tools/bootconfig: Show line and column in parse error

Show line and column when we got a parse error in bootconfig tool.
Current lib/bootconfig shows the parse error with byte offset, but
that is not human readable.
This makes xbc_init() not showing error message itself but able to
pass the error message and position to caller, so that the caller
can decode it and show the error message with line number and columns.

With this patch, bootconfig tool shows an error with line:column as
below.

  $ cat samples/bad-dotword.bconf
  # do not start keyword with .
  key {
    .word = 1
  }
  $ ./bootconfig -a samples/bad-dotword.bconf initrd
  Parse Error: Invalid keyword at 3:3

Link: http://lkml.kernel.org/r/158323469002.10560.4023923847704522760.stgit@devnote2

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

1 files changed, 31 insertions, 4 deletions

diff --git a/tools/bootconfig/main.c b/tools/bootconfig/main.c
index a9b97814d1a9..16b9a420e6fd 100644
--- a/tools/bootconfig/main.c
+++ b/tools/bootconfig/main.c
@@ -130,6 +130,7 @@ int load_xbc_from_initrd(int fd, char **buf)
 	int ret;
 	u32 size = 0, csum = 0, rcsum;
 	char magic[BOOTCONFIG_MAGIC_LEN];
+	const char *msg;
 
 	ret = fstat(fd, &stat);
 	if (ret < 0)
@@ -182,10 +183,12 @@ int load_xbc_from_initrd(int fd, char **buf)
 		return -EINVAL;
 	}
 
-	ret = xbc_init(*buf);
+	ret = xbc_init(*buf, &msg, NULL);
 	/* Wrong data */
-	if (ret < 0)
+	if (ret < 0) {
+		pr_err("parse error: %s.\n", msg);
 		return ret;
+	}
 
 	return size;
 }
@@ -244,11 +247,34 @@ int delete_xbc(const char *path)
 	return ret;
 }
 
+static void show_xbc_error(const char *data, const char *msg, int pos)
+{
+	int lin = 1, col, i;
+
+	if (pos < 0) {
+		pr_err("Error: %s.\n", msg);
+		return;
+	}
+
+	/* Note that pos starts from 0 but lin and col should start from 1. */
+	col = pos + 1;
+	for (i = 0; i < pos; i++) {
+		if (data[i] == '\n') {
+			lin++;
+			col = pos - i;
+		}
+	}
+	pr_err("Parse Error: %s at %d:%d\n", msg, lin, col);
+
+}
+
 int apply_xbc(const char *path, const char *xbc_path)
 {
 	u32 size, csum;
 	char *buf, *data;
 	int ret, fd;
+	const char *msg;
+	int pos;
 
 	ret = load_xbc_file(xbc_path, &buf);
 	if (ret < 0) {
@@ -267,11 +293,12 @@ int apply_xbc(const char *path, const char *xbc_path)
 	*(u32 *)(data + size + 4) = csum;
 
 	/* Check the data format */
-	ret = xbc_init(buf);
+	ret = xbc_init(buf, &msg, &pos);
 	if (ret < 0) {
-		pr_err("Failed to parse %s: %d\n", xbc_path, ret);
+		show_xbc_error(data, msg, pos);
 		free(data);
 		free(buf);
+
 		return ret;
 	}
 	printf("Apply %s to %s\n", xbc_path, path);