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FUSE 文件系统在打开文件时崩溃（仅在发布模式下）

发布于 2024-10-29 04:47:47 字数 6190 浏览 4 评论 0原文

我有一些问题，我找不到解决方案：/我需要在我的保险丝文件系统中打开一个文本文件。在调试中一切正常，但在发布系统中崩溃。我用这个做了一个简单的例子。有人能说出这段代码有什么问题吗？

/*
  FUSE: Filesystem in Userspace
  Copyright (C) 2001-2007  Miklos Szeredi <[email protected]>

  This program can be distributed under the terms of the GNU GPL.
  See the file COPYING.

  gcc -Wall `pkg-config fuse --cflags --libs` hello.c -o hello
*/
#    define FUSE_USE_VERSION 26

#include  <fuse.h>
#include  <stdio.h>
#include  <string.h>
#include  <errno.h>
#include  <fcntl.h>

void stripnl(char *str) {
  while(strlen(str) && ( (str[strlen(str) - 1] == 13) || 
       ( str[strlen(str) - 1] == 10 ))) {
    str[strlen(str) - 1] = 0;
  }
}

static const char *hello_str = "Hello World!\n";
static const char *hello_path = "/hello";

static int hello_getattr(const char *path, struct stat *stbuf)
{
    int res = 0;
    memset(stbuf, 0, sizeof(struct stat));
    if (strcmp(path, "/") == 0) {
        stbuf->st_mode = S_IFDIR | 0755;
        stbuf->st_nlink = 2;
    } else if (strcmp(path, hello_path) == 0) {
        stbuf->st_mode = S_IFREG | 0444;
        stbuf->st_nlink = 1;
        stbuf->st_size = strlen(hello_str);
    } else
        res = -ENOENT;

    return res;
}

static int hello_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
             off_t offset, struct fuse_file_info *fi)
{
    (void) offset;
    (void) fi;

    if (strcmp(path, "/") != 0)
        return -ENOENT;

    filler(buf, ".", NULL, 0);
    filler(buf, "..", NULL, 0);

    filler(buf, hello_path + 1, NULL, 0);

  FILE *infile;
  char fname[40];
  char line[100];
  int lcount;

      /* We need to get rid of the newline char. */
  stripnl(fname);

  /* Open the file.  If NULL is returned there was an error */
  if((infile = fopen("ex.txt", "r")) == NULL) {
    printf("Error Opening File.\n");
  }

  while( fgets(line, sizeof(line), infile) != NULL ) {
    /* Get each line from the infile */
    lcount++;
    /* print the line number and data */
    printf("Line %d: %s", lcount, line);  
    filler(buf, line, NULL, 0);
  }

  fclose(infile);  /* Close the file */

    return 0;
}

static int hello_open(const char *path, struct fuse_file_info *fi)
{
    if (strcmp(path, hello_path) != 0)
        return -ENOENT;

    if ((fi->flags & 3) != O_RDONLY)
        return -EACCES;

    return 0;
}

static int hello_read(const char *path, char *buf, size_t size, off_t offset,
              struct fuse_file_info *fi)
{
    size_t len;
    (void) fi;
    if(strcmp(path, hello_path) != 0)
        return -ENOENT;

    len = strlen(hello_str);
    if (offset < len) {
        if (offset + size > len)
            size = len - offset;
        memcpy(buf, hello_str + offset, size);
    } else
        size = 0;

    return size;
}

static struct fuse_operations hello_oper = {
    .getattr    = hello_getattr,
    .readdir    = hello_readdir,
    .open       = hello_open,
    .read       = hello_read,
};

int main(int argc, char *argv[])
{
    return fuse_main(argc, argv, &hello_oper, NULL);
}

更新

好的，我找到了解决方案，路径必须是绝对文件路径（不确定这是否是正确的句子），但这里是示例代码，它在发布和调试中都有效：

/*
  FUSE: Filesystem in Userspace
  Copyright (C) 2001-2007  Miklos Szeredi <[email protected]>

  This program can be distributed under the terms of the GNU GPL.
  See the file COPYING.

  gcc -Wall `pkg-config fuse --cflags --libs` hello.c -o hello
*/
#    define FUSE_USE_VERSION 26

#include  <fuse.h>
#include  <stdio.h>
#include  <string.h>
#include  <errno.h>
#include  <fcntl.h>

void stripnl(char *str) {
  while(strlen(str) && ( (str[strlen(str) - 1] == 13) || 
       ( str[strlen(str) - 1] == 10 ))) {
    str[strlen(str) - 1] = 0;
  }
}

static const char *hello_str = "Hello World!\n";
static const char *hello_path = "/hello";

static int hello_getattr(const char *path, struct stat *stbuf)
{
    int res = 0;
    memset(stbuf, 0, sizeof(struct stat));
    if (strcmp(path, "/") == 0) {
        stbuf->st_mode = S_IFDIR | 0755;
        stbuf->st_nlink = 2;
    } else if (strcmp(path, hello_path) == 0) {
        stbuf->st_mode = S_IFREG | 0444;
        stbuf->st_nlink = 1;
        stbuf->st_size = strlen(hello_str);
    } else
        res = -ENOENT;

    return res;
}

static int hello_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
             off_t offset, struct fuse_file_info *fi)
{
    (void) offset;
    (void) fi;

    if (strcmp(path, "/") != 0)
        return -ENOENT;

    filler(buf, ".", NULL, 0);
    filler(buf, "..", NULL, 0);

    filler(buf, hello_path + 1, NULL, 0);

    FILE *infile;
    char line[100];

    if((infile = fopen("/root/Desktop/fexamples/ex.txt", "rb")) == NULL) 
    {
        return -1;
    }

    while( fgets(line, sizeof(line), infile) != NULL ) 
    {
            filler(buf, line, NULL, 0);
    }

    fclose(infile);  /* Close the file */

    return 0;
}

static int hello_open(const char *path, struct fuse_file_info *fi)
{
    if (strcmp(path, hello_path) != 0)
        return -ENOENT;

    if ((fi->flags & 3) != O_RDONLY)
        return -EACCES;

    return 0;
}

static int hello_read(const char *path, char *buf, size_t size, off_t offset,
              struct fuse_file_info *fi)
{
    size_t len;
    (void) fi;
    if(strcmp(path, hello_path) != 0)
        return -ENOENT;

    len = strlen(hello_str);
    if (offset < len) {
        if (offset + size > len)
            size = len - offset;
        memcpy(buf, hello_str + offset, size);
    } else
        size = 0;

    return size;
}

static struct fuse_operations hello_oper = {
    .getattr    = hello_getattr,
    .readdir    = hello_readdir,
    .open       = hello_open,
    .read       = hello_read,
};

int main(int argc, char *argv[])
{
    return fuse_main(argc, argv, &hello_oper, NULL);
}
原文

I have some problem, and i can't find solution of this :/ I need to open a text file inside my fuse filesystem. In debug everything works fine, but in release system is crashing. I made a simples example, with this. Could anybody tell what's wrong in this code?

/*
  FUSE: Filesystem in Userspace
  Copyright (C) 2001-2007  Miklos Szeredi <[email protected]>

  This program can be distributed under the terms of the GNU GPL.
  See the file COPYING.

  gcc -Wall `pkg-config fuse --cflags --libs` hello.c -o hello
*/
#    define FUSE_USE_VERSION 26

#include  <fuse.h>
#include  <stdio.h>
#include  <string.h>
#include  <errno.h>
#include  <fcntl.h>

void stripnl(char *str) {
  while(strlen(str) && ( (str[strlen(str) - 1] == 13) || 
       ( str[strlen(str) - 1] == 10 ))) {
    str[strlen(str) - 1] = 0;
  }
}

static const char *hello_str = "Hello World!\n";
static const char *hello_path = "/hello";

static int hello_getattr(const char *path, struct stat *stbuf)
{
    int res = 0;
    memset(stbuf, 0, sizeof(struct stat));
    if (strcmp(path, "/") == 0) {
        stbuf->st_mode = S_IFDIR | 0755;
        stbuf->st_nlink = 2;
    } else if (strcmp(path, hello_path) == 0) {
        stbuf->st_mode = S_IFREG | 0444;
        stbuf->st_nlink = 1;
        stbuf->st_size = strlen(hello_str);
    } else
        res = -ENOENT;

    return res;
}

static int hello_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
             off_t offset, struct fuse_file_info *fi)
{
    (void) offset;
    (void) fi;

    if (strcmp(path, "/") != 0)
        return -ENOENT;

    filler(buf, ".", NULL, 0);
    filler(buf, "..", NULL, 0);

    filler(buf, hello_path + 1, NULL, 0);

  FILE *infile;
  char fname[40];
  char line[100];
  int lcount;

      /* We need to get rid of the newline char. */
  stripnl(fname);

  /* Open the file.  If NULL is returned there was an error */
  if((infile = fopen("ex.txt", "r")) == NULL) {
    printf("Error Opening File.\n");
  }

  while( fgets(line, sizeof(line), infile) != NULL ) {
    /* Get each line from the infile */
    lcount++;
    /* print the line number and data */
    printf("Line %d: %s", lcount, line);  
    filler(buf, line, NULL, 0);
  }

  fclose(infile);  /* Close the file */

    return 0;
}

static int hello_open(const char *path, struct fuse_file_info *fi)
{
    if (strcmp(path, hello_path) != 0)
        return -ENOENT;

    if ((fi->flags & 3) != O_RDONLY)
        return -EACCES;

    return 0;
}

static int hello_read(const char *path, char *buf, size_t size, off_t offset,
              struct fuse_file_info *fi)
{
    size_t len;
    (void) fi;
    if(strcmp(path, hello_path) != 0)
        return -ENOENT;

    len = strlen(hello_str);
    if (offset < len) {
        if (offset + size > len)
            size = len - offset;
        memcpy(buf, hello_str + offset, size);
    } else
        size = 0;

    return size;
}

static struct fuse_operations hello_oper = {
    .getattr    = hello_getattr,
    .readdir    = hello_readdir,
    .open       = hello_open,
    .read       = hello_read,
};

int main(int argc, char *argv[])
{
    return fuse_main(argc, argv, &hello_oper, NULL);
}

Update

Ok, i've found solution, path must be absolute file path (not sure is this is proper sentence), but here is example code, which is working in release as well as in debug:

/*
  FUSE: Filesystem in Userspace
  Copyright (C) 2001-2007  Miklos Szeredi <[email protected]>

  This program can be distributed under the terms of the GNU GPL.
  See the file COPYING.

  gcc -Wall `pkg-config fuse --cflags --libs` hello.c -o hello
*/
#    define FUSE_USE_VERSION 26

#include  <fuse.h>
#include  <stdio.h>
#include  <string.h>
#include  <errno.h>
#include  <fcntl.h>

void stripnl(char *str) {
  while(strlen(str) && ( (str[strlen(str) - 1] == 13) || 
       ( str[strlen(str) - 1] == 10 ))) {
    str[strlen(str) - 1] = 0;
  }
}

static const char *hello_str = "Hello World!\n";
static const char *hello_path = "/hello";

static int hello_getattr(const char *path, struct stat *stbuf)
{
    int res = 0;
    memset(stbuf, 0, sizeof(struct stat));
    if (strcmp(path, "/") == 0) {
        stbuf->st_mode = S_IFDIR | 0755;
        stbuf->st_nlink = 2;
    } else if (strcmp(path, hello_path) == 0) {
        stbuf->st_mode = S_IFREG | 0444;
        stbuf->st_nlink = 1;
        stbuf->st_size = strlen(hello_str);
    } else
        res = -ENOENT;

    return res;
}

static int hello_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
             off_t offset, struct fuse_file_info *fi)
{
    (void) offset;
    (void) fi;

    if (strcmp(path, "/") != 0)
        return -ENOENT;

    filler(buf, ".", NULL, 0);
    filler(buf, "..", NULL, 0);

    filler(buf, hello_path + 1, NULL, 0);

    FILE *infile;
    char line[100];

    if((infile = fopen("/root/Desktop/fexamples/ex.txt", "rb")) == NULL) 
    {
        return -1;
    }

    while( fgets(line, sizeof(line), infile) != NULL ) 
    {
            filler(buf, line, NULL, 0);
    }

    fclose(infile);  /* Close the file */

    return 0;
}

static int hello_open(const char *path, struct fuse_file_info *fi)
{
    if (strcmp(path, hello_path) != 0)
        return -ENOENT;

    if ((fi->flags & 3) != O_RDONLY)
        return -EACCES;

    return 0;
}

static int hello_read(const char *path, char *buf, size_t size, off_t offset,
              struct fuse_file_info *fi)
{
    size_t len;
    (void) fi;
    if(strcmp(path, hello_path) != 0)
        return -ENOENT;

    len = strlen(hello_str);
    if (offset < len) {
        if (offset + size > len)
            size = len - offset;
        memcpy(buf, hello_str + offset, size);
    } else
        size = 0;

    return size;
}

static struct fuse_operations hello_oper = {
    .getattr    = hello_getattr,
    .readdir    = hello_readdir,
    .open       = hello_open,
    .read       = hello_read,
};

int main(int argc, char *argv[])
{
    return fuse_main(argc, argv, &hello_oper, NULL);
}

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评论（2）

烛影斜 2024-11-05 04:47:47

readdir 实现中至少存在两个问题。

char fname[40];
char line[100];
int lcount;

/* We need to get rid of the newline char. */
stripnl(fname);

您正在对未在任何地方初始化的 fname 内容进行操作。这几乎可以做任何事情。此后您没有使用 fname 的事实是无关紧要的，您可以使用该 stripnl 调用来修改完全随机的数据。

/* Open the file.  If NULL is returned there was an error */
if((infile = fopen("ex.txt", "r")) == NULL) {
    printf("Error Opening File.\n");
}

如果 fopen 失败，您应该错误地输出（或直接离开）此函数。否则，下一行将调用 fgets 并将 NULL 作为其文件参数。

There are at least two issues in your readdir implementation.

char fname[40];
char line[100];
int lcount;

/* We need to get rid of the newline char. */
stripnl(fname);

You're acting on the contents of fname that you're not initializing anywhere. This could do just about anything. The fact that you're not using fname after that is irrelevant, you could be modifying completely random data with that stripnl call.

/* Open the file.  If NULL is returned there was an error */
if((infile = fopen("ex.txt", "r")) == NULL) {
    printf("Error Opening File.\n");
}

If fopen fails, you should error out (or just leave) this function. Otherwise the next line will call fgets with NULL as its file argument.

回复 原文
我不咬妳我踢妳 2024-11-05 04:47:47

好的，我找到了解决方案，路径必须是绝对文件路径（不确定这是否是正确的句子），但这里是示例代码，它在发布和调试中都有效：

/*
  FUSE: Filesystem in Userspace
  Copyright (C) 2001-2007  Miklos Szeredi <[email protected]>

  This program can be distributed under the terms of the GNU GPL.
  See the file COPYING.

  gcc -Wall `pkg-config fuse --cflags --libs` hello.c -o hello
*/
#    define FUSE_USE_VERSION 26

#include  <fuse.h>
#include  <stdio.h>
#include  <string.h>
#include  <errno.h>
#include  <fcntl.h>

void stripnl(char *str) {
  while(strlen(str) && ( (str[strlen(str) - 1] == 13) || 
       ( str[strlen(str) - 1] == 10 ))) {
    str[strlen(str) - 1] = 0;
  }
}

static const char *hello_str = "Hello World!\n";
static const char *hello_path = "/hello";

static int hello_getattr(const char *path, struct stat *stbuf)
{
    int res = 0;
    memset(stbuf, 0, sizeof(struct stat));
    if (strcmp(path, "/") == 0) {
        stbuf->st_mode = S_IFDIR | 0755;
        stbuf->st_nlink = 2;
    } else if (strcmp(path, hello_path) == 0) {
        stbuf->st_mode = S_IFREG | 0444;
        stbuf->st_nlink = 1;
        stbuf->st_size = strlen(hello_str);
    } else
        res = -ENOENT;

    return res;
}

static int hello_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
             off_t offset, struct fuse_file_info *fi)
{
    (void) offset;
    (void) fi;

    if (strcmp(path, "/") != 0)
        return -ENOENT;

    filler(buf, ".", NULL, 0);
    filler(buf, "..", NULL, 0);

    filler(buf, hello_path + 1, NULL, 0);

    FILE *infile;
    char line[100];

    if((infile = fopen("/root/Desktop/fexamples/ex.txt", "rb")) == NULL) 
    {
        return -1;
    }

    while( fgets(line, sizeof(line), infile) != NULL ) 
    {
            filler(buf, line, NULL, 0);
    }

    fclose(infile);  /* Close the file */

    return 0;
}

static int hello_open(const char *path, struct fuse_file_info *fi)
{
    if (strcmp(path, hello_path) != 0)
        return -ENOENT;

    if ((fi->flags & 3) != O_RDONLY)
        return -EACCES;

    return 0;
}

static int hello_read(const char *path, char *buf, size_t size, off_t offset,
              struct fuse_file_info *fi)
{
    size_t len;
    (void) fi;
    if(strcmp(path, hello_path) != 0)
        return -ENOENT;

    len = strlen(hello_str);
    if (offset < len) {
        if (offset + size > len)
            size = len - offset;
        memcpy(buf, hello_str + offset, size);
    } else
        size = 0;

    return size;
}

static struct fuse_operations hello_oper = {
    .getattr    = hello_getattr,
    .readdir    = hello_readdir,
    .open       = hello_open,
    .read       = hello_read,
};

int main(int argc, char *argv[])
{
    return fuse_main(argc, argv, &hello_oper, NULL);
}

Ok, i've found solution, path must be absolute file path (not sure is this is proper sentence), but here is example code, which is working in release as well as in debug:

/*
  FUSE: Filesystem in Userspace
  Copyright (C) 2001-2007  Miklos Szeredi <[email protected]>

  This program can be distributed under the terms of the GNU GPL.
  See the file COPYING.

  gcc -Wall `pkg-config fuse --cflags --libs` hello.c -o hello
*/
#    define FUSE_USE_VERSION 26

#include  <fuse.h>
#include  <stdio.h>
#include  <string.h>
#include  <errno.h>
#include  <fcntl.h>

void stripnl(char *str) {
  while(strlen(str) && ( (str[strlen(str) - 1] == 13) || 
       ( str[strlen(str) - 1] == 10 ))) {
    str[strlen(str) - 1] = 0;
  }
}

static const char *hello_str = "Hello World!\n";
static const char *hello_path = "/hello";

static int hello_getattr(const char *path, struct stat *stbuf)
{
    int res = 0;
    memset(stbuf, 0, sizeof(struct stat));
    if (strcmp(path, "/") == 0) {
        stbuf->st_mode = S_IFDIR | 0755;
        stbuf->st_nlink = 2;
    } else if (strcmp(path, hello_path) == 0) {
        stbuf->st_mode = S_IFREG | 0444;
        stbuf->st_nlink = 1;
        stbuf->st_size = strlen(hello_str);
    } else
        res = -ENOENT;

    return res;
}

static int hello_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
             off_t offset, struct fuse_file_info *fi)
{
    (void) offset;
    (void) fi;

    if (strcmp(path, "/") != 0)
        return -ENOENT;

    filler(buf, ".", NULL, 0);
    filler(buf, "..", NULL, 0);

    filler(buf, hello_path + 1, NULL, 0);

    FILE *infile;
    char line[100];

    if((infile = fopen("/root/Desktop/fexamples/ex.txt", "rb")) == NULL) 
    {
        return -1;
    }

    while( fgets(line, sizeof(line), infile) != NULL ) 
    {
            filler(buf, line, NULL, 0);
    }

    fclose(infile);  /* Close the file */

    return 0;
}

static int hello_open(const char *path, struct fuse_file_info *fi)
{
    if (strcmp(path, hello_path) != 0)
        return -ENOENT;

    if ((fi->flags & 3) != O_RDONLY)
        return -EACCES;

    return 0;
}

static int hello_read(const char *path, char *buf, size_t size, off_t offset,
              struct fuse_file_info *fi)
{
    size_t len;
    (void) fi;
    if(strcmp(path, hello_path) != 0)
        return -ENOENT;

    len = strlen(hello_str);
    if (offset < len) {
        if (offset + size > len)
            size = len - offset;
        memcpy(buf, hello_str + offset, size);
    } else
        size = 0;

    return size;
}

static struct fuse_operations hello_oper = {
    .getattr    = hello_getattr,
    .readdir    = hello_readdir,
    .open       = hello_open,
    .read       = hello_read,
};

int main(int argc, char *argv[])
{
    return fuse_main(argc, argv, &hello_oper, NULL);
}
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