Prebaked scripts for zpool status/iostat -c

This patch updates the "zpool status/iostat -c" commands to only run
"pre-baked" scripts from the /etc/zfs/zpool.d directory (or wherever
you install to).  The scripts can only be run from -c as an unprivileged
user (unless the ZPOOL_SCRIPTS_AS_ROOT environment var is
set by root).  This was done to encourage scripts to be written is such
a way that normal users can use them, and to be cautious.  If your
script needs to run a privileged command, consider adding the
appropriate line in /etc/sudoers.  See zpool(8) for an example of how
to do this.

The patch also allows the scripts to output custom column names.  If
the script outputs a line like:

name=value

then "name" is used for the column name, and "value" is its value.
Multiple columns can be specified by outputting multiple lines.  Column
names and values can have spaces.  If the value is empty, a dash (-) is
printed instead.

After all the "name=value" lines are read (if any), zpool will take the
next the next line of output (if any) and print it without a column
header.  After that, no more lines will be processed. This can be
useful for printing errors.

Lastly, this patch also disables the -c option with the latency and
request size histograms, since it produced awkward output and made the
code harder to maintain.

Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed-by: Giuseppe Di Natale <[email protected]>
Signed-off-by: Tony Hutter <[email protected]>
Closes #5852 

1 files changed, 251 insertions, 36 deletions

diff --git a/cmd/zpool/zpool_main.c b/cmd/zpool/zpool_main.c
index cc6c18eed..4b67bfde0 100644
--- a/cmd/zpool/zpool_main.c
+++ b/cmd/zpool/zpool_main.c
@@ -45,6 +45,7 @@
 #include <unistd.h>
 #include <pwd.h>
 #include <zone.h>
+#include <sys/wait.h>
 #include <zfs_prop.h>
 #include <sys/fs/zfs.h>
 #include <sys/stat.h>
@@ -52,6 +53,7 @@
 #include <sys/fm/util.h>
 #include <sys/fm/protocol.h>
 #include <sys/zfs_ioctl.h>
+
 #include <math.h>
 
 #include <libzfs.h>
@@ -314,10 +316,10 @@ get_usage(zpool_help_t idx)
 		    "[-R root] [-F [-n]]\n"
 		    "\t    <pool | id> [newpool]\n"));
 	case HELP_IOSTAT:
-		return (gettext("\tiostat [-c CMD] [-T d | u] [-ghHLpPvy] "
-		    "[[-lq]|[-r|-w]]\n"
-		    "\t    [[pool ...]|[pool vdev ...]|[vdev ...]] "
-		    "[interval [count]]\n"));
+		return (gettext("\tiostat [[[-c [script1,script2,...]"
+		    "[-lq]]|[-rw]] [-T d | u] [-ghHLpPvy]\n"
+		    "\t    [[pool ...]|[pool vdev ...]|[vdev ...]]"
+		    " [interval [count]]\n"));
 	case HELP_LABELCLEAR:
 		return (gettext("\tlabelclear [-f] <vdev>\n"));
 	case HELP_LIST:
@@ -337,8 +339,8 @@ get_usage(zpool_help_t idx)
 	case HELP_SCRUB:
 		return (gettext("\tscrub [-s] <pool> ...\n"));
 	case HELP_STATUS:
-		return (gettext("\tstatus [-c CMD] [-gLPvxD] [-T d|u] [pool]"
-		    " ... [interval [count]]\n"));
+		return (gettext("\tstatus [-c [script1,script2,...]] [-gLPvxD]"
+		    "[-T d|u] [pool] ... [interval [count]]\n"));
 	case HELP_UPGRADE:
 		return (gettext("\tupgrade\n"
 		    "\tupgrade -v\n"
@@ -1542,17 +1544,68 @@ typedef struct status_cbdata {
 	vdev_cmd_data_list_t	*vcdl;
 } status_cbdata_t;
 
-/* Print output line for specific vdev in a specific pool */
+/* Return 1 if string is NULL, empty, or whitespace; return 0 otherwise. */
+static int
+is_blank_str(char *str)
+{
+	while (str != NULL && *str != '\0') {
+		if (!isblank(*str))
+			return (0);
+		str++;
+	}
+	return (1);
+}
+
+/* Print command output lines for specific vdev in a specific pool */
 static void
 zpool_print_cmd(vdev_cmd_data_list_t *vcdl, const char *pool, char *path)
 {
-	int i;
+	vdev_cmd_data_t *data;
+	int i, j;
+	char *val;
+
 	for (i = 0; i < vcdl->count; i++) {
-		if ((strcmp(vcdl->data[i].path, path) == 0) &&
-		    (strcmp(vcdl->data[i].pool, pool) == 0)) {
-			printf("%s", vcdl->data[i].line);
-			break;
+		if ((strcmp(vcdl->data[i].path, path) != 0) ||
+		    (strcmp(vcdl->data[i].pool, pool) != 0)) {
+			/* Not the vdev we're looking for */
+			continue;
 		}
+
+		data = &vcdl->data[i];
+		/* Print out all the output values for this vdev */
+		for (j = 0; j < vcdl->uniq_cols_cnt; j++) {
+			val = NULL;
+			/* Does this vdev have values for this column? */
+			for (int k = 0; k < data->cols_cnt; k++) {
+				if (strcmp(data->cols[k],
+				    vcdl->uniq_cols[j]) == 0) {
+					/* yes it does, record the value */
+					val = data->lines[k];
+					break;
+				}
+			}
+			/*
+			 * Mark empty values with dashes to make output
+			 * awk-able.
+			 */
+			if (is_blank_str(val))
+				val = "-";
+
+			printf("%*s", vcdl->uniq_cols_width[j], val);
+			if (j < vcdl->uniq_cols_cnt - 1)
+				printf("  ");
+		}
+
+		/* Print out any values that aren't in a column at the end */
+		for (j = data->cols_cnt; j < data->lines_cnt; j++) {
+			/* Did we have any columns?  If so print a spacer. */
+			if (vcdl->uniq_cols_cnt > 0)
+				printf("  ");
+
+			val = data->lines[j];
+			printf("%s", val ? val : "");
+		}
+		break;
 	}
 }
 
@@ -2799,9 +2852,54 @@ print_iostat_labels(iostat_cbdata_t *cb, unsigned int force_column_width,
 
 		}
 	}
-	printf("\n");
 }
 
+
+/*
+ * print_cmd_columns - Print custom column titles from -c
+ *
+ * If the user specified the "zpool status|iostat -c" then print their custom
+ * column titles in the header.  For example, print_cmd_columns() would print
+ * the "  col1  col2" part of this:
+ *
+ * $ zpool iostat -vc 'echo col1=val1; echo col2=val2'
+ * ...
+ *	      capacity     operations     bandwidth
+ * pool        alloc   free   read  write   read  write  col1  col2
+ * ----------  -----  -----  -----  -----  -----  -----  ----  ----
+ * mypool       269K  1008M      0      0    107    946
+ *   mirror     269K  1008M      0      0    107    946
+ *     sdb         -      -      0      0    102    473  val1  val2
+ *     sdc         -      -      0      0      5    473  val1  val2
+ * ----------  -----  -----  -----  -----  -----  -----  ----  ----
+ */
+void
+print_cmd_columns(vdev_cmd_data_list_t *vcdl, int use_dashes)
+{
+	int i, j;
+	vdev_cmd_data_t *data = &vcdl->data[0];
+
+	if (vcdl->count == 0 || data == NULL)
+		return;
+
+	/*
+	 * Each vdev cmd should have the same column names unless the user did
+	 * something weird with their cmd.  Just take the column names from the
+	 * first vdev and assume it works for all of them.
+	 */
+	for (i = 0; i < vcdl->uniq_cols_cnt; i++) {
+		printf("  ");
+		if (use_dashes) {
+			for (j = 0; j < vcdl->uniq_cols_width[i]; j++)
+				printf("-");
+		} else {
+			printf("%*s", vcdl->uniq_cols_width[i],
+			    vcdl->uniq_cols[i]);
+		}
+	}
+}
+
+
 /*
  * Utility function to print out a line of dashes like:
  *
@@ -2870,7 +2968,6 @@ print_iostat_dashes(iostat_cbdata_t *cb, unsigned int force_column_width,
 				    "--------------------");
 		}
 	}
-	printf("\n");
 }
 
 
@@ -2912,12 +3009,22 @@ print_iostat_header_impl(iostat_cbdata_t *cb, unsigned int force_column_width,
 
 
 	print_iostat_labels(cb, force_column_width, iostat_top_labels);
+	printf("\n");
 
 	printf("%-*s", namewidth, title);
 
 	print_iostat_labels(cb, force_column_width, iostat_bottom_labels);
+	if (cb->vcdl != NULL)
+		print_cmd_columns(cb->vcdl, 0);
+
+	printf("\n");
 
 	print_iostat_separator_impl(cb, force_column_width);
+
+	if (cb->vcdl != NULL)
+		print_cmd_columns(cb->vcdl, 1);
+
+	printf("\n");
 }
 
 static void
@@ -3451,11 +3558,8 @@ print_vdev_stats(zpool_handle_t *zhp, const char *name, nvlist_t *oldnv,
 		char *path;
 		if (nvlist_lookup_string(newnv, ZPOOL_CONFIG_PATH,
 		    &path) == 0) {
-			if (!(cb->cb_flags & IOS_ANYHISTO_M))
-				printf("  ");
+			printf("  ");
 			zpool_print_cmd(cb->vcdl, zpool_get_name(zhp), path);
-			if (cb->cb_flags & IOS_ANYHISTO_M)
-				printf("\n");
 		}
 	}
 
@@ -3602,6 +3706,10 @@ print_iostat(zpool_handle_t *zhp, void *data)
 	if ((ret != 0) && !(cb->cb_flags & IOS_ANYHISTO_M) &&
 	    !cb->cb_scripted && cb->cb_verbose && !cb->cb_vdev_names_count) {
 		print_iostat_separator(cb);
+		if (cb->vcdl != NULL) {
+			print_cmd_columns(cb->vcdl, 1);
+		}
+		printf("\n");
 	}
 
 	return (ret);
@@ -3990,11 +4098,72 @@ fsleep(float sec)
 	nanosleep(&req, NULL);
 }
 
+/*
+ * Run one of the zpool status/iostat -c scripts with the help (-h) option and
+ * print the result.
+ *
+ * name:	Short name of the script ('iostat').
+ * path:	Full path to the script ('/usr/local/etc/zfs/zpool.d/iostat');
+ */
+static void
+print_zpool_script_help(char *name, char *path)
+{
+	char *argv[] = {path, "-h", NULL};
+	char **lines = NULL;
+	int lines_cnt = 0;
+	int rc;
+
+	rc = libzfs_run_process_get_stdout_nopath(path, argv, NULL, &lines,
+	    &lines_cnt);
+	if (rc != 0 || lines == NULL || lines_cnt <= 0)
+		return;
+
+	for (int i = 0; i < lines_cnt; i++)
+		if (!is_blank_str(lines[i]))
+			printf("  %-14s  %s\n", name, lines[i]);
+
+	libzfs_free_str_array(lines, lines_cnt);
+}
+
 
 /*
- * zpool iostat [-c CMD] [-ghHLpPvy] [[-lq]|[-r|-w]] [-n name] [-T d|u]
- *		[[ pool ...]|[pool vdev ...]|[vdev ...]]
- *		[interval [count]]
+ * Go though the list of all the zpool status/iostat -c scripts, run their
+ * help option (-h), and print out the results.
+ */
+static void
+print_zpool_script_list(void)
+{
+	DIR *dir;
+	struct dirent *ent;
+	char fullpath[MAXPATHLEN];
+	struct stat dir_stat;
+
+	if ((dir = opendir(ZPOOL_SCRIPTS_DIR)) != NULL) {
+		printf("\n");
+		/* print all the files and directories within directory */
+		while ((ent = readdir(dir)) != NULL) {
+			sprintf(fullpath, "%s/%s", ZPOOL_SCRIPTS_DIR,
+			    ent->d_name);
+
+			/* Print the scripts */
+			if (stat(fullpath, &dir_stat) == 0)
+				if (dir_stat.st_mode & S_IXUSR &&
+				    S_ISREG(dir_stat.st_mode))
+					print_zpool_script_help(ent->d_name,
+					    fullpath);
+		}
+		printf("\n");
+		closedir(dir);
+	} else {
+		fprintf(stderr, gettext("Can't open %s scripts dir\n"),
+		    ZPOOL_SCRIPTS_DIR);
+	}
+}
+
+/*
+ * zpool iostat [[-c [script1,script2,...]] [-lq]|[-rw]] [-ghHLpPvy] [-n name]
+ *              [-T d|u] [[ pool ...]|[pool vdev ...]|[vdev ...]]
+ *              [interval [count]]
  *
  *	-c CMD  For each vdev, run command CMD
  *	-g	Display guid for individual vdev name.
@@ -4046,7 +4215,20 @@ zpool_do_iostat(int argc, char **argv)
 	while ((c = getopt(argc, argv, "c:gLPT:vyhplqrwH")) != -1) {
 		switch (c) {
 		case 'c':
+			if (cmd != NULL) {
+				fprintf(stderr,
+				    gettext("Can't set -c flag twice\n"));
+				exit(1);
+			}
+			if ((getuid() <= 0 || geteuid() <= 0) &&
+			    !libzfs_envvar_is_set("ZPOOL_SCRIPTS_AS_ROOT")) {
+				fprintf(stderr, gettext(
+				    "Can't run -c with root privileges "
+				    "unless ZPOOL_SCRIPTS_AS_ROOT is set.\n"));
+				exit(1);
+			}
 			cmd = optarg;
+			verbose = B_TRUE;
 			break;
 		case 'g':
 			guid = B_TRUE;
@@ -4089,8 +4271,11 @@ zpool_do_iostat(int argc, char **argv)
 			break;
 		case '?':
 			if (optopt == 'c') {
-				fprintf(stderr,
-				    gettext("Missing CMD for -c\n"));
+				fprintf(stderr, gettext(
+				    "Current scripts in %s:\n"),
+				    ZPOOL_SCRIPTS_DIR);
+				print_zpool_script_list();
+				exit(0);
 			} else {
 				fprintf(stderr,
 				    gettext("invalid option '%c'\n"), optopt);
@@ -4185,10 +4370,10 @@ zpool_do_iostat(int argc, char **argv)
 		return (1);
 	}
 
-	if ((l_histo || rq_histo) && (queues || latency)) {
+	if ((l_histo || rq_histo) && (cmd != NULL || latency || queues)) {
 		pool_list_free(list);
 		(void) fprintf(stderr,
-		    gettext("[-r|-w] isn't allowed with [-q|-l]\n"));
+		    gettext("[-r|-w] isn't allowed with [-c|-l|-q]\n"));
 		usage(B_FALSE);
 		return (1);
 	}
@@ -4276,6 +4461,15 @@ zpool_do_iostat(int argc, char **argv)
 			if (timestamp_fmt != NODATE)
 				print_timestamp(timestamp_fmt);
 
+			if (cmd != NULL && cb.cb_verbose &&
+			    !(cb.cb_flags & IOS_ANYHISTO_M)) {
+				cb.vcdl = all_pools_for_each_vdev_run(argc,
+				    argv, cmd, g_zfs, cb.cb_vdev_names,
+				    cb.cb_vdev_names_count, cb.cb_name_flags);
+			} else {
+				cb.vcdl = NULL;
+			}
+
 			/*
 			 * If it's the first time and we're not skipping it,
 			 * or either skip or verbose mode, print the header.
@@ -4294,16 +4488,9 @@ zpool_do_iostat(int argc, char **argv)
 				continue;
 			}
 
-			if (cmd != NULL && cb.cb_verbose)
-				cb.vcdl = all_pools_for_each_vdev_run(argc,
-				    argv, cmd, g_zfs, cb.cb_vdev_names,
-				    cb.cb_vdev_names_count, cb.cb_name_flags);
 
 			pool_list_iter(list, B_FALSE, print_iostat, &cb);
 
-			if (cb.vcdl != NULL)
-				free_vdev_cmd_data_list(cb.vcdl);
-
 			/*
 			 * If there's more than one pool, and we're not in
 			 * verbose mode (which prints a separator for us),
@@ -4318,7 +4505,14 @@ zpool_do_iostat(int argc, char **argv)
 			    cb.cb_vdev_names_count)) &&
 			    !cb.cb_scripted) {
 				print_iostat_separator(&cb);
+				if (cb.vcdl != NULL)
+					print_cmd_columns(cb.vcdl, 1);
+				printf("\n");
 			}
+
+			if (cb.vcdl != NULL)
+				free_vdev_cmd_data_list(cb.vcdl);
+
 		}
 
 		/*
@@ -6036,9 +6230,14 @@ status_callback(zpool_handle_t *zhp, void *data)
 			cbp->cb_namewidth = 10;
 
 		(void) printf(gettext("config:\n\n"));
-		(void) printf(gettext("\t%-*s  %-8s %5s %5s %5s\n"),
+		(void) printf(gettext("\t%-*s  %-8s %5s %5s %5s"),
 		    cbp->cb_namewidth, "NAME", "STATE", "READ", "WRITE",
 		    "CKSUM");
+
+		if (cbp->vcdl != NULL)
+			print_cmd_columns(cbp->vcdl, 0);
+
+		printf("\n");
 		print_status_config(zhp, cbp, zpool_get_name(zhp), nvroot, 0,
 		    B_FALSE);
 
@@ -6098,7 +6297,8 @@ status_callback(zpool_handle_t *zhp, void *data)
 }
 
 /*
- * zpool status [-c CMD] [-gLPvx] [-T d|u] [pool] ... [interval [count]]
+ * zpool status [-c [script1,script2,...]] [-gLPvx] [-T d|u] [pool] ...
+ *              [interval [count]]
  *
  *	-c CMD	For each vdev, run command CMD
  *	-g	Display guid for individual vdev name.
@@ -6125,6 +6325,18 @@ zpool_do_status(int argc, char **argv)
 	while ((c = getopt(argc, argv, "c:gLPvxDT:")) != -1) {
 		switch (c) {
 		case 'c':
+			if (cmd != NULL) {
+				fprintf(stderr,
+				    gettext("Can't set -c flag twice\n"));
+				exit(1);
+			}
+			if ((getuid() <= 0 || geteuid() <= 0) &&
+			    !libzfs_envvar_is_set("ZPOOL_SCRIPTS_AS_ROOT")) {
+				fprintf(stderr, gettext(
+				    "Can't run -c with root privileges "
+				    "unless ZPOOL_SCRIPTS_AS_ROOT is set.\n"));
+				exit(1);
+			}
 			cmd = optarg;
 			break;
 		case 'g':
@@ -6150,8 +6362,11 @@ zpool_do_status(int argc, char **argv)
 			break;
 		case '?':
 			if (optopt == 'c') {
-				fprintf(stderr,
-				    gettext("Missing CMD for -c\n"));
+				fprintf(stderr, gettext(
+				    "Current scripts in %s:\n"),
+				    ZPOOL_SCRIPTS_DIR);
+				print_zpool_script_list();
+				exit(0);
 			} else {
 				fprintf(stderr,
 				    gettext("invalid option '%c'\n"), optopt);