c - 目录中文件的链接列表，最后附加

Question

我正在尝试刷我的链表概念。作为一个例子，我试图创建一个包含目录文件的链接列表，按序列顺序。

struct node *head = NULL;
    struct node *prev = head;

    DIR *d;
    struct dirent *dir;
    d = opendir("/var/amit12/test1/");
    if(d) {
        while ((dir = readdir(d)) != NULL) {
            if(dir->d_type == DT_REG) {
                struct node *last = (struct node*) malloc(sizeof(struct node));
                char full_path[18 + strlen(dir->d_name)];
                strcpy(full_path, "/var/amit12/test1/");
                strcat(full_path, dir->d_name);
                last->song_id = open(full_path, O_RDONLY);
                last->name = full_path;
                last->next = NULL;
                if(head == NULL) {
                    head = last;
                    prev = last;
                } else {
                    prev->next = last;
                    prev = last;
                }
                //prev.next = &last;
                //prev = last;
                printf("%s\n", dir->d_name);
            }
        }
        closedir(d);
    }

printf("printing\n");

    struct node *root = head;

    while(root != NULL) {
        printf("%s\n", root->name);
        root = root->next;
    }

这似乎总是以段错误结束。

Answer 1

正如 WhozCraigh 所说，每次 fullpath 时都必须 malloc，否则每次迭代都会被销毁。

这将完成这项工作:

struct node *head = NULL;
struct node *prev = head;
char *full_path = NULL;

DIR *d;
struct dirent *dir;
d = opendir("/var/amit12/test1/");
if(d) {
    while ((dir = readdir(d)) != NULL) {
        if(dir->d_type == DT_REG) {
            struct node *last = (struct node*) malloc(sizeof(struct node));
            full_path = strnew(strlen("/var/amit12/test1/") + strlen(dir->d_name);
            strcpy(full_path, "/var/amit12/test1/");
            strcat(full_path, dir->d_name);
            last->song_id = open(full_path, O_RDONLY);
            last->name = full_path;
            last->next = NULL;
            if(head == NULL) {
                head = last;
                prev = last;
            } else {
                prev->next = last;
                prev = last;
            }
            //prev.next = &last;
            //prev = last;
            printf("%s\n", dir->d_name);
        }
    }
    closedir(d);
}

printf("printing\n");

struct node *root = head;

while(root != NULL) {
    printf("%s\n", root->name);
    root = root->next;
}