skill.c

linux下获取一些环境信息的代码

/*
 * Copyright 1998-2002 by Albert Cahalan; all rights resered.
 * This file may be used subject to the terms and conditions of the
 * GNU Library General Public License Version 2, or any later version
 * at your option, as published by the Free Software Foundation.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Library General Public License for more details.
 */
#include <fcntl.h>
#include <pwd.h>
#include <dirent.h>
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>
#include "proc/pwcache.h"
#include "proc/sig.h"
#include "proc/devname.h"
#include "proc/procps.h"  /* char *user_from_uid(uid_t uid) */
#include "proc/version.h" /* procps_version */

static int f_flag, i_flag, v_flag, w_flag, n_flag;

static int tty_count, uid_count, cmd_count, pid_count;
static int *ttys;
static uid_t *uids;
static const char **cmds;
static int *pids;

#define ENLIST(thing,addme) do{ \
if(!thing##s) thing##s = malloc(sizeof(*thing##s)*saved_argc); \
if(!thing##s) fprintf(stderr,"No memory.\n"),exit(2); \
thing##s[thing##_count++] = addme; \
}while(0)

static int my_pid;
static int saved_argc;

static int sig_or_pri;

static int program;
#define PROG_GARBAGE 0  /* keep this 0 */
#define PROG_KILL  1
#define PROG_SKILL 2
/* #define PROG_NICE  3 */ /* easy, but the old one isn't broken */
#define PROG_SNICE 4


/********************************************************************/

static void display_kill_version(void){
  switch(program) {
    case PROG_KILL:
      fprintf(stdout, "kill (%s)\n",procps_version);
      return;
    case PROG_SKILL:
      fprintf(stdout, "skill (%s)\n",procps_version);
      return;
    case PROG_SNICE:
      fprintf(stdout, "snice (%s)\n",procps_version);
      return;
    default:
      fprintf(stdout, "unknown (%s)\n",procps_version);
      return;
  }
}

/***** kill or nice a process */
static void hurt_proc(int tty, int uid, int pid, const char *restrict const cmd){
  int failed;
  int saved_errno;
  char dn_buf[1000];
  dev_to_tty(dn_buf, 999, tty, pid, ABBREV_DEV);
  if(i_flag){
    char buf[8];
    fprintf(stderr, "%-8s %-8s %5d %-16.16s   ? ",
      (char*)dn_buf,user_from_uid(uid),pid,cmd
    );
    if(!fgets(buf,7,stdin)){
      printf("\n");
      exit(0);
    }
    if(*buf!='y' && *buf!='Y') return;
  }
  /* do the actual work */
  if(program==PROG_SKILL) failed=kill(pid,sig_or_pri);
  else                    failed=setpriority(PRIO_PROCESS,pid,sig_or_pri);
  saved_errno = errno;
  if(w_flag && failed){
    fprintf(stderr, "%-8s %-8s %5d %-16.16s   ",
      (char*)dn_buf,user_from_uid(uid),pid,cmd
    );
    errno = saved_errno;
    perror("");
    return;
  }
  if(i_flag) return;
  if(v_flag){
    printf("%-8s %-8s %5d %-16.16s\n",
      (char*)dn_buf,user_from_uid(uid),pid,cmd
    );
    return;
  }
  if(n_flag){
   printf("%d\n",pid);
   return;
  }
}


/***** check one process */
static void check_proc(int pid){
  char buf[128];
  struct stat statbuf;
  char *tmp;
  int tty;
  int fd;
  int i;
  if(pid==my_pid) return;
  sprintf(buf, "/proc/%d/stat", pid); /* pid (cmd) state ppid pgrp session tty */
  fd = open(buf,O_RDONLY);
  if(fd==-1){  /* process exited maybe */
    if(pids && w_flag) printf("WARNING: process %d could not be found.",pid);
    return;
  }
  fstat(fd, &statbuf);
  if(uids){  /* check the EUID */
    i=uid_count;
    while(i--) if(uids[i]==statbuf.st_uid) break;
    if(i==-1) goto closure;
  }
  read(fd,buf,128);
  buf[127] = '\0';
  tmp = strrchr(buf, ')');
  *tmp++ = '\0';
  i = 5; while(i--) while(*tmp++!=' '); /* scan to find tty */
  tty = atoi(tmp);
  if(ttys){
    i=tty_count;
    while(i--) if(ttys[i]==tty) break;
    if(i==-1) goto closure;
  }
  tmp = strchr(buf, '(') + 1;
  if(cmds){
    i=cmd_count;
    /* fast comparison trick -- useful? */
    while(i--) if(cmds[i][0]==*tmp && !strcmp(cmds[i],tmp)) break;
    if(i==-1) goto closure;
  }
  /* This is where we kill/nice something. */
/*  fprintf(stderr, "PID %d, UID %d, TTY %d,%d, COMM %s\n",
    pid, statbuf.st_uid, tty>>8, tty&0xf, tmp
  );
*/
  hurt_proc(tty, statbuf.st_uid, pid, tmp);
closure:
  close(fd); /* kill/nice _first_ to avoid PID reuse */
}


/***** debug function */
#if 0
static void show_lists(void){
  int i;

  fprintf(stderr, "%d TTY: ", tty_count);
  if(ttys){
    i=tty_count;
    while(i--){
      fprintf(stderr, "%d,%d%c", (ttys[i]>>8)&0xff, ttys[i]&0xff, i?' ':'\n');
    }
  }else fprintf(stderr, "\n");
  
  fprintf(stderr, "%d UID: ", uid_count);
  if(uids){
    i=uid_count;
    while(i--) fprintf(stderr, "%d%c", uids[i], i?' ':'\n');
  }else fprintf(stderr, "\n");
  
  fprintf(stderr, "%d PID: ", pid_count);
  if(pids){
    i=pid_count;
    while(i--) fprintf(stderr, "%d%c", pids[i], i?' ':'\n');
  }else fprintf(stderr, "\n");
  
  fprintf(stderr, "%d CMD: ", cmd_count);
  if(cmds){
    i=cmd_count;
    while(i--) fprintf(stderr, "%s%c", cmds[i], i?' ':'\n');
  }else fprintf(stderr, "\n");
}
#endif


/***** iterate over all PIDs */
static void iterate(void){
  int pid;
  DIR *d;
  struct dirent *de;
  if(pids){
    pid = pid_count;
    while(pid--) check_proc(pids[pid]);
    return;
  }
#if 0
  /* could setuid() and kill -1 to have the kernel wipe out a user */
  if(!ttys && !cmds && !pids && !i_flag){
  }
#endif
  d = opendir("/proc");
  if(!d){
    perror("/proc");
    exit(1);
  }
  while(( de = readdir(d) )){
    if(de->d_name[0] > '9') continue;
    if(de->d_name[0] < '1') continue;
    pid = atoi(de->d_name);
    if(pid) check_proc(pid);
  }
  closedir (d);
}

/***** kill help */
static void kill_usage(void) NORETURN;
static void kill_usage(void){
  fprintf(stderr,
    "Usage:\n"
    "  kill pid ...              Send SIGTERM to every process listed.\n"
    "  kill signal pid ...       Send a signal to every process listed.\n"
    "  kill -s signal pid ...    Send a signal to every process listed.\n"
    "  kill -l                   List all signal names.\n"
    "  kill -L                   List all signal names in a nice table.\n"
    "  kill -l signal            Convert between signal numbers and names.\n"
  );
  exit(1);
}

/***** kill */
static void kill_main(int argc, const char *restrict const *restrict argv) NORETURN;
static void kill_main(int argc, const char *restrict const *restrict argv){
  const char *sigptr;
  int signo = SIGTERM;
  int exitvalue = 0;
  if(argc<2) kill_usage();
  if(!strcmp(argv[1],"-V")|| !strcmp(argv[1],"--version")){
    display_kill_version();
    exit(0);
  }
  if(argv[1][0]!='-'){
    argv++;
    argc--;
    goto no_more_args;
  }

  /* The -l option prints out signal names. */
  if(argv[1][1]=='l' && argv[1][2]=='\0'){
    if(argc==2){
      unix_print_signals();
      exit(0);
    }
    /* at this point, argc must be 3 or more */
    if(argc>128 || argv[2][0] == '-') kill_usage();
    exit(print_given_signals(argc-2, argv+2, 80));
  }

  /* The -L option prints out signal names in a nice table. */
  if(argv[1][1]=='L' && argv[1][2]=='\0'){
    if(argc==2){
      pretty_print_signals();
      exit(0);
    }
    kill_usage();
  }
  if(argv[1][1]=='-' && argv[1][2]=='\0'){
    argv+=2;
    argc-=2;
    goto no_more_args;
  }
  if(argv[1][1]=='-') kill_usage(); /* likely --help */
  // FIXME: "kill -sWINCH $$" not handled