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cifs: fix composing of mount options for DFS referrals
With the change to ignore the unc= and prefixpath= mount options, there
is no longer any need to add them to the options string when mounting.
By the same token, we now need to build a device name that includes the
prefixpath when mounting.
To make things neater, the delimiters on the devicename are changed
to '/' since that's preferred when mounting anyway.
v2: fix some comments and don't bother looking at whether there is
a prepath in the ref->node_name when deciding whether to pass
a prepath to cifs_build_devname.
v3: rebase on top of potential buffer overrun fix for stable
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
This commit is contained in:
Jeff Layton
Steve French
parent
9c9c29e1af
commit
d9deef0a3f
@ -49,58 +49,74 @@ void cifs_dfs_release_automount_timer(void)
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}
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/**
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* cifs_get_share_name - extracts share name from UNC
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* @node_name: pointer to UNC string
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* cifs_build_devname - build a devicename from a UNC and optional prepath
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* @nodename: pointer to UNC string
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* @prepath: pointer to prefixpath (or NULL if there isn't one)
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*
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* Extracts sharename form full UNC.
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* i.e. strips from UNC trailing path that is not part of share
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* name and fixup missing '\' in the beginning of DFS node refferal
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* if necessary.
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* Returns pointer to share name on success or ERR_PTR on error.
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* Caller is responsible for freeing returned string.
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* Build a new cifs devicename after chasing a DFS referral. Allocate a buffer
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* big enough to hold the final thing. Copy the UNC from the nodename, and
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* concatenate the prepath onto the end of it if there is one.
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*
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* Returns pointer to the built string, or a ERR_PTR. Caller is responsible
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* for freeing the returned string.
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*/
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static char *cifs_get_share_name(const char *node_name)
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static char *
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cifs_build_devname(char *nodename, const char *prepath)
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{
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int len;
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char *UNC;
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char *pSep;
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size_t pplen;
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size_t unclen;
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char *dev;
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char *pos;
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len = strlen(node_name);
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UNC = kmalloc(len+2 /*for term null and additional \ if it's missed */,
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GFP_KERNEL);
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if (!UNC)
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/* skip over any preceding delimiters */
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nodename += strspn(nodename, "\\");
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if (!*nodename)
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return ERR_PTR(-EINVAL);
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/* get length of UNC and set pos to last char */
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unclen = strlen(nodename);
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pos = nodename + unclen - 1;
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/* trim off any trailing delimiters */
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while (*pos == '\\') {
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--pos;
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--unclen;
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}
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/* allocate a buffer:
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* +2 for preceding "//"
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* +1 for delimiter between UNC and prepath
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* +1 for trailing NULL
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*/
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pplen = prepath ? strlen(prepath) : 0;
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dev = kmalloc(2 + unclen + 1 + pplen + 1, GFP_KERNEL);
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if (!dev)
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return ERR_PTR(-ENOMEM);
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/* get share name and server name */
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if (node_name[1] != '\\') {
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UNC[0] = '\\';
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strncpy(UNC+1, node_name, len);
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len++;
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UNC[len] = 0;
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} else {
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strncpy(UNC, node_name, len);
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UNC[len] = 0;
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pos = dev;
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/* add the initial "//" */
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*pos = '/';
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++pos;
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*pos = '/';
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++pos;
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/* copy in the UNC portion from referral */
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memcpy(pos, nodename, unclen);
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pos += unclen;
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/* copy the prefixpath remainder (if there is one) */
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if (pplen) {
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*pos = '/';
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++pos;
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memcpy(pos, prepath, pplen);
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pos += pplen;
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}
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/* find server name end */
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pSep = memchr(UNC+2, '\\', len-2);
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if (!pSep) {
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cifs_dbg(VFS, "%s: no server name end in node name: %s\n",
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__func__, node_name);
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kfree(UNC);
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return ERR_PTR(-EINVAL);
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}
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/* NULL terminator */
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*pos = '\0';
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/* find sharename end */
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pSep++;
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pSep = memchr(UNC+(pSep-UNC), '\\', len-(pSep-UNC));
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if (pSep) {
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/* trim path up to sharename end
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* now we have share name in UNC */
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*pSep = 0;
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}
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return UNC;
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convert_delimiter(dev, '/');
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return dev;
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}
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@ -124,6 +140,7 @@ char *cifs_compose_mount_options(const char *sb_mountdata,
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{
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int rc;
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char *mountdata = NULL;
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const char *prepath = NULL;
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int md_len;
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char *tkn_e;
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char *srvIP = NULL;
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@ -133,7 +150,10 @@ char *cifs_compose_mount_options(const char *sb_mountdata,
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if (sb_mountdata == NULL)
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return ERR_PTR(-EINVAL);
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*devname = cifs_get_share_name(ref->node_name);
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if (strlen(fullpath) - ref->path_consumed)
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prepath = fullpath + ref->path_consumed;
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*devname = cifs_build_devname(ref->node_name, prepath);
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if (IS_ERR(*devname)) {
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rc = PTR_ERR(*devname);
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*devname = NULL;
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@ -147,13 +167,14 @@ char *cifs_compose_mount_options(const char *sb_mountdata,
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goto compose_mount_options_err;
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}
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/* md_len = strlen(...) + 12 for 'sep+prefixpath='
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* assuming that we have 'unc=' and 'ip=' in
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* the original sb_mountdata
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/*
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* In most cases, we'll be building a shorter string than the original,
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* but we do have to assume that the address in the ip= option may be
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* much longer than the original. Add the max length of an address
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* string to the length of the original string to allow for worst case.
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*/
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md_len = strlen(sb_mountdata) + rc + strlen(ref->node_name) + 12 +
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INET6_ADDRSTRLEN;
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mountdata = kzalloc(md_len+1, GFP_KERNEL);
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md_len = strlen(sb_mountdata) + INET6_ADDRSTRLEN;
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mountdata = kzalloc(md_len + 1, GFP_KERNEL);
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if (mountdata == NULL) {
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rc = -ENOMEM;
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goto compose_mount_options_err;
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@ -197,26 +218,6 @@ char *cifs_compose_mount_options(const char *sb_mountdata,
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strncat(mountdata, &sep, 1);
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strcat(mountdata, "ip=");
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strcat(mountdata, srvIP);
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strncat(mountdata, &sep, 1);
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strcat(mountdata, "unc=");
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strcat(mountdata, *devname);
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/* find & copy prefixpath */
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tkn_e = strchr(ref->node_name + 2, '\\');
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if (tkn_e == NULL) {
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/* invalid unc, missing share name*/
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rc = -EINVAL;
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goto compose_mount_options_err;
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}
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tkn_e = strchr(tkn_e + 1, '\\');
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if (tkn_e || (strlen(fullpath) - ref->path_consumed)) {
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strncat(mountdata, &sep, 1);
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strcat(mountdata, "prefixpath=");
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if (tkn_e)
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strcat(mountdata, tkn_e + 1);
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strcat(mountdata, fullpath + ref->path_consumed);
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}
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/*cifs_dbg(FYI, "%s: parent mountdata: %s\n", __func__, sb_mountdata);*/
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/*cifs_dbg(FYI, "%s: submount mountdata: %s\n", __func__, mountdata );*/
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@ -34,7 +34,7 @@
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/**
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* dns_resolve_server_name_to_ip - Resolve UNC server name to ip address.
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* @unc: UNC path specifying the server
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* @unc: UNC path specifying the server (with '/' as delimiter)
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* @ip_addr: Where to return the IP address.
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*
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* The IP address will be returned in string form, and the caller is
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@ -64,7 +64,7 @@ dns_resolve_server_name_to_ip(const char *unc, char **ip_addr)
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hostname = unc + 2;
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/* Search for server name delimiter */
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sep = memchr(hostname, '\\', len);
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sep = memchr(hostname, '/', len);
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if (sep)
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len = sep - hostname;
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else
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