From 5e78dff4248da3f4efe3a399d66b091b97940ddf Mon Sep 17 00:00:00 2001 From: Andre Przywara Date: Wed, 1 Jul 2015 00:31:27 +0100 Subject: guess input file format based on file content or file name 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 Signed-off-by: David Gibson --- dtc.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 50 insertions(+), 1 deletion(-) (limited to 'dtc.c') diff --git a/dtc.c b/dtc.c index 8c4add6..53793bf 100644 --- a/dtc.c +++ b/dtc.c @@ -18,6 +18,8 @@ * USA */ +#include + #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")) -- cgit v1.1