZFS_DIFF_TIMESTAMP) != 0;

err = zfs_iter_diffs(zhp, fromsnap, tosnap, flags,
diff_json_callback, &cbd);
} else {
err = zfs_show_diffs(zhp, STDOUT_FILENO, fromsnap, tosnap,
flags);
}
out:
zfs_close(zhp);

Expand Down
63 changes: 63 additions & 0 deletions include/libzfs.h
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Original file line number Diff line number Diff line change
Expand Up @@ -941,8 +941,71 @@ typedef enum diff_flags {
ZFS_DIFF_NO_MANGLE = 1 << 3
} diff_flags_t;

typedef enum zfs_diff_type {
ZFS_DIFF_ADDED = '+',
ZFS_DIFF_REMOVED = '-',
ZFS_DIFF_MODIFIED = 'M',
ZFS_DIFF_RENAMED = 'R',
} zfs_diff_type_t;

typedef struct zfs_diff_entry {
zfs_diff_type_t de_type;

/* ctime [seconds, nanoseconds] in from-snapshot; zero for added */
uint64_t de_ctime_from[2];

/* dataset mount point; prepend to de_path / de_path2 for full path */
const char *de_mntpt;

/* relative path in tosnap (adds/modifies) or fromsnap (removes) */
const char *de_path;

/* relative rename destination; NULL unless ZFS_DIFF_RENAMED */
const char *de_path2;

/* ZFS object number, equals st_ino */
uint64_t de_inode;

/* txg in which the object was created; lower 32 bits equal st_gen */
uint64_t de_gen;

/* full POSIX mode word (type bits + permission bits) */
uint64_t de_mode;

/* hard link count */
uint64_t de_nlink;

/* ctime [seconds, nanoseconds] in to-snapshot; zero for removed */
uint64_t de_ctime_to[2];

/*
* The following fields are set for ZFS_DIFF_MODIFIED entries only.
*/

/* nlink in from-snapshot; 0 if nlink did not change */
uint64_t de_nlink_from;

/* mode in from-snapshot; 0 if mode did not change */
uint64_t de_mode_from;
} zfs_diff_entry_t;

/*
* Callback for zfs_iter_diffs(). Return non-zero to abort iteration.
*
* Some snapshot management operations are blocked for the duration of the
* zfs_iter_diffs() call, so long-running work inside the callback is not
* advisable.
*
* The entry and the strings it points to (de_mntpt, de_path, de_path2) are
* stack-allocated and valid only for the duration of the call. Make a copy
* if any of them need to outlive the callback.
*/
typedef int (*zfs_diff_cb_t)(zfs_diff_entry_t *entry, void *arg);

_LIBZFS_H int zfs_show_diffs(zfs_handle_t *, int, const char *, const char *,
int);
_LIBZFS_H int zfs_iter_diffs(zfs_handle_t *, const char *, const char *,
int, zfs_diff_cb_t, void *);

/*
* Miscellaneous functions.
Expand Down
69 changes: 69 additions & 0 deletions lib/libzfs/libzfs.abi
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Original file line number Diff line number Diff line change
Expand Up @@ -408,6 +408,7 @@
<elf-symbol name='zfs_iter_children_v2' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
<elf-symbol name='zfs_iter_dependents' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
<elf-symbol name='zfs_iter_dependents_v2' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
<elf-symbol name='zfs_iter_diffs' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
<elf-symbol name='zfs_iter_filesystems' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
<elf-symbol name='zfs_iter_filesystems_v2' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
<elf-symbol name='zfs_iter_mounted' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
Expand Down Expand Up @@ -5404,6 +5405,74 @@
<parameter type-id='eaa32e2f'/>
<return type-id='eaa32e2f'/>
</function-type>
<subrange-type id='zdf00001' length='2' type-id='7359adad'/>
<array-type-def dimensions='1' type-id='9c313c2d' size-in-bits='128' id='zdf00002'>
<subrange length='2' type-id='7359adad' id='zdf00001'/>
</array-type-def>
<enum-decl name='zfs_diff_type' id='zdf00003'>
<underlying-type type-id='95e97e5e'/>
<enumerator name='ZFS_DIFF_ADDED' value='43'/>
<enumerator name='ZFS_DIFF_MODIFIED' value='77'/>
<enumerator name='ZFS_DIFF_REMOVED' value='45'/>
<enumerator name='ZFS_DIFF_RENAMED' value='82'/>
</enum-decl>
<typedef-decl name='zfs_diff_type_t' type-id='zdf00003' id='zdf00004'/>
<class-decl name='zfs_diff_entry' size-in-bits='896' is-struct='yes' visibility='default' id='zdf00005'>
<data-member access='public' layout-offset-in-bits='0'>
<var-decl name='de_type' type-id='zdf00004' visibility='default'/>
</data-member>
<data-member access='public' layout-offset-in-bits='64'>
<var-decl name='de_ctime_from' type-id='zdf00002' visibility='default'/>
</data-member>
<data-member access='public' layout-offset-in-bits='192'>
<var-decl name='de_mntpt' type-id='80f4b756' visibility='default'/>
</data-member>
<data-member access='public' layout-offset-in-bits='256'>
<var-decl name='de_path' type-id='80f4b756' visibility='default'/>
</data-member>
<data-member access='public' layout-offset-in-bits='320'>
<var-decl name='de_path2' type-id='80f4b756' visibility='default'/>
</data-member>
<data-member access='public' layout-offset-in-bits='384'>
<var-decl name='de_inode' type-id='9c313c2d' visibility='default'/>
</data-member>
<data-member access='public' layout-offset-in-bits='448'>
<var-decl name='de_gen' type-id='9c313c2d' visibility='default'/>
</data-member>
<data-member access='public' layout-offset-in-bits='512'>
<var-decl name='de_mode' type-id='9c313c2d' visibility='default'/>
</data-member>
<data-member access='public' layout-offset-in-bits='576'>
<var-decl name='de_nlink' type-id='9c313c2d' visibility='default'/>
</data-member>
<data-member access='public' layout-offset-in-bits='640'>
<var-decl name='de_ctime_to' type-id='zdf00002' visibility='default'/>
</data-member>
<data-member access='public' layout-offset-in-bits='768'>
<var-decl name='de_nlink_from' type-id='9c313c2d' visibility='default'/>
</data-member>
<data-member access='public' layout-offset-in-bits='832'>
<var-decl name='de_mode_from' type-id='9c313c2d' visibility='default'/>
</data-member>
</class-decl>
<typedef-decl name='zfs_diff_entry_t' type-id='zdf00005' id='zdf00006'/>
<pointer-type-def type-id='zdf00006' size-in-bits='64' id='zdf0000a'/>
<function-type size-in-bits='64' id='zdf00007'>
<parameter type-id='zdf0000a'/>
<parameter type-id='eaa32e2f'/>
<return type-id='95e97e5e'/>
</function-type>
<pointer-type-def type-id='zdf00007' size-in-bits='64' id='zdf00008'/>
<typedef-decl name='zfs_diff_cb_t' type-id='zdf00008' id='zdf00009'/>
<function-decl name='zfs_iter_diffs' mangled-name='zfs_iter_diffs' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zfs_iter_diffs'>
<parameter type-id='9200a744' name='zhp'/>
<parameter type-id='80f4b756' name='fromsnap'/>
<parameter type-id='80f4b756' name='tosnap'/>
<parameter type-id='95e97e5e' name='flags'/>
<parameter type-id='zdf00009' name='cb'/>
<parameter type-id='eaa32e2f' name='cbarg'/>
<return type-id='95e97e5e'/>
</function-decl>
</abi-instr>
<abi-instr address-size='64' path='lib/libzfs/libzfs_import.c' language='LANG_C99'>
<array-type-def dimensions='1' type-id='03085adc' size-in-bits='192' id='083f8d58'>
Expand Down
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