busybox/procps/top.c

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2002-09-18 03:44:58 +05:30
/*
* A tiny 'top' utility.
*
* This is written specifically for the linux /proc/<PID>/status
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* 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 int process_status(const char *buf, const char *id, char *store, size_t size)
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{
int len, i;
/* check status field name */
len = strlen(id);
if (strncmp(buf, id, len) != 0) {
if(store)
error_msg_and_die("ERROR status: line doesn't start with '%s' in:\n%s\n", id, buf);
else
return 0;
}
if (!store) {
/* ignoring this field */
return 1;
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}
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';
return 1;
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}
/* 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);
if(process_status(buf, "Tgid", NULL, 0))
fgets(buf, sizeof(buf), fp);
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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);
if(process_status(buf, "TracerPid", NULL, 0))
fgets(buf, sizeof(buf), fp);
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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);
if(process_status(buf, "FDSize", NULL, 0))
fgets(buf, sizeof(buf), fp);
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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 - 5 lines for status */
lines = 25 - 5;
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/* 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 - 5;
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#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;
}