strchr() and strrchr() are already present in the kernel, but with less

popular names. Hence:

- comment current index() and rindex() functions, as these serve the same
  functionality as, respectively, strchr() and strrchr() from userland;
- add inlined version of strchr() and strrchr(), as we tend to use them more
  often;
- remove str[r]chr() definitions from ZFS code;

Reviewed by:	pjd
Approved by:	cognet (mentor)

sys/cddl/compat/opensolaris/kern/opensolaris_string.c

@@ -31,37 +31,6 @@
 #define	IS_ALPHA(c)	\
 	(((c) >= 'a' && (c) <= 'z') || ((c) >= 'A' && (c) <= 'Z'))
 
-char *
-strchr(const char *s, int c)
-{
-	char ch;
-
-	ch = c;
-	for (;; ++s) {
-		if (*s == ch)
-			return ((char *)s);
-		if (*s == '\0')
-			return (NULL);
-	}
-	/* NOTREACHED */
-}
-
-char *
-strrchr(const char *s, int c)
-{
-	char *save;
-	char ch;
-
-	ch = c;
-	for (save = NULL;; ++s) {
-		if (*s == ch)
-			save = (char *)s;
-		if (*s == '\0')
-			return (save);
-	}
-	/* NOTREACHED */
-}
-
 char *
 strpbrk(const char *s, const char *b)
 {

sys/cddl/compat/opensolaris/sys/string.h

@@ -29,8 +29,8 @@
 #ifndef _OPENSOLARIS_SYS_STRING_H_
 #define	_OPENSOLARIS_SYS_STRING_H_
 
-char	*strchr(const char *, int);
-char	*strrchr(const char *p, int c);
+#include <sys/libkern.h>
+
 char	*strpbrk(const char *, const char *);
 void	 strident_canon(char *s, size_t n);
 

sys/compat/opensolaris/kern/opensolaris_string.c

@@ -31,37 +31,6 @@
 #define	IS_ALPHA(c)	\
 	(((c) >= 'a' && (c) <= 'z') || ((c) >= 'A' && (c) <= 'Z'))
 
-char *
-strchr(const char *s, int c)
-{
-	char ch;
-
-	ch = c;
-	for (;; ++s) {
-		if (*s == ch)
-			return ((char *)s);
-		if (*s == '\0')
-			return (NULL);
-	}
-	/* NOTREACHED */
-}
-
-char *
-strrchr(const char *s, int c)
-{
-	char *save;
-	char ch;
-
-	ch = c;
-	for (save = NULL;; ++s) {
-		if (*s == ch)
-			save = (char *)s;
-		if (*s == '\0')
-			return (save);
-	}
-	/* NOTREACHED */
-}
-
 char *
 strpbrk(const char *s, const char *b)
 {

sys/compat/opensolaris/sys/string.h

@@ -29,8 +29,8 @@
 #ifndef _OPENSOLARIS_SYS_STRING_H_
 #define	_OPENSOLARIS_SYS_STRING_H_
 
-char	*strchr(const char *, int);
-char	*strrchr(const char *p, int c);
+#include <sys/libkern.h>
+
 char	*strpbrk(const char *, const char *);
 void	 strident_canon(char *s, size_t n);
 

sys/libkern/index.c

@@ -33,6 +33,10 @@ __FBSDID("$FreeBSD$");
 #include <sys/param.h>
 #include <sys/libkern.h>
 
+/*
+ * index() is also present as the strchr() in the kernel; it does exactly the
+ * same thing as it's userland equivalent.
+ */
 char *
 index(p, ch)
 	const char *p;

sys/libkern/rindex.c

@@ -33,6 +33,10 @@ __FBSDID("$FreeBSD$");
 #include <sys/param.h>
 #include <sys/libkern.h>
 
+/*
+ * rindex() is also present as the strrchr() in the kernel; it does exactly the
+ * same thing as it's userland equivalent.
+ */
 char *
 rindex(p, ch)
 	const char *p;

sys/sys/libkern.h

@@ -153,6 +153,18 @@ memset(void *b, int c, size_t len)
 	return (b);
 }
 
+static __inline char *
+strchr(const char *p, int ch)
+{
+	return (index(p, ch));
+}
+
+static __inline char *
+strrchr(const char *p, int ch)
+{
+	return (rindex(p, ch));
+}
+
 /* fnmatch() return values. */
 #define	FNM_NOMATCH	1	/* Match failed. */