top,ps: improve /proc/PID/cmdinfo reading code

function                                             old     new   delta
display_status                                         -    1231   +1231
read_cmdline                                           -     101    +101
parse_conf                                          1284    1303     +19
arith                                               2033    2042      +9
collect_blk                                          467     474      +7
fsck_main                                           1909    1911      +2
dhcprelay_main                                      1125    1122      -3
singlemount                                         4555    4547      -8
read_close                                            50      36     -14
get_lcm                                              123     105     -18
ed_main                                             3111    3084     -27
func_args                                             73      28     -45
procps_scan                                          732     658     -74
top_main                                            2187     899   -1288
------------------------------------------------------------------------------
(add/remove: 2/0 grow/shrink: 4/8 up/down: 1369/-1477)       Total: -108 bytes
   text    data     bss     dec     hex filename
 676048    2744   13968  692760   a9218 busybox_old
 675940    2744   13968  692652   a91ac busybox_unstripped

1 files changed, 10 insertions, 12 deletions

diff --git a/procps/top.c b/procps/top.c
index 136f1404a..a37a0d07f 100644
--- a/procps/top.c
+++ b/procps/top.c
@@ -40,11 +40,10 @@ typedef struct top_status_t {
         unsigned pid, ppid;
         unsigned uid;
         char state[4];
-/* TODO: read /proc/$PID/cmdline only for processes which are displayed */
-        char cmd[64];
+        char comm[COMM_LEN];
 } top_status_t;
 
-typedef struct jiffy_counts_t{
+typedef struct jiffy_counts_t {
         unsigned long long usr,nic,sys,idle,iowait,irq,softirq,steal;
         unsigned long long total;
         unsigned long long busy;
@@ -421,7 +420,7 @@ static void display_status(int count, int scr_width)
 
         /* Ok, all prelim data is ready, go thru the list */
         while (count-- > 0) {
-                int col = scr_width+1;
+                int col = scr_width;
                 CALC_STAT(pmem, (s->vsz*pmem_scale + pmem_half) >> pmem_shift);
 #if ENABLE_FEATURE_TOP_CPU_USAGE_PERCENTAGE
                 CALC_STAT(pcpu, (s->pcpu*pcpu_scale + pcpu_half) >> pcpu_shift);
@@ -444,8 +443,11 @@ static void display_status(int count, int scr_width)
                                 , SHOW_STAT(pcpu)
 #endif
                 );
-                if (col > 0)
-                        printf("%.*s", col, s->cmd);
+                if (col > 0) {
+                        char buf[col + 1];
+                        read_cmdline(buf, col, s->pid, s->comm);
+                        fputs(buf, stdout);
+                }
                 /* printf(" %d/%d %lld/%lld", s->pcpu, total_pcpu,
                         jif.busy - prev_jif.busy, jif.total - prev_jif.total); */
                 s++;
@@ -560,12 +562,11 @@ int top_main(int argc, char **argv)
                                 | PSSCAN_UTIME
                                 | PSSCAN_STATE
                                 | PSSCAN_COMM
-                                | PSSCAN_CMD
                                 | PSSCAN_SID
                                 | PSSCAN_UIDGID
                 ))) {
                         int n = ntop;
-                        top = xrealloc(top, (++ntop)*sizeof(top_status_t));
+                        top = xrealloc(top, (++ntop) * sizeof(*top));
                         top[n].pid = p->pid;
                         top[n].ppid = p->ppid;
                         top[n].vsz = p->vsz;
@@ -574,10 +575,7 @@ int top_main(int argc, char **argv)
 #endif
                         top[n].uid = p->uid;
                         strcpy(top[n].state, p->state);
-                        if (p->cmd)
-                                safe_strncpy(top[n].cmd, p->cmd, sizeof(top[n].cmd));
-                        else /* mimic ps */
-                                sprintf(top[n].cmd, "[%s]", p->comm);
+                        strcpy(top[n].comm, p->comm);
                 }
                 if (ntop == 0) {
                         bb_error_msg_and_die("no process info in /proc");