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authorSam Ravnborg <sam@ravnborg.org>2011-01-04 11:39:10 +0000
committerDavid S. Miller <davem@davemloft.net>2011-01-04 19:25:02 -0800
commit2fe74fa9662f8df51e6ef18227089f54cc07e16a (patch)
treefc981e735c7dd282e1e22686f1004fa0bb68757f /arch/sparc/boot
parentf28f3313aa97dcb46954f90f596d75f8faf4626e (diff)
downloadlinux-2fe74fa9662f8df51e6ef18227089f54cc07e16a.tar.bz2
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: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch/sparc/boot')
-rw-r--r--arch/sparc/boot/piggyback_32.c142
1 files changed, 102 insertions, 40 deletions
diff --git a/arch/sparc/boot/piggyback_32.c b/arch/sparc/boot/piggyback_32.c
index ac944aec7301..cfd95ec01f18 100644
--- a/arch/sparc/boot/piggyback_32.c
+++ b/arch/sparc/boot/piggyback_32.c
@@ -9,7 +9,7 @@
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
-
+
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
@@ -18,15 +18,16 @@
You should have received a copy of the GNU General Public License
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;
@@ -107,9 +160,11 @@ int main(int argc,char **argv)
exit(1);
}
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]);
+ i += (ld2(buffer + j + 2) << 2) - 512;
+ 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]);
- 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");
- return 0;
+ 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");
+ return 0;
}