1 files changed, 24 insertions, 16 deletions

diff --git a/arch/x86/boot/tools/build.c b/arch/x86/boot/tools/build.c
index c941d6a8887f..8e15b22391fc 100644
--- a/arch/x86/boot/tools/build.c
+++ b/arch/x86/boot/tools/build.c
@@ -5,14 +5,15 @@
  */
 
 /*
- * This file builds a disk-image from two different files:
+ * This file builds a disk-image from three different files:
  *
  * - setup: 8086 machine code, sets up system parm
  * - system: 80386 code for actual system
+ * - zoffset.h: header with ZO_* defines
  *
- * It does some checking that all files are of the correct type, and
- * just writes the result to stdout, removing headers and padding to
- * the right amount. It also writes some system data to stderr.
+ * It does some checking that all files are of the correct type, and writes
+ * the result to the specified destination, removing headers and padding to
+ * the right amount. It also writes some system data to stdout.
  */
 
 /*
@@ -136,7 +137,7 @@ static void die(const char * str, ...)
 
 static void usage(void)
 {
-        die("Usage: build setup system [zoffset.h] [> image]");
+        die("Usage: build setup system zoffset.h image");
 }
 
 #ifdef CONFIG_EFI_STUB
@@ -265,7 +266,7 @@ int main(int argc, char ** argv)
         int c;
         u32 sys_size;
         struct stat sb;
-        FILE *file;
+        FILE *file, *dest;
         int fd;
         void *kernel;
         u32 crc = 0xffffffffUL;
@@ -280,10 +281,13 @@ int main(int argc, char ** argv)
         startup_64 = 0x200;
 #endif
 
-        if (argc == 4)
-                parse_zoffset(argv[3]);
-        else if (argc != 3)
+        if (argc != 5)
                 usage();
+        parse_zoffset(argv[3]);
+
+        dest = fopen(argv[4], "w");
+        if (!dest)
+                die("Unable to write `%s': %m", argv[4]);
 
         /* Copy the setup code */
         file = fopen(argv[1], "r");
@@ -318,7 +322,7 @@ int main(int argc, char ** argv)
         /* Set the default root device */
         put_unaligned_le16(DEFAULT_ROOT_DEV, &buf[508]);
 
-        fprintf(stderr, "Setup is %d bytes (padded to %d bytes).\n", c, i);
+        printf("Setup is %d bytes (padded to %d bytes).\n", c, i);
 
         /* Open and stat the kernel file */
         fd = open(argv[2], O_RDONLY);
@@ -327,7 +331,7 @@ int main(int argc, char ** argv)
         if (fstat(fd, &sb))
                 die("Unable to stat `%s': %m", argv[2]);
         sz = sb.st_size;
-        fprintf (stderr, "System is %d kB\n", (sz+1023)/1024);
+        printf("System is %d kB\n", (sz+1023)/1024);
         kernel = mmap(NULL, sz, PROT_READ, MAP_SHARED, fd, 0);
         if (kernel == MAP_FAILED)
                 die("Unable to mmap '%s': %m", argv[2]);
@@ -348,27 +352,31 @@ int main(int argc, char ** argv)
 #endif
 
         crc = partial_crc32(buf, i, crc);
-        if (fwrite(buf, 1, i, stdout) != i)
+        if (fwrite(buf, 1, i, dest) != i)
                 die("Writing setup failed");
 
         /* Copy the kernel code */
         crc = partial_crc32(kernel, sz, crc);
-        if (fwrite(kernel, 1, sz, stdout) != sz)
+        if (fwrite(kernel, 1, sz, dest) != sz)
                 die("Writing kernel failed");
 
         /* Add padding leaving 4 bytes for the checksum */
         while (sz++ < (sys_size*16) - 4) {
                 crc = partial_crc32_one('\0', crc);
-                if (fwrite("\0", 1, 1, stdout) != 1)
+                if (fwrite("\0", 1, 1, dest) != 1)
                         die("Writing padding failed");
         }
 
         /* Write the CRC */
-        fprintf(stderr, "CRC %x\n", crc);
+        printf("CRC %x\n", crc);
         put_unaligned_le32(crc, buf);
-        if (fwrite(buf, 1, 4, stdout) != 4)
+        if (fwrite(buf, 1, 4, dest) != 4)
                 die("Writing CRC failed");
 
+        /* Catch any delayed write failures */
+        if (fclose(dest))
+                die("Writing image failed");
+
         close(fd);
 
         /* Everything is OK */