count: add ability to select columnt being shown

* count.c (set_count_summary_columns): New function.
* defs.h (set_count_summary_columns): New declaration.
* strace.c (init) <-U>: Pass option argument to
set_count_summary_columns.
* strace.1.in (.SH OPTIONS): Document it.

count.c

@@ -188,6 +188,61 @@ set_sortby(const char *sortby)
 	error_msg_and_help("invalid sortby: '%s'", sortby);
 }
 
+void
+set_count_summary_columns(const char *s)
+{
+	static const char *cnames[] = {
+		[CSC_TIME_100S]  = "time_percent",
+		[CSC_TIME_TOTAL] = "total_time",
+		[CSC_TIME_AVG]   = "avg_time",
+		[CSC_CALLS]      = "calls",
+		[CSC_ERRORS]     = "errors",
+		[CSC_SC_NAME]    = "syscall",
+	};
+
+	const char *pos = s;
+	const char *prev = s;
+	size_t cur = 0;
+
+	memset(columns, 0, sizeof(columns));
+	memset(visible, 0, sizeof(visible));
+
+	do {
+		bool found = false;
+
+		pos = strchr(prev, ',');
+
+		for (size_t i = 0; i < ARRAY_SIZE(cnames); i++) {
+			if (!cnames[i] || (pos
+			    ? ((size_t) (pos - prev) != strlen(cnames[i]))
+			      || strncmp(prev, cnames[i], pos - prev)
+			    : strcmp(prev, cnames[i]))) {
+				continue;
+			}
+
+			if (visible[i])
+				error_msg_and_help("call summary column "
+						   "has been provided more "
+						   "than once: '%s' (-U option "
+						   "residual: '%s')",
+						   cnames[i], prev);
+
+			columns[cur++] = i;
+			visible[i] = 1;
+			found = true;
+
+			break;
+		}
+
+		if (!found)
+			error_msg_and_help("unknown column name: '%.*s'",
+					   (int) (pos ? pos - prev : INT_MAX),
+					   prev);
+
+		prev = pos + 1;
+	} while (pos);
+}
+
 void
 set_overhead(const char *str)
 {

defs.h

@@ -432,6 +432,7 @@ extern int read_int_from_file(struct tcb *, const char *, int *);
 
 extern void set_sortby(const char *);
 extern void set_overhead(const char *);
+extern void set_count_summary_columns(const char *columns);
 extern void print_pc(struct tcb *);
 
 extern int syscall_entering_decode(struct tcb *);

strace.1.in

@@ -67,6 +67,9 @@ strace \- trace system calls and signals
 .OP \-I n
 .OP \-b execve
 .OM \-e expr
+.OP \-O overhead
+.OP \-S sortby
+.OP \-U columns
 .OP \-a column
 .OP \-o file
 .OP \-s strsize
@@ -90,6 +93,7 @@ strace \- trace system calls and signals
 .OM \-e expr
 .OP \-O overhead
 .OP \-S sortby
+.OP \-U columns
 .OM \-P path
 .OM \-p pid
 .BR "" {
@@ -422,6 +426,37 @@ and
 default is
 .BR time .
 .TP
+.BI "\-U " columns
+Configure a set (and order) of columns being shown in the call summary.
+The
+.I columns
+argument is a comma-separated list with items being one of the following:
+.RS
+.TP 14
+.B time_percent
+Percentage of cumulative time consumed by a specific system call.
+.TQ
+.B total_time
+Total system (or wall clock, if
+.B \-w
+option is provided) time consumed by a specific process.
+.TQ
+.B avg_time
+Average call duration.
+.TQ
+.B calls
+Call count.
+.TQ
+.B errors
+Error count.
+.TQ
+.B syscall
+Syscall name.
+.RE
+.IP
+The default value is
+.BR time_percent , total_time , avg_time , calls , errors , syscall .
+.TP
 .B \-w
 Summarise the wall clock time difference between the beginning and the end of
 each system call.  The default is to summarise the system time.

strace.c

@@ -1615,7 +1615,7 @@ init(int argc, char *argv[])
 #ifdef ENABLE_STACKTRACE
 	    "k"
 #endif
-	    "a:Ab:cCdDe:E:fFhiI:o:O:p:P:qrs:S:tTu:vVwxX:yz")) != EOF) {
+	    "a:Ab:cCdDe:E:fFhiI:o:O:p:P:qrs:S:tTu:U:vVwxX:yz")) != EOF) {
 		switch (c) {
 		case 'a':
 			acolumn = string_to_uint(optarg);
@@ -1714,6 +1714,9 @@ init(int argc, char *argv[])
 		case 'u':
 			username = optarg;
 			break;
+		case 'U':
+			set_count_summary_columns(optarg);
+			break;
 		case 'v':
 			qualify("abbrev=none");
 			break;