[Rpm-maint] [PATCH] Use getauxval(3) to read auxv data

[Kirill A. Shutemov]

From: "Kirill A. Shutemov" <kirill at shutemov.name>

glibc >= 2.16 provides getauxval(): a reliable way to retrieve a value
from the auxiliary vector. It doesn't rely on /proc filesystem.

Let's switch to it and get rid of /proc dependency.

Signed-off-by: Kirill A. Shutemov <kirill at shutemov.name>
---
 configure.ac |  1 +
 lib/rpmrc.c  | 17 ++++++++++++++---
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/configure.ac b/configure.ac
index 0f2cb28..ec85ede 100644
--- a/configure.ac
+++ b/configure.ac
@@ -520,6 +520,7 @@ AC_CHECK_FUNCS(mempcpy)
 AC_CHECK_FUNCS(fdatasync)
 AC_CHECK_FUNCS(lutimes)
 AC_CHECK_FUNCS(mergesort)
+AC_CHECK_FUNCS(getauxval)
 
 AC_REPLACE_FUNCS(stpcpy stpncpy)
 
diff --git a/lib/rpmrc.c b/lib/rpmrc.c
index d6546c4..794d028 100644
--- a/lib/rpmrc.c
+++ b/lib/rpmrc.c
@@ -21,6 +21,10 @@
 #define __power_pc() 0
 #endif
 
+#ifdef HAVE_GETAUXVAL
+#include <sys/auxv.h>
+#endif
+
 #include <rpm/rpmlib.h>			/* RPM_MACTABLE*, Rc-prototypes */
 #include <rpm/rpmmacro.h>
 #include <rpm/rpmfileutil.h>
@@ -934,13 +938,19 @@ static int is_geode(void)
 
 #if defined(__linux__)
 /**
- * Populate rpmat structure with parsed info from /proc/self/auxv
+ * Populate rpmat structure with auxv values
  */
-static void parse_auxv(void)
+static void read_auxv(void)
 {
     static int oneshot = 1;
 
     if (oneshot) {
+#ifdef HAVE_GETAUXVAL
+	rpmat.platform = (char *) getauxval(AT_PLATFORM);
+	if (!rpmat.platform)
+	    rpmat.platform = "";
+	rpmat.hwcap = getauxval(AT_HWCAP);
+#else
 	rpmat.platform = "";
 	int fd = open("/proc/self/auxv", O_RDONLY);
 
@@ -965,6 +975,7 @@ static void parse_auxv(void)
 	    }
 	    close(fd);
 	}
+#endif
 	oneshot = 0; /* only try once even if it fails */
     }
     return;
@@ -984,7 +995,7 @@ static void defaultMachine(rpmrcCtx ctx, const char ** arch, const char ** os)
 
 #if defined(__linux__)
     /* Populate rpmat struct with hw info */
-    parse_auxv();
+    read_auxv();
 #endif
 
     while (!gotDefaults) {
-- 
1.8.3.1