pxe: Clean up the use of bootfile

The 'bootfile' environment variable is read in the bowels of pxe_util to
provide a directory to which all loaded files are relative.

This is not obvious from the API to PXE and it is strange to make the
caller set an environment variable rather than pass this as a parameter.

The code is also convoluted, which this feature implemented by
get_bootfile_path().

Update the API to improve this. Unfortunately this means that
pxe_setup_ctx() can fail, so add error checking.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Artem Lapkin <email2tema@gmail.com>
Tested-by: Artem Lapkin <email2tema@gmail.com>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>

1 files changed, 38 insertions, 22 deletions

diff --git a/boot/pxe_utils.c b/boot/pxe_utils.c
index f40ad2b161..5d47d30a9e 100644
--- a/boot/pxe_utils.c
+++ b/boot/pxe_utils.c
@@ -67,10 +67,10 @@ int format_mac_pxe(char *outbuf, size_t outbuf_len)
 /**
  * get_bootfile_path() - Figure out the path of a file to read
  *
- * Returns the directory the file specified in the 'bootfile' env variable is
- * in. If bootfile isn't defined in the environment, return NULL, which should
- * be interpreted as "don't prepend anything to paths".
+ * Copies the boot directory into the supplied buffer. If there is no boot
+ * directory, set it to ""
  *
+ * @ctx: PXE context
  * @file_path: File path to read (relative to the PXE file)
  * @bootfile_path: Place to put the bootfile path
  * @bootfile_path_size: Size of @bootfile_path in bytes
@@ -79,34 +79,25 @@ int format_mac_pxe(char *outbuf, size_t outbuf_len)
  * Returns 1 for success, -ENOSPC if bootfile_path_size is to small to hold the
  *	resulting path
  */
-static int get_bootfile_path(const char *file_path, char *bootfile_path,
-			     size_t bootfile_path_size, bool allow_abs_path)
+static int get_bootfile_path(struct pxe_context *ctx, const char *file_path,
+			     char *bootfile_path, size_t bootfile_path_size,
+			     bool allow_abs_path)
 {
-	char *bootfile, *last_slash;
 	size_t path_len = 0;
 
 	/* Only syslinux allows absolute paths */
 	if (file_path[0] == '/' && allow_abs_path)
 		goto ret;
 
-	bootfile = from_env("bootfile");
-	if (!bootfile)
-		goto ret;
-
-	last_slash = strrchr(bootfile, '/');
-	if (!last_slash)
-		goto ret;
-
-	path_len = (last_slash - bootfile) + 1;
-
-	if (bootfile_path_size < path_len) {
+	path_len = strlen(ctx->bootdir);
+	if (bootfile_path_size < path_len + 1) {
 		printf("bootfile_path too small. (%zd < %zd)\n",
 		       bootfile_path_size, path_len);
 
 		return -ENOSPC;
 	}
 
-	strncpy(bootfile_path, bootfile, path_len);
+	strncpy(bootfile_path, ctx->bootdir, path_len);
 
  ret:
 	bootfile_path[path_len] = '\0';
@@ -135,7 +126,7 @@ static int get_relfile(struct pxe_context *ctx, const char *file_path,
 	char addr_buf[18];
 	int err;
 
-	err = get_bootfile_path(file_path, relfile, sizeof(relfile),
+	err = get_bootfile_path(ctx, file_path, relfile, sizeof(relfile),
 				ctx->allow_abs_path);
 	if (err < 0)
 		return err;
@@ -1496,14 +1487,39 @@ void handle_pxe_menu(struct pxe_context *ctx, struct pxe_menu *cfg)
 	boot_unattempted_labels(ctx, cfg);
 }
 
-void pxe_setup_ctx(struct pxe_context *ctx, struct cmd_tbl *cmdtp,
-		   pxe_getfile_func getfile, void *userdata,
-		   bool allow_abs_path)
+int pxe_setup_ctx(struct pxe_context *ctx, struct cmd_tbl *cmdtp,
+		  pxe_getfile_func getfile, void *userdata,
+		  bool allow_abs_path, const char *bootfile)
 {
+	const char *last_slash;
+	size_t path_len = 0;
+
+	memset(ctx, '\0', sizeof(*ctx));
 	ctx->cmdtp = cmdtp;
 	ctx->getfile = getfile;
 	ctx->userdata = userdata;
 	ctx->allow_abs_path = allow_abs_path;
+
+	/* figure out the boot directory, if there is one */
+	if (bootfile && strlen(bootfile) >= MAX_TFTP_PATH_LEN)
+		return -ENOSPC;
+	ctx->bootdir = strdup(bootfile ? bootfile : "");
+	if (!ctx->bootdir)
+		return -ENOMEM;
+
+	if (bootfile) {
+		last_slash = strrchr(bootfile, '/');
+		if (last_slash)
+			path_len = (last_slash - bootfile) + 1;
+	}
+	ctx->bootdir[path_len] = '\0';
+
+	return 0;
+}
+
+void pxe_destroy_ctx(struct pxe_context *ctx)
+{
+	free(ctx->bootdir);
 }
 
 int pxe_process(struct pxe_context *ctx, ulong pxefile_addr_r, bool prompt)