Use sysinfo(2) to implement more of <sys/sysinfo.h>.
We already had implementations of some of the functions, and I didn't
bother rewriting them when we added sysinfo(2). Ross Anderson said in
https://www.lightbluetouchpaper.org/2016/07/29/yet-another-android-side-channel/
that we should "simply disable access to all procfs files", which made
me curious how many places we use /proc in bionic. This is the one that's
obviously unnecessary. The others I'm not aware of alternative APIs for.
Change-Id: Ia64f36b76f29a7a1dd67845270a5472e121aae10
diff --git a/libc/bionic/sysinfo.cpp b/libc/bionic/sysinfo.cpp
index 1cb5c79..304634a 100644
--- a/libc/bionic/sysinfo.cpp
+++ b/libc/bionic/sysinfo.cpp
@@ -76,29 +76,14 @@
return cpu_count;
}
-static int __get_meminfo_page_count(const char* pattern) {
- FILE* fp = fopen("/proc/meminfo", "re");
- if (fp == NULL) {
- return -1;
- }
-
- int page_count = -1;
- char buf[256];
- while (fgets(buf, sizeof(buf), fp) != NULL) {
- long total;
- if (sscanf(buf, pattern, &total) == 1) {
- page_count = static_cast<int>(total / (sysconf(_SC_PAGE_SIZE) / 1024));
- break;
- }
- }
- fclose(fp);
- return page_count;
-}
-
long get_phys_pages() {
- return __get_meminfo_page_count("MemTotal: %ld kB");
+ struct sysinfo si;
+ sysinfo(&si);
+ return (si.totalram * si.mem_unit) / sysconf(_SC_PAGE_SIZE);
}
long get_avphys_pages() {
- return __get_meminfo_page_count("MemFree: %ld kB");
+ struct sysinfo si;
+ sysinfo(&si);
+ return ((si.freeram + si.bufferram) * si.mem_unit) / sysconf(_SC_PAGE_SIZE);
}
diff --git a/tests/sys_sysinfo_test.cpp b/tests/sys_sysinfo_test.cpp
index b00e13f..d7d0f6e 100644
--- a/tests/sys_sysinfo_test.cpp
+++ b/tests/sys_sysinfo_test.cpp
@@ -17,17 +17,28 @@
#include <gtest/gtest.h>
#include <sys/sysinfo.h>
+#include <unistd.h>
TEST(sys_sysinfo, smoke) {
- int nprocessor = get_nprocs();
- ASSERT_GT(nprocessor, 0);
+ int nprocs = get_nprocs();
+ ASSERT_GT(nprocs, 0);
+ ASSERT_EQ(sysconf(_SC_NPROCESSORS_ONLN), nprocs);
- int nprocessor_conf = get_nprocs_conf();
- ASSERT_GE(nprocessor_conf, nprocessor);
+ int nprocs_conf = get_nprocs_conf();
+ ASSERT_GE(nprocs_conf, nprocs);
+ ASSERT_EQ(sysconf(_SC_NPROCESSORS_CONF), nprocs_conf);
long avail_phys_pages = get_avphys_pages();
ASSERT_GT(avail_phys_pages, 0);
+ ASSERT_EQ(sysconf(_SC_AVPHYS_PAGES), avail_phys_pages);
long phys_pages = get_phys_pages();
ASSERT_GE(phys_pages, avail_phys_pages);
+ ASSERT_EQ(sysconf(_SC_PHYS_PAGES), phys_pages);
+}
+
+TEST(sys_sysinfo, sysinfo) {
+ struct sysinfo si;
+ memset(&si, 0, sizeof(si));
+ ASSERT_EQ(0, sysinfo(&si));
}