From: Karel Zak <kzak@redhat.com>
Date: Tue, 1 Apr 2025 17:45:01 +0200
Subject: treewide: avoid strcasecmp() for ASCII-only strings

Use cctype.h for locale-independent string comparison and to avoid
tricky string conversions like in tr_TR locales.

Fixes: https://github.com/util-linux/util-linux/issues/3490
Signed-off-by: Karel Zak <kzak@redhat.com>
(cherry picked from commit 107293a68206f24e531fd906e8114b578911bb7a)
---
 lib/blkdev.c                    |  7 ++++---
 lib/colors.c                    |  3 ++-
 lib/logindefs.c                 |  7 ++++---
 lib/match.c                     |  5 +++--
 lib/sysfs.c                     |  3 ++-
 libsmartcols/src/filter-param.c |  5 +++--
 login-utils/chfn.c              |  3 ++-
 login-utils/lslogins.c          |  3 ++-
 lsfd-cmd/lsfd.c                 |  3 ++-
 misc-utils/fincore.c            |  3 ++-
 misc-utils/findmnt.c            | 11 ++++++-----
 misc-utils/logger.c             |  3 ++-
 misc-utils/lsclocks.c           |  3 ++-
 misc-utils/lslocks.c            |  3 ++-
 misc-utils/uuidparse.c          |  3 ++-
 misc-utils/wipefs.c             |  3 ++-
 schedutils/ionice.c             |  3 ++-
 sys-utils/chmem.c               |  7 ++++---
 sys-utils/dmesg.c               |  5 +++--
 sys-utils/irq-common.c          | 11 ++++++-----
 sys-utils/ldattach.c            |  3 ++-
 sys-utils/losetup.c             |  3 ++-
 sys-utils/lscpu.c               |  5 +++--
 sys-utils/lsipc.c               |  3 ++-
 sys-utils/lsmem.c               | 27 +++++++++++++++------------
 sys-utils/lsns.c                |  3 ++-
 sys-utils/prlimit.c             |  3 ++-
 sys-utils/rfkill.c              |  3 ++-
 sys-utils/swapon.c              |  3 ++-
 sys-utils/wdctl.c               |  5 +++--
 sys-utils/zramctl.c             |  3 ++-
 term-utils/script.c             |  5 +++--
 tests/helpers/test_mkfds.c      |  7 ++++---
 33 files changed, 101 insertions(+), 66 deletions(-)

diff --git a/lib/blkdev.c b/lib/blkdev.c
index b10da99..110abcd 100644
--- a/lib/blkdev.c
+++ b/lib/blkdev.c
@@ -35,6 +35,7 @@
 #include "all-io.h"
 #include "blkdev.h"
 #include "c.h"
+#include "cctype.h"
 #include "linux_version.h"
 #include "fileutils.h"
 #include "nls.h"
@@ -384,14 +385,14 @@ int blkdev_lock(int fd, const char *devname, const char *lockmode)
 	if (!lockmode)
 		return 0;
 
-	if (strcasecmp(lockmode, "yes") == 0 ||
+	if (c_strcasecmp(lockmode, "yes") == 0 ||
 	    strcmp(lockmode, "1") == 0)
 		oper = LOCK_EX;
 
-	else if (strcasecmp(lockmode, "nonblock") == 0)
+	else if (c_strcasecmp(lockmode, "nonblock") == 0)
 		oper = LOCK_EX | LOCK_NB;
 
-	else if (strcasecmp(lockmode, "no") == 0 ||
+	else if (c_strcasecmp(lockmode, "no") == 0 ||
 		 strcmp(lockmode, "0") == 0)
 		return 0;
 	else {
diff --git a/lib/colors.c b/lib/colors.c
index c9a9518..4852a87 100644
--- a/lib/colors.c
+++ b/lib/colors.c
@@ -32,6 +32,7 @@
 #endif
 
 #include "c.h"
+#include "cctype.h"
 #include "colors.h"
 #include "pathnames.h"
 #include "strutils.h"
@@ -744,7 +745,7 @@ int colormode_from_string(const char *str)
 	assert(ARRAY_SIZE(modes) == __UL_NCOLORMODES);
 
 	for (i = 0; i < ARRAY_SIZE(modes); i++) {
-		if (strcasecmp(str, modes[i]) == 0)
+		if (c_strcasecmp(str, modes[i]) == 0)
 			return i;
 	}
 
diff --git a/lib/logindefs.c b/lib/logindefs.c
index 7b69599..4fee839 100644
--- a/lib/logindefs.c
+++ b/lib/logindefs.c
@@ -32,6 +32,7 @@
 #include <pwd.h>
 
 #include "c.h"
+#include "cctype.h"
 #include "closestream.h"
 #include "logindefs.h"
 #include "nls.h"
@@ -171,7 +172,7 @@ static struct item *search(const char *name)
 
 	ptr = list;
 	while (ptr != NULL) {
-		if (strcasecmp(name, ptr->name) == 0)
+		if (c_strcasecmp(name, ptr->name) == 0)
 			return ptr;
 		ptr = ptr->next;
 	}
@@ -185,7 +186,7 @@ static const char *search_config(const char *name)
 
 	ptr = list;
 	while (ptr != NULL) {
-		if (strcasecmp(name, ptr->name) == 0)
+		if (c_strcasecmp(name, ptr->name) == 0)
 			return ptr->path;
 		ptr = ptr->next;
 	}
@@ -196,7 +197,7 @@ static const char *search_config(const char *name)
 int getlogindefs_bool(const char *name, int dflt)
 {
 	struct item *ptr = search(name);
-	return ptr && ptr->value ? (strcasecmp(ptr->value, "yes") == 0) : dflt;
+	return ptr && ptr->value ? (c_strcasecmp(ptr->value, "yes") == 0) : dflt;
 }
 
 unsigned long getlogindefs_num(const char *name, unsigned long dflt)
diff --git a/lib/match.c b/lib/match.c
index a286a19..2e0b3ce 100644
--- a/lib/match.c
+++ b/lib/match.c
@@ -8,6 +8,7 @@
 #include <string.h>
 
 #include "match.h"
+#include "cctype.h"
 
 /*
  * match_fstype:
@@ -39,10 +40,10 @@ int match_fstype(const char *type, const char *pattern)
 	len = strlen(type);
 	p = pattern;
 	while(1) {
-		if (!strncmp(p, "no", 2) && !strncasecmp(p+2, type, len) &&
+		if (!strncmp(p, "no", 2) && !c_strncasecmp(p+2, type, len) &&
 		    (p[len+2] == 0 || p[len+2] == ','))
 			return 0;
-		if (strncasecmp(p, type, len) == 0 && (p[len] == 0 || p[len] == ','))
+		if (c_strncasecmp(p, type, len) == 0 && (p[len] == 0 || p[len] == ','))
 			return !no;
 		p = strchr(p,',');
 		if (!p)
diff --git a/lib/sysfs.c b/lib/sysfs.c
index ac9c5c3..0a016be 100644
--- a/lib/sysfs.c
+++ b/lib/sysfs.c
@@ -11,6 +11,7 @@
 #include <unistd.h>
 
 #include "c.h"
+#include "cctype.h"
 #include "pathnames.h"
 #include "sysfs.h"
 #include "fileutils.h"
@@ -576,7 +577,7 @@ int sysfs_blkdev_get_wholedisk(	struct path_cxt *pc,
 	tmp = uuid;
 	prefix = uuid ? strsep(&tmp, "-") : NULL;
 
-        if (prefix && strncasecmp(prefix, "part", 4) == 0)
+        if (prefix && c_strncasecmp(prefix, "part", 4) == 0)
             is_part = 1;
         free(uuid);
 
diff --git a/libsmartcols/src/filter-param.c b/libsmartcols/src/filter-param.c
index 4a67cbf..63af4c6 100644
--- a/libsmartcols/src/filter-param.c
+++ b/libsmartcols/src/filter-param.c
@@ -4,6 +4,7 @@
 #include <unistd.h>
 #include <regex.h>
 
+#include "cctype.h"
 #include "rpmatch.h"
 #include "smartcolsP.h"
 
@@ -627,8 +628,8 @@ static int string_cast(int type, struct filter_param *n)
 	case SCOLS_DATA_BOOLEAN:
 	{
 		bool x = str && *str
-			     && (strcasecmp(str, "1") == 0
-				 || strcasecmp(str, "true") == 0
+			     && (strcmp(str, "1") == 0
+				 || c_strcasecmp(str, "true") == 0
 				 || rpmatch(str) == RPMATCH_YES);
 		n->val.boolean = x;
 		break;
diff --git a/login-utils/chfn.c b/login-utils/chfn.c
index b82492e..7067ffa 100644
--- a/login-utils/chfn.c
+++ b/login-utils/chfn.c
@@ -33,6 +33,7 @@
 #include <unistd.h>
 
 #include "c.h"
+#include "cctype.h"
 #include "env.h"
 #include "closestream.h"
 #include "islocal.h"
@@ -245,7 +246,7 @@ static char *ask_new_field(struct chfn_control *ctl, const char *question,
 			free(buf);
 			return xstrdup(def_val);
 		}
-		if (!strcasecmp(buf, "none")) {
+		if (!c_strcasecmp(buf, "none")) {
 			free(buf);
 			ctl->changed = 1;
 			return xstrdup("");
diff --git a/login-utils/lslogins.c b/login-utils/lslogins.c
index ae7047d..88b0c4b 100644
--- a/login-utils/lslogins.c
+++ b/login-utils/lslogins.c
@@ -52,6 +52,7 @@
 #endif
 
 #include "c.h"
+#include "cctype.h"
 #include "nls.h"
 #include "closestream.h"
 #include "xalloc.h"
@@ -324,7 +325,7 @@ static int column_name_to_id(const char *name, size_t namesz)
 	for (i = 0; i < ARRAY_SIZE(coldescs); i++) {
 		const char *cn = coldescs[i].name;
 
-		if (!strncasecmp(name, cn, namesz) && !*(cn + namesz))
+		if (!c_strncasecmp(name, cn, namesz) && !*(cn + namesz))
 			return i;
 	}
 	warnx(_("unknown column: %s"), name);
diff --git a/lsfd-cmd/lsfd.c b/lsfd-cmd/lsfd.c
index 714083e..78f0c2c 100644
--- a/lsfd-cmd/lsfd.c
+++ b/lsfd-cmd/lsfd.c
@@ -46,6 +46,7 @@
 #define PF_KTHREAD		0x00200000	/* I am a kernel thread */
 
 #include "c.h"
+#include "cctype.h"
 #include "list.h"
 #include "closestream.h"
 #include "column-list-table.h"
@@ -611,7 +612,7 @@ static int column_name_to_id(const char *name, size_t namesz)
 	for (i = 0; i < ARRAY_SIZE(infos); i++) {
 		const char *cn = infos[i].name;
 
-		if (!strncasecmp(name, cn, namesz) && !*(cn + namesz))
+		if (!c_strncasecmp(name, cn, namesz) && !*(cn + namesz))
 			return i;
 	}
 	warnx(_("unknown column: %s"), name);
diff --git a/misc-utils/fincore.c b/misc-utils/fincore.c
index 25ce5aa..ea48f3e 100644
--- a/misc-utils/fincore.c
+++ b/misc-utils/fincore.c
@@ -27,6 +27,7 @@
 #include <string.h>
 
 #include "c.h"
+#include "cctype.h"
 #include "nls.h"
 #include "closestream.h"
 #include "xalloc.h"
@@ -149,7 +150,7 @@ static int column_name_to_id(const char *name, size_t namesz)
 	for (i = 0; i < ARRAY_SIZE(infos); i++) {
 		const char *cn = infos[i].name;
 
-		if (!strncasecmp(name, cn, namesz) && !*(cn + namesz))
+		if (!c_strncasecmp(name, cn, namesz) && !*(cn + namesz))
 			return i;
 	}
 	warnx(_("unknown column: %s"), name);
diff --git a/misc-utils/findmnt.c b/misc-utils/findmnt.c
index fbfb84c..46955fc 100644
--- a/misc-utils/findmnt.c
+++ b/misc-utils/findmnt.c
@@ -44,6 +44,7 @@
 #include "nls.h"
 #include "closestream.h"
 #include "c.h"
+#include "cctype.h"
 #include "strutils.h"
 #include "xalloc.h"
 #include "optutils.h"
@@ -344,13 +345,13 @@ static int poll_action_name_to_id(const char *name, size_t namesz)
 {
 	int id = -1;
 
-	if (strncasecmp(name, "move", namesz) == 0 && namesz == 4)
+	if (c_strncasecmp(name, "move", namesz) == 0 && namesz == 4)
 		id = MNT_TABDIFF_MOVE;
-	else if (strncasecmp(name, "mount", namesz) == 0 && namesz == 5)
+	else if (c_strncasecmp(name, "mount", namesz) == 0 && namesz == 5)
 		id = MNT_TABDIFF_MOUNT;
-	else if (strncasecmp(name, "umount", namesz) == 0 && namesz == 6)
+	else if (c_strncasecmp(name, "umount", namesz) == 0 && namesz == 6)
 		id = MNT_TABDIFF_UMOUNT;
-	else if (strncasecmp(name, "remount", namesz) == 0 && namesz == 7)
+	else if (c_strncasecmp(name, "remount", namesz) == 0 && namesz == 7)
 		id = MNT_TABDIFF_REMOUNT;
 	else
 		warnx(_("unknown action: %s"), name);
@@ -396,7 +397,7 @@ static int column_name_to_id(const char *name, size_t namesz)
 	for (i = 0; i < ARRAY_SIZE(infos); i++) {
 		const char *cn = column_id_to_name(i);
 
-		if (!strncasecmp(name, cn, namesz) && !*(cn + namesz))
+		if (!c_strncasecmp(name, cn, namesz) && !*(cn + namesz))
 			return i;
 	}
 	warnx(_("unknown column: %s"), name);
diff --git a/misc-utils/logger.c b/misc-utils/logger.c
index bcdff06..a96b005 100644
--- a/misc-utils/logger.c
+++ b/misc-utils/logger.c
@@ -56,6 +56,7 @@
 
 #include "all-io.h"
 #include "c.h"
+#include "cctype.h"
 #include "closestream.h"
 #include "nls.h"
 #include "pathnames.h"
@@ -220,7 +221,7 @@ static int decode(const char *name, const CODE *codetab)
 		return -1;
 	}
 	for (c = codetab; c->c_name; c++)
-		if (!strcasecmp(name, c->c_name))
+		if (!c_strcasecmp(name, c->c_name))
 			return (c->c_val);
 
 	return -1;
diff --git a/misc-utils/lsclocks.c b/misc-utils/lsclocks.c
index 0a87256..376bc6e 100644
--- a/misc-utils/lsclocks.c
+++ b/misc-utils/lsclocks.c
@@ -31,6 +31,7 @@
 #include <linux/rtc.h>
 
 #include "c.h"
+#include "cctype.h"
 #include "nls.h"
 #include "strutils.h"
 #include "timeutils.h"
@@ -172,7 +173,7 @@ static int column_name_to_id(const char *name, size_t namesz)
 	for (i = 0; i < ARRAY_SIZE(infos); i++) {
 		const char *cn = infos[i].name;
 
-		if (!strncasecmp(name, cn, namesz) && !*(cn + namesz))
+		if (!c_strncasecmp(name, cn, namesz) && !*(cn + namesz))
 			return i;
 	}
 	warnx(_("unknown column: %s"), name);
diff --git a/misc-utils/lslocks.c b/misc-utils/lslocks.c
index bbf5d38..6cc7431 100644
--- a/misc-utils/lslocks.c
+++ b/misc-utils/lslocks.c
@@ -43,6 +43,7 @@
 #include "xalloc.h"
 #include "strutils.h"
 #include "c.h"
+#include "cctype.h"
 #include "list.h"
 #include "closestream.h"
 #include "optutils.h"
@@ -552,7 +553,7 @@ static int column_name_to_id(const char *name, size_t namesz)
 	for (i = 0; i < ARRAY_SIZE(infos); i++) {
 		const char *cn = infos[i].name;
 
-		if (!strncasecmp(name, cn, namesz) && !*(cn + namesz))
+		if (!c_strncasecmp(name, cn, namesz) && !*(cn + namesz))
 			return i;
 	}
 	warnx(_("unknown column: %s"), name);
diff --git a/misc-utils/uuidparse.c b/misc-utils/uuidparse.c
index 7ad1e2e..98f2aee 100644
--- a/misc-utils/uuidparse.c
+++ b/misc-utils/uuidparse.c
@@ -48,6 +48,7 @@
 #include <uuid.h>
 
 #include "c.h"
+#include "cctype.h"
 #include "closestream.h"
 #include "nls.h"
 #include "optutils.h"
@@ -118,7 +119,7 @@ static int column_name_to_id(const char *name, size_t namesz)
 
 	for (i = 0; i < ARRAY_SIZE(infos); i++) {
 		const char *cn = infos[i].name;
-		if (!strncasecmp(name, cn, namesz) && !*(cn + namesz))
+		if (!c_strncasecmp(name, cn, namesz) && !*(cn + namesz))
 			return i;
 	}
 	warnx(_("unknown column: %s"), name);
diff --git a/misc-utils/wipefs.c b/misc-utils/wipefs.c
index 148907f..4bd2e58 100644
--- a/misc-utils/wipefs.c
+++ b/misc-utils/wipefs.c
@@ -40,6 +40,7 @@
 #include "all-io.h"
 #include "match.h"
 #include "c.h"
+#include "cctype.h"
 #include "closestream.h"
 #include "optutils.h"
 #include "blkdev.h"
@@ -126,7 +127,7 @@ static int column_name_to_id(const char *name, size_t namesz)
 
 	for (i = 0; i < ARRAY_SIZE(infos); i++) {
 		const char *cn = infos[i].name;
-		if (!strncasecmp(name, cn, namesz) && !*(cn + namesz))
+		if (!c_strncasecmp(name, cn, namesz) && !*(cn + namesz))
 			return i;
 	}
 	warnx(_("unknown column: %s"), name);
diff --git a/schedutils/ionice.c b/schedutils/ionice.c
index 6e897ec..0ac65b1 100644
--- a/schedutils/ionice.c
+++ b/schedutils/ionice.c
@@ -19,6 +19,7 @@
 #include "nls.h"
 #include "strutils.h"
 #include "c.h"
+#include "cctype.h"
 #include "closestream.h"
 
 static int tolerant;
@@ -65,7 +66,7 @@ static int parse_ioclass(const char *str)
 	size_t i;
 
 	for (i = 0; i < ARRAY_SIZE(to_prio); i++)
-		if (!strcasecmp(str, to_prio[i]))
+		if (!c_strcasecmp(str, to_prio[i]))
 			return i;
 	return -1;
 }
diff --git a/sys-utils/chmem.c b/sys-utils/chmem.c
index 4105d19..69e04fe 100644
--- a/sys-utils/chmem.c
+++ b/sys-utils/chmem.c
@@ -25,6 +25,7 @@
 #include <dirent.h>
 
 #include "c.h"
+#include "cctype.h"
 #include "nls.h"
 #include "path.h"
 #include "strutils.h"
@@ -84,7 +85,7 @@ static int zone_name_to_id(const char *name)
 	size_t i;
 
 	for (i = 0; i < ARRAY_SIZE(zone_names); i++) {
-		if (!strcasecmp(name, zone_names[i]))
+		if (!c_strcasecmp(name, zone_names[i]))
 			return i;
 	}
 	return -1;
@@ -133,7 +134,7 @@ static int chmem_size(struct chmem_desc *desc, int enable, int zone_id)
 				zn = zone_names[zone_id];
 				if (enable && !strcasestr(line, zn))
 					continue;
-				if (!enable && strncasecmp(line, zn, strlen(zn)) != 0)
+				if (!enable && c_strncasecmp(line, zn, strlen(zn)) != 0)
 					continue;
 			} else if (enable) {
 				/* By default, use zone Movable for online, if valid */
@@ -218,7 +219,7 @@ static int chmem_range(struct chmem_desc *desc, int enable, int zone_id)
 					warnx(_("%s enable failed: Zone mismatch"), str);
 					continue;
 				}
-				if (!enable && strncasecmp(line, zn, strlen(zn)) != 0) {
+				if (!enable && c_strncasecmp(line, zn, strlen(zn)) != 0) {
 					warnx(_("%s disable failed: Zone mismatch"), str);
 					continue;
 				}
diff --git a/sys-utils/dmesg.c b/sys-utils/dmesg.c
index 75ca4b6..dc9a287 100644
--- a/sys-utils/dmesg.c
+++ b/sys-utils/dmesg.c
@@ -29,6 +29,7 @@
 #include <fcntl.h>
 
 #include "c.h"
+#include "cctype.h"
 #include "colors.h"
 #include "nls.h"
 #include "strutils.h"
@@ -460,7 +461,7 @@ static int parse_level(const char *str, size_t len)
 		for (i = 0; i < ARRAY_SIZE(level_names); i++) {
 			const char *n = level_names[i].name;
 
-			if (strncasecmp(str, n, len) == 0 && *(n + len) == '\0')
+			if (c_strncasecmp(str, n, len) == 0 && *(n + len) == '\0')
 				return i + offset;
 		}
 	}
@@ -498,7 +499,7 @@ static int parse_facility(const char *str, size_t len)
 		for (i = 0; i < ARRAY_SIZE(facility_names); i++) {
 			const char *n = facility_names[i].name;
 
-			if (strncasecmp(str, n, len) == 0 && *(n + len) == '\0')
+			if (c_strncasecmp(str, n, len) == 0 && *(n + len) == '\0')
 				return i;
 		}
 	}
diff --git a/sys-utils/irq-common.c b/sys-utils/irq-common.c
index f069d8a..e546fcc 100644
--- a/sys-utils/irq-common.c
+++ b/sys-utils/irq-common.c
@@ -25,6 +25,7 @@
 #include <libsmartcols.h>
 
 #include "c.h"
+#include "cctype.h"
 #include "nls.h"
 #include "pathnames.h"
 #include "strutils.h"
@@ -89,7 +90,7 @@ int irq_column_name_to_id(const char *name, size_t namesz)
 	for (i = 0; i < ARRAY_SIZE(infos); i++) {
 		const char *cn = infos[i].name;
 
-		if (!strncasecmp(name, cn, namesz) && !*(cn + namesz))
+		if (!c_strncasecmp(name, cn, namesz) && !*(cn + namesz))
 			return i;
 	}
 	warnx(_("unknown column: %s"), name);
@@ -407,13 +408,13 @@ static void sort_result(struct irq_output *out,
 
 void set_sort_func_by_name(struct irq_output *out, const char *name)
 {
-	if (strcasecmp(name, "IRQ") == 0)
+	if (c_strcasecmp(name, "IRQ") == 0)
 		out->sort_cmp_func = cmp_interrupts;
-	else if (strcasecmp(name, "TOTAL") == 0)
+	else if (c_strcasecmp(name, "TOTAL") == 0)
 		out->sort_cmp_func = cmp_total;
-	else if (strcasecmp(name, "DELTA") == 0)
+	else if (c_strcasecmp(name, "DELTA") == 0)
 		out->sort_cmp_func = cmp_delta;
-	else if (strcasecmp(name, "NAME") == 0)
+	else if (c_strcasecmp(name, "NAME") == 0)
 		out->sort_cmp_func = cmp_name;
 	else
 		errx(EXIT_FAILURE, _("unsupported column name to sort output"));
diff --git a/sys-utils/ldattach.c b/sys-utils/ldattach.c
index 2a24b3d..e06047c 100644
--- a/sys-utils/ldattach.c
+++ b/sys-utils/ldattach.c
@@ -22,6 +22,7 @@
 #include <unistd.h>
 
 #include "c.h"
+#include "cctype.h"
 #include "all-io.h"
 #include "nls.h"
 #include "strutils.h"
@@ -152,7 +153,7 @@ static int lookup_table(const struct ld_table *tab, const char *str)
 	const struct ld_table *t;
 
 	for (t = tab; t && t->name; t++)
-		if (!strcasecmp(t->name, str))
+		if (!c_strcasecmp(t->name, str))
 			return t->value;
 	return -1;
 }
diff --git a/sys-utils/losetup.c b/sys-utils/losetup.c
index 7134542..eafab72 100644
--- a/sys-utils/losetup.c
+++ b/sys-utils/losetup.c
@@ -26,6 +26,7 @@
 #include <libsmartcols.h>
 
 #include "c.h"
+#include "cctype.h"
 #include "nls.h"
 #include "strutils.h"
 #include "loopdev.h"
@@ -124,7 +125,7 @@ static int column_name_to_id(const char *name, size_t namesz)
 	for (i = 0; i < ARRAY_SIZE(infos); i++) {
 		const char *cn = infos[i].name;
 
-		if (!strncasecmp(name, cn, namesz) && !*(cn + namesz))
+		if (!c_strncasecmp(name, cn, namesz) && !*(cn + namesz))
 			return i;
 	}
 	warnx(_("unknown column: %s"), name);
diff --git a/sys-utils/lscpu.c b/sys-utils/lscpu.c
index ffec372..108efb1 100644
--- a/sys-utils/lscpu.c
+++ b/sys-utils/lscpu.c
@@ -29,6 +29,7 @@
 
 #include <libsmartcols.h>
 
+#include "cctype.h"
 #include "closestream.h"
 #include "optutils.h"
 #include "c_strtod.h"
@@ -186,7 +187,7 @@ cpu_column_name_to_id(const char *name, size_t namesz)
 	for (i = 0; i < ARRAY_SIZE(coldescs_cpu); i++) {
 		const char *cn = coldescs_cpu[i].name;
 
-		if (!strncasecmp(name, cn, namesz) && !*(cn + namesz))
+		if (!c_strncasecmp(name, cn, namesz) && !*(cn + namesz))
 			return i;
 	}
 	warnx(_("unknown column: %s"), name);
@@ -201,7 +202,7 @@ cache_column_name_to_id(const char *name, size_t namesz)
 	for (i = 0; i < ARRAY_SIZE(coldescs_cache); i++) {
 		const char *cn = coldescs_cache[i].name;
 
-		if (!strncasecmp(name, cn, namesz) && !*(cn + namesz))
+		if (!c_strncasecmp(name, cn, namesz) && !*(cn + namesz))
 			return i;
 	}
 	warnx(_("unknown column: %s"), name);
diff --git a/sys-utils/lsipc.c b/sys-utils/lsipc.c
index 133957e..693be9b 100644
--- a/sys-utils/lsipc.c
+++ b/sys-utils/lsipc.c
@@ -35,6 +35,7 @@
 #include <libsmartcols.h>
 
 #include "c.h"
+#include "cctype.h"
 #include "nls.h"
 #include "closestream.h"
 #include "strutils.h"
@@ -244,7 +245,7 @@ static int column_name_to_id(const char *name, size_t namesz)
 	for (i = 0; i < ARRAY_SIZE(coldescs); i++) {
 		const char *cn = coldescs[i].name;
 
-		if (!strncasecmp(name, cn, namesz) && !*(cn + namesz)) {
+		if (!c_strncasecmp(name, cn, namesz) && !*(cn + namesz)) {
 			if (i > COL_CTIME) {
 				if (i >= LOWER && i <= UPPER)
 					return i;
diff --git a/sys-utils/lsmem.c b/sys-utils/lsmem.c
index 9aa6745..2b79114 100644
--- a/sys-utils/lsmem.c
+++ b/sys-utils/lsmem.c
@@ -11,23 +11,26 @@
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  */
-#include <c.h>
-#include <nls.h>
-#include <path.h>
-#include <strutils.h>
-#include <closestream.h>
-#include <xalloc.h>
-#include <getopt.h>
-#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <getopt.h>
+#include <stdbool.h>
 #include <dirent.h>
 #include <fcntl.h>
 #include <inttypes.h>
 #include <assert.h>
-#include <optutils.h>
+
 #include <libsmartcols.h>
 
+#include "c.h"
+#include "cctype.h"
+#include "nls.h"
+#include "path.h"
+#include "strutils.h"
+#include "closestream.h"
+#include "xalloc.h"
+#include "optutils.h"
+
 #define _PATH_SYS_MEMORY		"/sys/devices/system/memory"
 
 #define MEMORY_STATE_ONLINE		0
@@ -150,7 +153,7 @@ static int zone_name_to_id(const char *name)
 	size_t i;
 
 	for (i = 0; i < ARRAY_SIZE(zone_names); i++) {
-		if (!strcasecmp(name, zone_names[i]))
+		if (!c_strcasecmp(name, zone_names[i]))
 			return i;
 	}
 	return ZONE_UNKNOWN;
@@ -166,7 +169,7 @@ static int column_name_to_id(const char *name, size_t namesz)
 	for (i = 0; i < ARRAY_SIZE(coldescs); i++) {
 		const char *cn = coldescs[i].name;
 
-		if (!strncasecmp(name, cn, namesz) && !*(cn + namesz))
+		if (!c_strncasecmp(name, cn, namesz) && !*(cn + namesz))
 			return i;
 	}
 	warnx(_("unknown column: %s"), name);
@@ -737,7 +740,7 @@ int main(int argc, char **argv)
 		int split[ARRAY_SIZE(coldescs)] = { 0 };
 		static size_t nsplits = 0;
 
-		if (strcasecmp(splitarg, "none") == 0)
+		if (c_strcasecmp(splitarg, "none") == 0)
 			;
 		else if (string_add_to_idarray(splitarg, split, ARRAY_SIZE(split),
 					&nsplits, column_name_to_id) < 0)
diff --git a/sys-utils/lsns.c b/sys-utils/lsns.c
index fc590f8..812afe7 100644
--- a/sys-utils/lsns.c
+++ b/sys-utils/lsns.c
@@ -42,6 +42,7 @@
 #include "nls.h"
 #include "xalloc.h"
 #include "c.h"
+#include "cctype.h"
 #include "widechar.h"
 #include "list.h"
 #include "closestream.h"
@@ -271,7 +272,7 @@ static int column_name_to_id(const char *name, size_t namesz)
 	for (i = 0; i < ARRAY_SIZE(infos); i++) {
 		const char *cn = infos[i].name;
 
-		if (!strncasecmp(name, cn, namesz) && !*(cn + namesz))
+		if (!c_strncasecmp(name, cn, namesz) && !*(cn + namesz))
 			return i;
 	}
 	warnx(_("unknown column: %s"), name);
diff --git a/sys-utils/prlimit.c b/sys-utils/prlimit.c
index 57c11fb..fbab008 100644
--- a/sys-utils/prlimit.c
+++ b/sys-utils/prlimit.c
@@ -24,6 +24,7 @@
 #include <libsmartcols.h>
 
 #include "c.h"
+#include "cctype.h"
 #include "nls.h"
 #include "xalloc.h"
 #include "strutils.h"
@@ -277,7 +278,7 @@ static int column_name_to_id(const char *name, size_t namesz)
 	for (i = 0; i < ARRAY_SIZE(infos); i++) {
 		const char *cn = infos[i].name;
 
-		if (!strncasecmp(name, cn, namesz) && !*(cn + namesz))
+		if (!c_strncasecmp(name, cn, namesz) && !*(cn + namesz))
 			return i;
 	}
 	warnx(_("unknown column: %s"), name);
diff --git a/sys-utils/rfkill.c b/sys-utils/rfkill.c
index 860e864..d1c38b0 100644
--- a/sys-utils/rfkill.c
+++ b/sys-utils/rfkill.c
@@ -30,6 +30,7 @@
 #include <sys/time.h>
 
 #include "c.h"
+#include "cctype.h"
 #include "closestream.h"
 #include "nls.h"
 #include "optutils.h"
@@ -156,7 +157,7 @@ static int column_name_to_id(const char *name, size_t namesz)
 	for (i = 0; i < ARRAY_SIZE(infos); i++) {
 		const char *cn = infos[i].name;
 
-		if (!strncasecmp(name, cn, namesz) && !*(cn + namesz))
+		if (!c_strncasecmp(name, cn, namesz) && !*(cn + namesz))
 			return i;
 	}
 	warnx(_("unknown column: %s"), name);
diff --git a/sys-utils/swapon.c b/sys-utils/swapon.c
index 15efa48..7667857 100644
--- a/sys-utils/swapon.c
+++ b/sys-utils/swapon.c
@@ -29,6 +29,7 @@
 #include <libsmartcols.h>
 
 #include "c.h"
+#include "cctype.h"
 #include "nls.h"
 #include "bitops.h"
 #include "blkdev.h"
@@ -158,7 +159,7 @@ static int column_name_to_id(const char *name, size_t namesz)
 	for (i = 0; i < ARRAY_SIZE(infos); i++) {
 		const char *cn = infos[i].name;
 
-		if (!strncasecmp(name, cn, namesz) && !*(cn + namesz))
+		if (!c_strncasecmp(name, cn, namesz) && !*(cn + namesz))
 			return i;
 	}
 	warnx(_("unknown column: %s"), name);
diff --git a/sys-utils/wdctl.c b/sys-utils/wdctl.c
index ba013a3..6559b54 100644
--- a/sys-utils/wdctl.c
+++ b/sys-utils/wdctl.c
@@ -32,6 +32,7 @@
 
 #include "nls.h"
 #include "c.h"
+#include "cctype.h"
 #include "xalloc.h"
 #include "closestream.h"
 #include "optutils.h"
@@ -165,7 +166,7 @@ static long name2bit(const char *name, size_t namesz)
 
 	for (i = 0; i < ARRAY_SIZE(wdflags); i++) {
 		const char *cn = wdflags[i].name;
-		if (!strncasecmp(name, cn, namesz) && !*(cn + namesz))
+		if (!c_strncasecmp(name, cn, namesz) && !*(cn + namesz))
 			return wdflags[i].flag;
 	}
 	warnx(_("unknown flag: %s"), name);
@@ -178,7 +179,7 @@ static int column2id(const char *name, size_t namesz)
 
 	for (i = 0; i < ARRAY_SIZE(infos); i++) {
 		const char *cn = infos[i].name;
-		if (!strncasecmp(name, cn, namesz) && !*(cn + namesz))
+		if (!c_strncasecmp(name, cn, namesz) && !*(cn + namesz))
 			return i;
 	}
 	warnx(_("unknown column: %s"), name);
diff --git a/sys-utils/zramctl.c b/sys-utils/zramctl.c
index dfe752b..9aa7296 100644
--- a/sys-utils/zramctl.c
+++ b/sys-utils/zramctl.c
@@ -29,6 +29,7 @@
 #include <libsmartcols.h>
 
 #include "c.h"
+#include "cctype.h"
 #include "nls.h"
 #include "closestream.h"
 #include "strutils.h"
@@ -143,7 +144,7 @@ static int column_name_to_id(const char *name, size_t namesz)
 	for (i = 0; i < ARRAY_SIZE(infos); i++) {
 		const char *cn = infos[i].name;
 
-		if (!strncasecmp(name, cn, namesz) && !*(cn + namesz))
+		if (!c_strncasecmp(name, cn, namesz) && !*(cn + namesz))
 			return i;
 	}
 	warnx(_("unknown column: %s"), name);
diff --git a/term-utils/script.c b/term-utils/script.c
index 4da25fa..9007024 100644
--- a/term-utils/script.c
+++ b/term-utils/script.c
@@ -58,6 +58,7 @@
 #include "closestream.h"
 #include "nls.h"
 #include "c.h"
+#include "cctype.h"
 #include "ttyutils.h"
 #include "all-io.h"
 #include "monotonic.h"
@@ -864,9 +865,9 @@ int main(int argc, char **argv)
 			ctl.quiet = 1;
 			break;
 		case 'm':
-			if (strcasecmp(optarg, "classic") == 0)
+			if (c_strcasecmp(optarg, "classic") == 0)
 				format = SCRIPT_FMT_TIMING_SIMPLE;
-			else if (strcasecmp(optarg, "advanced") == 0)
+			else if (c_strcasecmp(optarg, "advanced") == 0)
 				format = SCRIPT_FMT_TIMING_MULTI;
 			else
 				errx(EXIT_FAILURE, _("unsupported logging format: '%s'"), optarg);
diff --git a/tests/helpers/test_mkfds.c b/tests/helpers/test_mkfds.c
index 5ceaa3f..f7673c8 100644
--- a/tests/helpers/test_mkfds.c
+++ b/tests/helpers/test_mkfds.c
@@ -18,6 +18,7 @@
  */
 
 #include "c.h"
+#include "cctype.h"
 #include "xalloc.h"
 #include "test_mkfds.h"
 #include "exitcodes.h"
@@ -242,10 +243,10 @@ static union value boolean_read(const char *arg, const union value *defv)
 	if (!arg)
 		return *defv;
 
-	if (strcasecmp(arg, "true") == 0
+	if (c_strcasecmp(arg, "true") == 0
 	    || strcmp(arg, "1") == 0
-	    || strcasecmp(arg, "yes") == 0
-	    || strcasecmp(arg, "y") == 0)
+	    || c_strcasecmp(arg, "yes") == 0
+	    || c_strcasecmp(arg, "y") == 0)
 		r.boolean = true;
 	else
 		r.boolean = false;