Re: Resend [PATCH] Make KOBJ_NAME_LEN match BUS_ID_SIZE

[René Scharfe]

On Sun, 25 May 2003 14:16:22 -0400 Ben Collins <[e-mail]> wrote:
> Your strlcat doesn't take into consideration that a zero bufsize could
> mean that dest is not NUL-terminated, in which case strlen(dest) could
> blow up in your face.

You are right. How about that one?

René

diff -ur linux-a/include/linux/string.h linux-b/include/linux/string.h
--- linux-a/include/linux/string.h	2003-05-05 01:53:13.000000000 +0200
+++ linux-b/include/linux/string.h	2003-05-25 19:25:01.000000000 +0200
@@ -77,6 +77,12 @@
 #ifndef __HAVE_ARCH_MEMCHR
 extern void * memchr(const void *,int,__kernel_size_t);
 #endif
+#ifndef __HAVE_ARCH_STRLCPY
+__kernel_size_t strlcpy(char *, const char *, __kernel_size_t);
+#endif
+#ifndef __HAVE_ARCH_STRLCAT
+__kernel_size_t strlcat(char *, const char *, __kernel_size_t);
+#endif
 
 #ifdef __cplusplus
 }
diff -ur linux-a/kernel/ksyms.c linux-b/kernel/ksyms.c
--- linux-a/kernel/ksyms.c	2003-05-05 01:52:49.000000000 +0200
+++ linux-b/kernel/ksyms.c	2003-05-25 19:25:21.000000000 +0200
@@ -588,6 +588,8 @@
 EXPORT_SYMBOL(strnicmp);
 EXPORT_SYMBOL(strspn);
 EXPORT_SYMBOL(strsep);
+EXPORT_SYMBOL(strlcpy);
+EXPORT_SYMBOL(strlcat);
 
 /* software interrupts */
 EXPORT_SYMBOL(tasklet_init);
diff -ur linux-a/lib/string.c linux-b/lib/string.c
--- linux-a/lib/string.c	2003-05-05 01:53:40.000000000 +0200
+++ linux-b/lib/string.c	2003-05-25 22:04:06.000000000 +0200
@@ -5,6 +5,11 @@
  */
 
 /*
+ * The implementations of strlcpy() and strlcat() are taken from Samba, and
+ * Copyright (C) Andrew Tridgell 2001.
+ */
+
+/*
  * stupid library routines.. The optimized versions should generally be found
  * as inline code in <asm-xx/string.h>
  *
@@ -17,6 +22,11 @@
  * * Sat Feb 09 2002, Jason Thomas <[e-mail]>,
  *                    Matthew Hawkins <[e-mail]>
  * -  Kissed strtok() goodbye
+ *
+ * * Sun May 25 2003, René Scharfe <[e-mail]>
+ * - Imported strlcpy() and strlcat() from Samba.
+ * - Fixed strlcpy() return value in case of a zero-sized buffer.
+ * - Made strlcat() able to cope with a zero-sized buffer.
  */
  
 #include <linux/types.h>
@@ -527,3 +537,56 @@
 }
 
 #endif
+
+#ifndef __HAVE_ARCH_STRLCPY
+/**
+ * strlcpy - Copy a length-limited, %NUL-terminated string
+ * @dest: Where to copy the string to
+ * @src: Where to copy the string from
+ * @bufsize: Size of the destination buffer
+ *
+ * Returns the length of @src. Unlike strncpy(), strlcpy() always
+ * %NUL-terminates @dest (unless @bufsize is 0) and does no padding.
+ */
+size_t strlcpy(char *dest, const char *src, size_t bufsize)
+{
+	size_t len = strlen(src);
+	size_t ret = len;
+
+	if (bufsize == 0)
+		return ret;
+	if (len >= bufsize)
+		len = bufsize-1;
+	memcpy(dest, src, len);
+	dest[len] = '\0';   
+	return ret;
+}
+#endif
+
+#ifndef __HAVE_ARCH_STRLCAT
+/**
+ * strlcat - Append a length-limited, %NUL-terminated string to another
+ * @dest: The string to be appended to
+ * @src: The string to append to it
+ * @bufsize: Size of the destination buffer
+ *
+ * Returns the sum of the initial lengths of @src and @dest. The resulting
+ * string is always %NUL-terminated (unless @bufsize is 0).
+ */
+size_t strlcat(char *dest, const char *src, size_t bufsize)
+{
+	size_t len1 = strnlen(dest, bufsize);
+	size_t len2 = strlen(src);
+	size_t ret = len1 + len2;
+
+	if (bufsize == 0)
+		return ret;
+	if (len1+len2 >= bufsize)
+		len2 = bufsize - (len1+1);
+	if (len2 > 0) {
+		memcpy(dest+len1, src, len2);
+		dest[len1+len2] = '\0';
+	}
+	return ret;
+}
+#endif