support colon in filenames

Problem: It is impossible to feed filenames with the character colon because
qemu interprets such names as a protocol. For example filename scsi:0, is
interpreted as a protocol by name "scsi".

This patch allows user to espace colon characters. For example the above
filename can now be expressed either as 'scsi\:0' or as file:scsi:0

anything following the "file:" tag is interpreted verbatin. However if "file:"
tag is omitted then any colon characters in the string must be escaped using
backslash.

Here are couple of examples:

scsi\:0\:abc is a local file scsi:0:abc
http\://myweb is a local file by name http://myweb
file:scsi:0:abc is a local file scsi:0:abc
file:http://myweb is a local file by name http://myweb

Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 26 insertions, 0 deletions

diff --git a/cutils.c b/cutils.c
index 0623cf70da..73d4e1fbbd 100644
--- a/cutils.c
+++ b/cutils.c
@@ -24,6 +24,32 @@
 #include "qemu-common.h"
 #include "host-utils.h"
 
+/*
+ * fill first 'len' characters of 'buff' with pruned
+ * contents of 'str' delimited by the character 'c'.
+ * Escape character '\' is pruned off.
+ * Return pointer to the delimiting character.
+ */
+const char *fill_token(char *buf, const int len, const char *str, const char c)
+{
+    const char *p=str;
+    char *q=buf;
+
+    while (p < str+len-1) {
+    if (*p == c)
+        break;
+        if (*p == '\\') {
+            p++;
+            if (*p == '\0')
+                break;
+        }
+        *q++ = *p++;
+    }
+    *q='\0';
+    return p;
+}
+
+
 void pstrcpy(char *buf, int buf_size, const char *str)
 {
     int c;