replace /proc scanning code by more versatile one.
Use it where appropriate. Stop scanning /etc/passwd *for every process*!!! (uid->username) top: reduce memory usage - we won't save unneeded fields from /proc info anymore. Downside: ~+250 bytes of code
This commit is contained in:
Denis Vlasenko
267
libbb/procps.c
267
libbb/procps.c
@@ -11,6 +11,35 @@
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#include "libbb.h"
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typedef struct {
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uid_t uid;
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char username[12];
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} user_map_t;
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static user_map_t *username_cache;
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static int username_cache_size;
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void clear_username_cache(void)
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{
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free(username_cache);
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username_cache = NULL;
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username_cache_size = 0;
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}
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const char* get_cached_username(uid_t uid)
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{
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int i;
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for (i = 0; i < username_cache_size; i++)
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if (username_cache[i].uid == uid)
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return username_cache[i].username;
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i = username_cache_size++;
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username_cache = xrealloc(username_cache, username_cache_size * sizeof(*username_cache));
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username_cache[i].uid = uid;
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bb_getpwuid(username_cache[i].username, uid, sizeof(username_cache[i].username));
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return username_cache[i].username;
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}
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#define PROCPS_BUFSIZE 1024
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static int read_to_buf(const char *filename, void *buf)
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@@ -21,119 +50,171 @@ static int read_to_buf(const char *filename, void *buf)
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return ret;
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}
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procps_status_t * procps_scan(int save_user_arg0)
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procps_status_t* alloc_procps_scan(int flags)
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{
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static DIR *dir;
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static procps_status_t ret_status;
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procps_status_t* sp = xzalloc(sizeof(procps_status_t));
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sp->dir = xopendir("/proc");
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return sp;
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}
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void free_procps_scan(procps_status_t* sp)
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{
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closedir(sp->dir);
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free(sp->cmd);
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free(sp);
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}
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void BUG_comm_size(void);
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procps_status_t* procps_scan(procps_status_t* sp, int flags)
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{
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struct dirent *entry;
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char *name;
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char buf[PROCPS_BUFSIZE];
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char status[sizeof("/proc//cmdline") + sizeof(int)*3];
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char *status_tail;
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procps_status_t curstatus;
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char filename[sizeof("/proc//cmdline") + sizeof(int)*3];
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char *filename_tail;
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long tasknice;
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int pid;
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unsigned pid;
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int n;
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struct stat sb;
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if (!dir) {
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dir = xopendir("/proc");
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}
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if (!sp)
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sp = alloc_procps_scan(flags);
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for (;;) {
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entry = readdir(dir);
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entry = readdir(sp->dir);
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if (entry == NULL) {
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closedir(dir);
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dir = 0;
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return 0;
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free_procps_scan(sp);
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return NULL;
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}
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name = entry->d_name;
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if (!(*name >= '0' && *name <= '9'))
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if (safe_strtou(entry->d_name, &pid))
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continue;
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memset(&curstatus, 0, sizeof(procps_status_t));
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pid = atoi(name);
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curstatus.pid = pid;
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/* After this point we have to break, not continue
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* ("continue" would mean that current /proc/NNN
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* is not a valid process info) */
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status_tail = status + sprintf(status, "/proc/%d", pid);
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if (stat(status, &sb))
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continue;
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bb_getpwuid(curstatus.user, sb.st_uid, sizeof(curstatus.user));
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memset(&sp->rss, 0, sizeof(*sp) - offsetof(procps_status_t, rss));
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/* see proc(5) for some details on this */
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strcpy(status_tail, "/stat");
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n = read_to_buf(status, buf);
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if (n < 0)
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continue;
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name = strrchr(buf, ')'); /* split into "PID (cmd" and "<rest>" */
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if (name == 0 || name[1] != ' ')
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continue;
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*name = 0;
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sscanf(buf, "%*s (%15c", curstatus.short_cmd);
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n = sscanf(name+2,
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"%c %d "
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"%*s %*s %*s %*s " /* pgrp, session, tty, tpgid */
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"%*s %*s %*s %*s %*s " /* flags, min_flt, cmin_flt, maj_flt, cmaj_flt */
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#ifdef CONFIG_FEATURE_TOP_CPU_USAGE_PERCENTAGE
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"%lu %lu " /* utime, stime */
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#else
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"%*s %*s " /* utime, stime */
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#endif
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"%*s %*s %*s " /* cutime, cstime, priority */
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"%ld " /* nice */
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"%*s %*s %*s " /* timeout, it_real_value, start_time */
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"%*s " /* vsize */
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"%ld", /* rss */
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curstatus.state, &curstatus.ppid,
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#ifdef CONFIG_FEATURE_TOP_CPU_USAGE_PERCENTAGE
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&curstatus.utime, &curstatus.stime,
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#endif
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&tasknice,
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&curstatus.rss);
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#ifdef CONFIG_FEATURE_TOP_CPU_USAGE_PERCENTAGE
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if (n != 6)
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#else
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if (n != 4)
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#endif
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continue;
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sp->pid = pid;
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if (!(flags & ~PSSCAN_PID)) break;
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if (curstatus.rss == 0 && curstatus.state[0] != 'Z')
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curstatus.state[1] = 'W';
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else
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curstatus.state[1] = ' ';
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if (tasknice < 0)
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curstatus.state[2] = '<';
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else if (tasknice > 0)
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curstatus.state[2] = 'N';
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else
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curstatus.state[2] = ' ';
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filename_tail = filename + sprintf(filename, "/proc/%d", pid);
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if (flags & PSSCAN_UIDGID) {
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if (stat(filename, &sb))
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break;
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/* Need comment - is this effective or read UID/GID? */
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sp->uid = sb.st_uid;
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sp->gid = sb.st_gid;
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}
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if (flags & PSSCAN_STAT) {
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char *cp;
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/* see proc(5) for some details on this */
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strcpy(filename_tail, "/stat");
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n = read_to_buf(filename, buf);
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if (n < 0)
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break;
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cp = strrchr(buf, ')'); /* split into "PID (cmd" and "<rest>" */
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if (!cp || cp[1] != ' ')
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break;
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cp[0] = '\0';
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if (sizeof(sp->comm) < 16)
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BUG_comm_size();
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sscanf(buf, "%*s (%15c", sp->comm);
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n = sscanf(cp+2,
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"%c %u " /* state, ppid */
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"%u %u %*s %*s " /* pgid, sid, tty, tpgid */
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"%*s %*s %*s %*s %*s " /* flags, min_flt, cmin_flt, maj_flt, cmaj_flt */
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"%lu %lu " /* utime, stime */
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"%*s %*s %*s " /* cutime, cstime, priority */
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"%ld " /* nice */
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"%*s %*s %*s " /* timeout, it_real_value, start_time */
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"%*s " /* vsize */
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"%lu", /* rss */
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sp->state, &sp->ppid,
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&sp->pgid, &sp->sid,
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&sp->utime, &sp->stime,
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&tasknice,
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&sp->rss);
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if (n != 8)
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break;
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if (sp->rss == 0 && sp->state[0] != 'Z')
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sp->state[1] = 'W';
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else
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sp->state[1] = ' ';
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if (tasknice < 0)
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sp->state[2] = '<';
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else if (tasknice > 0)
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sp->state[2] = 'N';
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else
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sp->state[2] = ' ';
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#ifdef PAGE_SHIFT
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curstatus.rss <<= (PAGE_SHIFT - 10); /* 2**10 = 1kb */
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sp->rss <<= (PAGE_SHIFT - 10); /* 2**10 = 1kb */
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#else
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curstatus.rss *= (getpagesize() >> 10); /* 2**10 = 1kb */
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sp->rss *= (getpagesize() >> 10); /* 2**10 = 1kb */
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#endif
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if (save_user_arg0) {
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strcpy(status_tail, "/cmdline");
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n = read_to_buf(status, buf);
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if (n > 0) {
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if (buf[n-1]=='\n')
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buf[--n] = 0;
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name = buf;
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while (n) {
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if (((unsigned char)*name) < ' ')
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*name = ' ';
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name++;
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n--;
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}
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*name = 0;
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if (buf[0])
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curstatus.cmd = strdup(buf);
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/* if NULL it work true also */
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}
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}
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return memcpy(&ret_status, &curstatus, sizeof(procps_status_t));
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if (flags & PSSCAN_CMD) {
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free(sp->cmd);
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sp->cmd = NULL;
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strcpy(filename_tail, "/cmdline");
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n = read_to_buf(filename, buf);
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if (n <= 0)
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break;
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if (buf[n-1] == '\n') {
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if (!--n)
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break;
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buf[n] = '\0';
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}
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do {
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n--;
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if ((unsigned char)(buf[n]) < ' ')
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buf[n] = ' ';
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} while (n);
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sp->cmd = strdup(buf);
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}
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break;
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}
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return sp;
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}
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/* from kernel:
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// pid comm S ppid pgid sid tty_nr tty_pgrp flg
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sprintf(buffer,"%d (%s) %c %d %d %d %d %d %lu %lu \
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%lu %lu %lu %lu %lu %ld %ld %ld %ld %d 0 %llu %lu %ld %lu %lu %lu %lu %lu \
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%lu %lu %lu %lu %lu %lu %lu %lu %d %d %lu %lu %llu\n",
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task->pid,
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tcomm,
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state,
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ppid,
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pgid,
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sid,
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tty_nr,
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tty_pgrp,
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task->flags,
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min_flt,
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cmin_flt,
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maj_flt,
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cmaj_flt,
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cputime_to_clock_t(utime),
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cputime_to_clock_t(stime),
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cputime_to_clock_t(cutime),
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cputime_to_clock_t(cstime),
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priority,
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nice,
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num_threads,
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// 0,
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start_time,
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vsize,
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mm ? get_mm_rss(mm) : 0,
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rsslim,
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mm ? mm->start_code : 0,
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mm ? mm->end_code : 0,
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mm ? mm->start_stack : 0,
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esp,
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eip,
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the rest is some obsolete cruft
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*/
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