nvpair: Constify string functions

After addressing coverity complaints involving `nvpair_name()`, the
compiler started complaining about dropping const. This lead to a rabbit
hole where not only `nvpair_name()` needed to be constified, but also
`nvpair_value_string()`, `fnvpair_value_string()` and a few other static
functions, plus variable pointers throughout the code. The result became
a fairly big change, so it has been split out into its own patch.

Reviewed-by: Tino Reichardt <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Richard Yao <[email protected]>
Closes #14612

3 files changed, 64 insertions, 55 deletions

diff --git a/lib/libnvpair/libnvpair.abi b/lib/libnvpair/libnvpair.abi
index 5900a6551..ef92f3e9b 100644
--- a/lib/libnvpair/libnvpair.abi
+++ b/lib/libnvpair/libnvpair.abi
@@ -243,6 +243,9 @@
     <array-type-def dimensions='1' type-id='a84c031d' size-in-bits='160' id='664ac0b7'>
       <subrange length='20' type-id='7359adad' id='fdca39cf'/>
     </array-type-def>
+    <array-type-def dimensions='1' type-id='a84c031d' size-in-bits='infinite' id='e84913bd'>
+      <subrange length='infinite' type-id='7359adad' id='031f2035'/>
+    </array-type-def>
     <class-decl name='_IO_codecvt' is-struct='yes' visibility='default' is-declaration-only='yes' id='a4036571'/>
     <class-decl name='_IO_marker' is-struct='yes' visibility='default' is-declaration-only='yes' id='010ae0b9'/>
     <class-decl name='_IO_wide_data' is-struct='yes' visibility='default' is-declaration-only='yes' id='79bd3751'/>
@@ -321,6 +324,9 @@
       <data-member access='public' layout-offset-in-bits='96'>
         <var-decl name='nvp_type' type-id='8d0687d2' visibility='default'/>
       </data-member>
+      <data-member access='public' layout-offset-in-bits='128'>
+        <var-decl name='nvp_name' type-id='e84913bd' visibility='default'/>
+      </data-member>
     </class-decl>
     <typedef-decl name='nvpair_t' type-id='1c34e459' id='57928edf'/>
     <class-decl name='nvlist' size-in-bits='192' is-struct='yes' visibility='default' id='ac266fd9'>
@@ -698,7 +704,7 @@
     </class-decl>
     <class-decl name='__anonymous_struct__12' size-in-bits='128' is-struct='yes' is-anonymous='yes' visibility='default' id='e7f43f7e'>
       <data-member access='public' layout-offset-in-bits='0'>
-        <var-decl name='op' type-id='c0d0f877' visibility='default'/>
+        <var-decl name='op' type-id='bfc48fe4' visibility='default'/>
       </data-member>
       <data-member access='public' layout-offset-in-bits='64'>
         <var-decl name='arg' type-id='eaa32e2f' visibility='default'/>
@@ -802,7 +808,7 @@
     </class-decl>
     <class-decl name='__anonymous_struct__25' size-in-bits='128' is-struct='yes' is-anonymous='yes' visibility='default' id='e7f43f8b'>
       <data-member access='public' layout-offset-in-bits='0'>
-        <var-decl name='op' type-id='de20bf07' visibility='default'/>
+        <var-decl name='op' type-id='337f4a72' visibility='default'/>
       </data-member>
       <data-member access='public' layout-offset-in-bits='64'>
         <var-decl name='arg' type-id='eaa32e2f' visibility='default'/>
@@ -858,11 +864,11 @@
     <pointer-type-def type-id='c19b74c3' size-in-bits='64' id='37e3bd22'/>
     <pointer-type-def type-id='37e3bd22' size-in-bits='64' id='03829398'/>
     <pointer-type-def type-id='a84c031d' size-in-bits='64' id='26a90f95'/>
-    <pointer-type-def type-id='26a90f95' size-in-bits='64' id='9b23c9ad'/>
-    <pointer-type-def type-id='9b23c9ad' size-in-bits='64' id='c0563f85'/>
     <qualified-type-def type-id='a84c031d' const='yes' id='9b45d938'/>
     <pointer-type-def type-id='9b45d938' size-in-bits='64' id='80f4b756'/>
     <qualified-type-def type-id='80f4b756' restrict='yes' id='9d26089a'/>
+    <pointer-type-def type-id='80f4b756' size-in-bits='64' id='7d3cd834'/>
+    <pointer-type-def type-id='7d3cd834' size-in-bits='64' id='44c8373a'/>
     <qualified-type-def type-id='57928edf' const='yes' id='642ee20f'/>
     <pointer-type-def type-id='642ee20f' size-in-bits='64' id='dace003f'/>
     <qualified-type-def type-id='aca3bac8' const='yes' id='2498fd78'/>
@@ -871,8 +877,8 @@
     <pointer-type-def type-id='a0eb0f08' size-in-bits='64' id='7408d286'/>
     <pointer-type-def type-id='cebdd548' size-in-bits='64' id='e379e62d'/>
     <pointer-type-def type-id='9f88f76e' size-in-bits='64' id='7ef0e988'/>
-    <pointer-type-def type-id='c5bb1a2b' size-in-bits='64' id='c0d0f877'/>
-    <pointer-type-def type-id='573fea1b' size-in-bits='64' id='de20bf07'/>
+    <pointer-type-def type-id='889f3b42' size-in-bits='64' id='bfc48fe4'/>
+    <pointer-type-def type-id='49055dd8' size-in-bits='64' id='337f4a72'/>
     <pointer-type-def type-id='70284cc6' size-in-bits='64' id='3be4d568'/>
     <pointer-type-def type-id='700c3bca' size-in-bits='64' id='6d994334'/>
     <pointer-type-def type-id='18ac1860' size-in-bits='64' id='506ab59a'/>
@@ -898,8 +904,8 @@
     <pointer-type-def type-id='3bd73b0c' size-in-bits='64' id='7e85a9b6'/>
     <pointer-type-def type-id='0d445e26' size-in-bits='64' id='330cc0d0'/>
     <pointer-type-def type-id='e4b89f30' size-in-bits='64' id='ed8aa8ba'/>
-    <pointer-type-def type-id='be7f4941' size-in-bits='64' id='2809de35'/>
-    <pointer-type-def type-id='fe5ae69d' size-in-bits='64' id='90d5edb9'/>
+    <pointer-type-def type-id='78e3bec8' size-in-bits='64' id='b38a1022'/>
+    <pointer-type-def type-id='a5193bb2' size-in-bits='64' id='6263eda4'/>
     <pointer-type-def type-id='2783af3c' size-in-bits='64' id='e44553b6'/>
     <pointer-type-def type-id='33c6e3d8' size-in-bits='64' id='1263777a'/>
     <pointer-type-def type-id='dadb9eca' size-in-bits='64' id='cbda43ac'/>
@@ -966,7 +972,7 @@
     </function-decl>
     <function-decl name='nvpair_name' mangled-name='nvpair_name' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='nvpair_name'>
       <parameter type-id='dace003f'/>
-      <return type-id='26a90f95'/>
+      <return type-id='80f4b756'/>
     </function-decl>
     <function-decl name='nvpair_type' mangled-name='nvpair_type' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='nvpair_type'>
       <parameter type-id='dace003f'/>
@@ -1027,8 +1033,8 @@
       <return type-id='95e97e5e'/>
     </function-decl>
     <function-decl name='nvpair_value_string' mangled-name='nvpair_value_string' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='nvpair_value_string'>
-      <parameter type-id='3fa542f0'/>
-      <parameter type-id='9b23c9ad'/>
+      <parameter type-id='dace003f'/>
+      <parameter type-id='7d3cd834'/>
       <return type-id='95e97e5e'/>
     </function-decl>
     <function-decl name='nvpair_value_nvlist' mangled-name='nvpair_value_nvlist' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='nvpair_value_nvlist'>
@@ -1098,7 +1104,7 @@
     </function-decl>
     <function-decl name='nvpair_value_string_array' mangled-name='nvpair_value_string_array' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='nvpair_value_string_array'>
       <parameter type-id='3fa542f0'/>
-      <parameter type-id='c0563f85'/>
+      <parameter type-id='44c8373a'/>
       <parameter type-id='4dd26a40'/>
       <return type-id='95e97e5e'/>
     </function-decl>
@@ -1280,7 +1286,7 @@
     </function-decl>
     <function-decl name='nvlist_prtctlop_string' mangled-name='nvlist_prtctlop_string' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='nvlist_prtctlop_string'>
       <parameter type-id='b0c1ff8d' name='pctl'/>
-      <parameter type-id='2809de35' name='func'/>
+      <parameter type-id='b38a1022' name='func'/>
       <parameter type-id='eaa32e2f' name='private'/>
       <return type-id='48b5725f'/>
     </function-decl>
@@ -1358,7 +1364,7 @@
     </function-decl>
     <function-decl name='nvlist_prtctlop_string_array' mangled-name='nvlist_prtctlop_string_array' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='nvlist_prtctlop_string_array'>
       <parameter type-id='b0c1ff8d' name='pctl'/>
-      <parameter type-id='90d5edb9' name='func'/>
+      <parameter type-id='6263eda4' name='func'/>
       <parameter type-id='eaa32e2f' name='private'/>
       <return type-id='48b5725f'/>
     </function-decl>
@@ -1393,16 +1399,16 @@
     <function-decl name='nvpair_value_match_regex' mangled-name='nvpair_value_match_regex' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='nvpair_value_match_regex'>
       <parameter type-id='3fa542f0' name='nvp'/>
       <parameter type-id='95e97e5e' name='ai'/>
-      <parameter type-id='26a90f95' name='value'/>
+      <parameter type-id='80f4b756' name='value'/>
       <parameter type-id='d33f11cb' name='value_regex'/>
-      <parameter type-id='9b23c9ad' name='ep'/>
+      <parameter type-id='7d3cd834' name='ep'/>
       <return type-id='95e97e5e'/>
     </function-decl>
     <function-decl name='nvpair_value_match' mangled-name='nvpair_value_match' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='nvpair_value_match'>
       <parameter type-id='3fa542f0' name='nvp'/>
       <parameter type-id='95e97e5e' name='ai'/>
-      <parameter type-id='26a90f95' name='value'/>
-      <parameter type-id='9b23c9ad' name='ep'/>
+      <parameter type-id='80f4b756' name='value'/>
+      <parameter type-id='7d3cd834' name='ep'/>
       <return type-id='95e97e5e'/>
     </function-decl>
     <function-type size-in-bits='64' id='9f88f76e'>
@@ -1414,20 +1420,20 @@
       <parameter type-id='3502e3ff'/>
       <return type-id='95e97e5e'/>
     </function-type>
-    <function-type size-in-bits='64' id='c5bb1a2b'>
+    <function-type size-in-bits='64' id='889f3b42'>
       <parameter type-id='196db161'/>
       <parameter type-id='eaa32e2f'/>
       <parameter type-id='5ce45b60'/>
       <parameter type-id='80f4b756'/>
-      <parameter type-id='26a90f95'/>
+      <parameter type-id='80f4b756'/>
       <return type-id='95e97e5e'/>
     </function-type>
-    <function-type size-in-bits='64' id='573fea1b'>
+    <function-type size-in-bits='64' id='49055dd8'>
       <parameter type-id='196db161'/>
       <parameter type-id='eaa32e2f'/>
       <parameter type-id='5ce45b60'/>
       <parameter type-id='80f4b756'/>
-      <parameter type-id='9b23c9ad'/>
+      <parameter type-id='7d3cd834'/>
       <parameter type-id='3502e3ff'/>
       <return type-id='95e97e5e'/>
     </function-type>
@@ -1642,20 +1648,20 @@
       <parameter type-id='3502e3ff'/>
       <return type-id='95e97e5e'/>
     </function-type>
-    <function-type size-in-bits='64' id='be7f4941'>
+    <function-type size-in-bits='64' id='78e3bec8'>
       <parameter type-id='b0c1ff8d'/>
       <parameter type-id='eaa32e2f'/>
       <parameter type-id='5ce45b60'/>
       <parameter type-id='80f4b756'/>
-      <parameter type-id='26a90f95'/>
+      <parameter type-id='80f4b756'/>
       <return type-id='95e97e5e'/>
     </function-type>
-    <function-type size-in-bits='64' id='fe5ae69d'>
+    <function-type size-in-bits='64' id='a5193bb2'>
       <parameter type-id='b0c1ff8d'/>
       <parameter type-id='eaa32e2f'/>
       <parameter type-id='5ce45b60'/>
       <parameter type-id='80f4b756'/>
-      <parameter type-id='9b23c9ad'/>
+      <parameter type-id='7d3cd834'/>
       <parameter type-id='3502e3ff'/>
       <return type-id='95e97e5e'/>
     </function-type>
@@ -1930,8 +1936,8 @@
       <return type-id='9c313c2d'/>
     </function-decl>
     <function-decl name='fnvpair_value_string' mangled-name='fnvpair_value_string' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='fnvpair_value_string'>
-      <parameter type-id='3fa542f0'/>
-      <return type-id='26a90f95'/>
+      <parameter type-id='dace003f'/>
+      <return type-id='80f4b756'/>
     </function-decl>
     <function-decl name='fnvpair_value_nvlist' mangled-name='fnvpair_value_nvlist' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='fnvpair_value_nvlist'>
       <parameter type-id='3fa542f0'/>
@@ -2327,9 +2333,9 @@
       <return type-id='9c313c2d'/>
     </function-decl>
     <function-decl name='fnvlist_lookup_string' mangled-name='fnvlist_lookup_string' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='fnvlist_lookup_string'>
-      <parameter type-id='5ce45b60' name='nvl'/>
+      <parameter type-id='22cce67b' name='nvl'/>
       <parameter type-id='80f4b756' name='name'/>
-      <return type-id='26a90f95'/>
+      <return type-id='80f4b756'/>
     </function-decl>
     <function-decl name='fnvlist_lookup_nvlist' mangled-name='fnvlist_lookup_nvlist' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='fnvlist_lookup_nvlist'>
       <parameter type-id='5ce45b60' name='nvl'/>
@@ -2466,7 +2472,9 @@
     <typedef-decl name='u_quad_t' type-id='5f3d50a6' id='bd226ac0'/>
     <pointer-type-def type-id='bc407f0e' size-in-bits='64' id='17fd1621'/>
     <pointer-type-def type-id='755707df' size-in-bits='64' id='812c6697'/>
+    <pointer-type-def type-id='26a90f95' size-in-bits='64' id='9b23c9ad'/>
     <qualified-type-def type-id='9b23c9ad' restrict='yes' id='8c85230f'/>
+    <pointer-type-def type-id='9b23c9ad' size-in-bits='64' id='c0563f85'/>
     <qualified-type-def type-id='c19b74c3' const='yes' id='12373e33'/>
     <pointer-type-def type-id='12373e33' size-in-bits='64' id='c5f6c15b'/>
     <qualified-type-def type-id='80f4b756' const='yes' id='b99c00c9'/>
@@ -2925,9 +2933,9 @@
       <return type-id='95e97e5e'/>
     </function-decl>
     <function-decl name='nvlist_lookup_string' mangled-name='nvlist_lookup_string' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='nvlist_lookup_string'>
-      <parameter type-id='5ce45b60' name='nvl'/>
+      <parameter type-id='22cce67b' name='nvl'/>
       <parameter type-id='80f4b756' name='name'/>
-      <parameter type-id='9b23c9ad' name='val'/>
+      <parameter type-id='7d3cd834' name='val'/>
       <return type-id='95e97e5e'/>
     </function-decl>
     <function-decl name='nvlist_lookup_nvlist' mangled-name='nvlist_lookup_nvlist' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='nvlist_lookup_nvlist'>
@@ -3043,7 +3051,7 @@
       <parameter type-id='80f4b756' name='name'/>
       <parameter type-id='0b283d2e' name='ret'/>
       <parameter type-id='7292109c' name='ip'/>
-      <parameter type-id='9b23c9ad' name='ep'/>
+      <parameter type-id='7d3cd834' name='ep'/>
       <return type-id='95e97e5e'/>
     </function-decl>
     <function-decl name='nvlist_exists' mangled-name='nvlist_exists' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='nvlist_exists'>
diff --git a/lib/libnvpair/libnvpair.c b/lib/libnvpair/libnvpair.c
index a75e73167..f19ee707a 100644
--- a/lib/libnvpair/libnvpair.c
+++ b/lib/libnvpair/libnvpair.c
@@ -70,7 +70,7 @@ struct nvlist_printops {
 	DEFINEOP(print_int64, int64_t);
 	DEFINEOP(print_uint64, uint64_t);
 	DEFINEOP(print_double, double);
-	DEFINEOP(print_string, char *);
+	DEFINEOP(print_string, const char *);
 	DEFINEOP(print_hrtime, hrtime_t);
 	DEFINEOP(print_nvlist, nvlist_t *);
 	DEFINEARROP(print_boolean_array, boolean_t *);
@@ -83,7 +83,7 @@ struct nvlist_printops {
 	DEFINEARROP(print_uint32_array, uint32_t *);
 	DEFINEARROP(print_int64_array, int64_t *);
 	DEFINEARROP(print_uint64_array, uint64_t *);
-	DEFINEARROP(print_string_array, char **);
+	DEFINEARROP(print_string_array, const char **);
 	DEFINEARROP(print_nvlist_array, nvlist_t **);
 };
 
@@ -222,7 +222,7 @@ NVLIST_PRTFUNC(uint32, uint32_t, uint32_t, "0x%x")
 NVLIST_PRTFUNC(int64, int64_t, longlong_t, "%lld")
 NVLIST_PRTFUNC(uint64, uint64_t, u_longlong_t, "0x%llx")
 NVLIST_PRTFUNC(double, double, double, "0x%f")
-NVLIST_PRTFUNC(string, char *, char *, "%s")
+NVLIST_PRTFUNC(string, const char *, const char *, "%s")
 NVLIST_PRTFUNC(hrtime, hrtime_t, hrtime_t, "0x%llx")
 #if defined(__GNUC__) && !defined(__clang__) && \
 	defined(ZFS_UBSAN_ENABLED) && defined(HAVE_FORMAT_OVERFLOW)
@@ -266,7 +266,7 @@ NVLIST_ARRPRTFUNC(int32_array, int32_t, int32_t, "%d")
 NVLIST_ARRPRTFUNC(uint32_array, uint32_t, uint32_t, "0x%x")
 NVLIST_ARRPRTFUNC(int64_array, int64_t, longlong_t, "%lld")
 NVLIST_ARRPRTFUNC(uint64_array, uint64_t, u_longlong_t, "0x%llx")
-NVLIST_ARRPRTFUNC(string_array, char *, char *, "%s")
+NVLIST_ARRPRTFUNC(string_array, const char *, const char *, "%s")
 
 static int
 nvprint_nvlist(nvlist_prtctl_t pctl, void *private,
@@ -398,13 +398,13 @@ nvlist_prtctl_dofmt(nvlist_prtctl_t pctl, enum nvlist_prtctl_fmt which, ...)
 {
 	FILE *fp = pctl->nvprt_fp;
 	va_list ap;
-	char *name;
+	const char *name;
 
 	va_start(ap, which);
 
 	switch (which) {
 	case NVLIST_FMT_MEMBER_NAME:
-		name = va_arg(ap, char *);
+		name = va_arg(ap, const char *);
 		(void) fprintf(fp, pctl->nvprt_nmfmt, name);
 		break;
 
@@ -453,7 +453,7 @@ NVLIST_PRINTCTL_REPLACE(uint32, uint32_t)
 NVLIST_PRINTCTL_REPLACE(int64, int64_t)
 NVLIST_PRINTCTL_REPLACE(uint64, uint64_t)
 NVLIST_PRINTCTL_REPLACE(double, double)
-NVLIST_PRINTCTL_REPLACE(string, char *)
+NVLIST_PRINTCTL_REPLACE(string, const char *)
 NVLIST_PRINTCTL_REPLACE(hrtime, hrtime_t)
 NVLIST_PRINTCTL_REPLACE(nvlist, nvlist_t *)
 
@@ -477,7 +477,7 @@ NVLIST_PRINTCTL_AREPLACE(int32_array, int32_t *)
 NVLIST_PRINTCTL_AREPLACE(uint32_array, uint32_t *)
 NVLIST_PRINTCTL_AREPLACE(int64_array, int64_t *)
 NVLIST_PRINTCTL_AREPLACE(uint64_array, uint64_t *)
-NVLIST_PRINTCTL_AREPLACE(string_array, char **)
+NVLIST_PRINTCTL_AREPLACE(string_array, const char **)
 NVLIST_PRINTCTL_AREPLACE(nvlist_array, nvlist_t **)
 
 /*
@@ -580,7 +580,7 @@ static void
 nvlist_print_with_indent(nvlist_t *nvl, nvlist_prtctl_t pctl)
 {
 	FILE *fp = pctl->nvprt_fp;
-	char *name;
+	const char *name;
 	uint_t nelem;
 	nvpair_t *nvp;
 
@@ -670,7 +670,7 @@ nvlist_print_with_indent(nvlist_t *nvl, nvlist_prtctl_t pctl)
 			break;
 		}
 		case DATA_TYPE_STRING: {
-			char *val;
+			const char *val;
 			(void) nvpair_value_string(nvp, &val);
 			RENDER(pctl, string, nvl, name, val);
 			break;
@@ -736,7 +736,7 @@ nvlist_print_with_indent(nvlist_t *nvl, nvlist_prtctl_t pctl)
 			break;
 		}
 		case DATA_TYPE_STRING_ARRAY: {
-			char **val;
+			const char **val;
 			(void) nvpair_value_string_array(nvp, &val, &nelem);
 			ARENDER(pctl, string_array, nvl, name, val, nelem);
 			break;
@@ -866,7 +866,7 @@ dump_nvlist(nvlist_t *list, int indent)
 			break;
 
 		case DATA_TYPE_STRING:
-			NVP(elem, string, char *, char *, "'%s'");
+			NVP(elem, string, const char *, const char *, "'%s'");
 			break;
 
 		case DATA_TYPE_BYTE_ARRAY:
@@ -907,7 +907,8 @@ dump_nvlist(nvlist_t *list, int indent)
 			break;
 
 		case DATA_TYPE_STRING_ARRAY:
-			NVPA(elem, string_array, char *, char *, "'%s'");
+			NVPA(elem, string_array, const char *, const char *,
+			    "'%s'");
 			break;
 
 		case DATA_TYPE_NVLIST:
@@ -961,11 +962,11 @@ dump_nvlist(nvlist_t *list, int indent)
  */
 int
 nvpair_value_match_regex(nvpair_t *nvp, int ai,
-    char *value, regex_t *value_regex, char **ep)
+    const char *value, regex_t *value_regex, const char **ep)
 {
-	char	*evalue;
-	uint_t	a_len;
-	int	sr;
+	const char	*evalue;
+	uint_t		a_len;
+	int		sr;
 
 	if (ep)
 		*ep = NULL;
@@ -993,7 +994,7 @@ nvpair_value_match_regex(nvpair_t *nvp, int ai,
 	sr = EOF;
 	switch (nvpair_type(nvp)) {
 	case DATA_TYPE_STRING: {
-		char	*val;
+		const char *val;
 
 		/* check string value for match */
 		if (nvpair_value_string(nvp, &val) == 0) {
@@ -1009,7 +1010,7 @@ nvpair_value_match_regex(nvpair_t *nvp, int ai,
 		break;
 	}
 	case DATA_TYPE_STRING_ARRAY: {
-		char **val_array;
+		const char **val_array;
 
 		/* check indexed string value of array for match */
 		if ((nvpair_value_string_array(nvp, &val_array, &a_len) == 0) &&
@@ -1285,7 +1286,7 @@ nvpair_value_match_regex(nvpair_t *nvp, int ai,
 }
 
 int
-nvpair_value_match(nvpair_t *nvp, int ai, char *value, char **ep)
+nvpair_value_match(nvpair_t *nvp, int ai, const char *value, const char **ep)
 {
 	return (nvpair_value_match_regex(nvp, ai, value, NULL, ep));
 }
diff --git a/lib/libnvpair/libnvpair_json.c b/lib/libnvpair/libnvpair_json.c
index 19acea8f5..b8029dd4d 100644
--- a/lib/libnvpair/libnvpair_json.c
+++ b/lib/libnvpair/libnvpair_json.c
@@ -134,7 +134,7 @@ nvlist_print_json(FILE *fp, nvlist_t *nvl)
 
 		switch (type) {
 		case DATA_TYPE_STRING: {
-			char *string = fnvpair_value_string(curr);
+			const char *string = fnvpair_value_string(curr);
 			if (nvlist_print_json_string(fp, string) == -1)
 				return (-1);
 			break;
@@ -220,7 +220,7 @@ nvlist_print_json(FILE *fp, nvlist_t *nvl)
 		}
 
 		case DATA_TYPE_STRING_ARRAY: {
-			char **val;
+			const char **val;
 			uint_t valsz, i;
 			VERIFY0(nvpair_value_string_array(curr, &val, &valsz));
 			FPRINTF(fp, "[");