From: Eugene Syromyatnikov <evgsyr@gmail.com>
Date: Mon, 27 Aug 2018 13:16:10 +0000 (+0200)
Subject: print_ifindex: add public get_ifname method
X-Git-Tag: v4.25~34
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=9a969eb6704ef0f12f14ddb53bfe01f9a16e287e;p=strace

print_ifindex: add public get_ifname method

In order to be able to obtain sanitised device name internally.

* defs.h (get_ifname): New declaration.
* print_ifindex.c (get_ifname): Refactor, leaving out addition
of if_nametoindex("") part.
(sprint_ifname): New function, adds if_nametoindex("")
to get_ifname's output.
(print_ifindex): Use sprint_ifname instead of get_ifname.
---

diff --git a/defs.h b/defs.h
index 394f509e..ec96bf61 100644
--- a/defs.h
+++ b/defs.h
@@ -949,6 +949,7 @@ fetch_perf_event_attr(struct tcb *const tcp, const kernel_ulong_t addr);
 extern void
 print_perf_event_attr(struct tcb *const tcp, const kernel_ulong_t addr);
 
+extern const char *get_ifname(const unsigned int ifindex);
 extern void print_ifindex(unsigned int);
 
 extern void print_bpf_filter_code(const uint16_t code, bool extended);
diff --git a/print_ifindex.c b/print_ifindex.c
index 2df1e3be..1bdac382 100644
--- a/print_ifindex.c
+++ b/print_ifindex.c
@@ -31,37 +31,53 @@
 #ifdef HAVE_IF_INDEXTONAME
 # include "xstring.h"
 
-# define INI_PFX "if_nametoindex("
-# define INI_SFX ")"
+# define INI_PFX "if_nametoindex(\""
+# define INI_SFX "\")"
 # define IFNAME_QUOTED_SZ (sizeof(IFNAMSIZ) * 4 + 3)
 
-static const char *
+const char *
 get_ifname(const unsigned int ifindex)
 {
-	static char res[IFNAME_QUOTED_SZ + sizeof(INI_PFX INI_SFX)];
-
+	static char name_quoted_buf[IFNAME_QUOTED_SZ];
 	char name_buf[IFNAMSIZ];
-	char name_quoted_buf[IFNAME_QUOTED_SZ];
 
-	if (if_indextoname(ifindex, name_buf)) {
-		if (string_quote(name_buf, name_quoted_buf, sizeof(name_buf),
-				 QUOTE_0_TERMINATED, NULL))
-			return NULL;
+	if (!if_indextoname(ifindex, name_buf))
+		return NULL;
+
+	if (string_quote(name_buf, name_quoted_buf, sizeof(name_buf),
+			 QUOTE_0_TERMINATED | QUOTE_OMIT_LEADING_TRAILING_QUOTES,
+			 NULL))
+		return NULL;
+
+	return name_quoted_buf;
+}
+
+static const char *
+sprint_ifname(const unsigned int ifindex)
+{
+	static char res[IFNAME_QUOTED_SZ + sizeof(INI_PFX INI_SFX)];
+
+	const char *name_quoted = get_ifname(ifindex);
 
-		xsprintf(res, INI_PFX "%s" INI_SFX, name_quoted_buf);
+	if (!name_quoted)
+		return NULL;
 
-		return res;
-	}
+	xsprintf(res, INI_PFX "%s" INI_SFX, name_quoted);
 
-	return NULL;
+	return res;
 }
+
+#else /* !HAVE_IF_INDEXTONAME */
+
+const char *get_ifname(const unsigned int ifindex) { return NULL; }
+
 #endif /* HAVE_IF_INDEXTONAME */
 
 void
 print_ifindex(const unsigned int ifindex)
 {
 #ifdef HAVE_IF_INDEXTONAME
-	print_xlat_ex(ifindex, get_ifname(ifindex), XLAT_STYLE_FMT_U);
+	print_xlat_ex(ifindex, sprint_ifname(ifindex), XLAT_STYLE_FMT_U);
 #else
 	tprintf("%u", ifindex);
 #endif