Do it by following the trail of the existing commented code, which implemented it by calling get_phys_pages() and get_avphys_pages(). This patch implements these two functions, which are also glibc extensions. Some program/libraries (e.g. libuv) assumes that sysconf(_SC_PHYS_PAGES) works on linux and never check for -1, thus they report an insane amount of memory. Signed-off-by: Nicolas Cavallari &lt;nicolas.cavallari(a)green-communications.fr&gt; --- include/sys/sysinfo.h | 2 -- libc/unistd/sysconf.c | 34 ++++++++++++++++++++++++++-------- 2 files changed, 26 insertions(+), 10 deletions(-) diff --git a/include/sys/sysinfo.h b/include/sys/sysinfo.h index 00e3633..4e756e9 100644 --- a/include/sys/sysinfo.h +++ b/include/sys/sysinfo.h @@ -56,13 +56,11 @@ extern int sysinfo (struct sysinfo *__info) __THROW; #define get_nprocs() (sysconf(_SC_NPROCESSORS_ONLN)) -#if 0 /* Return number of physical pages of memory in the system. */ extern long int get_phys_pages (void) __THROW; /* Return number of available physical pages of memory in the system. */ extern long int get_avphys_pages (void) __THROW; -#endif __END_DECLS diff --git a/libc/unistd/sysconf.c b/libc/unistd/sysconf.c index 503b395..3d3b1a5 100644 --- a/libc/unistd/sysconf.c +++ b/libc/unistd/sysconf.c @@ -43,6 +43,32 @@ #include <dirent.h> #include "internal/parse_config.h" +long int get_phys_pages(void) +{ + struct sysinfo si; + int ps = getpagesize();; + + sysinfo(&si); + + if (ps >= si.mem_unit) + return si.totalram / (ps / si.mem_unit); + else + return si.totalram * (si.mem_unit / ps); +} + +long int get_avphys_pages(void) +{ + struct sysinfo si; + int ps = getpagesize();; + + sysinfo(&si); + + if (ps >= si.mem_unit) + return si.freeram / (ps / si.mem_unit); + else + return si.freeram * (si.mem_unit / ps); +} + static int nprocessors_onln(void) { char **l = NULL; @@ -747,18 +773,10 @@ long int sysconf(int name) RETURN_FUNCTION(nprocessors_onln()); case _SC_PHYS_PAGES: -#if 0 RETURN_FUNCTION(get_phys_pages()); -#else - RETURN_NEG_1; -#endif case _SC_AVPHYS_PAGES: -#if 0 RETURN_FUNCTION(get_avphys_pages()); -#else - RETURN_NEG_1; -#endif case _SC_ATEXIT_MAX: return __UCLIBC_MAX_ATEXIT; -- 2.8.1