Re: [PATCH 05/13] perf tools: Introduce strtobool() to string.c

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Mon, Nov 16, 2015 at 11:17:18AM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Mon, Nov 16, 2015 at 12:10:07PM +0000, Wang Nan escreveu:
> > This patch clones strtobool() from kernel's string.c to perf's string.c,
> > then add the function entry to tools/perf/util/include/linux/string.h.
> > 
> > string.h in perf utils doesn't have #ifdef guard. This patch fixes it.
> > 
> > This is preparation for enforcing BPF program configuration, which
> > would allow config string like 'inlines=yes'.
> 
> This is not perf specific at all, we're trying to move stuff out of
> tools/perf/ so that it becomes generally usable by other tools/ living
> code, not just perf.
> 
> I'll move it to where I think it should be and post as a reply to this
> message.

Find it at the bottom, I had to do a prep patch to move memdup() first,
so that I could move tools/perf/util/include/linux/string.h to
tools/include/linux/string.h, there is still work to do to fully move
tools/perf/util/string.c to tools/lib/, will do eventually, for now what
you need is there.

- Arnaldo

commit 939d89c6acc78ee48e8ad83e9565a372b9f3987a
Author: Wang Nan <wangnan0@huawei.com>
Date:   Mon Nov 16 11:42:05 2015 -0300

    tools: Clone the kernel's strtobool function
    
    Copying it to tools/lib/string.c, the counterpart to the kernel's
    lib/string.c.
    
    This is preparation for enhancing BPF program configuration, which will
    allow config string like 'inlines=yes'.
    
    Signed-off-by: Wang Nan <wangnan0@huawei.com>
    Cc: Alexei Starovoitov <ast@kernel.org>
    Cc: Jonathan Cameron <jic23@cam.ac.uk>
    Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
    Cc: Zefan Li <lizefan@huawei.com>
    Cc: pi3orama@163.com
    Link: http://lkml.kernel.org/r/1447675815-166222-6-git-send-email-wangnan0@huawei.com
    [ Copied it to tools/lib/string.c instead, to make it usable by other tools/ ]
    Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/include/linux/string.h b/tools/include/linux/string.h
index f3a6db6ad732..2e2f736c039c 100644
--- a/tools/include/linux/string.h
+++ b/tools/include/linux/string.h
@@ -6,4 +6,6 @@
 
 void *memdup(const void *src, size_t len);
 
+int strtobool(const char *s, bool *res);
+
 #endif /* _LINUX_STRING_H_ */
diff --git a/tools/lib/string.c b/tools/lib/string.c
index ecfd43a9b24e..065e54f42d8f 100644
--- a/tools/lib/string.c
+++ b/tools/lib/string.c
@@ -1,5 +1,20 @@
+/*
+ *  linux/tools/lib/string.c
+ *
+ *  Copied from linux/lib/string.c, where it is:
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  More specifically, the first copied function was strtobool, which
+ *  was introduced by:
+ *
+ *  d0f1fed29e6e ("Add a strtobool function matching semantics of existing in kernel equivalents")
+ *  Author: Jonathan Cameron <jic23@cam.ac.uk>
+ */
+
 #include <stdlib.h>
 #include <string.h>
+#include <errno.h>
 #include <linux/string.h>
 
 /**
@@ -17,3 +32,31 @@ void *memdup(const void *src, size_t len)
 
 	return p;
 }
+
+/**
+ * strtobool - convert common user inputs into boolean values
+ * @s: input string
+ * @res: result
+ *
+ * This routine returns 0 iff the first character is one of 'Yy1Nn0'.
+ * Otherwise it will return -EINVAL.  Value pointed to by res is
+ * updated upon finding a match.
+ */
+int strtobool(const char *s, bool *res)
+{
+	switch (s[0]) {
+	case 'y':
+	case 'Y':
+	case '1':
+		*res = true;
+		break;
+	case 'n':
+	case 'N':
+	case '0':
+		*res = false;
+		break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}