kallsyms: remove usage of memmem and _GNU_SOURCE from scripts/kallsyms.c

The only in-kernel user of "memmem" is scripts/kallsyms.c and it only uses it to find tokens that are 2 bytes in size. It is trivial to replace it with a simple function that finds 2-byte tokens. This should help users from systems that don't have the memmem GNU extension available. Signed-off-by: Paulo Marques <pmarques@grupopie.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

kallsyms: remove usage of memmem and _GNU_SOURCE from scripts/kallsyms.c
The only in-kernel user of "memmem" is scripts/kallsyms.c and it only uses it to find tokens that are 2 bytes in size. It is trivial to replace it with a simple function that finds 2-byte tokens. This should help users from systems that don't have the memmem GNU extension available. Signed-off-by: Paulo Marques <pmarques@grupopie.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Paulo Marques · Sam Ravnborg
1 parent af332aa387
Showing 1 changed file with 13 additions and 4 deletions Side-by-side Diff
scripts/kallsyms.c
@@ -24,8 +24,6 @@
  *
  */
  
-#define _GNU_SOURCE
-
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -378,6 +376,17 @@
 	table_cnt = pos;
 }
  
+static void *find_token(unsigned char *str, int len, unsigned char *token)
+{
+	int i;
+
+	for (i = 0; i < len - 1; i++) {
+		if (str[i] == token[0] && str[i+1] == token[1])
+			return &str[i];
+	}
+	return NULL;
+}
+
 /* replace a given token in all the valid symbols. Use the sampled symbols
  * to update the counts */
 static void compress_symbols(unsigned char *str, int idx)
@@ -391,7 +400,7 @@
 		p1 = table[i].sym;
  
 		/* find the token on the symbol */
-		p2 = memmem(p1, len, str, 2);
+		p2 = find_token(p1, len, str);
 		if (!p2) continue;
  
 		/* decrease the counts for this symbol's tokens */
@@ -410,7 +419,7 @@
 			if (size < 2) break;
  
 			/* find the token on the symbol */
-			p2 = memmem(p1, size, str, 2);
+			p2 = find_token(p1, size, str);
  
 		} while (p2);
...	...	@@ -24,8 +24,6 @@
24	24	*
25	25	*/
26	26
27		-#define _GNU_SOURCE
28		-
29	27	#include <stdio.h>
30	28	#include <stdlib.h>
31	29	#include <string.h>
...	...	@@ -378,6 +376,17 @@
378	376	table_cnt = pos;
379	377	}
380	378
	379	+static void find_token(unsigned char str, int len, unsigned char *token)
	380	+{
	381	+ int i;
	382	+
	383	+ for (i = 0; i < len - 1; i++) {
	384	+ if (str[i] == token[0] && str[i+1] == token[1])
	385	+ return &str[i];
	386	+ }
	387	+ return NULL;
	388	+}
	389	+
381	390	/* replace a given token in all the valid symbols. Use the sampled symbols
382	391	* to update the counts */
383	392	static void compress_symbols(unsigned char *str, int idx)
...	...	@@ -391,7 +400,7 @@
391	400	p1 = table[i].sym;
392	401
393	402	/* find the token on the symbol */
394		- p2 = memmem(p1, len, str, 2);
	403	+ p2 = find_token(p1, len, str);
395	404	if (!p2) continue;
396	405
397	406	/* decrease the counts for this symbol's tokens */
...	...	@@ -410,7 +419,7 @@
410	419	if (size < 2) break;
411	420
412	421	/* find the token on the symbol */
413		- p2 = memmem(p1, size, str, 2);
	422	+ p2 = find_token(p1, size, str);
414	423
415	424	} while (p2);
416	425