--- /dev/null
+/*
+ * A tiny 'top' utility.
+ *
+ * This is written specifically for the linux 2.4 /proc/<PID>/status
+ * file format, but it checks that the file actually conforms to the
+ * format that this utility expects.
+
+ * This reads the PIDs of all processes at startup and then shows the
+ * status of those processes at given intervals. User can give
+ * maximum number of processes to show. If a process exits, it's PID
+ * is shown as 'EXIT'. If new processes are started while this works,
+ * it doesn't add them to the list of shown processes.
+ *
+ * NOTES:
+ * - At startup this changes to /proc, all the reads are then
+ * relative to that.
+ * - Includes code from the scandir() manual page.
+ *
+ * TODO:
+ * - ppid, uid etc could be read only once when program starts
+ * and rest of the information could be gotten from the
+ * /proc/<PID>/statm file.
+ * - Add process CPU and memory usage *percentages*.
+ *
+ * (C) Eero Tamminen <oak at welho dot com>
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <dirent.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include "busybox.h"
+
+
+/* process information taken from /proc,
+ * The code takes into account how long the fields below are,
+ * starting from copying the file from 'status' file to displaying it!
+ */
+typedef struct {
+ char uid[6]; /* User ID */
+ char pid[6]; /* Pid */
+ char ppid[6]; /* Parent Pid */
+ char name[12]; /* Name */
+ char cmd[20]; /* command line[read/show size] */
+ char state[2]; /* State: S, W... */
+ char size[9]; /* VmSize */
+ char lck[9]; /* VmLck */
+ char rss[9]; /* VmRSS */
+ char data[9]; /* VmData */
+ char stk[9]; /* VmStk */
+ char exe[9]; /* VmExe */
+ char lib[9]; /* VmLib */
+} status_t;
+
+/* display generic info (meminfo / loadavg) */
+static void display_generic(void)
+{
+ FILE *fp;
+ char buf[80];
+ float avg1, avg2, avg3;
+ unsigned long total, used, mfree, shared, buffers, cached;
+
+ /* read memory info */
+ fp = fopen("meminfo", "r");
+ if (!fp) {
+ perror("fopen('meminfo')");
+ return;
+ }
+ fgets(buf, sizeof(buf), fp); /* skip first line */
+
+ if (fscanf(fp, "Mem: %lu %lu %lu %lu %lu %lu",
+ &total, &used, &mfree, &shared, &buffers, &cached) != 6) {
+ fprintf(stderr, "Error: failed to read 'meminfo'");
+ fclose(fp);
+ }
+ fclose(fp);
+
+ /* read load average */
+ fp = fopen("loadavg", "r");
+ if (!fp) {
+ perror("fopen('loadavg')");
+ return;
+ }
+ if (fscanf(fp, "%f %f %f", &avg1, &avg2, &avg3) != 3) {
+ fprintf(stderr, "Error: failed to read 'loadavg'");
+ fclose(fp);
+ return;
+ }
+ fclose(fp);
+
+ /* convert to kilobytes */
+ if (total) total /= 1024;
+ if (used) used /= 1024;
+ if (mfree) mfree /= 1024;
+ if (shared) shared /= 1024;
+ if (buffers) buffers /= 1024;
+ if (cached) cached /= 1024;
+
+ /* output memory info and load average */
+ printf("Mem: %ldK, %ldK used, %ldK free, %ldK shrd, %ldK buff, %ldK cached\n",
+ total, used, mfree, shared, buffers, cached);
+ printf("Load average: %.2f, %.2f, %.2f (State: S=sleeping R=running, W=waiting)\n",
+ avg1, avg2, avg3);
+}
+
+
+/* display process statuses */
+static void display_status(int count, const status_t *s)
+{
+ const char *fmt, *cmd;
+
+ /* clear screen & go to top */
+ printf("\e[2J\e[1;1H");
+
+ display_generic();
+
+ /* what info of the processes is shown */
+ printf("\n%*s %*s %*s %*s %*s %*s %-*s\n",
+ sizeof(s->pid)-1, "Pid:",
+ sizeof(s->state)-1, "",
+ sizeof(s->ppid)-1, "PPid:",
+ sizeof(s->uid)-1, "UID:",
+ sizeof(s->size)-1, "WmSize:",
+ sizeof(s->rss)-1, "WmRSS:",
+ sizeof(s->cmd)-1, "command line:");
+
+ while (count--) {
+ if (s->cmd[0]) {
+ /* normal process, has command line */
+ cmd = s->cmd;
+ fmt = "%*s %*s %*s %*s %*s %*s %s\n";
+ } else {
+ /* no command line, show only process name */
+ cmd = s->name;
+ fmt = "%*s %*s %*s %*s %*s %*s [%s]\n";
+ }
+ printf(fmt,
+ sizeof(s->pid)-1, s->pid,
+ sizeof(s->state)-1, s->state,
+ sizeof(s->ppid)-1, s->ppid,
+ sizeof(s->uid)-1, s->uid,
+ sizeof(s->size)-1, s->size,
+ sizeof(s->rss)-1, s->rss,
+ cmd);
+ s++;
+ }
+}
+
+
+/* checks if given 'buf' for process starts with 'id' + ':' + TAB
+ * and stores rest of the buf to 'store' with max size 'size'
+ */
+static void process_status(const char *buf, const char *id, char *store, size_t size)
+{
+ int len, i;
+
+ if (!store) {
+ /* ignoring this field */
+ return;
+ }
+
+ /* check status field name */
+ len = strlen(id);
+ if (strncmp(buf, id, len) != 0) {
+ error_msg_and_die("ERROR status: line doesn't start with '%s' in:\n%s\n", id, buf);
+ }
+ buf += len;
+
+ /* check status field format */
+ if ((*buf++ != ':') || (*buf++ != '\t')) {
+ error_msg_and_die("ERROR status: field '%s' not followed with ':' + TAB in:\n%s\n", id, buf);
+ }
+
+ /* skip whitespace in Wm* fields */
+ if (id[0] == 'V' && id[1] == 'm') {
+ i = 3;
+ while (i--) {
+ if (*buf == ' ') {
+ buf++;
+ } else {
+ error_msg_and_die("ERROR status: can't skip whitespace for "
+ "'%s' field in:\n%s\n", id, buf);
+ }
+ }
+ }
+
+ /* copy at max (size-1) chars and force '\0' to the end */
+ while (--size) {
+ if (*buf < ' ') {
+ break;
+ }
+ *store++ = *buf++;
+ }
+ *store = '\0';
+}
+
+
+/* read process statuses */
+static void read_status(int num, status_t *s)
+{
+ char status[20];
+ char buf[80];
+ FILE *fp;
+
+ while (num--) {
+ sprintf(status, "%s/status", s->pid);
+
+ /* read the command line from 'cmdline' in PID dir */
+ fp = fopen(status, "r");
+ if (!fp) {
+ strncpy(s->pid, "EXIT", sizeof(s->pid));
+ continue;
+ }
+
+ /* get and process the information */
+ fgets(buf, sizeof(buf), fp);
+ process_status(buf, "Name", s->name, sizeof(s->name));
+ fgets(buf, sizeof(buf), fp);
+ process_status(buf, "State", s->state, sizeof(s->state));
+ fgets(buf, sizeof(buf), fp);
+ process_status(buf, "Tgid", NULL, 0);
+ fgets(buf, sizeof(buf), fp);
+ process_status(buf, "Pid", NULL, 0);
+ fgets(buf, sizeof(buf), fp);
+ process_status(buf, "PPid", s->ppid, sizeof(s->ppid));
+ fgets(buf, sizeof(buf), fp);
+ process_status(buf, "TracePid", NULL, 0);
+ fgets(buf, sizeof(buf), fp);
+ process_status(buf, "Uid", s->uid, sizeof(s->uid));
+ fgets(buf, sizeof(buf), fp);
+ process_status(buf, "Gid", NULL, 0);
+ fgets(buf, sizeof(buf), fp);
+ process_status(buf, "FDSize", NULL, 0);
+ fgets(buf, sizeof(buf), fp);
+ process_status(buf, "Groups", NULL, 0);
+ fgets(buf, sizeof(buf), fp);
+ /* only user space processes have command line
+ * and memory statistics
+ */
+ if (s->cmd[0]) {
+ process_status(buf, "VmSize", s->size, sizeof(s->size));
+ fgets(buf, sizeof(buf), fp);
+ process_status(buf, "VmLck", s->lck, sizeof(s->lck));
+ fgets(buf, sizeof(buf), fp);
+ process_status(buf, "VmRSS", s->rss, sizeof(s->rss));
+ fgets(buf, sizeof(buf), fp);
+ process_status(buf, "VmData", s->data, sizeof(s->data));
+ fgets(buf, sizeof(buf), fp);
+ process_status(buf, "VmStk", s->stk, sizeof(s->stk));
+ fgets(buf, sizeof(buf), fp);
+ process_status(buf, "VmExe", s->exe, sizeof(s->exe));
+ fgets(buf, sizeof(buf), fp);
+ process_status(buf, "VmLib", s->lib, sizeof(s->lib));
+ }
+ fclose(fp);
+
+ /* next process */
+ s++;
+ }
+}
+
+
+/* allocs statuslist and reads process command lines, frees namelist,
+ * returns filled statuslist or NULL in case of error.
+ */
+static status_t *read_info(int num, struct dirent **namelist)
+{
+ status_t *statuslist, *s;
+ char cmdline[20];
+ FILE *fp;
+ int idx;
+
+ /* allocate & zero status for each of the processes */
+ statuslist = calloc(num, sizeof(status_t));
+ if (!statuslist) {
+ return NULL;
+ }
+
+ /* go through the processes */
+ for (idx = 0; idx < num; idx++) {
+
+ /* copy PID string to status struct and free name */
+ s = &(statuslist[idx]);
+ if (strlen(namelist[idx]->d_name) > sizeof(s->pid)-1) {
+ fprintf(stderr, "PID '%s' too long\n", namelist[idx]->d_name);
+ return NULL;
+ }
+ strncpy(s->pid, namelist[idx]->d_name, sizeof(s->pid));
+ s->pid[sizeof(s->pid)-1] = '\0';
+ free(namelist[idx]);
+
+ /* read the command line from 'cmdline' in PID dir */
+ sprintf(cmdline, "%s/cmdline", s->pid);
+ fp = fopen(cmdline, "r");
+ if (!fp) {
+ perror("fopen('cmdline')");
+ return NULL;
+ }
+ fgets(statuslist[idx].cmd, sizeof(statuslist[idx].cmd), fp);
+ fclose(fp);
+ }
+ free(namelist);
+ return statuslist;
+}
+
+
+/* returns true for file names which are PID dirs
+ * (i.e. start with number)
+ */
+static int filter_pids(const struct dirent *dir)
+{
+ status_t dummy;
+ char *name = dir->d_name;
+
+ if (*name >= '0' && *name <= '9') {
+ if (strlen(name) > sizeof(dummy.pid)-1) {
+ fprintf(stderr, "PID name '%s' too long\n", name);
+ return 0;
+ }
+ return 1;
+ }
+ return 0;
+}
+
+
+/* compares two directory entry names as numeric strings
+ */
+static int num_sort(const void *a, const void *b)
+{
+ int ia = atoi((*(struct dirent **)a)->d_name);
+ int ib = atoi((*(struct dirent **)b)->d_name);
+
+ if (ia == ib) {
+ return 0;
+ }
+ /* NOTE: by switching the check, you change the process sort order */
+ if (ia < ib) {
+ return -1;
+ } else {
+ return 1;
+ }
+}
+
+
+int top_main(int argc, char **argv)
+{
+ status_t *statuslist;
+ struct dirent **namelist;
+ int opt, num, interval, lines;
+#if defined CONFIG_FEATURE_AUTOWIDTH && defined CONFIG_FEATURE_USE_TERMIOS
+ struct winsize win = { 0, 0, 0, 0 };
+#endif
+ /* Default update rate is 5 seconds */
+ interval = 5;
+ /* Default to 25 lines */
+ lines = 25;
+
+ /* do normal option parsing */
+ while ((opt = getopt(argc, argv, "d:")) > 0) {
+ switch (opt) {
+ case 'd':
+ interval = atoi(optarg);
+ break;
+ default:
+ show_usage();
+ }
+ }
+
+#if defined CONFIG_FEATURE_AUTOWIDTH && defined CONFIG_FEATURE_USE_TERMIOS
+ ioctl(fileno(stdout), TIOCGWINSZ, &win);
+ if (win.ws_row > 4)
+ lines = win.ws_row - 6;
+#endif
+
+ /* change to proc */
+ if (chdir("/proc") < 0) {
+ perror_msg_and_die("chdir('/proc')");
+ }
+
+ /* read process IDs for all the processes from the procfs */
+ num = scandir(".", &namelist, filter_pids, num_sort);
+ if (num < 0) {
+ perror_msg_and_die("scandir('/proc')");
+ }
+ if (lines > num) {
+ lines = num;
+ }
+
+ /* read command line for each of the processes */
+ statuslist = read_info(num, namelist);
+ if (!statuslist) {
+ return EXIT_FAILURE;
+ }
+
+ while (1) {
+ /* read status for each of the processes */
+ read_status(num, statuslist);
+
+ /* display status */
+ display_status(lines, statuslist);
+
+ sleep(interval);
+ }
+
+ free(statuslist);
+ return EXIT_SUCCESS;
+}
projects / oweals / busybox.git / commitdiff