[xen master] tools/xenstore: rework get_node()

[patchbot@xxxxxxx]

commit 0becb6ca5ad74ed99dbeed70e3e8d0d7d859164c
Author:     Juergen Gross <jgross@xxxxxxxx>
AuthorDate: Mon Aug 14 09:47:04 2023 +0200
Commit:     Julien Grall <jgrall@xxxxxxxxxx>
CommitDate: Fri Aug 18 13:49:50 2023 +0100

    tools/xenstore: rework get_node()
    
    Today get_node_canonicalized() is the only caller of get_node().
    
    In order to prepare introducing a get_node() variant returning a
    pointer to const struct node, do the following restructuring:
    
    - move the call of read_node() from get_node() into
      get_node_canonicalized()
    
    - rename get_node() to get_node_chk_perm()
    
    - rename get_node_canonicalized() to get_node()
    
    Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
    Reviewed-by: Julien Grall <jgrall@xxxxxxxxxx>
---
 tools/xenstore/xenstored_core.c | 57 ++++++++++++++++++-----------------------
 1 file changed, 25 insertions(+), 32 deletions(-)

diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c
index 69e147df2c..9098b7eee2 100644
--- a/tools/xenstore/xenstored_core.c
+++ b/tools/xenstore/xenstored_core.c
@@ -1000,23 +1000,22 @@ static int errno_from_parents(struct connection *conn, 
const void *ctx,
  * If it fails, returns NULL and sets errno.
  * Temporary memory allocations are done with ctx.
  */
-static struct node *get_node(struct connection *conn,
-                            const void *ctx,
-                            const char *name,
-                            unsigned int perm)
+static bool get_node_chk_perm(struct connection *conn, const void *ctx,
+                             const struct node *node, const char *name,
+                             unsigned int perm)
 {
-       struct node *node;
+       bool success = node;
 
-       node = read_node(conn, ctx, name);
        /* If we don't have permission, we don't have node. */
        if (node && (perm_for_conn_from_node(conn, node) & perm) != perm) {
                errno = EACCES;
-               node = NULL;
+               success = false;
        }
        /* Clean up errno if they weren't supposed to know. */
-       if (!node && !read_node_can_propagate_errno())
+       if (!success && !read_node_can_propagate_errno())
                errno = errno_from_parents(conn, ctx, name, errno, perm);
-       return node;
+
+       return success;
 }
 
 static struct buffered_data *new_buffer(void *ctx)
@@ -1298,14 +1297,12 @@ const char *canonicalize(struct connection *conn, const 
void *ctx,
        return NULL;
 }
 
-static struct node *get_node_canonicalized(struct connection *conn,
-                                          const void *ctx,
-                                          const char *name,
-                                          const char **canonical_name,
-                                          unsigned int perm,
-                                          bool allow_special)
+static struct node *get_node(struct connection *conn, const void *ctx,
+                            const char *name, const char **canonical_name,
+                            unsigned int perm, bool allow_special)
 {
        const char *tmp_name;
+       struct node *node;
 
        if (!canonical_name)
                canonical_name = &tmp_name;
@@ -1313,7 +1310,10 @@ static struct node *get_node_canonicalized(struct 
connection *conn,
        if (!*canonical_name)
                return NULL;
 
-       return get_node(conn, ctx, *canonical_name, perm);
+       node = read_node(conn, ctx, *canonical_name);
+
+       return get_node_chk_perm(conn, ctx, node, *canonical_name, perm)
+              ? node : NULL;
 }
 
 static int send_directory(const void *ctx, struct connection *conn,
@@ -1321,8 +1321,7 @@ static int send_directory(const void *ctx, struct 
connection *conn,
 {
        struct node *node;
 
-       node = get_node_canonicalized(conn, ctx, onearg(in), NULL,
-                                     XS_PERM_READ, false);
+       node = get_node(conn, ctx, onearg(in), NULL, XS_PERM_READ, false);
        if (!node)
                return errno;
 
@@ -1343,8 +1342,7 @@ static int send_directory_part(const void *ctx, struct 
connection *conn,
                return EINVAL;
 
        /* First arg is node name. */
-       node = get_node_canonicalized(conn, ctx, in->buffer, NULL,
-                                     XS_PERM_READ, false);
+       node = get_node(conn, ctx, in->buffer, NULL, XS_PERM_READ, false);
        if (!node)
                return errno;
 
@@ -1393,8 +1391,7 @@ static int do_read(const void *ctx, struct connection 
*conn,
 {
        struct node *node;
 
-       node = get_node_canonicalized(conn, ctx, onearg(in), NULL,
-                                     XS_PERM_READ, false);
+       node = get_node(conn, ctx, onearg(in), NULL, XS_PERM_READ, false);
        if (!node)
                return errno;
 
@@ -1608,8 +1605,7 @@ static int do_write(const void *ctx, struct connection 
*conn,
        offset = strlen(vec[0]) + 1;
        datalen = in->used - offset;
 
-       node = get_node_canonicalized(conn, ctx, vec[0], &name, XS_PERM_WRITE,
-                                     false);
+       node = get_node(conn, ctx, vec[0], &name, XS_PERM_WRITE, false);
        if (!node) {
                /* No permissions, invalid input? */
                if (errno != ENOENT)
@@ -1637,8 +1633,7 @@ static int do_mkdir(const void *ctx, struct connection 
*conn,
        struct node *node;
        const char *name;
 
-       node = get_node_canonicalized(conn, ctx, onearg(in), &name,
-                                     XS_PERM_WRITE, false);
+       node = get_node(conn, ctx, onearg(in), &name, XS_PERM_WRITE, false);
 
        /* If it already exists, fine. */
        if (!node) {
@@ -1767,8 +1762,7 @@ static int do_rm(const void *ctx, struct connection *conn,
        const char *name;
        char *parentname;
 
-       node = get_node_canonicalized(conn, ctx, onearg(in), &name,
-                                     XS_PERM_WRITE, false);
+       node = get_node(conn, ctx, onearg(in), &name, XS_PERM_WRITE, false);
        if (!node) {
                /* Didn't exist already?  Fine, if parent exists. */
                if (errno == ENOENT) {
@@ -1809,8 +1803,7 @@ static int do_get_perms(const void *ctx, struct 
connection *conn,
        char *strings;
        unsigned int len;
 
-       node = get_node_canonicalized(conn, ctx, onearg(in), NULL, XS_PERM_READ,
-                                     true);
+       node = get_node(conn, ctx, onearg(in), NULL, XS_PERM_READ, true);
        if (!node)
                return errno;
 
@@ -1853,8 +1846,8 @@ static int do_set_perms(const void *ctx, struct 
connection *conn,
                return ENOENT;
 
        /* We must own node to do this (tools can do this too). */
-       node = get_node_canonicalized(conn, ctx, in->buffer, &name,
-                                     XS_PERM_WRITE | XS_PERM_OWNER, true);
+       node = get_node(conn, ctx, in->buffer, &name,
+                       XS_PERM_WRITE | XS_PERM_OWNER, true);
        if (!node)
                return errno;
 
--
generated by git-patchbot for /home/xen/git/xen.git#master