From: Marcus Comstedt <redacted>
Date: Fri, 4 Jul 2014 09:55:04 +0000 (+0200)
Subject: Don't use readlinkat if it does not exist
X-Git-Tag: libserialport-0.1.1~120
X-Git-Url: https://sigrok.org/gitweb/?p=libserialport.git;a=commitdiff_plain;h=5bd33b7c8be499b970192d144409bec7072fc701

Don't use readlinkat if it does not exist

This fixes bug #377.
---

diff --git a/configure.ac b/configure.ac
index 857e4ba..22c47ce 100644
--- a/configure.ac
+++ b/configure.ac
@@ -119,6 +119,9 @@ AC_CHECK_MEMBERS([struct termios.c_ispeed, struct termios.c_ospeed],
 AC_CHECK_MEMBERS([struct termios2.c_ispeed, struct termios2.c_ospeed],
 	[AC_DEFINE(HAVE_TERMIOS2_SPEED, 1)], [], [[#include <linux/termios.h>]])
 
+# Check for readlinkat.
+AC_CHECK_FUNC([readlinkat], [AC_DEFINE(HAVE_READLINKAT, 1)], [])
+
 saved="$CFLAGS"; CFLAGS="$CFLAGS -Werror"
 AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
 		__attribute__((visibility("hidden"))) void foo(void) { }
diff --git a/linux.c b/linux.c
index 9274e36..d70a45f 100644
--- a/linux.c
+++ b/linux.c
@@ -161,6 +161,9 @@ SP_PRIV enum sp_return list_ports(struct sp_port ***list)
 	char name[PATH_MAX], target[PATH_MAX];
 	struct dirent entry, *result;
 	struct serial_struct serial_info;
+#ifndef HAVE_READLINKAT
+	char buf[sizeof(entry.d_name) + 16];
+#endif
 	int len, fd, ioctl_result;
 	DIR *dir;
 	int ret = SP_OK;
@@ -171,7 +174,12 @@ SP_PRIV enum sp_return list_ports(struct sp_port ***list)
 
 	DEBUG("Iterating over results");
 	while (!readdir_r(dir, &entry, &result) && result) {
+#ifdef HAVE_READLINKAT
 		len = readlinkat(dirfd(dir), entry.d_name, target, sizeof(target));
+#else
+		snprintf(buf, sizeof(buf), "/sys/class/tty/%s", entry.d_name);
+		len = readlink(buf, target, sizeof(target));
+#endif
 		if (len <= 0 || len >= (int) sizeof(target)-1)
 			continue;
 		target[len] = 0;