free: handle "cached" value too

function                                             old     new   delta
free_main                                            356     481    +125

Signed-off-by: Guillermo Rodriguez <guille.rodriguez@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 46 insertions, 31 deletions

diff --git a/procps/free.c b/procps/free.c
index 47f2fc3b2..0d023f740 100644
--- a/procps/free.c
+++ b/procps/free.c
@@ -44,11 +44,28 @@ static unsigned long long scale(unsigned long d)
         return ((unsigned long long)d * G.mem_unit) >> G_unit_steps;
 }
 
+static unsigned long parse_cached_kb(void)
+{
+        char buf[60]; /* actual lines we expect are ~30 chars or less */
+        FILE *fp;
+        unsigned long cached = 0;
+
+        fp = xfopen_for_read("/proc/meminfo");
+        while (fgets(buf, sizeof(buf), fp) != NULL) {
+                if (sscanf(buf, "Cached: %lu %*s\n", &cached) == 1)
+                        break;
+        }
+        if (ENABLE_FEATURE_CLEAN_UP)
+                fclose(fp);
+
+        return cached;
+}
 
 int free_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int free_main(int argc UNUSED_PARAM, char **argv IF_NOT_DESKTOP(UNUSED_PARAM))
 {
         struct sysinfo info;
+        unsigned long long cached;
 
         INIT_G();
 
@@ -73,49 +90,47 @@ int free_main(int argc UNUSED_PARAM, char **argv IF_NOT_DESKTOP(UNUSED_PARAM))
                 }
         }
 #endif
-
-        sysinfo(&info);
-
-        /* Kernels prior to 2.4.x will return info.mem_unit==0, so cope... */
-        G.mem_unit = (info.mem_unit ? info.mem_unit : 1);
-
-        printf("     %13s%13s%13s%13s%13s\n",
+        printf("       %11s%11s%11s%11s%11s%11s\n"
+        "Mem:   ",
                 "total",
                 "used",
                 "free",
-                "shared", "buffers" /* swap and total don't have these columns */
-                /* procps version 3.2.8 also shows "cached" column, but
-                 * sysinfo() does not provide this value, need to parse
-                 * /proc/meminfo instead and get "Cached: NNN kB" from there.
-                 */
+                "shared", "buffers", "cached" /* swap and total don't have these columns */
         );
 
-#define FIELDS_5 "%13llu%13llu%13llu%13llu%13llu\n"
-#define FIELDS_3 (FIELDS_5 + 2*6)
-#define FIELDS_2 (FIELDS_5 + 3*6)
+        sysinfo(&info);
+        /* Kernels prior to 2.4.x will return info.mem_unit==0, so cope... */
+        G.mem_unit = (info.mem_unit ? info.mem_unit : 1);
+        /* Extract cached from /proc/meminfo and convert to mem_units */
+        cached = ((unsigned long long) parse_cached_kb() * 1024) / G.mem_unit;
+
+#define FIELDS_6 "%11llu%11llu%11llu%11llu%11llu%11llu\n"
+#define FIELDS_3 (FIELDS_6 + 3*6)
+#define FIELDS_2 (FIELDS_6 + 4*6)
 
-        printf("Mem: ");
-        printf(FIELDS_5,
-                scale(info.totalram),
-                scale(info.totalram - info.freeram),
-                scale(info.freeram),
-                scale(info.sharedram),
-                scale(info.bufferram)
+        printf(FIELDS_6,
+                scale(info.totalram),                //total
+                scale(info.totalram - info.freeram), //used
+                scale(info.freeram),                 //free
+                scale(info.sharedram),               //shared
+                scale(info.bufferram),               //buffers
+                scale(cached)                        //cached
         );
         /* Show alternate, more meaningful busy/free numbers by counting
-         * buffer cache as free memory (make it "-/+ buffers/cache"
-         * if/when we add support for "cached" column): */
-        printf("-/+ buffers:      ");
+         * buffer cache as free memory. */
+        printf("-/+ buffers/cache:");
+        cached += info.freeram;
+        cached += info.bufferram;
         printf(FIELDS_2,
-                scale(info.totalram - info.freeram - info.bufferram),
-                scale(info.freeram + info.bufferram)
+                scale(info.totalram - cached), //used
+                scale(cached)                  //free
         );
 #if BB_MMU
-        printf("Swap:");
+        printf("Swap:  ");
         printf(FIELDS_3,
-                scale(info.totalswap),
-                scale(info.totalswap - info.freeswap),
-                scale(info.freeswap)
+                scale(info.totalswap),                 //total
+                scale(info.totalswap - info.freeswap), //used
+                scale(info.freeswap)                   //free
         );
 #endif
         return EXIT_SUCCESS;