Use setproctitle to report progress of zfs send

This allows parsing of zfs send progress by checking the process
title.
Doing so requires some changes to the send code in libzfs_sendrecv.c;
primarily these changes move some of the accounting around, to allow
for the code to be verbose as normal, or set the process title. Unlike
BSD, setproctitle() isn't standard in Linux; thus, borrowed it from
libbsd with slight modifications.

Authored-by: Sean Eric Fagan <[email protected]>
Co-authored-by: Ryan Moeller <[email protected]>
Co-authored-by: Ameer Hamza <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed-by: Ryan Moeller <[email protected]>
Signed-off-by: Ameer Hamza <[email protected]>
Closes openzfs#14376

Author: ixhamza

cmd/zfs/zfs_main.c

@@ -327,15 +327,15 @@ get_usage(zfs_help_t idx)
 	case HELP_ROLLBACK:
 		return (gettext("\trollback [-rRf] <snapshot>\n"));
 	case HELP_SEND:
-		return (gettext("\tsend [-DLPbcehnpsvw] "
+		return (gettext("\tsend [-DLPbcehnpsVvw] "
 		    "[-i|-I snapshot]\n"
 		    "\t     [-R [-X dataset[,dataset]...]]     <snapshot>\n"
-		    "\tsend [-DnvPLecw] [-i snapshot|bookmark] "
+		    "\tsend [-DnVvPLecw] [-i snapshot|bookmark] "
 		    "<filesystem|volume|snapshot>\n"
-		    "\tsend [-DnPpvLec] [-i bookmark|snapshot] "
+		    "\tsend [-DnPpVvLec] [-i bookmark|snapshot] "
 		    "--redact <bookmark> <snapshot>\n"
-		    "\tsend [-nvPe] -t <receive_resume_token>\n"
-		    "\tsend [-Pnv] --saved filesystem\n"));
+		    "\tsend [-nVvPe] -t <receive_resume_token>\n"
+		    "\tsend [-PnVv] --saved filesystem\n"));
 	case HELP_SET:
 		return (gettext("\tset <property=value> ... "
 		    "<filesystem|volume|snapshot> ...\n"));
@@ -4388,6 +4388,7 @@ zfs_do_send(int argc, char **argv)
 		{"props",	no_argument,		NULL, 'p'},
 		{"parsable",	no_argument,		NULL, 'P'},
 		{"dedup",	no_argument,		NULL, 'D'},
+		{"proctitle",	no_argument,		NULL, 'V'},
 		{"verbose",	no_argument,		NULL, 'v'},
 		{"dryrun",	no_argument,		NULL, 'n'},
 		{"large-block",	no_argument,		NULL, 'L'},
@@ -4403,7 +4404,7 @@ zfs_do_send(int argc, char **argv)
 	};
 
 	/* check options */
-	while ((c = getopt_long(argc, argv, ":i:I:RsDpvnPLeht:cwbd:SX:",
+	while ((c = getopt_long(argc, argv, ":i:I:RsDpVvnPLeht:cwbd:SX:",
 	    long_options, NULL)) != -1) {
 		switch (c) {
 		case 'X':
@@ -4452,6 +4453,9 @@ zfs_do_send(int argc, char **argv)
 		case 'P':
 			flags.parsable = B_TRUE;
 			break;
+		case 'V':
+			flags.progressastitle = B_TRUE;
+			break;
 		case 'v':
 			flags.verbosity++;
 			flags.progress = B_TRUE;
@@ -8668,6 +8672,7 @@ main(int argc, char **argv)
 	int i = 0;
 	const char *cmdname;
 	char **newargv;
+	extern char **environ;
 
 	(void) setlocale(LC_ALL, "");
 	(void) setlocale(LC_NUMERIC, "C");
@@ -8725,6 +8730,8 @@ main(int argc, char **argv)
 
 	libzfs_print_on_error(g_zfs, B_TRUE);
 
+	zfs_setproctitle_init(argc, argv, environ);
+
 	/*
 	 * Many commands modify input strings for string parsing reasons.
 	 * We create a copy to protect the original argv.

include/libzfs.h

@@ -740,6 +740,9 @@ typedef struct sendflags {
 	/* show progress (ie. -v) */
 	boolean_t progress;
 
+	/* show progress as process title (ie. -V) */
+	boolean_t progressastitle;
+
 	/* large blocks (>128K) are permitted */
 	boolean_t largeblock;
 

include/libzutil.h

@@ -182,6 +182,13 @@ _LIBZUTIL_H int printf_color(const char *color, const char *format, ...);
 
 _LIBZUTIL_H const char *zfs_basename(const char *path);
 _LIBZUTIL_H ssize_t zfs_dirnamelen(const char *path);
+#ifdef __linux__
+_LIBZUTIL_H void zfs_setproctitle_init(int argc, char *argv[], char *envp[]);
+_LIBZUTIL_H void zfs_setproctitle(const char *fmt, ...);
+#else
+#define	zfs_setproctitle(fmt, ...)	setproctitle(fmt, ##__VA_ARGS__)
+#define	zfs_setproctitle_init(x, y, z)	((void)0)
+#endif
 
 /*
  * These functions are used by the ZFS libraries and cmd/zpool code, but are

lib/libzfs/libzfs.abi

@@ -416,6 +416,8 @@
     <elf-symbol name='zfs_send_resume_token_to_nvlist' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='zfs_send_saved' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='zfs_set_fsacl' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
+    <elf-symbol name='zfs_setproctitle' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
+    <elf-symbol name='zfs_setproctitle_init' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='zfs_share' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='zfs_show_diffs' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='zfs_smb_acl_add' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
@@ -3834,6 +3836,11 @@
     <pointer-type-def type-id='9e59d1d4' size-in-bits='64' id='4ea84b4f'/>
     <pointer-type-def type-id='945467e6' size-in-bits='64' id='8def7735'/>
     <pointer-type-def type-id='3d3ffb69' size-in-bits='64' id='72a26210'/>
+    <function-decl name='zfs_setproctitle' mangled-name='zfs_setproctitle' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zfs_setproctitle'>
+      <parameter type-id='80f4b756'/>
+      <parameter is-variadic='yes'/>
+      <return type-id='48b5725f'/>
+    </function-decl>
     <function-decl name='zfs_send_progress' mangled-name='zfs_send_progress' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zfs_send_progress'>
       <parameter type-id='9200a744' name='zhp'/>
       <parameter type-id='95e97e5e' name='fd'/>
@@ -4525,6 +4532,12 @@
       <parameter type-id='5ce45b60' name='nv'/>
       <return type-id='48b5725f'/>
     </function-decl>
+    <function-decl name='zfs_setproctitle_init' mangled-name='zfs_setproctitle_init' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zfs_setproctitle_init'>
+      <parameter type-id='95e97e5e' name='argc'/>
+      <parameter type-id='9b23c9ad' name='argv'/>
+      <parameter type-id='9b23c9ad' name='envp'/>
+      <return type-id='48b5725f'/>
+    </function-decl>
   </abi-instr>
   <abi-instr address-size='64' path='lib/libzutil/zutil_device_path.c' language='LANG_C99'>
     <typedef-decl name='ssize_t' type-id='41060289' id='79a0948f'/>

lib/libzfs/libzfs_sendrecv.c

@@ -83,6 +83,8 @@ typedef struct progress_arg {
 	boolean_t pa_parsable;
 	boolean_t pa_estimate;
 	int pa_verbosity;
+	boolean_t pa_astitle;
+	uint64_t pa_size;
 } progress_arg_t;
 
 static int
@@ -733,6 +735,7 @@ typedef struct send_dump_data {
 	boolean_t seenfrom, seento, replicate, doall, fromorigin;
 	boolean_t dryrun, parsable, progress, embed_data, std_out;
 	boolean_t large_block, compress, raw, holds;
+	boolean_t progressastitle;
 	int outfd;
 	boolean_t err;
 	nvlist_t *fss;
@@ -931,12 +934,13 @@ send_progress_thread(void *arg)
 	zfs_handle_t *zhp = pa->pa_zhp;
 	uint64_t bytes;
 	uint64_t blocks;
+	uint64_t total = pa->pa_size / 100;
 	char buf[16];
 	time_t t;
 	struct tm tm;
 	int err;
 
-	if (!pa->pa_parsable) {
+	if (!pa->pa_parsable && pa->pa_verbosity != 0) {
 		(void) fprintf(stderr,
 		    "TIME       %s   %sSNAPSHOT %s\n",
 		    pa->pa_estimate ? "BYTES" : " SENT",
@@ -959,6 +963,17 @@ send_progress_thread(void *arg)
 		(void) time(&t);
 		localtime_r(&t, &tm);
 
+		if (pa->pa_astitle) {
+			char buf_bytes[16];
+			char buf_size[16];
+			int pct;
+			zfs_nicenum(bytes, buf_bytes, sizeof (buf_bytes));
+			zfs_nicenum(pa->pa_size, buf_size, sizeof (buf_size));
+			pct = (total > 0) ? bytes / total : 100;
+			zfs_setproctitle("sending %s (%d%%: %s/%s)",
+			    zhp->zfs_name, MIN(pct, 100), buf_bytes, buf_size);
+		}
+
 		if (pa->pa_verbosity >= 2 && pa->pa_parsable) {
 			(void) fprintf(stderr,
 			    "%02d:%02d:%02d\t%llu\t%llu\t%s\n",
@@ -975,7 +990,7 @@ send_progress_thread(void *arg)
 			(void) fprintf(stderr, "%02d:%02d:%02d\t%llu\t%s\n",
 			    tm.tm_hour, tm.tm_min, tm.tm_sec,
 			    (u_longlong_t)bytes, zhp->zfs_name);
-		} else {
+		} else if (pa->pa_verbosity != 0) {
 			zfs_nicebytes(bytes, buf, sizeof (buf));
 			(void) fprintf(stderr, "%02d:%02d:%02d   %5s   %s\n",
 			    tm.tm_hour, tm.tm_min, tm.tm_sec,
@@ -1183,12 +1198,14 @@ dump_snapshot(zfs_handle_t *zhp, void *arg)
 		 * If progress reporting is requested, spawn a new thread to
 		 * poll ZFS_IOC_SEND_PROGRESS at a regular interval.
 		 */
-		if (sdd->progress) {
+		if (sdd->progress || sdd->progressastitle) {
 			pa.pa_zhp = zhp;
 			pa.pa_fd = sdd->outfd;
 			pa.pa_parsable = sdd->parsable;
 			pa.pa_estimate = B_FALSE;
 			pa.pa_verbosity = sdd->verbosity;
+			pa.pa_size = sdd->size;
+			pa.pa_astitle = sdd->progressastitle;
 
 			if ((err = pthread_create(&tid, NULL,
 			    send_progress_thread, &pa)) != 0) {
@@ -1200,7 +1217,7 @@ dump_snapshot(zfs_handle_t *zhp, void *arg)
 		err = dump_ioctl(zhp, sdd->prevsnap, sdd->prevsnap_obj,
 		    fromorigin, sdd->outfd, flags, sdd->debugnv);
 
-		if (sdd->progress &&
+		if ((sdd->progress || sdd->progressastitle) &&
 		    send_progress_thread_exit(zhp->zfs_hdl, tid))
 			return (-1);
 	}
@@ -1536,15 +1553,15 @@ lzc_flags_from_sendflags(const sendflags_t *flags)
 static int
 estimate_size(zfs_handle_t *zhp, const char *from, int fd, sendflags_t *flags,
     uint64_t resumeobj, uint64_t resumeoff, uint64_t bytes,
-    const char *redactbook, char *errbuf)
+    const char *redactbook, char *errbuf, uint64_t *sizep)
 {
 	uint64_t size;
 	FILE *fout = flags->dryrun ? stdout : stderr;
 	progress_arg_t pa = { 0 };
 	int err = 0;
 	pthread_t ptid;
 
-	if (flags->progress) {
+	if (flags->progress || flags->progressastitle) {
 		pa.pa_zhp = zhp;
 		pa.pa_fd = fd;
 		pa.pa_parsable = flags->parsable;
@@ -1563,10 +1580,15 @@ estimate_size(zfs_handle_t *zhp, const char *from, int fd, sendflags_t *flags,
 	err = lzc_send_space_resume_redacted(zhp->zfs_name, from,
 	    lzc_flags_from_sendflags(flags), resumeobj, resumeoff, bytes,
 	    redactbook, fd, &size);
+	*sizep = size;
 
-	if (flags->progress && send_progress_thread_exit(zhp->zfs_hdl, ptid))
+	if ((flags->progress || flags->progressastitle) &&
+	    send_progress_thread_exit(zhp->zfs_hdl, ptid))
 		return (-1);
 
+	if (!flags->progress && !flags->parsable)
+		return (err);
+
 	if (err != 0) {
 		zfs_error_aux(zhp->zfs_hdl, "%s", strerror(err));
 		return (zfs_error(zhp->zfs_hdl, EZFS_BADBACKUP,
@@ -1743,6 +1765,7 @@ zfs_send_resume_impl_cb_impl(libzfs_handle_t *hdl, sendflags_t *flags,
 	uint64_t *redact_snap_guids = NULL;
 	int num_redact_snaps = 0;
 	char *redact_book = NULL;
+	uint64_t size = 0;
 
 	(void) snprintf(errbuf, sizeof (errbuf), dgettext(TEXT_DOMAIN,
 	    "cannot resume send"));
@@ -1828,7 +1851,7 @@ zfs_send_resume_impl_cb_impl(libzfs_handle_t *hdl, sendflags_t *flags,
 	enum lzc_send_flags lzc_flags = lzc_flags_from_sendflags(flags) |
 	    lzc_flags_from_resume_nvl(resume_nvl);
 
-	if (flags->verbosity != 0) {
+	if (flags->verbosity != 0 || flags->progressastitle) {
 		/*
 		 * Some of these may have come from the resume token, set them
 		 * here for size estimate purposes.
@@ -1845,7 +1868,7 @@ zfs_send_resume_impl_cb_impl(libzfs_handle_t *hdl, sendflags_t *flags,
 		if (lzc_flags & LZC_SEND_FLAG_SAVED)
 			tmpflags.saved = B_TRUE;
 		error = estimate_size(zhp, fromname, outfd, &tmpflags,
-		    resumeobj, resumeoff, bytes, redact_book, errbuf);
+		    resumeobj, resumeoff, bytes, redact_book, errbuf, &size);
 	}
 
 	if (!flags->dryrun) {
@@ -1855,12 +1878,14 @@ zfs_send_resume_impl_cb_impl(libzfs_handle_t *hdl, sendflags_t *flags,
 		 * If progress reporting is requested, spawn a new thread to
 		 * poll ZFS_IOC_SEND_PROGRESS at a regular interval.
 		 */
-		if (flags->progress) {
+		if (flags->progress || flags->progressastitle) {
 			pa.pa_zhp = zhp;
 			pa.pa_fd = outfd;
 			pa.pa_parsable = flags->parsable;
 			pa.pa_estimate = B_FALSE;
 			pa.pa_verbosity = flags->verbosity;
+			pa.pa_size = size;
+			pa.pa_astitle = flags->progressastitle;
 
 			error = pthread_create(&tid, NULL,
 			    send_progress_thread, &pa);
@@ -1877,8 +1902,11 @@ zfs_send_resume_impl_cb_impl(libzfs_handle_t *hdl, sendflags_t *flags,
 		if (redact_book != NULL)
 			free(redact_book);
 
-		if (flags->progress && send_progress_thread_exit(hdl, tid))
+		if ((flags->progressastitle || flags->progress) &&
+		    send_progress_thread_exit(hdl, tid)) {
+			zfs_close(zhp);
 			return (-1);
+		}
 
 		char errbuf[ERRBUFLEN];
 		(void) snprintf(errbuf, sizeof (errbuf), dgettext(TEXT_DOMAIN,
@@ -2313,6 +2341,7 @@ zfs_send_cb_impl(zfs_handle_t *zhp, const char *fromsnap, const char *tosnap,
 	sdd.verbosity = flags->verbosity;
 	sdd.parsable = flags->parsable;
 	sdd.progress = flags->progress;
+	sdd.progressastitle = flags->progressastitle;
 	sdd.dryrun = flags->dryrun;
 	sdd.large_block = flags->largeblock;
 	sdd.embed_data = flags->embed_data;
@@ -2562,6 +2591,7 @@ zfs_send_one_cb_impl(zfs_handle_t *zhp, const char *from, int fd,
 	char *name = zhp->zfs_name;
 	pthread_t ptid;
 	progress_arg_t pa = { 0 };
+	uint64_t size = 0;
 
 	char errbuf[ERRBUFLEN];
 	(void) snprintf(errbuf, sizeof (errbuf), dgettext(TEXT_DOMAIN,
@@ -2644,9 +2674,9 @@ zfs_send_one_cb_impl(zfs_handle_t *zhp, const char *from, int fd,
 	/*
 	 * Perform size estimate if verbose was specified.
 	 */
-	if (flags->verbosity != 0) {
+	if (flags->verbosity != 0 || flags->progressastitle) {
 		err = estimate_size(zhp, from, fd, flags, 0, 0, 0, redactbook,
-		    errbuf);
+		    errbuf, &size);
 		if (err != 0)
 			return (err);
 	}
@@ -2658,12 +2688,14 @@ zfs_send_one_cb_impl(zfs_handle_t *zhp, const char *from, int fd,
 	 * If progress reporting is requested, spawn a new thread to poll
 	 * ZFS_IOC_SEND_PROGRESS at a regular interval.
 	 */
-	if (flags->progress) {
+	if (flags->progress || flags->progressastitle) {
 		pa.pa_zhp = zhp;
 		pa.pa_fd = fd;
 		pa.pa_parsable = flags->parsable;
 		pa.pa_estimate = B_FALSE;
 		pa.pa_verbosity = flags->verbosity;
+		pa.pa_size = size;
+		pa.pa_astitle = flags->progressastitle;
 
 		err = pthread_create(&ptid, NULL,
 		    send_progress_thread, &pa);
@@ -2677,7 +2709,8 @@ zfs_send_one_cb_impl(zfs_handle_t *zhp, const char *from, int fd,
 	err = lzc_send_redacted(name, from, fd,
 	    lzc_flags_from_sendflags(flags), redactbook);
 
-	if (flags->progress && send_progress_thread_exit(hdl, ptid))
+	if ((flags->progress || flags->progressastitle) &&
+	    send_progress_thread_exit(hdl, ptid))
 			return (-1);
 
 	if (err == 0 && (flags->props || flags->holds || flags->backup)) {

lib/libzutil/Makefile.am

@@ -17,6 +17,7 @@ libzutil_la_SOURCES = \
 
 if BUILD_LINUX
 libzutil_la_SOURCES += \
+	%D%/os/linux/zutil_setproctitle.c \
 	%D%/os/linux/zutil_device_path_os.c \
 	%D%/os/linux/zutil_import_os.c
 endif