[POWERPC] rewrite mkprep and mkbugboot in sane C

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/ppc/boot/utils/mkbugboot.c

@@ -19,36 +19,13 @@
 #include <stdlib.h>
 #include <errno.h>
 #include <fcntl.h>
+#include <netinet/in.h>
 #ifdef __sun__
 #include <inttypes.h>
 #else
 #include <stdint.h>
 #endif
 
-#ifdef __i386__
-#define cpu_to_be32(x) le32_to_cpu(x)
-#define cpu_to_be16(x) le16_to_cpu(x)
-#else
-#define cpu_to_be32(x) (x)
-#define cpu_to_be16(x) (x)
-#endif
-
-#define cpu_to_le32(x) le32_to_cpu((x))
-unsigned long le32_to_cpu(unsigned long x)
-{
-     	return (((x & 0x000000ffU) << 24) |
-		((x & 0x0000ff00U) <<  8) |
-		((x & 0x00ff0000U) >>  8) |
-		((x & 0xff000000U) >> 24));
-}
-
-#define cpu_to_le16(x) le16_to_cpu((x))
-unsigned short le16_to_cpu(unsigned short x)
-{
-	return (((x & 0x00ff) << 8) |
-		((x & 0xff00) >> 8));
-}
-
 /* size of read buffer */
 #define SIZE 0x1000
 
@@ -62,124 +39,109 @@ typedef struct bug_boot_header {
 
 #define HEADER_SIZE	sizeof(bug_boot_header_t)
 
-uint32_t copy_image(int32_t in_fd, int32_t out_fd)
+void update_checksum(void *buf, size_t size, uint16_t *sum)
 {
-  uint8_t buf[SIZE];
-  int n;
-  uint32_t image_size = 0;
-  uint8_t zero = 0;
-
-  lseek(in_fd, ELF_HEADER_SIZE, SEEK_SET);
-
-  /* Copy an image while recording its size */
-  while ( (n = read(in_fd, buf, SIZE)) > 0 )
-    {
-    image_size = image_size + n;
-    write(out_fd, buf, n);
-    }
-
-  /* BUG romboot requires that our size is divisible by 2 */
-  /* align image to 2 byte boundary */
-  if (image_size % 2)
-    {
-    image_size++;
-    write(out_fd, &zero, 1);
-    }
-
-  return image_size;
+	uint32_t csum = *sum;
+
+	while (size) {
+		csum += *(uint16_t *)buf;
+		if (csum > 0xffff)
+			csum -= 0xffff;
+		buf = (uint16_t *)buf + 1;
+		size -= 2;
+	}
+	*sum = csum;
 }
 
-void write_bugboot_header(int32_t out_fd, uint32_t boot_size)
+uint32_t copy_image(int in_fd, int out_fd, uint16_t *sum)
 {
-  uint8_t header_block[HEADER_SIZE];
-  bug_boot_header_t *bbh = (bug_boot_header_t *)&header_block[0];
-
-  memset(header_block, 0, HEADER_SIZE);
-
-  /* Fill in the PPCBUG ROM boot header */
-  strncpy(bbh->magic_word, "BOOT", 4);		/* PPCBUG magic word */
-  bbh->entry_offset = cpu_to_be32(HEADER_SIZE);	/* Entry address */
-  bbh->routine_length= cpu_to_be32(HEADER_SIZE+boot_size+2);	/* Routine length */
-  strncpy(bbh->routine_name, "LINUXROM", 8);		/* Routine name   */
-
-  /* Output the header and bootloader to the file */
-  write(out_fd, header_block, HEADER_SIZE);
+	uint8_t buf[SIZE];
+	int offset = 0;
+	int n;
+	uint32_t image_size = 0;
+
+	lseek(in_fd, ELF_HEADER_SIZE, SEEK_SET);
+
+	/* Copy an image while recording its size */
+	while ( (n = read(in_fd, buf + offset, SIZE - offset)) > 0 ) {
+		n += offset;
+		offset = n & 1;
+		n -= offset;
+		image_size = image_size + n;
+		/* who's going to deal with short writes? */
+		write(out_fd, buf, n);
+		update_checksum(buf, n, sum);
+		if (offset)
+			buf[0] = buf[n];
+	}
+
+	/* BUG romboot requires that our size is divisible by 2 */
+	/* align image to 2 byte boundary */
+	if (offset) {
+		image_size += 2;
+		buf[1] = '\0';
+		write(out_fd, buf, 2);
+		update_checksum(buf, 2, sum);
+	}
+	return image_size;
 }
 
-uint16_t calc_checksum(int32_t bug_fd)
+void write_bugboot_header(int out_fd, uint32_t boot_size, uint16_t *sum)
 {
-  uint32_t checksum_var = 0;
-  uint8_t buf[2];
-  int n;
-
-  /* Checksum loop */
-  while ( (n = read(bug_fd, buf, 2) ) )
-  {
-    checksum_var = checksum_var + *(uint16_t *)buf;
-
-    /* If we carry out, mask it and add one to the checksum */
-    if (checksum_var >> 16)
-      checksum_var = (checksum_var & 0x0000ffff) + 1;
-  }
-
-  return checksum_var;
+	static bug_boot_header_t bbh = {
+		.magic_word = "BOOT",
+		.routine_name = "LINUXROM"
+	};
+
+	/* Fill in the PPCBUG ROM boot header */
+	bbh.entry_offset = htonl(HEADER_SIZE);	/* Entry address */
+	bbh.routine_length= htonl(HEADER_SIZE+boot_size+2);	/* Routine length */
+
+	/* Output the header and bootloader to the file */
+	write(out_fd, &bbh, sizeof(bug_boot_header_t));
+	update_checksum(&bbh, sizeof(bug_boot_header_t), sum);
 }
 
 int main(int argc, char *argv[])
 {
-  int32_t image_fd, bugboot_fd;
-  int argptr = 1;
-  uint32_t kernel_size = 0;
-  uint16_t checksum = 0;
-  uint8_t bugbootname[256];
-
-  if ( (argc != 3) )
-  {
-    fprintf(stderr, "usage: %s <kernel_image> <bugboot>\n",argv[0]);
-    exit(-1);
-  }
-
-  /* Get file args */
-
-  /* kernel image file */
-    if ((image_fd = open( argv[argptr] , 0)) < 0)
-      exit(-1);
-  argptr++;
+	int image_fd, bugboot_fd;
+	uint32_t kernel_size = 0;
+	uint16_t checksum = 0;
 
-  /* bugboot file */
-  if ( !strcmp( argv[argptr], "-" ) )
-    bugboot_fd = 1;			/* stdout */
-  else
-    if ((bugboot_fd = creat( argv[argptr] , 0755)) < 0)
-      exit(-1);
-    else
-      strcpy(bugbootname, argv[argptr]);
-  argptr++;
+	if (argc != 3) {
+		fprintf(stderr, "usage: %s <kernel_image> <bugboot>\n",argv[0]);
+		exit(-1);
+	}
 
-  /* Set file position after ROM header block where zImage will be written */
-  lseek(bugboot_fd, HEADER_SIZE, SEEK_SET);
+	/* Get file args */
 
-  /* Copy kernel image into bugboot image */
-  kernel_size = copy_image(image_fd, bugboot_fd);
-  close(image_fd);
+	/* kernel image file */
+	if ((image_fd = open(argv[1] , 0)) < 0)
+		exit(-1);
 
-  /* Set file position to beginning where header/romboot will be written */
-  lseek(bugboot_fd, 0, SEEK_SET);
+	/* bugboot file */
+	if (!strcmp(argv[2], "-"))
+		bugboot_fd = 1;			/* stdout */
+	else if ((bugboot_fd = creat(argv[2] , 0755)) < 0)
+		exit(-1);
 
-  /* Write out BUG header/romboot */
-  write_bugboot_header(bugboot_fd, kernel_size);
+	/* Set file position after ROM header block where zImage will be written */
+	lseek(bugboot_fd, HEADER_SIZE, SEEK_SET);
 
-  /* Close bugboot file */
-  close(bugboot_fd);
+	/* Copy kernel image into bugboot image */
+	kernel_size = copy_image(image_fd, bugboot_fd, &checksum);
 
-  /* Reopen it as read/write */
-  bugboot_fd = open(bugbootname, O_RDWR);
+	/* Set file position to beginning where header/romboot will be written */
+	lseek(bugboot_fd, 0, SEEK_SET);
 
-  /* Calculate checksum */
-  checksum = calc_checksum(bugboot_fd);
+	/* Write out BUG header/romboot */
+	write_bugboot_header(bugboot_fd, kernel_size, &checksum);
 
-  /* Write out the calculated checksum */
-  write(bugboot_fd, &checksum, 2);
+	/* Write out the calculated checksum */
+	lseek(bugboot_fd, 0, SEEK_END);
+	write(bugboot_fd, &checksum, 2);
 
-  return 0;
+	/* Close bugboot file */
+	close(bugboot_fd);
+	return 0;
 }