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top: swat a potential buglet affecting new graph modes

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This patch will cure a potential aberration associated
with a terminal's size (SIGWINCH) and top's new graphs
modes. The symptoms were a dangling tilde (~) plus the
potential loss of a graph's right-most visual content.

The condition was only apparent when a %Cpu approached
100% usage. Also the apparent loss of content affected
the 'block' graph only. With 'bar' graphs, that affect
became the loss of proper right-most bar graph colors.

The cause was determined to be a combination of: 1) an
unnecessary snprintf precision specification; and 2) a
rounding quirk for any graphs which displayed distinct
types of information (as for user/syst, used/unavail).
These could then combine to produce an extra bar/block
which, in turn, resulted in the truncation of a pseudo
termcap attribute used by the show_special() function.

What was originally interpreted as an intractable race
condition turns out to be just a self inflicted wound.

Reference(s):
http://www.freelists.org/post/procps/top-Possible-bug-in-the-graphs,1

Signed-off-by: Jim Warner <james.warner@comcast.net>
This commit is contained in:
Jim Warner 2014-08-07 00:00:00 -05:00 committed by Jaromir Capik
parent bcbc3c5a02
commit e92b692932
2 changed files with 27 additions and 12 deletions
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38
top/top.c
View File

@ -1877,13 +1877,11 @@ static void adj_geometry (void) {
PSU_CLREOS(0);
// prepare to customize potential cpu/memory graphs
Graph_adj = ((float)Screen_cols - GRAPH_prefix - GRAPH_suffix) / 100.0;
if (Graph_adj > 1.0) Graph_adj = 1.0;
else if (Screen_cols < 80) Graph_adj = (80.0 - GRAPH_prefix - GRAPH_suffix) / 100.0;
Graph_len = Screen_cols - GRAPH_prefix - GRAPH_actual - GRAPH_suffix;
if (Graph_len >= 0) Graph_len = GRAPH_actual;
else if (Screen_cols > 80) Graph_len = Screen_cols - GRAPH_prefix - GRAPH_suffix;
else Graph_len = 80 - GRAPH_prefix - GRAPH_suffix;
Graph_adj = (float)Graph_len / 100.0;
fflush(stdout);
Frames_signal = BREAK_off;
@ -5089,11 +5087,19 @@ static void summary_hlp (CPU_t *cpu, const char *pfx) {
int ix = Curwin->rc.graph_cpus - 1;
float pct_user = (float)(u_frme + n_frme) * scale,
pct_syst = (float)s_frme * scale;
snprintf(user, sizeof(user), gtab[ix].user, (int)((pct_user * Graph_adj) + .5), gtab[ix].type);
snprintf(syst, sizeof(syst), gtab[ix].syst, (int)((pct_syst * Graph_adj) + .5), gtab[ix].type);
#ifndef QUICK_GRAPHS
int num_user = (int)((pct_user * Graph_adj) + .5),
num_syst = (int)((pct_syst * Graph_adj) + .5);
if (num_user + num_syst > Graph_len) --num_syst;
snprintf(user, sizeof(user), gtab[ix].user, num_user, gtab[ix].type);
snprintf(syst, sizeof(syst), gtab[ix].syst, num_syst, gtab[ix].type);
#else
snprintf(user, sizeof(user), gtab[ix].user, (int)((pct_user * Graph_adj) + .6), gtab[ix].type);
snprintf(syst, sizeof(syst), gtab[ix].syst, (int)((pct_syst * Graph_adj) + .4), gtab[ix].type);
#endif
snprintf(dual, sizeof(dual), "%s%s", user, syst);
show_special(0, fmtmk("%%%s ~3%#5.1f~2/%-#5.1f~3 %3.0f[~1%-*.*s]~1\n"
, pfx, pct_user, pct_syst, pct_user + pct_syst, Graph_len +4, Graph_len +4, dual));
show_special(0, fmtmk("%%%s ~3%#5.1f~2/%-#5.1f~3 %3.0f[~1%-*s]~1\n"
, pfx, pct_user, pct_syst, pct_user + pct_syst, Graph_len +4, dual));
} else {
show_special(0, fmtmk(Cpu_States_fmts, pfx
, (float)u_frme * scale, (float)s_frme * scale
@ -5243,14 +5249,22 @@ numa_nope:
pct_misc = (float)(kb_main_total - kb_main_available - kb_main_used) * (100.0 / (float)kb_main_total),
#endif
pct_swap = kb_swap_total ? (float)kb_swap_used * (100.0 / (float)kb_swap_total) : 0;
snprintf(used, sizeof(used), gtab[ix].used, (int)((pct_used * Graph_adj) + .5), gtab[ix].type);
snprintf(util, sizeof(util), gtab[ix].misc, (int)((pct_misc * Graph_adj) + .5), gtab[ix].type);
#ifndef QUICK_GRAPHS
int num_used = (int)((pct_used * Graph_adj) + .5),
num_misc = (int)((pct_misc * Graph_adj) + .5);
if (num_used + num_misc > Graph_len) --num_misc;
snprintf(used, sizeof(used), gtab[ix].used, num_used, gtab[ix].type);
snprintf(util, sizeof(util), gtab[ix].misc, num_misc, gtab[ix].type);
#else
snprintf(used, sizeof(used), gtab[ix].used, (int)((pct_used * Graph_adj) + .6), gtab[ix].type);
snprintf(util, sizeof(util), gtab[ix].misc, (int)((pct_misc * Graph_adj) + .4), gtab[ix].type);
#endif
snprintf(dual, sizeof(dual), "%s%s", used, util);
snprintf(util, sizeof(util), gtab[ix].swap, (int)((pct_swap * Graph_adj) + .5), gtab[ix].type);
prT(bfT(0), mkM(total)); prT(bfT(1), mkS(total));
show_special(0, fmtmk( "%s %s:~3%#5.1f~2/%-9.9s~3[~1%-*.*s]~1\n%s %s:~3%#5.1f~2/%-9.9s~3[~1%-*.*s]~1\n"
, scT(label), N_txt(WORD_abv_mem_txt), pct_used + pct_misc, bfT(0), Graph_len +4, Graph_len +4, dual
, scT(label), N_txt(WORD_abv_swp_txt), pct_swap, bfT(1), Graph_len +2, Graph_len +2, util));
show_special(0, fmtmk( "%s %s:~3%#5.1f~2/%-9.9s~3[~1%-*s]~1\n%s %s:~3%#5.1f~2/%-9.9s~3[~1%-*s]~1\n"
, scT(label), N_txt(WORD_abv_mem_txt), pct_used + pct_misc, bfT(0), Graph_len +4, dual
, scT(label), N_txt(WORD_abv_swp_txt), pct_swap, bfT(1), Graph_len +2, util));
} else {
unsigned long kb_main_my_misc = kb_main_buffers + kb_main_cached;
prT(bfT(0), mkM(total)); prT(bfT(1), mkM(free));

1
top/top.h
View File

@ -51,6 +51,7 @@
//#define PRETEND8CPUS /* pretend we're smp with 8 ticsers (sic) */
//#define PRETENDNOCAP /* use a terminal without essential caps */
//#define PRETEND_NUMA /* pretend 4 (or 3 w/o OFF_NUMASKIP) Nodes */
//#define QUICK_GRAPHS /* use fast algorithim, accept +2% distort */
//#define RCFILE_NOERR /* rcfile errs silently default, vs. fatal */
//#define RECALL_FIXED /* don't reorder saved strings if recalled */
//#define RMAN_IGNORED /* don't consider auto right margin glitch */