procps: shrink /proc scanning code a bit

function                                             old     new   delta
skip_fields                                           16      15      -1
.rodata                                           144266  144258      -8
procps_scan                                          739     692     -47
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-56)             Total: -56 bytes
   text    data     bss     dec     hex filename
 734845    3028   14400  752273   b7a91 busybox_old
 734789    3028   14400  752217   b7a59 busybox_unstripped

1 files changed, 22 insertions, 16 deletions

diff --git a/libbb/procps.c b/libbb/procps.c
index 9f5a4c062..5924d60a8 100644
--- a/libbb/procps.c
+++ b/libbb/procps.c
@@ -109,9 +109,10 @@ void free_procps_scan(procps_status_t* sp)
 
 #if ENABLE_FEATURE_FAST_TOP
 /* We cut a lot of corners here for speed */
-static unsigned long fast_strtoul_10(char *str, char **endptr)
+static unsigned long fast_strtoul_10(char **endptr)
 {
         char c;
+        char *str = *endptr;
         unsigned long n = *str - '0';
 
         while ((c = *++str) != ' ')
@@ -123,7 +124,9 @@ static unsigned long fast_strtoul_10(char *str, char **endptr)
 static char *skip_fields(char *str, int count)
 {
         do {
-                str = skip_non_whitespace(str); str++;
+                while (*str++ != ' ')
+                        continue;
+                /* we found a space char, str points after it */
         } while (--count);
         return str;
 }
@@ -181,11 +184,11 @@ procps_status_t* procps_scan(procps_status_t* sp, int flags)
                 }
 
                 if (flags & PSSCAN_STAT) {
-                        char *cp;
+                        char *cp, *comm1;
+                        int tty;
 #if !ENABLE_FEATURE_FAST_TOP
                         unsigned long vsz, rss;
 #endif
-                        int tty;
 
                         /* see proc(5) for some details on this */
                         strcpy(filename_tail, "/stat");
@@ -193,12 +196,14 @@ procps_status_t* procps_scan(procps_status_t* sp, int flags)
                         if (n < 0)
                                 break;
                         cp = strrchr(buf, ')'); /* split into "PID (cmd" and "<rest>" */
-                        if (!cp || cp[1] != ' ')
-                                break;
+                        /*if (!cp || cp[1] != ' ')
+                                break;*/
                         cp[0] = '\0';
                         if (sizeof(sp->comm) < 16)
                                 BUG_comm_size();
-                        sscanf(buf, "%*s (%15c", sp->comm);
+                        comm1 = strchr(buf, '(');
+                        /*if (comm1)*/
+                                safe_strncpy(sp->comm, comm1 + 1, sizeof(sp->comm));
 
 #if !ENABLE_FEATURE_FAST_TOP
                         n = sscanf(cp+2,
@@ -231,20 +236,21 @@ procps_status_t* procps_scan(procps_status_t* sp, int flags)
 /* This costs ~100 bytes more but makes top faster by 20%
  * If you run 10000 processes, this may be important for you */
                         sp->state[0] = cp[2];
-                        sp->ppid = fast_strtoul_10(cp + 4, &cp);
-                        sp->pgid = fast_strtoul_10(cp, &cp);
-                        sp->sid = fast_strtoul_10(cp, &cp);
-                        tty = fast_strtoul_10(cp, &cp);
+                        cp += 4;
+                        sp->ppid = fast_strtoul_10(&cp);
+                        sp->pgid = fast_strtoul_10(&cp);
+                        sp->sid = fast_strtoul_10(&cp);
+                        tty = fast_strtoul_10(&cp);
                         sp->tty_major = (tty >> 8) & 0xfff;
                         sp->tty_minor = (tty & 0xff) | ((tty >> 12) & 0xfff00);
                         cp = skip_fields(cp, 6); /* tpgid, flags, min_flt, cmin_flt, maj_flt, cmaj_flt */
-                        sp->utime = fast_strtoul_10(cp, &cp);
-                        sp->stime = fast_strtoul_10(cp, &cp);
+                        sp->utime = fast_strtoul_10(&cp);
+                        sp->stime = fast_strtoul_10(&cp);
                         cp = skip_fields(cp, 3); /* cutime, cstime, priority */
-                        tasknice = fast_strtoul_10(cp, &cp);
+                        tasknice = fast_strtoul_10(&cp);
                         cp = skip_fields(cp, 3); /* timeout, it_real_value, start_time */
-                        sp->vsz = fast_strtoul_10(cp, &cp) >> 10; /* vsize is in bytes and we want kb */
-                        sp->rss = fast_strtoul_10(cp, &cp) >> 10;
+                        sp->vsz = fast_strtoul_10(&cp) >> 10; /* vsize is in bytes and we want kb */
+                        sp->rss = fast_strtoul_10(&cp) >> 10;
 #endif
 
                         if (sp->vsz == 0 && sp->state[0] != 'Z')