Always needing to specify the input file format can be quite
annoying, especially since a dtb is easily detected by its magic.
Looking at the file name extension sounds useful as a hint, too.
Add heuristic file type guessing of the input file format in case
none has been specified on the command line.
The heuristics are as follows (in that order):
- Any issues with opening the file drop back to the current default
behaviour.
- A directory will be treated as the /proc/device-tree type.
- If the first 4 bytes are the DTB magic, assume "dtb".
- If no other test succeeded so far, use a file name based
guessing method: if the filename ends with .dts or .DTS, device tree
source text is assumed, .dtb or .DTB hint at a device tree blob.
For the majority of practical use cases this gets rid of the tedious
-I specification on the command line and simplifies actual typing of
dtc command lines.
Any explicit specification of the input type by using -I still avoids
any guessing, which resembles the current behaviour.
Signed-off-by: Andre Przywara <osp@xxxxxxxxx>
---
dtc.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 50 insertions(+), 1 deletion(-)
diff --git a/dtc.c b/dtc.c
index 8c4add6..53793bf 100644
--- a/dtc.c
+++ b/dtc.c
@@ -18,6 +18,8 @@
* USA
*/
+#include <sys/stat.h>
+
#include "dtc.h"
#include "srcpos.h"
@@ -104,10 +106,55 @@ static const char * const usage_opts_help[] = {
NULL,
};
+static const char *guess_type_by_name(const char *fname, const char *fallback)
+{
+ const char *s;
+
+ s = strrchr(fname, '.');
+ if (s == NULL)
+ return fallback;
+ if (!strcasecmp(s, ".dts"))
+ return "dts";
+ if (!strcasecmp(s, ".dtb"))
+ return "dtb";
+ return fallback;
+}
+
+static const char *guess_input_format(const char *fname, const char *fallback)
+{
+ struct stat statbuf;
+ uint32_t magic;
+ FILE *f;
+
+ if (stat(fname, &statbuf) != 0)
+ return fallback;
+
+ if (S_ISDIR(statbuf.st_mode))
+ return "fs";
+
+ if (!S_ISREG(statbuf.st_mode))
+ return fallback;
+
+ f = fopen(fname, "r");
+ if (f == NULL)
+ return fallback;
+ if (fread(&magic, 4, 1, f) != 1) {
+ fclose(f);
+ return fallback;
+ }
+ fclose(f);
+
+ magic = fdt32_to_cpu(magic);
+ if (magic == FDT_MAGIC)
+ return "dtb";
+
+ return guess_type_by_name(fname, fallback);
+}
+
int main(int argc, char *argv[])
{
struct boot_info *bi;
- const char *inform = "dts";
+ const char *inform = NULL;
const char *outform = "dts";
const char *outname = "-";
const char *depname = NULL;
@@ -213,6 +260,8 @@ int main(int argc, char *argv[])
fprintf(depfile, "%s:", outname);
}
+ if (inform == NULL)
+ inform = guess_input_format(arg, "dts");
if (streq(inform, "dts"))
bi = dt_from_source(arg);
else if (streq(inform, "fs"))
--
1.8.4
--
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