#! /bin/sh 
# supervisor process  
 
LOG_FILE=/var/log/supervisor_sh.log 
 
# log function  
function log() { 
  local t=$(date +"%F %X") 
  echo "[ $t ] $0 : $1 " >> ${LOG_FILE} 
} 
 
# check process number  
# $1 : process name  
function check_process() { 
  if [ -z $1 ]; then 
    log "Input parameter is empty." 
    return 0    
  fi 
   
  p_num=$(ps -e | grep "$1" | grep -v "grep" | wc -l) 
  log "p_num = $p_num"  
  echo $p_num 
} 
 
# supervisor process  
while [ 1 ] 
do  
  declare -i ch_num 
  p_name="apache2" 
  ch_num=$(check_process $p_name) 
  if [ $ch_num -eq 0 ]; then 
    killall $p_name 
    service $p_name start  
  fi 
  sleep 3  
done 

/** 
 * 
 * supervisor 
 * 
 * date: 2016-08-10 
 * 
 */ 
 
#include <stdio.h> 
#include <unistd.h> 
#include <errno.h> 
#include <string.h> 
#include <sys/types.h> 
#include <sys/wait.h> 
#include <stdlib.h> 
#include <time.h> 
 
#define LOG_FILE "/var/log/supervisor.log" 
 
void s_log(char *text) { 
  time_t   t; 
  struct tm *tm; 
  char *log_file; 
  FILE *fp_log; 
  char date[128]; 
   
  log_file = LOG_FILE; 
  fp_log = fopen(log_file, "a+"); 
  if (NULL == fp_log) { 
    fprintf(stderr, "Could not open logfile '%s' for writing\n", log_file); 
  } 
   
  time(&t); 
  tm = localtime(&t); 
  strftime(date, 127, "%Y-%m-%d %H:%M:%S", tm); 
   
  /* write the message to stdout and/or logfile */   
  fprintf(fp_log, "[%s] %s\n", date, text); 
  fflush(fp_log); 
  fclose(fp_log); 
}  
 
int main(int argc, char **argv) { 
  int ret, i, status; 
  char *child_argv[100] = {0}; 
  pid_t pid; 
  if (argc < 2) { 
    fprintf(stderr, "Usage:%s <exe_path> <args...>", argv[0]); 
    return -1; 
  } 
   
  for (i = 1; i < argc; ++i) { 
    child_argv[i-1] = (char *)malloc(strlen(argv[i])+1); 
    strncpy(child_argv[i-1], argv[i], strlen(argv[i])); 
    //child_argv[i-1][strlen(argv[i])] = '0'; 
  } 
   
  while(1) { 
    pid = fork();  
    if (pid == -1) { 
      fprintf(stderr, "fork() error.errno:%d error:%s", errno, strerror(errno)); 
      break; 
    } 
    if (pid == 0) { 
      s_log(child_argv[0]); 
      ret = execv(child_argv[0], (char **)child_argv); 
      s_log("execv return"); 
      if (ret < 0) { 
        fprintf(stderr, "execv ret:%d errno:%d error:%s", ret, errno, strerror(errno)); 
        continue; 
      } 
      s_log("exit child process"); 
      exit(0); 
    } 
    if (pid > 0) { 
      pid = wait(&status); 
      fprintf(stdout, "Child process id: %d\n", pid); 
      //fprintf(stdout, "wait return"); 
      s_log("Wait child process return"); 
    } 
  } 
   
  return 0; 
} 

/* 
* 
* demo  
* 
*/ 
#include <stdio.h> 
#include <unistd.h> 
#include <errno.h> 
#include <string.h> 
#include <sys/types.h> 
#include <sys/wait.h> 
#include <stdlib.h> 
#include <time.h> 
 
#define LOG_FILE "/var/log/demo.log" 
 
void demo_log(int num) { 
  time_t   t; 
  struct tm *tm; 
  char *log_file; 
  FILE *fp_log; 
  char date[128]; 
   
  log_file = LOG_FILE; 
  fp_log = fopen(log_file, "a+"); 
  if (NULL == fp_log) { 
    fprintf(stderr, "Could not open logfile '%s' for writing\n", log_file); 
  } 
   
  time(&t); 
  tm = localtime(&t); 
  strftime(date,127,"%Y-%m-%d %H:%M:%S",tm); 
   
  /* write the message to stdout and/or logfile */   
  fprintf(fp_log, "[%s] num = %d\n", date, num); 
  fflush(fp_log); 
  fclose(fp_log); 
}  
 
int main(int argc, char **argv[]) { 
  int num = 0; 
   
  while(1) { 
    sleep(10); 
    num++; 
    demo_log(num); 
  } 
}