utils: add print_escape_buf to format and print arbitrary bytes

colona · shemminger · commit 7c72df5a9517 · 2017-10-11T11:04:47.000-07:00
Keep it as simple as possible for now: just escape anything that is not
isprint-able, is among the "escape" parameter or '\' as an octal escape
sequence. This should be pretty easy to extend if any other user needs
something more complex in the future.

Signed-off-by: Ivan Delalande &lt;colona@arista.com&gt;
diff --git a/include/utils.h b/include/utils.h
@@ -195,6 +195,8 @@ static inline void __jiffies_to_tv(struct timeval *tv, unsigned long jiffies)
 	tv->tv_usec = tvusec - 1000000 * tv->tv_sec;
 }
 
+void print_escape_buf(const __u8 *buf, size_t len, const char *escape);
+
 int print_timestamp(FILE *fp);
 void print_nlmsg_timestamp(FILE *fp, const struct nlmsghdr *n);
 
diff --git a/lib/utils.c b/lib/utils.c
@@ -31,6 +31,7 @@
 #include <time.h>
 #include <sys/time.h>
 #include <errno.h>
+#include <ctype.h>
 
 #include "rt_names.h"
 #include "utils.h"
@@ -1047,6 +1048,20 @@ int addr64_n2a(__u64 addr, char *buff, size_t len)
 	return written;
 }
 
+/* Print buffer and escape bytes that are !isprint or among 'escape' */
+void print_escape_buf(const __u8 *buf, size_t len, const char *escape)
+{
+	size_t i;
+
+	for (i = 0; i < len; ++i) {
+		if (isprint(buf[i]) && buf[i] != '\\' &&
+		    !strchr(escape, buf[i]))
+			printf("%c", buf[i]);
+		else
+			printf("\\%03o", buf[i]);
+	}
+}
+
 int print_timestamp(FILE *fp)
 {
 	struct timeval tv;

Original file line number	Diff line number	Diff line change
`@@ -195,6 +195,8 @@ static inline void __jiffies_to_tv(struct timeval *tv, unsigned long jiffies)`
`195`	`195`	`tv->tv_usec = tvusec - 1000000 * tv->tv_sec;`
`196`	`196`	`}`
`197`	`197`
	`198`	`+void print_escape_buf(const __u8 buf, size_t len, const char escape);`
	`199`	`+`
`198`	`200`	`int print_timestamp(FILE *fp);`
`199`	`201`	`void print_nlmsg_timestamp(FILE fp, const struct nlmsghdr n);`
`200`	`202`