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Commit 2fe74fa9 authored by Sam Ravnborg's avatar Sam Ravnborg Committed by David S. Miller
Browse files

sparc: refactor piggy_32.c 



Refactoring to increase readability (a little).
- sort includes
- spaces around operators
- small helpers introduced
- added a few comments

Signed-off-by: default avatarSam Ravnborg <sam@ravnborg.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f28f3313

arch/sparc/boot/piggyback_32.c

+102 −40
Original line number Diff line number Diff line
@@ -19,14 +19,15 @@ 
   along with this program; if not, write to the Free Software

   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */



#include <stdio.h>

#include <dirent.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include <ctype.h>

#include <errno.h>

#include <fcntl.h>

#include <dirent.h>

#include <unistd.h>

#include <stdlib.h>

#include <stdio.h>



#include <sys/types.h>

#include <sys/stat.h>
@@ -35,16 +36,19 @@ 
 * as PROM looks for a.out image only.

 */



/* read two bytes as big endian */

static unsigned short ld2(char *p)

{

	return (p[0] << 8) | p[1];

}



/* read 4 bytes as big endian */

static unsigned int ld4(char *p)

{

	return (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];

}



/* save 4 bytes as big endian */

static void st4(char *p, unsigned int x)

{

	p[0] = x >> 24;
@@ -53,6 +57,12 @@ static void st4(char *p, unsigned int x) 
	p[3] = x;

}



static void die(const char *str)

{

	perror(str);

	exit(1);

}



static void usage(void)

{

	/* fs_img.gz is an image of initial ramdisk. */
@@ -61,10 +71,57 @@ static void usage(void) 
	exit(1);

}



static void die(char *str)

static int start_line(const char *line)

{

	perror (str);

	exit(1);

	if (strcmp(line + 8, " T start\n") == 0)

		return 1;

	else if (strcmp(line + 16, " T start\n") == 0)

		return 1;

	return 0;

}



static int end_line(const char *line)

{

	if (strcmp(line + 8, " A _end\n") == 0)

		return 1;

	else if (strcmp (line + 16, " A _end\n") == 0)

		return 1;

	return 0;

}



/*

 * Find address for start and end in System.map.

 * The file looks like this:

 * f0004000 T start

 * f0379f79 A _end

 * 1234567890123456

 * ^coloumn 1

 * There is support for 64 bit addresses too.

 *

 * Return 0 if either start or end is not found

 */

static int get_start_end(const char *filename, unsigned int *start, unsigned int *end)

{

	FILE *map;

	char buffer[1024];



	*start = 0;

	*end = 0;

	map = fopen(filename, "r");

	if (!map)

		die(filename);

	while (fgets(buffer, 1024, map)) {

		if (start_line(buffer))

			*start = strtoul(buffer, NULL, 16);

		else if (end_line(buffer))

			*end = strtoul(buffer, NULL, 16);

	}

	fclose (map);



	if (*start == 0 || *end == 0)

		return 0;



	return 1;

}



int main(int argc,char **argv)
@@ -72,33 +129,29 @@ int main(int argc,char **argv) 
	static char aout_magic[] = { 0x01, 0x03, 0x01, 0x07 };

	char buffer[1024], *q, *r;

	unsigned int i, j, k, start, end, offset;

	FILE *map;

	struct stat s;

	int image, tail;



	if (argc != 4) usage();

	start = end = 0;

	if (stat (argv[3], &s) < 0) die (argv[3]);

	map = fopen (argv[2], "r");

	if (!map) die(argv[2]);

	while (fgets (buffer, 1024, map)) {

		if (!strcmp (buffer + 8, " T start\n") || !strcmp (buffer + 16, " T start\n"))

			start = strtoul (buffer, NULL, 16);

		else if (!strcmp (buffer + 8, " A _end\n") || !strcmp (buffer + 16, " A _end\n"))

			end = strtoul (buffer, NULL, 16);

	}

	fclose (map);

	if (!start || !end) {

		fprintf (stderr, "Could not determine start and end from System.map\n");

	if (argc != 4)

		usage();

	if (stat (argv[3], &s) < 0)

		die(argv[3]);



	if (!get_start_end(argv[2], &start, &end)) {

		fprintf (stderr, "Could not determine start and end from %s\n", argv[2]);

		exit(1);

	}

	if ((image = open(argv[1],O_RDWR)) < 0) die(argv[1]);

	if (read(image,buffer,512) != 512) die(argv[1]);

	if ((image = open(argv[1], O_RDWR)) < 0)

		die(argv[1]);

	if (read(image, buffer, 512) != 512)

		die(argv[1]);

	if (memcmp (buffer, "\177ELF", 4) == 0) {

		q = buffer + ld4(buffer + 28);

		i = ld4(q + 4) + ld4(buffer + 24) - ld4(q + 8);

		if (lseek(image,i,0) < 0) die("lseek");

		if (read(image,buffer,512) != 512) die(argv[1]);

		if (lseek(image, i, 0) < 0)

			die("lseek");

		if (read(image, buffer, 512) != 512)

			die(argv[1]);

		j = 0;

	} else if (memcmp(buffer, aout_magic, 4) == 0) {

		i = j = 32;
@@ -108,8 +161,10 @@ int main(int argc,char **argv) 
	}

	k = i;

	i += (ld2(buffer + j + 2) << 2) - 512;

	if (lseek(image,i,0) < 0) die("lseek");

	if (read(image,buffer,1024) != 1024) die(argv[1]);

	if (lseek(image, i, 0) < 0)

		die("lseek");

	if (read(image, buffer, 1024) != 1024)

		die(argv[1]);

	for (q = buffer, r = q + 512; q < r; q += 4) {

		if (*q == 'H' && q[1] == 'd' && q[2] == 'r' && q[3] == 'S')

			break;
@@ -119,19 +174,26 @@ int main(int argc,char **argv) 
		exit(1);

	}

	offset = i + (q - buffer) + 10;

	if (lseek(image, offset, 0) < 0) die ("lseek");

	if (lseek(image, offset, 0) < 0)

		die("lseek");



	st4(buffer, 0);

	st4(buffer + 4, 0x01000000);

	st4(buffer + 8, (end + 32 + 4095) & ~4095);

	st4(buffer + 12, s.st_size);



	if (write(image,buffer+2,14) != 14) die (argv[1]);

	if (lseek(image, k - start + ((end + 32 + 4095) & ~4095), 0) < 0) die ("lseek");

	if ((tail = open(argv[3],O_RDONLY)) < 0) die(argv[3]);

	if (write(image, buffer + 2, 14) != 14)

		die(argv[1]);

	if (lseek(image, k - start + ((end + 32 + 4095) & ~4095), 0) < 0)

		die("lseek");

	if ((tail = open(argv[3],O_RDONLY)) < 0)

		die(argv[3]);

	while ((i = read (tail, buffer, 1024)) > 0)

		if (write(image,buffer,i) != i) die (argv[1]);

	if (close(image) < 0) die("close");

	if (close(tail) < 0) die("close");

		if (write(image, buffer, i) != i)

			die(argv[1]);

	if (close(image) < 0)

		die("close");

	if (close(tail) < 0)

		die("close");

	return 0;

}