diff options
Diffstat (limited to 'usr.sbin/iostat/iostat.c')
-rw-r--r-- | usr.sbin/iostat/iostat.c | 74 |
1 files changed, 71 insertions, 3 deletions
diff --git a/usr.sbin/iostat/iostat.c b/usr.sbin/iostat/iostat.c index 43d297e..f1a0556 100644 --- a/usr.sbin/iostat/iostat.c +++ b/usr.sbin/iostat/iostat.c @@ -113,6 +113,7 @@ #include <stdio.h> #include <stdlib.h> #include <string.h> +#include <termios.h> #include <unistd.h> #include <limits.h> #include <devstat.h> @@ -131,17 +132,23 @@ struct nlist namelist[] = { { NULL }, }; +#define IOSTAT_DEFAULT_ROWS 20 /* Traditional default `wrows' */ + struct statinfo cur, last; int num_devices; struct device_selection *dev_select; int maxshowdevs; volatile sig_atomic_t headercount; +volatile sig_atomic_t wresized; /* Tty resized, when non-zero. */ +unsigned short wrows; /* Current number of tty rows. */ int dflag = 0, Iflag = 0, Cflag = 0, Tflag = 0, oflag = 0, Kflag = 0; int xflag = 0, zflag = 0; /* local function declarations */ static void usage(void); static void needhdr(int signo); +static void needresize(int signo); +static void doresize(void); static void phdr(void); static void devstats(int perf_select, long double etime, int havelast); static void cpustats(void); @@ -426,6 +433,20 @@ main(int argc, char **argv) */ (void)signal(SIGCONT, needhdr); + /* + * If our standard output is a tty, then install a SIGWINCH handler + * and set wresized so that our first iteration through the main + * iostat loop will peek at the terminal's current rows to find out + * how many lines can fit in a screenful of output. + */ + if (isatty(fileno(stdout)) != 0) { + wresized = 1; + (void)signal(SIGWINCH, needresize); + } else { + wresized = 0; + wrows = IOSTAT_DEFAULT_ROWS; + } + for (headercount = 1;;) { struct devinfo *tmp_dinfo; long tmp; @@ -451,7 +472,9 @@ main(int argc, char **argv) if (!--headercount) { phdr(); - headercount = 20; + if (wresized != 0) + doresize(); + headercount = wrows; } tmp_dinfo = last.dinfo; @@ -493,7 +516,9 @@ main(int argc, char **argv) break; case 1: phdr(); - headercount = 20; + if (wresized != 0) + doresize(); + headercount = wrows; break; default: break; @@ -528,7 +553,9 @@ main(int argc, char **argv) break; case 1: phdr(); - headercount = 20; + if (wresized != 0) + doresize(); + headercount = wrows; break; default: break; @@ -589,6 +616,47 @@ needhdr(int signo) headercount = 1; } +/* + * When the terminal is resized, force an update of the maximum number of rows + * printed between each header repetition. Then force a new header to be + * prepended to the next output. + */ +void +needresize(int signo) +{ + + wresized = 1; + headercount = 1; +} + +/* + * Update the global `wrows' count of terminal rows. + */ +void +doresize(void) +{ + int status; + struct winsize w; + + for (;;) { + status = ioctl(fileno(stdout), TIOCGWINSZ, &w); + if (status == -1 && errno == EINTR) + continue; + else if (status == -1) + err(1, "ioctl"); + if (w.ws_row > 3) + wrows = w.ws_row - 3; + else + wrows = IOSTAT_DEFAULT_ROWS; + break; + } + + /* + * Inhibit doresize() calls until we are rescheduled by SIGWINCH. + */ + wresized = 0; +} + static void phdr(void) { |