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, 17 insertions, 10 deletions

diff --git a/block.c b/block.c
index aca5a6d28..3fe931702 100644
--- a/block.c
+++ b/block.c
@@ -225,7 +225,7 @@ static BlockDriver *find_protocol(const char *filename)
 {
     BlockDriver *drv1;
     char protocol[128];
-    int len;
+    int len = strnlen(filename, 127)+1;
     const char *p;
 
 #ifdef _WIN32
@@ -233,14 +233,9 @@ static BlockDriver *find_protocol(const char *filename)
         is_windows_drive_prefix(filename))
         return bdrv_find_format("raw");
 #endif
-    p = strchr(filename, ':');
-    if (!p)
+    p = fill_token(protocol, len, filename, ':');
+    if (*p != ':')
         return bdrv_find_format("raw");
-    len = p - filename;
-    if (len > sizeof(protocol) - 1)
-        len = sizeof(protocol) - 1;
-    memcpy(protocol, filename, len);
-    protocol[len] = '\0';
     for(drv1 = first_drv; drv1 != NULL; drv1 = drv1->next) {
         if (drv1->protocol_name &&
             !strcmp(drv1->protocol_name, protocol))
@@ -414,9 +409,9 @@ int bdrv_open2(BlockDriverState *bs, const char *filename, int flags,
         open_flags = BDRV_O_RDWR | (flags & BDRV_O_CACHE_MASK);
     else
         open_flags = flags & ~(BDRV_O_FILE | BDRV_O_SNAPSHOT);
-    ret = drv->bdrv_open(bs, filename, open_flags);
+    ret = bdrv_open3(bs, filename, open_flags, drv);
     if ((ret == -EACCES || ret == -EPERM) && !(flags & BDRV_O_FILE)) {
-        ret = drv->bdrv_open(bs, filename, open_flags & ~BDRV_O_RDWR);
+        ret = bdrv_open3(bs, filename, open_flags & ~BDRV_O_RDWR, drv);
         bs->read_only = 1;
     }
     if (ret < 0) {
@@ -461,6 +456,18 @@ int bdrv_open2(BlockDriverState *bs, const char *filename, int flags,
     return 0;
 }
 
+int bdrv_open3(BlockDriverState *bs, const char *filename, int flags, BlockDriver *drv)
+{
+    char myfile[PATH_MAX];
+    const char *f;
+
+    if (!strstart(filename, "file:", &f)) {
+        fill_token(myfile, PATH_MAX, filename, '\0');
+        return drv->bdrv_open(bs,myfile,flags);
+    }
+    return drv->bdrv_open(bs,f,flags);
+}
+
 void bdrv_close(BlockDriverState *bs)
 {
     if (bs->drv) {