minimal.c

linux下获取一些环境信息的代码

    P_start_time = p.pr_start.tv_sec;
    P_wchan   = p.pr_lwp.pr_wchan;
    P_state   = p.pr_lwp.pr_sname;
    P_nice    = p.pr_lwp.pr_nice;
    P_priority = p.pr_lwp.pr_pri;  // or pr_oldpri
//    P_ruid    = p.pr_uid;
//    P_rgid    = p.pr_gid;
//    P_egid    = p.pr_egid;

#if 0
    // don't support these
    P_tpgid; P_flags,
    P_min_flt, P_cmin_flt, P_maj_flt, P_cmaj_flt, P_utime, P_stime;
    P_cutime, P_cstime, P_timeout, P_alarm;
    P_rss_rlim, P_start_code, P_end_code, P_start_stack, P_kstk_esp, P_kstk_eip;
    P_signal, P_blocked, P_sigignore, P_sigcatch;
    P_nswap, P_cnswap;
#endif

    // we like it Linux-encoded :-)
    tty_maj = major(p.pr_ttydev);
    tty_min = minor(p.pr_ttydev);
    P_tty_num = DEV_ENCODE(tty_maj,tty_min);

    snprintf(P_tty_text, sizeof P_tty_text, "%3d,%-3d", tty_maj, tty_min);
#if 1
    if (tty_maj == 24) snprintf(P_tty_text, sizeof P_tty_text, "pts/%-3u", tty_min);
    if (P_tty_num == NO_TTY_VALUE)    memcpy(P_tty_text, "   ?   ", 8);
    if (P_tty_num == DEV_ENCODE(0,0)) memcpy(P_tty_text, "console", 8);
#endif

    if(P_pid != pid) return 0;
    return 1;
}
#endif

#ifdef __FreeBSD__
/* return 1 if it works, or 0 for failure */
static int stat2proc(int pid) {
    char buf[400];
    int num;
    int fd;
    char* tmp;
    int tty_maj, tty_min;
    snprintf(buf, 32, "/proc/%d/status", pid);
    if ( (fd = open(buf, O_RDONLY, 0) ) == -1 ) return 0;
    num = read(fd, buf, sizeof buf - 1);
    close(fd);
    if(num<43) return 0;
    buf[num] = '\0';

    P_state = '-';

    // FreeBSD /proc/*/status is seriously fucked. Unlike the Linux
    // files, we can't use strrchr to find the end of a command name.
    // Spaces in command names do not get escaped. To avoid spoofing,
    // one may skip 20 characters and then look _forward_ only to
    // find a pattern of entries that are {with,with,without} a comma.
    // The entry without a comma is wchan. Then count backwards!
    //
    // Don't bother for now. FreeBSD isn't worth the trouble.

    tmp = strchr(buf,' ');
    num = tmp - buf;
    if (num >= sizeof P_cmd) num = sizeof P_cmd - 1;
    memcpy(P_cmd,buf,num);
    P_cmd[num] = '\0';

    num = sscanf(tmp+1,
       "%d %d %d %d "
       "%d,%d "
       "%*s "
       "%ld,%*d "
       "%ld,%*d "
       "%ld,%*d "
       "%*s "
       "%d %d ",
       &P_pid, &P_ppid, &P_pgrp, &P_session,
       &tty_maj, &tty_min,
       /* SKIP funny flags thing */
       &P_start_time, /* SKIP microseconds */
       &P_utime, /* SKIP microseconds */
       &P_stime, /* SKIP microseconds */
       /* SKIP &P_wchan, for now -- it is a string */
       &P_euid, &P_euid   // don't know which is which
    );
/*    fprintf(stderr, "stat2proc converted %d fields.\n",num); */

    snprintf(P_tty_text, sizeof P_tty_text, "%3d,%-3d", tty_maj, tty_min);
    P_tty_num = DEV_ENCODE(tty_maj,tty_min);
// tty decode is 224 to 256 bytes on i386
#if 1
    tmp = NULL;
    if (tty_maj ==  5) tmp = " ttyp%c ";
    if (tty_maj == 12) tmp = " ttyv%c ";
    if (tty_maj == 28) tmp = " ttyd%c ";
    if (P_tty_num == NO_TTY_VALUE) tmp = "   ?   ";
    if (P_tty_num == DEV_ENCODE(0,0)) tmp = "console";
    if (P_tty_num == DEV_ENCODE(12,255)) tmp = "consolectl";
    if (tmp) {
      snprintf(
        P_tty_text,
        sizeof P_tty_text,
        tmp,
        "0123456789abcdefghijklmnopqrstuvwxyz"[tty_min&31]
      );
    }
#endif

    if(num < 9) return 0;
    if(P_pid != pid) return 0;
    return 1;
}
#endif

#ifdef __linux__
/* return 1 if it works, or 0 for failure */
static int stat2proc(int pid) {
    char buf[800]; /* about 40 fields, 64-bit decimal is about 20 chars */
    int num;
    int fd;
    char* tmp;
    struct stat sb; /* stat() used to get EUID */
    snprintf(buf, 32, "/proc/%d/stat", pid);
    if ( (fd = open(buf, O_RDONLY, 0) ) == -1 ) return 0;
    num = read(fd, buf, sizeof buf - 1);
    fstat(fd, &sb);
    P_euid = sb.st_uid;
    close(fd);
    if(num<80) return 0;
    buf[num] = '\0';
    tmp = strrchr(buf, ')');      /* split into "PID (cmd" and "<rest>" */
    *tmp = '\0';                  /* replace trailing ')' with NUL */
    /* parse these two strings separately, skipping the leading "(". */
    memset(P_cmd, 0, sizeof P_cmd);          /* clear */
    sscanf(buf, "%d (%15c", &P_pid, P_cmd);  /* comm[16] in kernel */
    num = sscanf(tmp + 2,                    /* skip space after ')' too */
       "%c "
       "%d %d %d %d %d "
       "%lu %lu %lu %lu %lu %lu %lu "
       "%ld %ld %ld %ld %ld %ld "
       "%lu %lu "
       "%ld "
       "%lu %lu %lu %lu %lu %lu "
       "%u %u %u %u " /* no use for RT signals */
       "%lu %lu %lu",
       &P_state,
       &P_ppid, &P_pgrp, &P_session, &P_tty_num, &P_tpgid,
       &P_flags, &P_min_flt, &P_cmin_flt, &P_maj_flt, &P_cmaj_flt, &P_utime, &P_stime,
       &P_cutime, &P_cstime, &P_priority, &P_nice, &P_timeout, &P_alarm,
       &P_start_time, &P_vsize,
       &P_rss,
       &P_rss_rlim, &P_start_code, &P_end_code, &P_start_stack, &P_kstk_esp, &P_kstk_eip,
       &P_signal, &P_blocked, &P_sigignore, &P_sigcatch,
       &P_wchan, &P_nswap, &P_cnswap
    );
/*    fprintf(stderr, "stat2proc converted %d fields.\n",num); */
    P_vsize /= 1024;
    P_rss *= (PAGE_SIZE/1024);

    memcpy(P_tty_text, "   ?   ", 8);
    if (P_tty_num != NO_TTY_VALUE) {
      int tty_maj = (P_tty_num>>8)&0xfff;
      int tty_min = (P_tty_num&0xff) | ((P_tty_num>>12)&0xfff00);
      snprintf(P_tty_text, sizeof P_tty_text, "%3d,%-3d", tty_maj, tty_min);
    }

    if(num < 30) return 0;
    if(P_pid != pid) return 0;
    return 1;
}
#endif

static const char *do_time(unsigned long t){
  int hh,mm,ss;
  static char buf[32];
  int cnt = 0;
  t /= HZ;
  ss = t%60;
  t /= 60;
  mm = t%60;
  t /= 60;
  hh = t%24;
  t /= 24;
  if(t) cnt = snprintf(buf, sizeof buf, "%d-", (int)t);
  snprintf(cnt + buf, sizeof(buf)-cnt, "%02d:%02d:%02d", hh, mm, ss);
  return buf;
}

static const char *do_user(void){
  static char buf[32];
  static struct passwd *p;
  static int lastuid = -1;
  if(P_euid != lastuid){
    p = getpwuid(P_euid);
    if(p) snprintf(buf, sizeof buf, "%-8.8s", p->pw_name);
    else  snprintf(buf, sizeof buf, "%5d   ", P_euid);
  }
  return buf;
}

static const char *do_cpu(int longform){
  static char buf[8];
  strcpy(buf," -  ");
  if(!longform) buf[2] = '\0';
  return buf;
}

static const char *do_mem(int longform){
  static char buf[8];
  strcpy(buf," -  ");
  if(!longform) buf[2] = '\0';
  return buf;
}

static const char *do_stime(void){
  static char buf[32];
  strcpy(buf,"  -  ");
  return buf;
}

static void print_proc(void){
  switch(ps_format){
  case 0:
    printf("%5d %s %s", P_pid, P_tty_text, do_time(P_utime+P_stime));
    break;
  case 'o':
    printf("%d\n", P_pid);
    return; /* don't want the command */
  case 'l':
    printf(
      "0 %c %5d %5d %5d %s %3d %3d - "
      "%5ld %06x %s %s",
      P_state, P_euid, P_pid, P_ppid, do_cpu(0),
      (int)P_priority, (int)P_nice, P_vsize/(PAGE_SIZE/1024),
      (unsigned)(P_wchan&0xffffff), P_tty_text, do_time(P_utime+P_stime)
    );
    break;
  case 'f':
    printf(
      "%8s %5d %5d %s %s %s %s",
      do_user(), P_pid, P_ppid, do_cpu(0), do_stime(), P_tty_text, do_time(P_utime+P_stime)
    );
    break;
  case 'j':
    printf(
      "%5d %5d %5d %s %s",
      P_pid, P_pgrp, P_session, P_tty_text, do_time(P_utime+P_stime)
    );
    break;
  case 'u'|0x80:
    printf(
      "%8s %5d %s %s %5ld %4ld %s %c %s %s",
      do_user(), P_pid, do_cpu(1), do_mem(1), P_vsize, P_rss, P_tty_text, P_state,
      do_stime(), do_time(P_utime+P_stime)
    );
    break;
  case 'v'|0x80:
    printf(
      "%5d %s %c %s %6d   -   - %5d %s",
      P_pid, P_tty_text, P_state, do_time(P_utime+P_stime), (int)P_maj_flt,
      (int)P_rss, do_mem(1)
    );
    break;
  case 'j'|0x80:
    printf(
      "%5d %5d %5d %5d %s %5d %c %5d %s",
      P_ppid, P_pid, P_pgrp, P_session, P_tty_text, P_tpgid, P_state, P_euid, do_time(P_utime+P_stime)
    );
    break;
  case 'l'|0x80:
    printf(
      "0 %5d %5d %5d %3d %3d "
      "%5ld %4ld %06x %c %s %s",
      P_euid, P_pid, P_ppid, (int)P_priority, (int)P_nice,
      P_vsize, P_rss, (unsigned)(P_wchan&0xffffff), P_state, P_tty_text, do_time(P_utime+P_stime)
    );
    break;
  default:
    ;
  }
  if(show_args) printf(" [%s]\n", P_cmd);
  else          printf(" %s\n", P_cmd);
}


int main(int argc, char *argv[]){
  arg_parse(argc, argv);
#if 0
  choose_dimensions();
#endif
  if(!old_h_option){
    const char *head;
    switch(ps_format){
    default: /* can't happen */
    case 0:        head = "  PID TTY         TIME CMD"; break;
    case 'l':      head = "F S   UID   PID  PPID  C PRI  NI ADDR SZ WCHAN    TTY       TIME CMD"; break;
    case 'f':      head = "USER       PID  PPID  C STIME   TTY       TIME CMD"; break;
    case 'j':      head = "  PID  PGID   SID TTY         TIME CMD"; break;
    case 'u'|0x80: head = "USER       PID %CPU %MEM   VSZ  RSS   TTY   S START     TIME COMMAND"; break;
    case 'v'|0x80: head = "  PID   TTY   S     TIME  MAJFL TRS DRS   RSS %MEM COMMAND"; break;
    case 'j'|0x80: head = " PPID   PID  PGID   SID   TTY   TPGID S   UID     TIME COMMAND"; break;
    case 'l'|0x80: head = "F   UID   PID  PPID PRI  NI   VSZ  RSS WCHAN  S   TTY       TIME COMMAND"; break;
    }
    printf("%s\n",head);
  }
  if(want_one_pid){
    if(stat2proc(want_one_pid)) print_proc();
    else exit(1);
  }else{
    struct dirent *ent;          /* dirent handle */
    DIR *dir;
    int ouruid;
    int found_a_proc;
    found_a_proc = 0;
    ouruid = getuid();
    dir = opendir("/proc");
    while(( ent = readdir(dir) )){
      if(*ent->d_name<'0' || *ent->d_name>'9') continue;
      if(!stat2proc(atoi(ent->d_name))) continue;
      if(want_one_command){
        if(strcmp(want_one_command,P_cmd)) continue;
      }else{
        if(!select_notty && P_tty_num==NO_TTY_VALUE) continue;
        if(!select_all && P_euid!=ouruid) continue;
      }
      found_a_proc++;
      print_proc();
    }
    closedir(dir);
    exit(!found_a_proc);
  }
  return 0;
}