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, 238 insertions, 28 deletions

diff --git a/cmd/zpool/zpool_iter.c b/cmd/zpool/zpool_iter.c
index 7ce0ccf9e..94777f076 100644
--- a/cmd/zpool/zpool_iter.c
+++ b/cmd/zpool/zpool_iter.c
@@ -36,6 +36,7 @@
 
 #include <libzfs.h>
 #include <sys/zfs_context.h>
+#include <sys/wait.h>
 
 #include "zpool_util.h"
 
@@ -321,41 +322,229 @@ for_each_vdev(zpool_handle_t *zhp, pool_vdev_iter_f func, void *data)
 	return (for_each_vdev_cb(zhp, nvroot, func, data));
 }
 
+/*
+ * Process the vcdl->vdev_cmd_data[] array to figure out all the unique column
+ * names and their widths.  When this function is done, vcdl->uniq_cols,
+ * vcdl->uniq_cols_cnt, and vcdl->uniq_cols_width will be filled in.
+ */
+static void
+process_unique_cmd_columns(vdev_cmd_data_list_t *vcdl)
+{
+	char **uniq_cols = NULL, **tmp = NULL;
+	int *uniq_cols_width;
+	vdev_cmd_data_t *data;
+	int cnt = 0;
+	int k;
+
+	/* For each vdev */
+	for (int i = 0; i < vcdl->count; i++) {
+		data = &vcdl->data[i];
+		/* For each column the vdev reported */
+		for (int j = 0; j < data->cols_cnt; j++) {
+			/* Is this column in our list of unique column names? */
+			for (k = 0; k < cnt; k++) {
+				if (strcmp(data->cols[j], uniq_cols[k]) == 0)
+					break; /* yes it is */
+			}
+			if (k == cnt) {
+				/* No entry for column, add to list */
+				tmp = realloc(uniq_cols, sizeof (*uniq_cols) *
+				    (cnt + 1));
+				if (tmp == NULL)
+					break; /* Nothing we can do... */
+				uniq_cols = tmp;
+				uniq_cols[cnt] = data->cols[j];
+				cnt++;
+			}
+		}
+	}
+
+	/*
+	 * We now have a list of all the unique column names.  Figure out the
+	 * max width of each column by looking at the column name and all its
+	 * values.
+	 */
+	uniq_cols_width = safe_malloc(sizeof (*uniq_cols_width) * cnt);
+	for (int i = 0; i < cnt; i++) {
+		/* Start off with the column title's width */
+		uniq_cols_width[i] = strlen(uniq_cols[i]);
+		/* For each vdev */
+		for (int j = 0; j < vcdl->count; j++) {
+			/* For each of the vdev's values in a column */
+			data = &vcdl->data[j];
+			for (k = 0; k < data->cols_cnt; k++) {
+				/* Does this vdev have a value for this col? */
+				if (strcmp(data->cols[k], uniq_cols[i]) == 0) {
+					/* Is the value width larger? */
+					uniq_cols_width[i] =
+					    MAX(uniq_cols_width[i],
+					    strlen(data->lines[k]));
+				}
+			}
+		}
+	}
+
+	vcdl->uniq_cols = uniq_cols;
+	vcdl->uniq_cols_cnt = cnt;
+	vcdl->uniq_cols_width = uniq_cols_width;
+}
+
+
+/*
+ * Process a line of command output
+ *
+ * When running 'zpool iostat|status -c' the lines of output can either be
+ * in the form of:
+ *
+ *	column_name=value
+ *
+ * Or just:
+ *
+ *	value
+ *
+ * Process the column_name (if any) and value.
+ *
+ * Returns 0 if line was processed, and there are more lines can still be
+ * processed.
+ *
+ * Returns 1 if this was the last line to process, or error.
+ */
+static int
+vdev_process_cmd_output(vdev_cmd_data_t *data, char *line)
+{
+	char *col = NULL;
+	char *val = line;
+	char *equals;
+	char **tmp;
+
+	if (line == NULL)
+		return (1);
+
+	equals = strchr(line, '=');
+	if (equals != NULL) {
+		/*
+		 * We have a 'column=value' type line.  Split it into the
+		 * column and value strings by turning the '=' into a '\0'.
+		 */
+		*equals = '\0';
+		col = line;
+		val = equals + 1;
+	} else {
+		val = line;
+	}
+
+	/* Do we already have a column by this name?  If so, skip it. */
+	if (col != NULL) {
+		for (int i = 0; i < data->cols_cnt; i++) {
+			if (strcmp(col, data->cols[i]) == 0)
+				return (0); /* Duplicate, skip */
+		}
+	}
+
+	if (val != NULL) {
+		tmp = realloc(data->lines,
+		    (data->lines_cnt + 1) * sizeof (*data->lines));
+		if (tmp == NULL)
+			return (1);
+
+		data->lines = tmp;
+		data->lines[data->lines_cnt] = strdup(val);
+		data->lines_cnt++;
+	}
+
+	if (col != NULL) {
+		tmp = realloc(data->cols,
+		    (data->cols_cnt + 1) * sizeof (*data->cols));
+		if (tmp == NULL)
+			return (1);
+
+		data->cols = tmp;
+		data->cols[data->cols_cnt] = strdup(col);
+		data->cols_cnt++;
+	}
+
+	if (val != NULL && col == NULL)
+		return (1);
+
+	return (0);
+}
+
+/*
+ * Run the cmd and store results in *data.
+ */
+static void
+vdev_run_cmd(vdev_cmd_data_t *data, char *cmd)
+{
+	int rc;
+	char *argv[2] = {cmd, 0};
+	char *env[5] = {"PATH=/bin:/sbin:/usr/bin:/usr/sbin", NULL, NULL, NULL,
+	    NULL};
+	char **lines = NULL;
+	int lines_cnt = 0;
+	int i;
+
+	/* Setup our custom environment variables */
+	rc = asprintf(&env[1], "VDEV_PATH=%s",
+	    data->path ? data->path : "");
+	if (rc == -1)
+		goto out;
+
+	rc = asprintf(&env[2], "VDEV_UPATH=%s",
+	    data->upath ? data->upath : "");
+	if (rc == -1)
+		goto out;
+
+	rc = asprintf(&env[3], "VDEV_ENC_SYSFS_PATH=%s",
+	    data->vdev_enc_sysfs_path ?
+	    data->vdev_enc_sysfs_path : "");
+	if (rc == -1)
+		goto out;
+
+	/* Run the command */
+	rc = libzfs_run_process_get_stdout_nopath(cmd, argv, env, &lines,
+	    &lines_cnt);
+	if (rc != 0)
+		goto out;
+
+	/* Process the output we got */
+	for (i = 0; i < lines_cnt; i++)
+		if (vdev_process_cmd_output(data, lines[i]) != 0)
+			break;
+
+out:
+	if (lines != NULL)
+		libzfs_free_str_array(lines, lines_cnt);
+
+	/* Start with i = 1 since env[0] was statically allocated */
+	for (i = 1; i < ARRAY_SIZE(env); i++)
+		if (env[i] != NULL)
+			free(env[i]);
+}
+
 /* Thread function run for each vdev */
 static void
 vdev_run_cmd_thread(void *cb_cmd_data)
 {
 	vdev_cmd_data_t *data = cb_cmd_data;
-	char *pos = NULL;
-	FILE *fp;
-	size_t len = 0;
-	char cmd[_POSIX_ARG_MAX];
-
-	/* Set our VDEV_PATH and VDEV_UPATH env vars and run command */
-	if (snprintf(cmd, sizeof (cmd), "VDEV_PATH=%s && VDEV_UPATH=\"%s\" && "
-	    "VDEV_ENC_SYSFS_PATH=\"%s\" && %s", data->path ? data->path : "",
-	    data->upath ? data->upath : "",
-	    data->vdev_enc_sysfs_path ? data->vdev_enc_sysfs_path : "",
-	    data->cmd) >= sizeof (cmd)) {
-		/* Our string was truncated */
-		return;
-	}
+	const char *sep = ",";
+	char *cmd = NULL, *cmddup, *rest;
+	char fullpath[MAXPATHLEN];
 
-	fp = popen(cmd, "r");
-	if (fp == NULL)
+	cmddup = strdup(data->cmd);
+	if (cmddup == NULL)
 		return;
 
-	data->line = NULL;
+	rest = cmddup;
+	while ((cmd = strtok_r(rest, sep, &rest))) {
+		if (snprintf(fullpath, sizeof (fullpath), "%s/%s",
+		    ZPOOL_SCRIPTS_DIR, cmd) == -1)
+			continue;
 
-	/* Save the first line of output from the command */
-	if (getline(&data->line, &len, fp) != -1) {
-		/* Success.  Remove newline from the end, if necessary. */
-		if ((pos = strchr(data->line, '\n')) != NULL)
-			*pos = '\0';
-	} else {
-		data->line = NULL;
+		/* Does the script exist in our zpool scripts dir? */
+		if (access(fullpath, X_OK) == 0)
+			vdev_run_cmd(data, fullpath);
 	}
-	pclose(fp);
+	free(cmddup);
 }
 
 /* For each vdev in the pool run a command */
@@ -412,6 +601,8 @@ for_each_vdev_run_cb(zpool_handle_t *zhp, nvlist_t *nv, void *cb_vcdl)
 	data->path = strdup(path);
 	data->upath = zfs_get_underlying_path(path);
 	data->cmd = vcdl->cmd;
+	data->lines = data->cols = NULL;
+	data->lines_cnt = data->cols_cnt = 0;
 	if (vdev_enc_sysfs_path)
 		data->vdev_enc_sysfs_path = strdup(vdev_enc_sysfs_path);
 	else
@@ -463,6 +654,7 @@ all_pools_for_each_vdev_run_vcdl(vdev_cmd_data_list_t *vcdl)
 	taskq_wait(t);
 	taskq_destroy(t);
 	thread_fini();
+
 }
 
 /*
@@ -495,6 +687,13 @@ all_pools_for_each_vdev_run(int argc, char **argv, char *cmd,
 	/* Run command on all vdevs in all pools */
 	all_pools_for_each_vdev_run_vcdl(vcdl);
 
+	/*
+	 * vcdl->data[] now contains all the column names and values for each
+	 * vdev.  We need to process that into a master list of unique column
+	 * names, and figure out the width of each column.
+	 */
+	process_unique_cmd_columns(vcdl);
+
 	return (vcdl);
 }
 
@@ -504,12 +703,23 @@ all_pools_for_each_vdev_run(int argc, char **argv, char *cmd,
 void
 free_vdev_cmd_data_list(vdev_cmd_data_list_t *vcdl)
 {
-	int i;
-	for (i = 0; i < vcdl->count; i++) {
+	free(vcdl->uniq_cols);
+	free(vcdl->uniq_cols_width);
+
+	for (int i = 0; i < vcdl->count; i++) {
 		free(vcdl->data[i].path);
 		free(vcdl->data[i].pool);
 		free(vcdl->data[i].upath);
-		free(vcdl->data[i].line);
+
+		for (int j = 0; j < vcdl->data[i].lines_cnt; j++)
+			free(vcdl->data[i].lines[j]);
+
+		free(vcdl->data[i].lines);
+
+		for (int j = 0; j < vcdl->data[i].cols_cnt; j++)
+			free(vcdl->data[i].cols[j]);
+
+		free(vcdl->data[i].cols);
 		free(vcdl->data[i].vdev_enc_sysfs_path);
 	}
 	free(vcdl->data);