Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
tools/delaytop: add interactive mode with keyboard controls
The original delaytop only supported static output with limited
interaction. Users had to restart the tool with different command-line
options to change sorting or display modes, which disrupted continuous
monitoring and reduced productivity during performance investigations.
Adds real-time interactive controls through keyboard input:
1) Add interactive menu system with visual prompts
2) Support dynamic sorting changes without restarting
3) Enable toggle of memory verbose mode with 'M' key
The interactive mode transforms delaytop from a static monitoring tool
into a dynamic investigation platform, allowing users to adapt the view in
real-time based on observed performance patterns.
Link: https://lkml.kernel.org/r/20250907001338580EURha20BxWFmBSrUpS8D1@zte.com.cn
Signed-off-by: Fan Yu <fan.yu9@zte.com.cn>
Reviewed-by: xu xin <xu.xin16@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
authored by
Fan Yu
and committed by
Andrew Morton
5e57515d
99d9c55f
+121
-45
+121
-45
tools/accounting/delaytop.c
+121
-45
tools/accounting/delaytop.c
···
73
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#define PSI_LINE_FORMAT "%-12s %6.1f%%/%6.1f%%/%6.1f%%/%8llu(ms)\n"
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#define DELAY_FMT_DEFAULT "%8.2f %8.2f %8.2f %8.2f\n"
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#define DELAY_FMT_MEMVERBOSE "%8.2f %8.2f %8.2f %8.2f %8.2f %8.2f\n"
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-
#define SORT_FIELD(name, modes) \
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{#name, \
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#define SORT_FIELD(name, cmd, modes) \
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{#name, #cmd, \
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offsetof(struct task_info, name##_delay_total), \
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offsetof(struct task_info, name##_count), \
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modes}
···
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/* Delay field structure */
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struct field_desc {
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const char *name; /* Field name for cmdline argument */
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const char *cmd_char; /* Interactive command */
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unsigned long total_offset; /* Offset of total delay in task_info */
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unsigned long count_offset; /* Offset of count in task_info */
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size_t supported_modes; /* Supported display modes */
···
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static int running = 1;
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static struct container_stats container_stats;
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static const struct field_desc sort_fields[] = {
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SORT_FIELD(cpu, MODE_DEFAULT),
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SORT_FIELD(blkio, MODE_DEFAULT),
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SORT_FIELD(irq, MODE_DEFAULT),
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SORT_FIELD(mem, MODE_DEFAULT | MODE_MEMVERBOSE),
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SORT_FIELD(swapin, MODE_MEMVERBOSE),
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SORT_FIELD(freepages, MODE_MEMVERBOSE),
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SORT_FIELD(thrashing, MODE_MEMVERBOSE),
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SORT_FIELD(compact, MODE_MEMVERBOSE),
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SORT_FIELD(wpcopy, MODE_MEMVERBOSE),
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SORT_FIELD(cpu, c, MODE_DEFAULT),
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SORT_FIELD(blkio, i, MODE_DEFAULT),
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SORT_FIELD(irq, q, MODE_DEFAULT),
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SORT_FIELD(mem, m, MODE_DEFAULT | MODE_MEMVERBOSE),
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SORT_FIELD(swapin, s, MODE_MEMVERBOSE),
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SORT_FIELD(freepages, r, MODE_MEMVERBOSE),
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SORT_FIELD(thrashing, t, MODE_MEMVERBOSE),
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SORT_FIELD(compact, p, MODE_MEMVERBOSE),
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SORT_FIELD(wpcopy, w, MODE_MEMVERBOSE),
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END_FIELD
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};
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static int sort_selected;
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/* Netlink socket variables */
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static int nl_sd = -1;
···
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static void disable_raw_mode(void)
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{
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tcsetattr(STDIN_FILENO, TCSAFLUSH, &orig_termios);
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}
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+
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/* Find field descriptor by command line */
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static const struct field_desc *get_field_by_cmd_char(char ch)
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{
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const struct field_desc *field;
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for (field = sort_fields; field->name != NULL; field++) {
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if (field->cmd_char[0] == ch)
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return field;
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}
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return NULL;
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}
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/* Find field descriptor by name with string comparison */
···
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container_stats.nr_stopped, container_stats.nr_uninterruptible,
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container_stats.nr_io_wait);
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}
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/* Interacive command */
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suc &= BOOL_FPRINT(out, "[o]sort [M]memverbose [q]quit\n");
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if (sort_selected) {
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if (cfg.display_mode == MODE_MEMVERBOSE)
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suc &= BOOL_FPRINT(out,
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"sort selection: [m]MEM [r]RCL [t]THR [p]CMP [w]WP\n");
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else
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suc &= BOOL_FPRINT(out,
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"sort selection: [c]CPU [i]IO [m]MEM [q]IRQ\n");
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}
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/* Task delay output */
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suc &= BOOL_FPRINT(out, "Top %d processes (sorted by %s delay):\n",
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cfg.max_processes, get_name_by_field(cfg.sort_field));
···
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perror("Error writing to output");
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}
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/* Check for keyboard input with timeout based on cfg.delay */
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static char check_for_keypress(void)
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{
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struct timeval tv = {cfg.delay, 0};
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fd_set readfds;
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char ch = 0;
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FD_ZERO(&readfds);
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FD_SET(STDIN_FILENO, &readfds);
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int r = select(STDIN_FILENO + 1, &readfds, NULL, NULL, &tv);
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+
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if (r > 0 && FD_ISSET(STDIN_FILENO, &readfds)) {
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read(STDIN_FILENO, &ch, 1);
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return ch;
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}
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+
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return 0;
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}
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+
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#define MAX_MODE_SIZE 2
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static void toggle_display_mode(void)
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{
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static const size_t modes[MAX_MODE_SIZE] = {MODE_DEFAULT, MODE_MEMVERBOSE};
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static size_t cur_index;
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cur_index = (cur_index + 1) % MAX_MODE_SIZE;
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cfg.display_mode = modes[cur_index];
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}
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/* Handle keyboard input: sorting selection, mode toggle, or quit */
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static void handle_keypress(char ch, int *running)
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{
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const struct field_desc *field;
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/* Change sort field */
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if (sort_selected) {
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field = get_field_by_cmd_char(ch);
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if (field && (field->supported_modes & cfg.display_mode))
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cfg.sort_field = field;
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sort_selected = 0;
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/* Handle mode changes or quit */
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} else {
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switch (ch) {
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case 'o':
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sort_selected = 1;
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break;
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case 'M':
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toggle_display_mode();
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for (field = sort_fields; field->name != NULL; field++) {
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if (field->supported_modes & cfg.display_mode) {
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cfg.sort_field = field;
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break;
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}
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}
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break;
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case 'q':
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case 'Q':
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*running = 0;
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break;
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default:
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break;
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}
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}
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}
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/* Main function */
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int main(int argc, char **argv)
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{
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const struct field_desc *field;
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int iterations = 0;
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int use_q_quit = 0;
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char keypress;
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/* Parse command line arguments */
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parse_args(argc, argv);
···
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exit(1);
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}
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if (!cfg.output_one_time) {
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use_q_quit = 1;
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enable_raw_mode();
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printf("Press 'q' to quit.\n");
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fflush(stdout);
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}
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/* Set terminal to non-canonical mode for interaction */
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enable_raw_mode();
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/* Main loop */
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while (running) {
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/* Exit when sort field do not match display mode */
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/* Auto-switch sort field when not matching display mode */
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if (!(cfg.sort_field->supported_modes & cfg.display_mode)) {
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fprintf(stderr, "Sort field not supported in this mode\n");
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display_available_fields(cfg.display_mode);
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break;
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for (field = sort_fields; field->name != NULL; field++) {
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if (field->supported_modes & cfg.display_mode) {
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cfg.sort_field = field;
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printf("Auto-switched sort field to: %s\n", field->name);
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break;
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}
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}
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}
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/* Read PSI statistics */
···
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if (cfg.output_one_time)
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break;
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/* Check for 'q' key to quit */
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if (use_q_quit) {
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struct timeval tv = {cfg.delay, 0};
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fd_set readfds;
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FD_ZERO(&readfds);
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FD_SET(STDIN_FILENO, &readfds);
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int r = select(STDIN_FILENO+1, &readfds, NULL, NULL, &tv);
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if (r > 0 && FD_ISSET(STDIN_FILENO, &readfds)) {
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char ch = 0;
1091
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read(STDIN_FILENO, &ch, 1);
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if (ch == 'q' || ch == 'Q') {
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running = 0;
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break;
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}
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}
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} else {
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sleep(cfg.delay);
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-
}
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/* Keypress for interactive usage */
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keypress = check_for_keypress();
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if (keypress)
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handle_keypress(keypress, &running);
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}
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/* Restore terminal mode */
1104
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if (use_q_quit)
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disable_raw_mode();
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disable_raw_mode();
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/* Cleanup */
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close(nl_sd);