lian/zvfs
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zvfs: 完成open/close/read/write/unlink的hook动态库代码编写、编译与简单功能测试。

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1iaan
2026-02-23 16:01:55 +00:00
parent 31dc307d0b
commit 6f8f2148c3
7 changed files with 527 additions and 196 deletions
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171
zvfs_hook.c
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@@ -1,5 +1,8 @@
#include "zvfs.h"
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <dlfcn.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
@@ -8,6 +11,7 @@
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include "zvfs.h"
/* ------------------------------------------------------------------ */
/* 全局状态 */
@@ -15,13 +19,42 @@
static zvfs_t *g_fs = NULL; /* 全局文件系统，NULL 表示未初始化 */
static bool g_mounted = false;
static bool g_env_init = false;
/* 元数据文件路径 */
static const char *META_FILE = "/home/lian/share/10.1-spdk/zvfs/zvfs_meta.txt";
/* 伪 fd 起始值，避免和真实 fd 冲突 */
#define FD_BASE 1000
#define FD_BASE 10000
/* 只拦截以 /zvfs 开头的路径 */
#define ZVFS_PATH_PREFIX "/zvfs"
static int (*real_open_fn) (const char*, int, ...) = NULL;
static ssize_t (*real_read_fn) (int, void*, size_t) = NULL;
static ssize_t (*real_write_fn)(int, const void*, size_t) = NULL;
static int (*real_close_fn)(int) = NULL;
static int (*real_unlink_fn)(const char *name) = NULL;
__attribute__((constructor))
static void zvfs_preload_init(void) {
real_open_fn = dlsym(RTLD_NEXT, "open");
real_read_fn = dlsym(RTLD_NEXT, "read");
real_write_fn = dlsym(RTLD_NEXT, "write");
real_close_fn = dlsym(RTLD_NEXT, "close");
real_unlink_fn= dlsym(RTLD_NEXT, "unlink");
}
/* 判断路径是否由我们接管 */
static inline bool is_zvfs_path(const char *path) {
return path && strncmp(path, ZVFS_PATH_PREFIX, sizeof(ZVFS_PATH_PREFIX) - 1) == 0;
}
/* 判断 fd 是否是我们的伪 fd */
static inline bool is_zvfs_fd(int fd) {
return fd >= FD_BASE && fd < FD_BASE + ZVFS_MAX_FD;
}
/* ------------------------------------------------------------------ */
/* 元数据文件 I/O */
@@ -36,7 +69,7 @@ static const char *META_FILE = "/home/lian/share/10.1-spdk/zvfs/zvfs_meta.txt";
*/
static int meta_load(zvfs_t *fs) {
int fd = open(META_FILE, O_RDONLY);
int fd = real_open_fn(META_FILE, O_RDONLY);
if (fd < 0) {
/* 文件不存在，当作空目录 */
fs->dirent_count = 0;
@@ -45,7 +78,7 @@ static int meta_load(zvfs_t *fs) {
/* 一次性读进来 */
char buf[4096] = {0};
ssize_t n = read(fd, buf, sizeof(buf) - 1);
ssize_t n = real_read_fn(fd, buf, sizeof(buf) - 1);
close(fd);
if (n <= 0) return 0;
@@ -65,7 +98,7 @@ static int meta_load(zvfs_t *fs) {
zvfs_dirent_t *d = calloc(1, sizeof(zvfs_dirent_t));
if (!d) break;
int ret = sscanf(line, "%255s %"PRIu64" %"PRIu64" %"PRIu32,
int ret = sscanf(line, "%255s %"PRIu64" %"PRIu64" %"PRIu64,
d->filename,
&d->blob_id,
&d->file_size,
@@ -85,7 +118,7 @@ static int meta_load(zvfs_t *fs) {
}
static int meta_save(zvfs_t *fs) {
int fd = open(META_FILE, O_WRONLY | O_CREAT | O_TRUNC, 0644);
int fd = real_open_fn (META_FILE, O_WRONLY | O_CREAT | O_TRUNC, 0644);
if (fd < 0) return -1;
for (uint32_t i = 0; i < fs->dirent_count; i++) {
@@ -93,12 +126,12 @@ static int meta_save(zvfs_t *fs) {
if (!d || !d->is_valid) continue;
char line[512];
int len = snprintf(line, sizeof(line), "%s %"PRIu64" %"PRIu64" %"PRIu32"\n",
int len = snprintf(line, sizeof(line), "%s %"PRIu64" %"PRIu64" %"PRIu64"\n",
d->filename, d->blob_id, d->file_size, d->allocated_clusters);
write(fd, line, len);
real_write_fn(fd, line, len);
}
close(fd);
real_close_fn(fd);
return 0;
}
@@ -106,6 +139,13 @@ static int meta_save(zvfs_t *fs) {
/* ------------------------------------------------------------------ */
/* 初始化（第一次 open 时调用） */
/* ------------------------------------------------------------------ */
// 退出的时候调用 save 和 unmount
static void zvfs_atexit(void) {
if (!g_mounted || !g_fs) return;
SPDK_NOTICELOG("umount\n");
meta_save(g_fs);
zvfs_umount(g_fs);
}
static int zvfs_ensure_mounted(void) {
if (g_mounted) return 0;
@@ -123,10 +163,13 @@ static int zvfs_ensure_mounted(void) {
}
/* 初始化 SPDK 环境并 mount */
if (zvfs_env_setup() != 0) {
free(g_fs);
g_fs = NULL;
return -1;
if (!g_env_init) {
if( zvfs_env_setup() != 0) {
free(g_fs);
g_fs = NULL;
return -1;
}
g_env_init = true;
}
if (!zvfs_mount(g_fs)) {
@@ -136,6 +179,8 @@ static int zvfs_ensure_mounted(void) {
}
g_mounted = true;
atexit(zvfs_atexit);
SPDK_NOTICELOG("mount\n");
return 0;
}
@@ -164,6 +209,7 @@ static zvfs_dirent_t *dirent_alloc(const char *filename) {
d->open_count = 0;
d->file_size = 0;
d->allocated_clusters = 0;
d->blob_id = 0;
g_fs->dirents[g_fs->dirent_count++] = d;
return d;
@@ -202,11 +248,25 @@ static zvfs_file_t *fd_lookup(int pseudo_fd) {
return g_fs->fd_table[idx];
}
/* ------------------------------------------------------------------ */
/* POSIX hook */
/* ------------------------------------------------------------------ */
/* ------------------------------------------------------------------ */
/* POSIX hook: open */
/* ------------------------------------------------------------------ */
int zvfs_open_hook(const char *path, int flags, ...) {
int open(const char *path, int flags, ...) {
if (!is_zvfs_path(path)) {
mode_t mode = 0;
if (flags & O_CREAT) {
va_list ap;
va_start(ap, flags);
mode = va_arg(ap, mode_t);
va_end(ap);
}
return real_open_fn(path, flags, mode);
}
/* 确保 fs 已经 mount */
if (zvfs_ensure_mounted() != 0) {
@@ -229,6 +289,7 @@ int zvfs_open_hook(const char *path, int flags, ...) {
errno = ENOMEM;
return -1;
}
meta_save(g_fs);
}
/* 创建 file 句柄 */
@@ -246,13 +307,14 @@ int zvfs_open_hook(const char *path, int flags, ...) {
int ok;
if (dirent->blob_id == 0) {
/* 新文件：create blob，open 时不 resize，write 时按需扩容 */
file->blob_id = 0;
ok = zvfs_create(file); /* 内部 create → open → (no resize) → alloc dma_buf */
ok = zvfs_create(file); /* 内部 create → open → resize → alloc dma_buf */
SPDK_DEBUGLOG("create: %ld\n", file->blob_id);
/* 把新分配的 blob_id 写回 dirent */
dirent->blob_id = file->blob_id;
} else {
/* 已有文件：直接 open 已有 blob */
file->blob_id = dirent->blob_id;
SPDK_DEBUGLOG("open: %ld\n", file->blob_id);
ok = zvfs_open(file);
}
@@ -279,7 +341,11 @@ int zvfs_open_hook(const char *path, int flags, ...) {
/* ------------------------------------------------------------------ */
/* POSIX hook: read */
/* ------------------------------------------------------------------ */
ssize_t zvfs_read_hook(int fd, void *buf, size_t count) {
ssize_t read(int fd, void *buf, size_t count) {
if (!is_zvfs_fd(fd)) {
return real_read_fn(fd, buf, count);
}
zvfs_file_t *file = fd_lookup(fd);
if (!file) {
errno = EBADF;
@@ -299,7 +365,11 @@ ssize_t zvfs_read_hook(int fd, void *buf, size_t count) {
/* POSIX hook: write */
/* ------------------------------------------------------------------ */
ssize_t zvfs_write_hook(int fd, const void *buf, size_t count) {
ssize_t write(int fd, const void *buf, size_t count) {
if (!is_zvfs_fd(fd)) {
return real_write_fn(fd, buf, count);
}
zvfs_file_t *file = fd_lookup(fd);
if (!file) {
errno = EBADF;
@@ -314,7 +384,11 @@ ssize_t zvfs_write_hook(int fd, const void *buf, size_t count) {
/* POSIX hook: close */
/* ------------------------------------------------------------------ */
int zvfs_close_hook(int fd) {
int close(int fd) {
if (!is_zvfs_fd(fd)) {
return real_close_fn(fd);
}
zvfs_file_t *file = fd_lookup(fd);
if (!file) {
errno = EBADF;
@@ -334,25 +408,64 @@ int zvfs_close_hook(int fd) {
dirent->open_count--;
if(dirent->open_count == 0 && !dirent->is_valid){
zvfs_delete(file);
/* 从 dirents 数组中移除 */
for (uint32_t i = 0; i < g_fs->dirent_count; i++) {
if (g_fs->dirents[i] == dirent) {
free(dirent);
g_fs->dirents[i] = g_fs->dirents[--g_fs->dirent_count];
g_fs->dirents[g_fs->dirent_count] = NULL;
break;
}
}
meta_save(g_fs);
}
}
free(file);
return 0;
}
/* 如果没有任何打开的文件了，保存元数据并 unmount */
if (g_fs->openfd_count == 0) {
meta_save(g_fs);
zvfs_umount(g_fs);
/* ------------------------------------------------------------------ */
/* POSIX hook: unlink */
/* ------------------------------------------------------------------ */
int unlink(const char *name) {
if (!is_zvfs_path(name)) {
return real_unlink_fn(name);
}
/* 释放所有 dirent */
if (zvfs_ensure_mounted() != 0) {
errno = EIO;
return -1;
}
zvfs_dirent_t *dirent = dirent_find(name);
if (!dirent) {
errno = ENOENT;
return -1;
}
if (dirent->open_count > 0) {
/* 还有人打开着，延迟删除：标记无效，等最后一次 close 时再 delete blob */
dirent->is_valid = false;
} else {
/* 没人打开，直接删除 blob */
zvfs_file_t tmp = {0};
tmp.fs = g_fs;
tmp.dirent = dirent;
tmp.blob_id = dirent->blob_id;
zvfs_delete(&tmp);
/* 从 dirents 数组中移除 */
for (uint32_t i = 0; i < g_fs->dirent_count; i++) {
free(g_fs->dirents[i]);
g_fs->dirents[i] = NULL;
if (g_fs->dirents[i] == dirent) {
free(dirent);
g_fs->dirents[i] = g_fs->dirents[--g_fs->dirent_count];
g_fs->dirents[g_fs->dirent_count] = NULL;
break;
}
}
free(g_fs);
g_fs = NULL;
g_mounted = false;
meta_save(g_fs);
}
return 0;