#14 Incorrect boot time display on 32-bit big-endian platforms

[WHR]

NMON running on 32-bit big-endian GNU/Linux systems (such as powerpc-unknown-linux-gnu) will incorrectly displaying the boot time as 0, 1970-01-01, due to the following code:

ts = *localtime((time_t *)&boottime);

where it converts the long long int * typed &boottime, to type time_t *; doing so is wrong becouse types long long int and time_t has different size on 32-bit GNU/Linux systems (sizeof(time_t) == 4). This especially affecting big-endian systems because the most-significant 4 bytes of boottime would be read by localtime(3) instead of least-significant 4 bytes that original author might expecting.

The following patch fixes the issue by first coverting boottime into a local time_t typed variable:

--- lmon16n.c.orig  2021-11-07 07:16:15.000000000 +0800
+++ lmon16n.c   2021-11-23 12:40:20.146989843 +0800
@@ -1869,11 +1869,12 @@
    sscanf(&proc[P_STAT].line[ctxt_line][0], "ctxt %lld",
           &p->cpu_total.ctxt);
     if(boottime == 0) {
-   struct tm ts;
-   if (proc[P_STAT].lines >= btime_line)
-   sscanf(&proc[P_STAT].line[btime_line][0], "btime %lld", &boottime);
-   ts = *localtime((time_t *)&boottime);
-   strftime (boottime_str, 64, "%I:%M %p %d-%b-%Y", &ts);
+   time_t t;
+   if (proc[P_STAT].lines >= btime_line) {
+       sscanf(&proc[P_STAT].line[btime_line][0], "btime %lld", &boottime);
+   }
+   t = boottime;
+   strftime (boottime_str, 64, "%I:%M %p %d-%b-%Y", localtime(&t));
     }
     if (proc[P_STAT].lines >= proc_line)
    sscanf(&proc[P_STAT].line[proc_line][0], "processes %lld",

it also adds the missing indentation of the sscanf(3) call.

Tested on powerpc-unknown-linux-gnu and x86_64-unknown-linux-gnu.

[WHR]

Upload the diff file as an attachment since the TABs got converted into spaces in the first inline version.