[PATCH] binfmt_misc: simplify entry_status()

From: Rasmus Villemoes
Date: Tue Feb 24 2015 - 11:27:45 EST


sprintf() reliably returns the number of characters printed, so we
don't need to ask strlen() where we are. Also replace calling
sprintf("%02x") in a loop with the much simpler bin2hex().

Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
---
fs/binfmt_misc.c | 30 +++++++++---------------------
1 file changed, 9 insertions(+), 21 deletions(-)

diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c
index 97aff2879cda..34de9ca78ced 100644
--- a/fs/binfmt_misc.c
+++ b/fs/binfmt_misc.c
@@ -24,6 +24,7 @@
#include <linux/syscalls.h>
#include <linux/fs.h>
#include <linux/uaccess.h>
+#include <linux/kernel.h>

#ifdef DEBUG
# define USE_DEBUG 1
@@ -521,9 +522,8 @@ static int parse_command(const char __user *buffer, size_t count)

static void entry_status(Node *e, char *page)
{
- char *dp;
- char *status = "disabled";
- const char *flags = "flags: ";
+ char *dp = page;
+ const char *status = "disabled";

if (test_bit(Enabled, &e->flags))
status = "enabled";
@@ -533,12 +533,10 @@ static void entry_status(Node *e, char *page)
return;
}

- sprintf(page, "%s\ninterpreter %s\n", status, e->interpreter);
- dp = page + strlen(page);
+ dp += sprintf(dp, "%s\ninterpreter %s\n", status, e->interpreter);

/* print the special flags */
- sprintf(dp, "%s", flags);
- dp += strlen(flags);
+ dp += sprintf(dp, "flags: ");
if (e->flags & MISC_FMT_PRESERVE_ARGV0)
*dp++ = 'P';
if (e->flags & MISC_FMT_OPEN_BINARY)
@@ -550,21 +548,11 @@ static void entry_status(Node *e, char *page)
if (!test_bit(Magic, &e->flags)) {
sprintf(dp, "extension .%s\n", e->magic);
} else {
- int i;
-
- sprintf(dp, "offset %i\nmagic ", e->offset);
- dp = page + strlen(page);
- for (i = 0; i < e->size; i++) {
- sprintf(dp, "%02x", 0xff & (int) (e->magic[i]));
- dp += 2;
- }
+ dp += sprintf(dp, "offset %i\nmagic ", e->offset);
+ dp = bin2hex(dp, e->magic, e->size);
if (e->mask) {
- sprintf(dp, "\nmask ");
- dp += 6;
- for (i = 0; i < e->size; i++) {
- sprintf(dp, "%02x", 0xff & (int) (e->mask[i]));
- dp += 2;
- }
+ dp += sprintf(dp, "\nmask ");
+ dp = bin2hex(dp, e->mask, e->size);
}
*dp++ = '\n';
*dp = '\0';
--
2.1.3

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