Linux find 命令的初步实现（C++）

标签：top   modified   leo   out   std   wildcard   opera   cte   stand   

Implement a myfind command following the find command in UNIX operating system. The myfind command starts from the specified directory and recursively looks up the specified file. The command format is as follows：
myfind PATH -option parameters
PATH：The directory for looking up.
-option parameters：
-name “file”： Specify the name of the file to be found, which can have wildcard characters? *, etc
-mtime n： Search by time, search for files modified n days before today
-ctime n：Search by time for files created n days before today.
Finally, output the search results to standard output.

#include <stdio.h>
#include <string.h>
#include <getopt.h>
#include <dirent.h>
#include <time.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>

int opterr = 0;
char path[1024] = "";
char targetname[100] = "";
int modifiedtime = -1;
int changetime = -1;

char match(char *first, char *second) 
{
    if (*first == '\0' && *second == '\0') 
        return 1; 
    if (*first == '*' && *(first+1) != '\0' && *second == '\0') 
        return 0; 
    if (*first == '?' || *first == *second) 
        return match(first+1, second+1); 
    if (*first == '*') 
        return match(first+1, second) || match(first, second+1); 
    return 0; 
}

char isFileOk(char *name, time_t mt, time_t ct){
    time_t now = time(0);
    int spd = 24*3600;
    int mtd = (now - mt)/spd;
    int ctd = (now - ct)/spd;

    //printf("filename: %s target: %s\n", name, targetname);
    if(match(targetname, name) == 1){
        if(modifiedtime != -1 && mtd > modifiedtime) return 0;
        if(changetime != -1 && ctd > changetime) return 0;
        return 1;
    }
    return 0;
}

void findInDir(char *path) {
    DIR *d;
    struct dirent *dir;
    d = opendir(path);
    if (d) {
        while ((dir = readdir(d)) != NULL) {
            char newpath[1024];
            snprintf(newpath, sizeof(newpath), "%s/%s", path, dir->d_name);
            if (dir->d_type == DT_DIR) {
                if (strcmp(dir->d_name, ".") == 0 || strcmp(dir->d_name, "..") == 0) continue;
                findInDir(newpath);
            } else {
                struct stat buf;
                if(stat(newpath, &buf)==0){
                    if(isFileOk(dir->d_name, buf.st_mtime, buf.st_ctime)){
                        printf("%s/%s\n", path, dir->d_name);
                    }
                }
            }
        }
        closedir(d);
    }
}

int main(int argc, char *argv[]){
    char *optstr = "p:n:m:c:";
    struct option opts[] = {
        {"path", 1, NULL, 'p'},
        {"name", 1, NULL, 'n'},
        {"mtime", 1, NULL, 'm'},
        {"ctime", 1, NULL, 'c'},
        {0, 0, 0, 0},
    };
    int opt;
    while((opt = getopt_long(argc, argv, optstr, opts, NULL)) != -1){
        switch(opt) {
            case 'p':
                strcpy(path, optarg);
                break;
            case 'n':
                strcpy(targetname, optarg);
                break;
            case 'm':
                modifiedtime = atoi(optarg);
                break;
            case 'c':
                changetime = atoi(optarg);
                break;
            case '?':
                if(strchr(optstr, optopt) == NULL){
                    fprintf(stderr, "unknown option '-%c'\n", optopt);
                }else{
                    fprintf(stderr, "option requires an argument '-%c'\n", optopt);
                }
                return 1;
        }
    }
    findInDir(path);
    return 0;
}

Linux find 命令的初步实现（C++）

标签：top   modified   leo   out   std   wildcard   opera   cte   stand   

原文地址：https://www.cnblogs.com/justsong/p/12219780.html