top: existing 'Inspect' pipe feature now more flexible

Currently, it isn't possible to establish an 'Inspect'
pipe that relies on SIGINT to end. That's because this
signal will also end the parent process (top) as well.

So this patch will temporarily ignore that signal when
processing any 'Inspect' pipe, allowing one like this:

. pipe ^I Trace Calls ^I /usr/bin/strace -r -p %d 2>&1

Signed-off-by: Jim Warner <james.warner@comcast.net>

diff --git a/top/top.1 b/top/top.1
index fec223ac62979c2fd845e899a5ed59bea1328f3c..945b09076f7a558020dab52ff97920903c9287ef 100644 (file)
--- a/top/top.1
+++ b/top/top.1
@@ -62,7 +62,7 @@
 .
 .\" Document /////////////////////////////////////////////////////////////
 .\" ----------------------------------------------------------------------
-.TH TOP 1 "June 2018" "procps-ng" "User Commands"
+.TH TOP 1 "July 2018" "procps-ng" "User Commands"
 .\" ----------------------------------------------------------------------
 
 .\" ----------------------------------------------------------------------
@@ -2272,12 +2272,13 @@ enable backslash interpretation regardless of which shell you use.
   "pipe\\tLog\\ttail -n200 /var/log/syslog | sort -Mr" >> ~/.toprc
 .fi
 
-\fBCaution\fR:
 If any inspect entry you create produces output with unprintable characters
 they will be displayed in either the ^C notation or hexadecimal <FF> form,
 depending on their value.
 This applies to tab characters as well, which will show as `^I'.
 If you want a truer representation, any embedded tabs should be expanded.
+The following example takes what could have been a `file' entry but employs
+a `pipe' instead so as to expand the embedded tabs.
 
 .nf
   # next would have contained `\\t' ...
@@ -2286,18 +2287,23 @@ If you want a truer representation, any embedded tabs should be expanded.
   pipe ^I <your_name> ^I cat /proc/%d/status | expand \-
 .fi
 
-The above example takes what could have been a `file' entry but employs
-a `pipe' instead so as to expand the embedded tabs.
+\*(NT Some programs might rely on \fISIGINT\fR to end.
+Therefore, if a `\fBpipe\fR' such as the following is established, one must
+use Ctrl-C to terminate it in order to review the results.
+This is the single occasion where a `^C' will not also terminate \*(We.
+
+.nf
+  pipe ^I Trace ^I /usr/bin/strace -p %d 2>&1
+.fi
 
-\*(NT While `\fBpipe\fR' type entries have been discussed in terms of pipelines
+Lastly, while `\fBpipe\fR' type entries have been discussed in terms of pipelines
 and commands, there is nothing to prevent you from including \fI shell scripts\fR
 as well.
 Perhaps even newly created scripts designed specifically for the `Y' \*(CI.
 
-Lastly, as the number of your Inspect entries grows over time, the `Options:'
+For example, as the number of your Inspect entries grows over time, the `Options:'
 row will be truncated when screen width is exceeded.
 That does not affect operation other than to make some selections invisible.
-
 However, if some choices are lost to truncation but you want to see more options,
 there is an easy solution hinted at below.
 

diff --git a/top/top.c b/top/top.c
index ab37377067ad22d0de8dd8b84e5c6b0f5295c25e..a1f3ceb0338a2f34561aa34bf6fb80edfd351093 100644 (file)
--- a/top/top.c
+++ b/top/top.c
@@ -2866,6 +2866,12 @@ static void sysinfo_refresh (int forced) {
          *     # file ^I <your_name> ^I /proc/%d/status
          *     # but this will eliminate embedded '\t' ...
          *     pipe ^I <your_name> ^I cat /proc/%d/status | expand -
+         *
+         * Note: If a pipe such as the following was established, one must
+         * use Ctrl-C to terminate that pipe in order to review the results.
+         * This is the single occasion where a '^C' will not terminate top.
+         *
+         *     pipe ^I Trace ^I /usr/bin/strace -p %d 2>&1
          */
 
         /*
@@ -2909,8 +2915,8 @@ static struct I_ent *Insp_sel;    // currently selected Inspect entry
         // Our 'row length' macro, equivalent to a strlen() call
 #define INSP_RLEN(idx) (int)(Insp_p[idx +1] - Insp_p[idx] -1)
 
-        // Our 'busy' (wait please) macro
-#define INSP_BUSY  { INSP_MKSL(0, N_txt(YINSP_workin_txt)); }
+        // Our 'busy/working' macro
+#define INSP_BUSY(enu)  { INSP_MKSL(0, N_txt(enu)) }
 
 
         /*
@@ -2991,9 +2997,15 @@ static void insp_do_file (char *fmts, int pid) {
          * The generalized PIPE utility. */
 static void insp_do_pipe (char *fmts, int pid) {
    char buf[LRGBUFSIZ];
+   struct sigaction sa;
    FILE *fp;
    int rc;
 
+   memset(&sa, 0, sizeof(sa));
+   sigemptyset(&sa.sa_mask);
+   sa.sa_handler = SIG_IGN;
+   sigaction(SIGINT, &sa, NULL);
+
    snprintf(buf, sizeof(buf), fmts, pid);
    fp = popen(buf, "r");
    rc = readfile(fp, &Insp_buf, &Insp_bufsz, &Insp_bufrd);
@@ -3001,6 +3013,9 @@ static void insp_do_pipe (char *fmts, int pid) {
    if (rc) Insp_bufrd = snprintf(Insp_buf, Insp_bufsz, "%s"
       , fmtmk(N_fmt(YINSP_failed_fmt), strerror(errno)));
    insp_cnt_nl();
+
+   sa.sa_handler = sig_endpgm;
+   sigaction(SIGINT, &sa, NULL);
 } // end: insp_do_pipe
 
 
@@ -3058,7 +3073,7 @@ static void insp_find_str (int ch, int *col, int *row) {
    if (Insp_sel->fstr[0]) {
       int xx, yy;
 
-      INSP_BUSY;
+      INSP_BUSY(YINSP_waitin_txt);
       for (xx = *col, yy = *row; yy < Insp_nl; ) {
          xx = insp_find_ofs(xx, yy);
          if (xx < INSP_RLEN(yy)) {
@@ -3425,7 +3440,8 @@ signify_that:
             key = INT_MAX;
             break;
          case kbd_ENTER:
-            INSP_BUSY;
+            INSP_BUSY(!strcmp("file", Inspect.tab[sel].type)
+               ? YINSP_waitin_txt : YINSP_workin_txt);
             Insp_sel = &Inspect.tab[sel];
             Inspect.tab[sel].func(Inspect.tab[sel].fmts, pid);
             Insp_utf8 = utf8_delta(Insp_buf);

diff --git a/top/top_nls.c b/top/top_nls.c
index e0d5c7d5a03dac44fdda2751857608e8d8c4ab76..c3227de95cf13eb8b6f31587fbc008edfa44fe91 100644 (file)
--- a/top/top_nls.c
+++ b/top/top_nls.c
@@ -473,7 +473,8 @@ static void build_norm_nlstab (void) {
    Norm_nlstab[YINSP_pidbad_fmt] = _("unable to inspect, pid %d not found");
    Norm_nlstab[YINSP_pidsee_fmt] = _("inspect at PID [default pid = %d]");
    Norm_nlstab[YINSP_status_fmt] = _("%s: %*d-%-*d lines, %*d-%*d columns, %lu bytes read");
-   Norm_nlstab[YINSP_workin_txt] = _("patience please, working...");
+   Norm_nlstab[YINSP_waitin_txt] = _("patience please, working ...");
+   Norm_nlstab[YINSP_workin_txt] = _("working, use Ctrl-C to end ...");
 /* Translation Hint: Below are 2 abbreviations which can be as long as needed:
    .                 FLD = FIELD, VAL = VALUE */
    Norm_nlstab[OSEL_prompts_fmt] = _("add filter #%d (%s) as: [!]FLD?VAL");

diff --git a/top/top_nls.h b/top/top_nls.h
index 8dece85554a4db2d5ee6d244d24e552039fa728c..9148c12b7d9caf63e34875a683f189f721746720 100644 (file)
--- a/top/top_nls.h
+++ b/top/top_nls.h
@@ -89,7 +89,7 @@ enum norm_nls {
    YINSP_deqtyp_txt, YINSP_dstory_txt,
 #endif
    YINSP_failed_fmt, YINSP_noents_txt, YINSP_pidbad_fmt, YINSP_pidsee_fmt,
-   YINSP_status_fmt, YINSP_workin_txt,
+   YINSP_status_fmt, YINSP_waitin_txt, YINSP_workin_txt,
       norm_MAX
 };