otrx: allow validating TRX from stdin

This makes "otrx check" work with stdin to allow e.g.
dd if=firmware.chk skip=1 bs=58 | otrx check -

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>

diff --git a/src/otrx.c b/src/otrx.c
index aa81c96c5475843a31b25e31ae0fd47a4d713fc4..af6e905cdc815bb3a88fbfc7d4125cbc516d718e 100644 (file)
--- a/src/otrx.c
+++ b/src/otrx.c
@@ -12,6 +12,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/stat.h>
 #include <unistd.h>
 
 #if !defined(__BYTE_ORDER)
@@ -130,6 +131,44 @@ uint32_t otrx_crc32(uint32_t crc, uint8_t *buf, size_t len) {
        return crc;
 }
 
+/**************************************************
+ * Helpers
+ **************************************************/
+
+static FILE *otrx_open(const char *pathname, const char *mode) {
+       if (strcmp(pathname, "-"))
+               return fopen(pathname, mode);
+
+       if (isatty(fileno(stdin))) {
+               fprintf(stderr, "Reading from TTY stdin is unsupported\n");
+               return NULL;
+       }
+
+       return stdin;
+}
+
+static int otrx_skip(FILE *fp, size_t length)
+{
+       if (fseek(fp, length, SEEK_CUR)) {
+               uint8_t buf[1024];
+               size_t bytes;
+
+               do {
+                       bytes = fread(buf, 1, otrx_min(sizeof(buf), length), fp);
+                       if (bytes <= 0)
+                               return -EIO;
+                       length -= bytes;
+               } while (length);
+       }
+
+       return 0;
+}
+
+static void otrx_close(FILE *fp) {
+       if (fp != stdin)
+               fclose(fp);
+}
+
 /**************************************************
  * Check
  **************************************************/
@@ -164,14 +203,19 @@ static int otrx_check(int argc, char **argv) {
        optind = 3;
        otrx_check_parse_options(argc, argv);
 
-       trx = fopen(trx_path, "r");
+       trx = otrx_open(trx_path, "r");
        if (!trx) {
                fprintf(stderr, "Couldn't open %s\n", trx_path);
                err = -EACCES;
                goto out;
        }
 
-       fseek(trx, trx_offset, SEEK_SET);
+       if (trx_offset && otrx_skip(trx, trx_offset)) {
+               fprintf(stderr, "Couldn't skip first %zd B\n", trx_offset);
+               err =  -EIO;
+               goto err_close;
+       }
+
        bytes = fread(&hdr, 1, sizeof(hdr), trx);
        if (bytes != sizeof(hdr)) {
                fprintf(stderr, "Couldn't read %s header\n", trx_path);
@@ -215,7 +259,7 @@ static int otrx_check(int argc, char **argv) {
        printf("Found a valid TRX version %d\n", le32_to_cpu(hdr.version));
 
 err_close:
-       fclose(trx);
+       otrx_close(trx);
 out:
        return err;
 }