1 files changed, 48 insertions, 12 deletions

diff --git a/procps/top.c b/procps/top.c
index cee1b52c1..9944598c2 100644
--- a/procps/top.c
+++ b/procps/top.c
@@ -311,14 +311,47 @@ static unsigned long display_generic(void)
         char buf[80];
         float avg1, avg2, avg3;
         unsigned long total, used, mfree, shared, buffers, cached;
+        unsigned int needs_conversion = 1;
 
         /* read memory info */
         fp = bb_xfopen("meminfo", "r");
-        fgets(buf, sizeof(buf), fp);    /* skip first line */
 
-        if (fscanf(fp, "Mem: %lu %lu %lu %lu %lu %lu",
-                   &total, &used, &mfree, &shared, &buffers, &cached) != 6) {
-                bb_error_msg_and_die("failed to read '%s'", "meminfo");
+        /*
+         * Old kernels (such as 2.4.x) had a nice summary of memory info that
+         * we could parse, however this is gone entirely in 2.6. Try parsing
+         * the old way first, and if that fails, parse each field manually.
+         *
+         * First, we read in the first line. Old kernels will have bogus
+         * strings we don't care about, whereas new kernels will start right
+         * out with MemTotal:
+         *                              -- PFM.
+         */
+        if (fscanf(fp, "MemTotal: %lu %s\n", &total, buf) != 2) {
+                fgets(buf, sizeof(buf), fp);    /* skip first line */
+
+                fscanf(fp, "Mem: %lu %lu %lu %lu %lu %lu",
+                   &total, &used, &mfree, &shared, &buffers, &cached);
+        } else {
+                /* 
+                 * Revert to manual parsing, which incidentally already has the
+                 * sizes in kilobytes. This should be safe for both 2.4 and
+                 * 2.6.
+                 */
+                needs_conversion = 0;
+
+                fscanf(fp, "MemFree: %lu %s\n", &mfree, buf);
+
+                /* 
+                 * MemShared: is no longer present in 2.6. Report this as 0,
+                 * to maintain consistent behavior with normal procps.
+                 */
+                if (fscanf(fp, "MemShared: %lu %s\n", &shared, buf) != 2)
+                        shared = 0;
+
+                fscanf(fp, "Buffers: %lu %s\n", &buffers, buf);
+                fscanf(fp, "Cached: %lu %s\n", &cached, buf);
+
+                used = total - mfree;
         }
         fclose(fp);
         
@@ -329,13 +362,16 @@ static unsigned long display_generic(void)
         }
         fclose(fp);
 
-        /* convert to kilobytes */
-        used /= 1024;
-        mfree /= 1024;
-        shared /= 1024;
-        buffers /= 1024;
-        cached /= 1024;
-        
+        if (needs_conversion) {
+                /* convert to kilobytes */
+                used /= 1024;
+                mfree /= 1024;
+                shared /= 1024;
+                buffers /= 1024;
+                cached /= 1024;
+                total /= 1024;
+        }
+                
         /* output memory info and load average */
         /* clear screen & go to top */
         printf("\e[H\e[J" "Mem: "
@@ -344,7 +380,7 @@ static unsigned long display_generic(void)
         printf("Load average: %.2f, %.2f, %.2f    "
                         "(State: S=sleeping R=running, W=waiting)\n",
                avg1, avg2, avg3);
-        return total / 1024;
+        return total;
 }