关于struct dirent 中d_name成员在某些系统中为1的问题。

本文探讨了C语言中伸缩型结构成员的应用,特别是如何使用char[0]或char[1]作为变长数组的末尾成员,通过malloc动态分配内存实现灵活的数据结构。

此为伸缩型结构成员的问题,详见c primer plus中相关章节

1楼 发表于 2007-9-19 23:19  
我在书中看到有以下结构描述.
struct dirent{
.......
.......
char a[1];}
其中a[1]是文件名地址.也有的书用a[255]描述.
我对此非常不解,a[1]怎么能放文件指针呢,作为字符数组,也只能够放'/0'.
请各位释疑,万分感谢.


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2楼 发表于 2007-9-20 09:03 
 


QUOTE:
原帖由 liurengui 于 2007-9-19 23:19 发表
我在书中看到有以下结构描述.
struct dirent{
.......
.......
char a[1];}
其中a[1]是文件名地址.也有的书用a[255]描述.
我对此非常不解,a[1]怎么能放文件指针呢,作为字符数组,也只能够放'/0'.
请各位释 ...
一般用于一些变长的数据结构, 方便访问结构体后面的地址. 可以让最后一位为char [0] 或者是 char [1]这种类型
如:

[Copy to clipboard] [ - ]CODE:
struct dirent
{
   int len;
   char a[0];
};

struct dirent *fun(char *str, int len)
{
   struct dirent* n = (struct dirent*)malloc(len +1 + sizeof(struct dirent));
   if (!n)
      return NULL;
   n->len = len;
   memcpy(n->a, str, len);
   return n;
}

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3楼 发表于 2007-9-20 09:20  
楼上是正解,还有一点值得说明的是.这些char a[0] 或者 char a[1] 必须作为结构体的最后一个成员.


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4楼 发表于 2007-9-20 11:37  


QUOTE:
原帖由 web_surf 于 2007-9-20 09:20 发表
楼上是正解,还有一点值得说明的是.这些char a[0] 或者 char a[1] 必须作为结构体的最后一个成员.
个人以为, char[0]更似更值得推荐,因为这样不会增加结构的size!而且大多数情况下,更利于对齐!


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5楼 发表于 2007-9-20 12:35  
但是字符数组长度定义成1,只能够存'/0',其他根本就存不下了。
为什么不直接定义成这样,char *a;这样不更简单.


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6楼 发表于 2007-9-20 12:45  
使用了malloc()给其分配了空间的, 所以说它可以有存放数据的空间. 使用char *p的方法也行, 不过这个结构体要多占sizeof(char*)这么多个字节, 在有些空间比较少的领域可以使用这种方式来减少空间的使用.


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7楼 发表于 2007-9-20 16:46  


QUOTE:
原帖由 独孤九贱 于 2007-9-20 11:37 发表


个人以为, char[0]更似更值得推荐,因为这样不会增加结构的size!而且大多数情况下,更利于对齐!
说得一点都没错,不过我有点疑惑, 既然是char [0], sizeof(struct)也没发现这个变量占用了内存空间,但还是可以访问这个变量.奇怪,晚上会去查查c99怎么定义char[0]的.

查到了, c99这样定义的
struct s
{
  int a;
  char b[];
};

struct ss
{
  int a;
  char b[1];
};

sizeof(struct s) = offsetof(struct s, b) = offsetof(struct ss, b);


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8楼 发表于 2007-9-20 16:54  


QUOTE:
原帖由 liurengui 于 2007-9-20 12:35 发表
但是字符数组长度定义成1,只能够存'/0',其他根本就存不下了。
为什么不直接定义成这样,char *a;这样不更简单.
谁说长度为1就只能存'/0'了.malloc时扩展了size的. 而扩展的size正好在struct的尾端, 也就是说扩展的内存跟最后一个成员char p[0]的地址是相邻的. 也就是说可以通过成员char p[0]访问.
用char p[0]比char *p的好处是:
(1) 前者malloc之后不需要给p赋值,因为前者是array.
(2) 前者实现了一个动态数组的功能,如果不需要,他根本就可以不占用任何内存,而后者会占用4个字节.


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#define _GNU_SOURCE #include <sys/ptrace.h> #include <sys/types.h> #include <sys/wait.h> #include <unistd.h> #include <stdio.h> #include <stdlib.h> #include <errno.h> #include <string.h> #include <elf.h> #include <sys/uio.h> #include <sys/stat.h> #include <dirent.h> #include <asm/ptrace.h> // 修复1: 正确定义ARM64硬件调试寄存器 #ifndef NT_ARM_HW_BREAK #define NT_ARM_HW_BREAK 0x402 // 执行断点 #endif #ifndef NT_ARM_HW_WATCH #define NT_ARM_HW_WATCH 0x403 // 观察点 #endif // 修复2: 正确定义调试寄存器状态结构体 struct user_hwdebug_state { uint32_t dbg_info; // 调试信息 uint32_t pad; // 填充 struct { uint64_t addr; // 地址寄存器 uint64_t ctrl; // 控制寄存器 } dbg_regs[16]; // 最大16个断点 }; // 获取线程ID int get_threads(pid_t pid, pid_t *threads, int max_threads) { char path[64]; int count = 0; snprintf(path, sizeof(path), "/proc/%d/task", pid); DIR *dir = opendir(path); if (!dir) { perror("opendir failed"); return 0; } struct dirent *entry; while ((entry = readdir(dir)) != NULL) { if (count >= max_threads) break; if (entry->d_type == DT_DIR && strcmp(entry->d_name, ".") != 0 && strcmp(entry->d_name, "..") != 0) { threads[count++] = atoi(entry->d_name); } } closedir(dir); return count; } // 附加到进程 bool attach_to_process(pid_t pid) { if (ptrace(PTRACE_ATTACH, pid, NULL, NULL) < 0) { perror("【错误】附加主进程失败"); return false; } int status; if (waitpid(pid, &status, 0) < 0) { perror("【错误】等待主进程失败"); return false; } pid_t threads[64]; int thread_count = get_threads(pid, threads, 64); if (thread_count == 0) { fprintf(stderr, "【警告】未找到任何线程\n"); return false; } for (int i = 0; i < thread_count; i++) { pid_t tid = threads[i]; if (tid == pid) continue; if (ptrace(PTRACE_ATTACH, tid, NULL, NULL) < 0) { perror("【错误】附加子线程失败"); continue; } if (waitpid(tid, &status, 0) < 0) { perror("【错误】等待子线程失败"); ptrace(PTRACE_DETACH, tid, NULL, NULL); continue; } printf("【已附加线程】tid=%d\n", tid); } return true; } // 修复3: 正确设置硬件断点 bool set_hw_breakpoint(pid_t pid, pid_t thread_id, uintptr_t addr, int len, int type) { // 选择寄存器集类型 int nt_type = (type == 0) ? NT_ARM_HW_BREAK : NT_ARM_HW_WATCH; struct user_hwdebug_state dbg_regs; struct iovec iov = { .iov_base = &dbg_regs, .iov_len = sizeof(dbg_regs) }; // 获取当前状态 if (ptrace(PTRACE_GETREGSET, thread_id, nt_type, &iov) < 0) { perror("【错误】PTRACE_GETREGSET获取失败"); return false; } // 查找空闲槽位 int slot = -1; for (int i = 0; i < 16; i++) { if (dbg_regs.dbg_regs[i].addr == 0) { slot = i; break; } } if (slot == -1) { fprintf(stderr, "【错误】线程%d无可用硬件断点\n", thread_id); return false; } // 设置控制寄存器 uint64_t ctrl_value = 0; if (type == 0) { // 执行断点 ctrl_value = (1 << 0) | // 启用 (0b01 << 8); // 用户空间(EL0) } else { // 观察点 // 计算BAS掩码 uint64_t bas = 0; switch (len) { case 1: bas = 0x1; break; case 2: bas = 0x3; break; case 4: bas = 0xF; break; case 8: bas = 0xFF; break; default: fprintf(stderr, "【错误】无效长度: %d\n", len); return false; } ctrl_value = (1 << 0) | // 启用 (0b01 << 8); // 用户空间(EL0) // 设置类型 if (type == 1) { // 读 ctrl_value |= (0b01 << 3); // Load } else if (type == 2) { // 写 ctrl_value |= (0b10 << 3); // Store } else if (type == 3) { // 读写 ctrl_value |= (0b11 << 3); // Load/Store } // 设置长度(BAS) ctrl_value |= (bas << 16); } // 设置地址和控制寄存器 dbg_regs.dbg_regs[slot].addr = addr; dbg_regs.dbg_regs[slot].ctrl = ctrl_value; // 应用设置 if (ptrace(PTRACE_SETREGSET, thread_id, nt_type, &iov) < 0) { perror("【错误】PTRACE_SETREGSET设置失败"); return false; } printf("【线程%d断点设置成功】 地址:0x%llx 类型:%s 长度:%d字节\n", thread_id, (unsigned long long)addr, type == 0 ? "执行" : type == 1 ? "读" : type == 2 ? "写" : "读写", len); return true; } // 清除所有硬件断点 bool clear_all_hw_breakpoints(pid_t thread_id) { struct user_hwdebug_state dbg_regs; struct iovec iov = { .iov_base = &dbg_regs, .iov_len = sizeof(dbg_regs) }; // 清除执行断点 memset(&dbg_regs, 0, sizeof(dbg_regs)); if (ptrace(PTRACE_SETREGSET, thread_id, NT_ARM_HW_BREAK, &iov) < 0) { perror("【错误】清除执行断点失败"); } // 清除观察点 memset(&dbg_regs, 0, sizeof(dbg_regs)); if (ptrace(PTRACE_SETREGSET, thread_id, NT_ARM_HW_WATCH, &iov) < 0) { perror("【错误】清除观察点失败"); return false; } return true; } // 获取寄存器信息 bool get_registers(pid_t tid, struct user_pt_regs *regs) { struct iovec iov = { .iov_base = regs, .iov_len = sizeof(*regs) }; if (ptrace(PTRACE_GETREGSET, tid, NT_PRSTATUS, &iov) < 0) { perror("【错误】PTRACE_GETREGSET获取失败"); return false; } return true; } int main() { pid_t target_pid; printf("【输入目标进程PID】\n"); scanf("%d", &target_pid); if (geteuid() != 0) { fprintf(stderr, "【错误】需要root权限\n"); return 1; } if (!attach_to_process(target_pid)) { fprintf(stderr, "【致命错误】无法附加目标进程\n"); return 1; } uintptr_t bp_addr; printf("【输入断点地址(十六进制)】\n"); scanf("%llx", (unsigned long long *)&bp_addr); int len, type; printf("【选择断点类型(0:执行,1:读,2:写,3:读写)】\n"); scanf("%d", &type); if (type != 0) { printf("【输入断点长度(1,2,4,8字节)】\n"); scanf("%d", &len); // 检查长度有效性 if (len != 1 && len != 2 && len != 4 && len != 8) { fprintf(stderr, "【错误】无效长度,使用默认值4字节\n"); len = 4; } } else { len = 4; // 执行断点长度固定 } pid_t threads[64]; int thread_count = get_threads(target_pid, threads, 64); for (int i = 0; i < thread_count; i++) { pid_t tid = threads[i]; printf("【处理线程】tid=%d\n", tid); if (!set_hw_breakpoint(target_pid, tid, bp_addr, len, type)) { fprintf(stderr, "【警告】线程%d断点设置失败\n", tid); continue; } } printf("【恢复进程执行...】\n"); if (ptrace(PTRACE_CONT, target_pid, NULL, NULL) < 0) { perror("【错误】恢复执行失败"); return 1; } printf("【等待断点触发...】\n"); int status; pid_t wait_pid = waitpid(-1, &status, 0); bool breakpoint_hit = false; for (int i = 0; i < thread_count; i++) { pid_t tid = threads[i]; int nt_type = (type == 0) ? NT_ARM_HW_BREAK : NT_ARM_HW_WATCH; struct user_hwdebug_state dbg_regs; struct iovec iov = { .iov_base = &dbg_regs, .iov_len = sizeof(dbg_regs) }; if (ptrace(PTRACE_GETREGSET, tid, nt_type, &iov) < 0) { perror("【错误】获取调试寄存器失败"); continue; } for (int j = 0; j < 16; j++) { if (dbg_regs.dbg_regs[j].addr == bp_addr && (dbg_regs.dbg_regs[j].ctrl & 0x1)) { breakpoint_hit = true; printf("\n【断点命中!】\n"); printf("触发线程:tid=%d\n", tid); printf("命中地址:0x%llx\n", (unsigned long long)bp_addr); const char *type_str = type == 0 ? "执行" : type == 1 ? "读" : type == 2 ? "写" : "读写"; printf("类型:%s | 长度:%d字节\n", type_str, len); struct user_pt_regs regs; if (get_registers(tid, &regs)) { printf("\n寄存器状态:\n"); printf("PC=0x%llx (程序计数器)\n", (unsigned long long)regs.pc); printf("LR=0x%llx (链接寄存器x30)\n", (unsigned long long)regs.regs[30]); printf("SP=0x%llx (栈指针sp)\n", (unsigned long long)regs.sp); printf("X0=0x%llx, X1=0x%llx, X2=0x%llx, X3=0x%llx\n", (unsigned long long)regs.regs[0], (unsigned long long)regs.regs[1], (unsigned long long)regs.regs[2], (unsigned long long)regs.regs[3]); } break; } } if (breakpoint_hit) break; } if (!breakpoint_hit) { printf("\n【未检测到断点命中,恢复进程执行...】\n"); ptrace(PTRACE_CONT, target_pid, NULL, NULL); } printf("\n【清理断点...】\n"); for (int i = 0; i < thread_count; i++) { pid_t tid = threads[i]; if (!clear_all_hw_breakpoints(tid)) { fprintf(stderr, "【警告】线程%d断点清除失败\n", tid); } else { printf("【已清除线程】tid=%d的断点\n", tid); } } printf("\n【分离调试会话...】\n"); for (int i = 0; i < thread_count; i++) { pid_t tid = threads[i]; if (ptrace(PTRACE_DETACH, tid, NULL, NULL) < 0) { perror("【错误】分离线程失败"); } } return 0; } Android NDK: src/ptrace断点.cpp.bak [arm64-v8a] Compile++ : 无痕hook.sh <= ptrace断点.cpp jni/src/ptrace断点.cpp:25:8: error: redefinition of 'user_hwdebug_state' struct user_hwdebug_state { ^ /data/data/com.aide.ui.mgai/no_backup/ndksupport-1710240003/android-ndk-aide/sysroot/usr/include/aarch64-linux-android/asm/ptrace.h:61:8: note: previous definition is here struct user_hwdebug_state { ^ 1 error generated. make: *** [/data/data/com.aide.ui.mgai/no_backup/ndksupport-1710240003/android-ndk-aide/build/core/build-binary.mk:530: obj/local/arm64-v8a/objs/无痕hook.sh/src/ptrace 断点.o] Error 1 修复好报错问题完整发给我
07-14
// 补全状态结构(优化版) typedef struct { char **matches; // 所有匹配项 int count; // 匹配项总数 char *base_dir; // 当前基础目录 char *original_prefix; // 原始前缀 char *current_text; // 当前输入文本 int last_state; // 上一次使用的state值 int current_level; // 当前目录层级 char *persistent_path; // 持久化路径(同时作为初始化标志) int is_directory; int max_level; // 最大允许层级(关键新增) } CompletionState; static CompletionState comp_state = { .matches = NULL, .count = 0, .base_dir = NULL, .original_prefix = NULL, .current_text = NULL, .last_state = -1, .current_level = 0, .persistent_path = NULL, .is_directory = 0, .max_level = 0 }; // 重置补全状态 void reset_completion_state() { if (comp_state.matches) { for (int i = 0; i < comp_state.count; i++) { XFREE(MTYPE_TMP, comp_state.matches[i]); } XFREE(MTYPE_TMP, comp_state.matches); comp_state.matches = NULL; } if (comp_state.original_prefix) { XFREE(MTYPE_TMP, comp_state.original_prefix); } if (comp_state.base_dir) { XFREE(MTYPE_TMP, comp_state.base_dir); } if (comp_state.current_text) { XFREE(MTYPE_TMP, comp_state.current_text); } if (comp_state.persistent_path) { XFREE(MTYPE_TMP, comp_state.persistent_path); } comp_state.count = 0; comp_state.original_prefix = NULL; comp_state.base_dir = NULL; comp_state.current_text = NULL; comp_state.last_state = -1; comp_state.current_level = 0; comp_state.persistent_path = NULL; // 关键:清除持久化路径 comp_state.is_directory = 0; comp_state.max_level = 0; } // 修复的路径解析函数 void parse_input_text(const char *text, char **base_dir, char **prefix, int *level) { *level = 0; const char *ptr = text; while (*ptr) { if (*ptr == '/') (*level)++; ptr++; } const char *last_slash = strrchr(text, '/'); const char *last_char = text + strlen(text) - 1; if (last_slash) { if (last_char == last_slash) { size_t base_len = last_slash - text + 1; *base_dir = (char *)XCALLOC(MTYPE_TMP, base_len + 1); strncpy(*base_dir, text, base_len); (*base_dir)[base_len] = '\0'; *prefix = XSTRDUP(MTYPE_TMP, ""); } else { size_t base_len = last_slash - text + 1; *base_dir = (char *)XCALLOC(MTYPE_TMP, base_len + 1); strncpy(*base_dir, text, base_len); (*base_dir)[base_len] = '\0'; *prefix = XSTRDUP(MTYPE_TMP, last_slash + 1); } } else { *base_dir = XSTRDUP(MTYPE_TMP, ""); *prefix = XSTRDUP(MTYPE_TMP, text); } printf("parse_input_text: text = %s, base_dir = %s, prefix = %s, level = %d\n", text, *base_dir, *prefix, *level); } // 修复的上下文检测函数 int is_same_completion_context(const char *text) { if (!comp_state.persistent_path || !text) return 0; // 临时解析获取当前层级 char *temp_base = NULL; char *temp_prefix = NULL; int current_level = 0; parse_input_text(text, &temp_base, &temp_prefix, &current_level); // 关键改进:检查是否超过最大层级 int within_level_limit = (current_level <= comp_state.max_level); // 检查路径前缀是否相同 size_t len = strlen(comp_state.persistent_path); int same_path = strncmp(text, comp_state.persistent_path, len) == 0; XFREE(MTYPE_TMP, temp_base); XFREE(MTYPE_TMP, temp_prefix); printf("is_same_completion_context: text=%s persistent=%s level=%d/%d same_path=%d within_level=%d\n", text, comp_state.persistent_path, current_level, comp_state.max_level, same_path, within_level_limit); return same_path && within_level_limit; } // 路径比较函数 int compare_paths(const void *a, const void *b) { const char *path1 = *(const char **)a; const char *path2 = *(const char **)b; return strcmp(path1, path2); } // 修复的目录内容生成函数 char **generate_current_dir_paths(const char *base_dir, const char *prefix, int add_empty) { // 关键修复:正确处理空目录路径 const char *scan_dir = base_dir; if (!scan_dir || strlen(scan_dir) == 0) { scan_dir = "."; } printf("[generate] Scanning: '%s' with prefix '%s'\n", scan_dir, prefix ? prefix : "(none)"); DIR *dir = opendir(scan_dir); if (!dir) { printf("opendir failed"); if (add_empty) { char **matches = (char **)XCALLOC(MTYPE_TMP, sizeof(char *)); matches[0] = XSTRDUP(MTYPE_TMP, ""); return matches; } return NULL; } int capacity = 32; int count = 0; char **matches = (char **)XCALLOC(MTYPE_TMP, capacity * sizeof(char *)); struct dirent *entry; while ((entry = readdir(dir)) != NULL) { char *name = entry->d_name; // 跳过特殊目录 if (strcmp(name, ".") == 0 || strcmp(name, "..") == 0) { continue; } // 应用前缀过滤 if (prefix && *prefix && strncmp(name, prefix, strlen(prefix)) != 0) { continue; } // 检测目录类型 int is_dir = 0; if (entry->d_type == DT_DIR) { is_dir = 1; } else if (entry->d_type == DT_UNKNOWN) { char full_path[PATH_MAX]; snprintf(full_path, sizeof(full_path), "%s/%s", scan_dir, name); struct stat statbuf; if (stat(full_path, &statbuf) == 0 && S_ISDIR(statbuf.st_mode)) { is_dir = 1; } } // 创建带斜杠的目录名 char *new_name; if (is_dir) { new_name = (char *)XCALLOC(MTYPE_TMP, strlen(name) + 2); sprintf(new_name, "%s/", name); } else { new_name = XSTRDUP(MTYPE_TMP, name); } // 添加到匹配列表 if (count >= capacity) { capacity *= 2; matches = (char **)XREALLOC(MTYPE_TMP, matches, capacity * sizeof(char *)); } matches[count++] = new_name; } closedir(dir); // 排序结果 if (count > 0) { qsort(matches, count, sizeof(char *), compare_paths); } // Null-terminate if (count >= capacity) { matches = (char **)XREALLOC(MTYPE_TMP, matches, (count+1) * sizeof(char *)); } matches[count] = NULL; // 在非顶级目录添加空字符串作为循环结束标记 if (count > 0 && !add_empty) { matches = (char **)XREALLOC(MTYPE_TMP, matches, (count+2) * sizeof(char *)); matches[count] = XSTRDUP(MTYPE_TMP, ""); matches[count+1] = NULL; count++; } printf("[generate] Found %d matches\n", count); return matches; } // 修复的智能文件补全函数 char *filename_completion_function(const char *text, int state) { printf("\n[COMP] Entering: text='%s', state=%d, last_state=%d\n", text, state, comp_state.last_state); // 初始化新补全 if (state == 0) { int same_context = is_same_completion_context(text); printf(" Same context: %d\n", same_context); if (!same_context) { // 上下文变化,重置状态 reset_completion_state(); char *current_base = NULL; char *current_prefix = NULL; int current_level = 0; // 解析当前输入文本 parse_input_text(text, &current_base, &current_prefix, &current_level); printf(" Parsed: base='%s', prefix='%s', level=%d\n", current_base, current_prefix, current_level); // 初始化状态 comp_state.base_dir = current_base; comp_state.current_text = XSTRDUP(MTYPE_TMP, text); comp_state.current_level = current_level; // 设置持久化路径(当前目录) if (strlen(current_base) > 0) { comp_state.persistent_path = XSTRDUP(MTYPE_TMP, current_base); } else { comp_state.persistent_path = XSTRDUP(MTYPE_TMP, "."); } // 仅在顶级目录添加空字符串项 int add_empty = (current_level == 0) ? 1 : 0; // 生成匹配项 comp_state.matches = generate_current_dir_paths(current_base, current_prefix, add_empty); // 计算匹配项数量 if (comp_state.matches) { comp_state.count = 0; while (comp_state.matches[comp_state.count]) { comp_state.count++; } printf(" Generated %d matches\n", comp_state.count); } else { comp_state.count = 0; } comp_state.last_state = -1; } } // 无匹配项时返回NULL if (!comp_state.matches || comp_state.count == 0) { printf("[COMP] No matches found\n"); return NULL; } // 循环获取下一个匹配项 int next_index = (comp_state.last_state + 1) % comp_state.count; comp_state.last_state = next_index; char *match = comp_state.matches[next_index]; printf(" Next index: %d/%d, match='%s'\n", next_index, comp_state.count - 1, match); // 构建完整路径 char *full_path = NULL; if (comp_state.base_dir && strlen(comp_state.base_dir) > 0) { int base_len = strlen(comp_state.base_dir); int needs_slash = (comp_state.base_dir[base_len - 1] != '/'); int len = base_len + strlen(match) + (needs_slash ? 1 : 0) + 1; full_path = (char *)XCALLOC(MTYPE_TMP, len); if (needs_slash) { snprintf(full_path, len, "%s/%s", comp_state.base_dir, match); } else { snprintf(full_path, len, "%s%s", comp_state.base_dir, match); } } else { full_path = XSTRDUP(MTYPE_TMP, match); } printf("[COMP] Returning: '%s'\n", full_path); return full_path; } // 补全匹配函数(返回单个匹配项) char **filename_completion_matches(const char *text, CPFunction* genfunc) { printf("\n[MATCHES] Called with text='%s'\n", text); // 获取下一个匹配项 char *match = (*genfunc)(text, 0); if (!match) { printf("[MATCHES] No matches found\n"); return NULL; } // 创建只包含一个匹配项的数组 char **matches = (char **)XCALLOC(MTYPE_TMP, 2 * sizeof(char *)); matches[0] = match; matches[1] = NULL; printf("[MATCHES] Returning single match: '%s'\n", match); return matches; } <dahua>dir e【cmlsh_completion】text = e [MATCHES] Called with text='e' [COMP] Entering: text='e', state=0, last_state=-1 Same context: 0 parse_input_text: text = e, base_dir = , prefix = e, level = 0 Parsed: base='', prefix='e', level=0 [generate] Scanning: '.' with prefix 'e' [generate] Found 1 matches Generated 1 matches Next index: 0/0, match='etc/' [COMP] Returning: 'etc/' [MATCHES] Returning single match: 'etc/' tc/【cmlsh_completion】text = etc/ [MATCHES] Called with text='etc/' [COMP] Entering: text='etc/', state=0, last_state=0 parse_input_text: text = etc/, base_dir = etc/, prefix = , level = 1 is_same_completion_context: text=etc/ persistent=. level=1/0 same_path=0 within_level=0 Same context: 0 parse_input_text: text = etc/, base_dir = etc/, prefix = , level = 1 Parsed: base='etc/', prefix='', level=1 [generate] Scanning: 'etc/' with prefix '' [generate] Found 5 matches Generated 5 matches Next index: 0/4, match='CML_DB.db' [COMP] Returning: 'etc/CML_DB.db' [MATCHES] Returning single match: 'etc/CML_DB.db' CML_DB.db【cmlsh_completion】text = etc/CML_DB.db [MATCHES] Called with text='etc/CML_DB.db' [COMP] Entering: text='etc/CML_DB.db', state=0, last_state=0 parse_input_text: text = etc/CML_DB.db, base_dir = etc/, prefix = CML_DB.db, level = 1 is_same_completion_context: text=etc/CML_DB.db persistent=etc/ level=1/0 same_path=1 within_level=0 Same context: 0 parse_input_text: text = etc/CML_DB.db, base_dir = etc/, prefix = CML_DB.db, level = 1 Parsed: base='etc Username: 上边的代码逻辑会异常退出
08-02
我现在有一个问题就是 我使用curl -X PUT http://localhost:8085/test.txt -d "Hello, WebDAV!" 这个命令的时候 他不会进入mod_smbdav_physical_handler 但是我要是curl -v http://localhost:8085/smb/test.txt 这个的话他就会进入这个函数 我把我写的给你看#include "first.h" /* first */ #include <sys/types.h> #include "sys-dirent.h" #include "sys-mmap.h" #include <sys/types.h> #include "sys-stat.h" #include "sys-time.h" #include "sys-unistd.h" /* <unistd.h> getpid() linkat() rmdir() unlinkat() */ #include <errno.h> #include <fcntl.h> #include <stdio.h> /* rename() */ #include <stdlib.h> /* strtol() */ #include <string.h> #include <sqlite3.h> #include "base.h" #include "buffer.h" #include "chunk.h" #include "fdevent.h" #include "http_chunk.h" #include "http_date.h" #include "http_etag.h" #include "http_header.h" #include "log.h" #include "request.h" #include "response.h" /* http_response_redirect_to_directory() */ #include "stat_cache.h" /* stat_cache_mimetype_by_ext() */ #include "plugin.h" #include <samba-4.0/libsmbclient.h> #define DBE 1 #ifdef DEBUG #define Cdbg(level, format, ...) \ do { \ if (level) { \ log_error_write(srv, __FILE__, __LINE__, "[smbdav] " format, ##__VA_ARGS__); \ } \ } while (0) #else #define Cdbg(level, format, ...) ((void)0) #endif #define http_status_get(r) ((r)->http_status) #define http_status_set_fin(r, code) ((r)->resp_body_finished = 1,\ (r)->handler_module = NULL, \ (r)->http_status = (code)) #define http_status_set(r, code) ((r)->http_status = (code)) #define http_status_unset(r) ((r)->http_status = 0) #define http_status_is_set(r) (0 != (r)->http_status) #define HTTP_STATUS_OK 200 #define HTTP_STATUS_CREATED 201 #define HTTP_STATUS_NO_CONTENT 204 #define HTTP_STATUS_NOT_MODIFIED 304 #define HTTP_STATUS_BAD_REQUEST 400 #define HTTP_STATUS_FORBIDDEN 403 #define HTTP_STATUS_NOT_FOUND 404 #define HTTP_STATUS_CONFLICT 409 #define HTTP_STATUS_INTERNAL_SERVER_ERROR 500 #define HTTP_STATUS_NOT_IMPLEMENTED 501 #define HTTP_STATUS_SERVICE_UNAVAILABLE 503 #define HTTP_SERVER_ERROR 500 #define HTTP_SERVER_NOT_IMPLEMENTED 501 #define HTTP_SERVER_BAD_GATEWAY 502 #define HTTP_SERVER_SERVICE_UNAVAILABLE 503 #define HTTP_SERVER_GATEWAY_TIMEOUT 504 #define HTTP_SERVER_VERSION_NOT_SUPPORTED 505 #define HTTP_SERVER_INSUFFICIENT_STORAGE 507 #define HTTP_STATUS_CONTINUE 100 #define HTTP_STATUS_SWITCHING_PROTOCOLS 101 #define HTTP_STATUS_PROCESSING 102 #define HTTP_STATUS_MULTI_STATUS 207 #define HTTP_STATUS_ALREADY_REPORTED 208 #define HTTP_STATUS_IM_USED 226 #define HTTP_METHOD_NOT_ALLOWED 405 #define HTTP_SERVER_INTERNAL_SERVER_ERROR 500 typedef struct { unsigned short enabled; unsigned short is_readonly; unsigned short log_xml; buffer *smb_share_root; buffer *sqlite_db_name; } plugin_config; typedef struct { PLUGIN_DATA; buffer *tmp_buf; request_uri uri; physical physical; plugin_config **config_storage; plugin_config conf; } plugin_data; static int handle_propfind(request_st *r, plugin_data *p, buffer *smb_path) { /* 1. 解析 PROPFIND 请求的 XML 内容 */ /* 2. 查询 SMB 资源的属性 */ /* 3. 生成 WebDAV 标准的 XML 响应 */ fprintf(stderr, "[TEST] handle_propfind called with path: %s\n", smb_path->ptr); return HANDLER_GO_ON; } static int handle_proppatch(request_st *r, plugin_data *p, buffer *smb_path) { /* 1. 解析 PROPPATCH 请求的 XML 内容 */ /* 2. 更新 SMB 资源的属性 */ /* 3. 返回操作结果 */ fprintf(stderr, "[TEST] handle_proppatch called with path: %s\n", smb_path->ptr); return HANDLER_GO_ON; } static int handle_lock(request_st *r, plugin_data *p, buffer *smb_path) { /* 1. 解析 LOCK 请求的 XML 内容 */ /* 2. 创建或更新资源的锁定状态 */ /* 3. 返回锁定令牌 */ fprintf(stderr, "[TEST] handle_lock called with path: %s\n", smb_path->ptr); return HANDLER_GO_ON; } static buffer *build_smb_path(plugin_data *p, const char *path) { buffer *smb_path = buffer_init(); if (!smb_path) return NULL; fprintf(stderr, "[TEST] smb_path2222222222: %s\n", p->conf.smb_share_root->ptr); /* 拼接 SMB 共享根目录和请求路径 */ /*自己写这个源码*/ buffer_copy_buffer(smb_path, p->conf.smb_share_root); fprintf(stderr, "[TEST] smb_path: %s\n", smb_path->ptr); buffer_append_string(smb_path, path); fprintf(stderr, "[TEST] smb_path1111111111: %s\n", smb_path->ptr); return smb_path; } INIT_FUNC(mod_smbdav_init) { plugin_data *p; p = calloc(1, sizeof(*p)); p->tmp_buf = buffer_init(); Cdbg(DBE,"complete smbc_init..."); return p; } int mod_smbdav_subrequest_handler(request_st *r, void *p_d) { fprintf(stderr, "[TEST] mod_smbdav_subrequest_handler called with path:"); plugin_data *p = p_d; connection *con = r->con; int ret = HANDLER_GO_ON; fprintf(stderr, "[TEST] mod_smbdav_physical_handler called with path: %s\n", r->physical.path.ptr); /* 1. 检查插件是否启用 */ if (!p->conf.enabled) { r->http_status = HTTP_SERVER_SERVICE_UNAVAILABLE; fprintf(stderr, "[TEST] mod_smbdav_conf.enabled is false"); return HANDLER_FINISHED; } else { fprintf(stderr, "[TEST] mod_smbdav_conf.enabled is true"); } /* 2. 解析 SMB 路径 */ buffer *smb_path = build_smb_path(p, r->physical.path.ptr); fprintf(stderr, "[TEST] smb_path: %s\n", smb_path->ptr); if (!smb_path) { r->http_status = HTTP_SERVER_INTERNAL_SERVER_ERROR; return HANDLER_FINISHED; } /* 3. 根据 HTTP 方法分发处理 */ fprintf(stderr, "[TEST] con->request.http_method: %d\n", con->request.http_method); switch (con->request.http_method) { case HTTP_METHOD_PROPFIND: ret = handle_propfind(r, p, smb_path); break; case HTTP_METHOD_PROPPATCH: ret = handle_proppatch(r, p, smb_path); break; case HTTP_METHOD_LOCK: ret = handle_lock(r, p, smb_path); break; default: r->http_status = HTTP_METHOD_NOT_ALLOWED; ret = HANDLER_FINISHED; } buffer_free(smb_path); return ret; } int mod_smbdav_physical_handler(request_st *r, void *p_d) { fprintf(stderr, "[TEST] mod_smbdav_physical_handler called with path:"); plugin_data *p = p_d; connection *con = r->con; int ret = HANDLER_GO_ON; fprintf(stderr, "[TEST] mod_smbdav_physical_handler called with path: %s\n", r->physical.path.ptr); /* 1. 检查插件是否启用 */ if (!p->conf.enabled) { r->http_status = HTTP_SERVER_SERVICE_UNAVAILABLE; fprintf(stderr, "[TEST] mod_smbdav_conf.enabled is false"); return HANDLER_FINISHED; } else { fprintf(stderr, "[TEST] mod_smbdav_conf.enabled is true"); } /* 2. 解析 SMB 路径 */ buffer *smb_path = build_smb_path(p, r->physical.path.ptr); fprintf(stderr, "[TEST] smb_path: %s\n", smb_path->ptr); if (!smb_path) { r->http_status = HTTP_SERVER_INTERNAL_SERVER_ERROR; return HANDLER_FINISHED; } /* 3. 根据 HTTP 方法分发处理 */ fprintf(stderr, "[TEST] con->request.http_method: %d\n", con->request.http_method); switch (con->request.http_method) { case HTTP_METHOD_PROPFIND: ret = handle_propfind(r, p, smb_path); break; case HTTP_METHOD_PROPPATCH: ret = handle_proppatch(r, p, smb_path); break; case HTTP_METHOD_LOCK: ret = handle_lock(r, p, smb_path); break; default: r->http_status = HTTP_METHOD_NOT_ALLOWED; ret = HANDLER_FINISHED; } buffer_free(smb_path); return ret; } int smbdav_set_defaults(server *srv, plugin_data *p) { static const config_plugin_keys_t config_keys[] = { /* SMB 共享根目录 */ { CONST_STR_LEN("smbdav.smb_share_root"), T_CONFIG_STRING, T_CONFIG_SCOPE_CONNECTION }, /* 是否启用模块 */ { CONST_STR_LEN("smbdav.enabled"), T_CONFIG_BOOL, T_CONFIG_SCOPE_CONNECTION }, /* 是否只读模式 */ { CONST_STR_LEN("smbdav.is_readonly"), T_CONFIG_BOOL, T_CONFIG_SCOPE_CONNECTION }, /* 是否记录 XML 请求 */ { CONST_STR_LEN("smbdav.log_xml"), T_CONFIG_BOOL, T_CONFIG_SCOPE_CONNECTION }, /* 终止标记 */ { NULL, 0, T_CONFIG_UNSET, T_CONFIG_SCOPE_UNSET } }; /* 初始化默认配置 */ p->conf.smb_share_root = buffer_init(); p->conf.smb_share_root->ptr = "/home/zhihonghe/smb_share"; p->conf.smb_share_root->used = 1000; p->conf.smb_share_root->size = 1000; p->conf.enabled = 1; p->conf.is_readonly = 0; p->conf.log_xml = 0; /* 解析配置文件 */ if (!config_plugin_values_init(srv, p, config_keys, "mod_smbdav")) { fprintf(stderr, "[TEST] config_plugin_values_init failed"); return HANDLER_ERROR; } /*打印配置信息*/ fprintf(stderr, "[TEST] smb_share_root: %s\n", p->conf.smb_share_root->ptr); fprintf(stderr, "[TEST] enabled: %d\n", p->conf.enabled); fprintf(stderr, "[TEST] is_readonly: %d\n", p->conf.is_readonly); fprintf(stderr, "[TEST] log_xml: %d\n", p->conf.log_xml); /* 检查 SMB 共享路径是否配置 */ if (buffer_string_is_empty(p->conf.smb_share_root)) { fprintf(stderr, "[TEST] smb_share_root is not configured"); return HANDLER_ERROR; } /* 绑定临时缓冲区 */ p->tmp_buf = srv->tmp_buf; fprintf(stderr, "[TEST] finished smbdav_set_defaults"); return HANDLER_GO_ON; } int mod_smbdav_plugin_init(plugin *p) { p->version = LIGHTTPD_VERSION_ID; p->name = "smbdav"; /* Core callbacks */ p->init = mod_smbdav_init; p->cleanup = NULL; p->set_defaults = smbdav_set_defaults; p->priv_defaults = NULL; /* Optional */ p->worker_init = NULL; /* Optional */ /* Request handlers */ p->handle_uri_raw = NULL; /* Not used */ p->handle_uri_clean = NULL; p->handle_docroot = NULL; /* Not used */ p->handle_physical = mod_smbdav_physical_handler; p->handle_request_env = NULL; /* Not used */ p->handle_request_done = NULL; /* Not used */ p->handle_subrequest = mod_smbdav_subrequest_handler; /* Not used */ p->handle_response_start = NULL; /* Not used */ p->handle_request_reset = NULL; /* Not used */ /* Connection handlers */ p->handle_connection_accept = NULL; /* Not used */ p->handle_connection_shut_wr = NULL; /* Not used */ p->handle_connection_close = NULL; /* Server handlers */ p->handle_trigger = NULL; /* Not used */ p->handle_sighup = NULL; /* Not used */ p->handle_waitpid = NULL; /* Not used */ p->data = NULL; p->lib = NULL; return 0; }
09-19
<think>我们有一个问题:如何判断 `struct dirent` 的成员 `d_name` 是否可以强制转换为 `std::istringstream`?实际上,我们并不是要强制转换,而是想用 `d_name` 的内容来初始化一个 `std::istringstream` 对象。 首先,我们需要明确: 1. `struct dirent` 是用于文件系统目录项的结构,定义在 `<dirent.h>` 或 `<sys/types.h>` 和 `<sys/dirent.h>` 中。其成员 `d_name` 是一个字符数组,存储的是文件名(以空字符结尾的字符串)。 2. `std::istringstream` 是标准库中的输入字符串流,用于从字符串中读取数据。 因此,我们可以用 `d_name` 中的字符串来构造一个 `std::istringstream` 对象,而不是强制转换(因为强制转换指针类型在这里没有意义,它们是不同的类型)。 具体步骤: 1. 包含必要的头文件:`<sstream>` 用于字符串流,`<dirent.h>` 用于目录操作。 2. 打开目录,读取目录项,获取 `dirent` 结构。 3. 使用 `d_name` 初始化一个 `std::istringstream` 对象。 示例代码: ```cpp #include <iostream> #include <sstream> #include <dirent.h> int main() { DIR *dir = opendir("."); // 打开当前目录 if (dir == nullptr) { perror("opendir"); return 1; } struct dirent *entry; while ((entry = readdir(dir)) != nullptr) { // 使用d_name构造一个istringstream对象 std::istringstream iss(entry->d_name); // 这里直接使用字符串构造 // 现在我们可以使用iss来读取内容,例如按空格分割文件名 std::string token; while (iss >> token) { std::cout << token << std::endl; } } closedir(dir); return 0; } ``` 注意: - 这里我们直接将 `entry->d_name` 作为构造函数的参数传递给 `std::istringstream`。因为 `d_name` 是一个 `char` 数组,可以隐式转换为 `const char*`,而 `std::istringstream` 的构造函数接受 `const std::string&` 或 `const char*`(通过隐式构造 `std::string`)。 - 所以,我们不需要强制转换,而是直接构造。 但是,如果问题是:是否可以将 `d_name` 强制转换为 `std::istringstream*`(指针)?那么答案是不可以,因为它们是无关的类型,强制转换没有意义,而且会导致未定义行为。 总结: 我们可以用 `d_name` 的内容来构造一个 `std::istringstream` 对象(通过构造函数),而不是强制转换。 因此,回答用户的问题:不能强制转换,但是可以用它来构造一个 `std::istringstream` 对象。 另外,注意构造时,`d_name` 必须是一个有效的以空字符结尾的字符串,而 `dirent` 结构中的 `d_name` 正是这样的字符串。 如果用户想要知道是否可以直接使用 `d_name` 来初始化一个字符串流,那么答案是可以的,如上例所示。</think>### 将 `struct dirent::d_name` 转换为 `std::istringstream` 在 C++ 中,`struct dirent` 的 `d_name` 成员是一个 `char` 数组(C 风格字符串),不能直接强制转换为 `std::istringstream`。但可以通过以下方法安全地构造字符串流: #### 正确转换方法 ```cpp #include <dirent.h> #include <sstream> #include <string> void process_dirent(const struct dirent* entry) { // 1. 获取d_name字符串 const char* cstr_name = entry->d_name; // C风格字符串 // 2. 转换为C++ string (隐式转换或显式构造) std::string filename = cstr_name; // 隐式转换 // 3. 构造istringstream std::istringstream iss(filename); // 正确构造字符串流 // 使用示例:解析文件名中的数字 int fileNumber; if (iss >> fileNumber) { std::cout << "文件编号: " << fileNumber << std::endl; } } ``` #### 关键说明 1. **类型特性**: - `d_name` 类型:`char d_name[256]`(POSIX 标准) - `std::istringstream` 需要 `std::string` 或 `const char*` 构造 - 直接强制转换会导致未定义行为 2. **安全步骤**: ```mermaid graph LR A[d_name char[256]] --> B[const char*] B --> C[std::string] C --> D[std::istringstream] ``` 3. **错误处理建议**: ```cpp // 检查空指针 if (!entry || !entry->d_name[0]) { std::cerr << "无效目录项" << std::endl; return; } ``` #### 完整目录遍历示例 ```cpp #include <dirent.h> #include <iostream> #include <sstream> int main() { DIR* dir = opendir("."); if (!dir) { perror("opendir失败"); return EXIT_FAILURE; } while (struct dirent* entry = readdir(dir)) { if (entry->d_type != DT_REG) continue; // 只处理普通文件 std::istringstream iss(entry->d_name); // 隐式构造 std::string prefix; int id; if (iss >> prefix >> id && prefix == "data") { std::cout << "找到数据文件: ID=" << id << std::endl; } } closedir(dir); return EXIT_SUCCESS; } ``` #### 重要注意事项 1. **编码问题**: - Windows 需处理宽字符路径:使用 `std::wistringstream` ```cpp #include <locale> #include <codecvt> std::wstring_convert<std::codecvt_utf8<wchar_t>> converter; std::wstring wname = converter.from_bytes(entry->d_name); std::wistringstream wiss(wname); ``` 2. **内存安全**: - 确保 `d_name` 以 null 结尾(POSIX 保证) - 避免缓冲区溢出:`strnlen(entry->d_name, 255)` 3. **替代方案**: ```cpp // 直接使用C++17 filesystem #include <filesystem> for (auto& entry : std::filesystem::directory_iterator(".")) { std::istringstream iss(entry.path().filename().string()); } ``` > **最佳实践**:优先使用 C++17 的 `<filesystem>` 库进行目录操作,它提供类型安全的路径处理[^1][^3]。 ---
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