libxc: break xc_get_physmem out into os-dependent files

NetBSD doesn't have sysconf(_SC_PHYS_PAGES).

Factor physmem() out into os-dependent files and rename it to
xc_get_physmem() so as not to pollute the namespace.

Signed-off-by: Christoph Egger <Christoph.Egger@amd.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/tools/libxc/xc_linux.c b/tools/libxc/xc_linux.c
index 9acf27573e..66b055cbe4 100644
--- a/tools/libxc/xc_linux.c
+++ b/tools/libxc/xc_linux.c
@@ -55,6 +55,27 @@ void discard_file_cache(xc_interface *xch, int fd, int flush)
     errno = saved_errno;
 }
 
+uint64_t xc_get_physmem(void)
+{
+    uint64_t ret = 0;
+    const long pagesize = sysconf(_SC_PAGESIZE);
+    const long pages = sysconf(_SC_PHYS_PAGES);
+
+    if ( (pagesize != -1) || (pages != -1) )
+    {
+        /*
+         * According to docs, pagesize * pages can overflow.
+         * Simple case is 32-bit box with 4 GiB or more RAM,
+         * which may report exactly 4 GiB of RAM, and "long"
+         * being 32-bit will overflow. Casting to uint64_t
+         * hopefully avoids overflows in the near future.
+         */
+        ret = (uint64_t)(pagesize) * (uint64_t)(pages);
+    }
+
+    return ret;
+}
+
 /*
  * Local variables:
  * mode: C