From 3d9f37026d65a9ab3244c04a37fc49d02841ba10 Mon Sep 17 00:00:00 2001
From: Tino Reichardt <milky-zfs@mcmilk.de>
Date: Wed, 5 Apr 2023 18:57:01 +0200
Subject: [PATCH] Fix "Add colored output to zfs list"

Running `zfs list -o avail rpool` resulted in a core dump.
This commit will fix this.

Run the needed overhead only, when `use_color()` is true.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Wilson <gwilson@delphix.com>
Signed-off-by: Tino Reichardt <milky-zfs@mcmilk.de>
Closes #14712
---
 cmd/zfs/zfs_main.c       | 17 +++++++++++++++--
 include/libzutil.h       |  1 +
 lib/libzfs/libzfs.abi    |  4 ++++
 lib/libzfs/libzfs_util.c |  2 +-
 4 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/cmd/zfs/zfs_main.c b/cmd/zfs/zfs_main.c
index ff6510e440..2d81ef31c4 100644
--- a/cmd/zfs/zfs_main.c
+++ b/cmd/zfs/zfs_main.c
@@ -3589,8 +3589,21 @@ print_dataset(zfs_handle_t *zhp, list_cbdata_t *cb)
 			right_justify = B_FALSE;
 		}
 
-		if (pl->pl_prop == ZFS_PROP_AVAILABLE)
-			color_start(zfs_list_avail_color(zhp));
+		/*
+		 * zfs_list_avail_color() needs ZFS_PROP_AVAILABLE + USED
+		 * - so we need another for() search for the USED part
+		 * - when no colors wanted, we can skip the whole thing
+		 */
+		if (use_color() && pl->pl_prop == ZFS_PROP_AVAILABLE) {
+			zprop_list_t *pl2 = cb->cb_proplist;
+			for (; pl2 != NULL; pl2 = pl2->pl_next) {
+				if (pl2->pl_prop == ZFS_PROP_USED) {
+					color_start(zfs_list_avail_color(zhp));
+					/* found it, no need for more loops */
+					break;
+				}
+			}
+		}
 
 		/*
 		 * If this is being called in scripted mode, or if this is the
diff --git a/include/libzutil.h b/include/libzutil.h
index 328487d78f..15024a4e88 100644
--- a/include/libzutil.h
+++ b/include/libzutil.h
@@ -163,6 +163,7 @@ int zfs_ioctl_fd(int fd, unsigned long request, struct zfs_cmd *zc);
 #define	ANSI_RESET	"\033[0m"
 #define	ANSI_BOLD	"\033[1m"
 
+int use_color(void);
 void color_start(const char *color);
 void color_end(void);
 int printf_color(const char *color, char *format, ...);
diff --git a/lib/libzfs/libzfs.abi b/lib/libzfs/libzfs.abi
index 51c77ab34a..13ce19df9b 100644
--- a/lib/libzfs/libzfs.abi
+++ b/lib/libzfs/libzfs.abi
@@ -99,6 +99,7 @@
     <elf-symbol name='sa_validate_shareopts' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='snapshot_namecheck' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='unshare_one' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
+    <elf-symbol name='use_color' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='zcmd_alloc_dst_nvlist' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='zcmd_expand_dst_nvlist' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='zcmd_free_nvlists' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
@@ -5070,6 +5071,9 @@
       <parameter type-id='9cf59a50'/>
       <return type-id='48b5725f'/>
     </function-decl>
+    <function-decl name='use_color' mangled-name='use_color' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='use_color'>
+      <return type-id='95e97e5e'/>
+    </function-decl>
     <function-decl name='mkdirp' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='80f4b756'/>
       <parameter type-id='d50d396c'/>
diff --git a/lib/libzfs/libzfs_util.c b/lib/libzfs/libzfs_util.c
index 8aee9d30cd..7c4d310782 100644
--- a/lib/libzfs/libzfs_util.c
+++ b/lib/libzfs/libzfs_util.c
@@ -2027,7 +2027,7 @@ zfs_version_print(void)
  * Return 1 if the user requested ANSI color output, and our terminal supports
  * it.  Return 0 for no color.
  */
-static int
+int
 use_color(void)
 {
 	static int use_color = -1;