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/*
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* getcwdʵ<64><CAB5>˼·<CBBC><C2B7><EFBFBD><EFBFBD><EFBFBD><EFBFBD>֮ǰ<D6AE><C7B0><EFBFBD><EFBFBD>ʵѵ<CAB5><D1B5>дһ<D0B4><D2BB><EFBFBD>Լ<EFBFBD><D4BC><EFBFBD>ls
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* <20><>ʱ<EFBFBD><CAB1><EFBFBD><EFBFBD><EFBFBD><EFBFBD>c<EFBFBD>⺯<EFBFBD><E2BAAF><EFBFBD>е<EFBFBD>opendir,readdir<69><72>closedir<69><72><EFBFBD><EFBFBD>
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* <20><><EFBFBD>Ծ<EFBFBD>ȥc<C8A5><63><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ӧ<EFBFBD>Ľṹ<C4BD><E1B9B9><EFBFBD><EFBFBD>˹<EFBFBD><CBB9><EFBFBD>
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* <20><><EFBFBD>⣬<EFBFBD>ٽ<EFBFBD><D9BD><EFBFBD><EFBFBD>ϵͳ<CFB5><CDB3><EFBFBD>ú<EFBFBD><C3BA><EFBFBD>read,fstat,stat<61><74>chdir
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* <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ʵ<EFBFBD><CAB5><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ͱȽϼ<C8BD><CFBC><EFBFBD>
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*/
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#define __LIBRARY__
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#include <unistd.h>
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#include <string.h>
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#include <errno.h>
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#include <sys/types.h>
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#include <fcntl.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <asm/segment.h>
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#include <sys/stat.h>
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#define BUF_MAX 128
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#define DIRBUF 8192
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#define NAME_MAX 14
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struct dirent { /* Ŀ¼<C4BF><C2BC>ṹ<EFBFBD><E1B9B9> */
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long d_ino; /* i<>ڵ<EFBFBD> */
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off_t d_off; /* λ<><CEBB> */
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unsigned short d_reclen; /* <20>ļ<EFBFBD><C4BC><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> */
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char d_name[NAME_MAX + 1]; /* <20>ļ<EFBFBD><C4BC><EFBFBD> */
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};
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typedef struct
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{
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int dd_fd; /* <20>ļ<EFBFBD><C4BC><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> */
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int dd_loc; /* <20><><EFBFBD><EFBFBD>ƫ<EFBFBD><C6AB> */
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int dd_size; /* <20><>Ч<EFBFBD><D0A7><EFBFBD>ݴ<EFBFBD>С */
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char* dd_buf; /* -> directory block */
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} DIR; /* Ŀ¼<C4BF><C2BC> */
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struct direct {
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ino_t d_ino;
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char d_name[NAME_MAX];
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};
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static struct dirent result;
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/* <20><><EFBFBD><EFBFBD>Ҫ<EFBFBD>õ<EFBFBD><C3B5><EFBFBD><EFBFBD>ں<EFBFBD>ϵͳ<CFB5><CDB3><EFBFBD>ú<EFBFBD><C3BA><EFBFBD> */
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_syscall3(int, read, int, fildes, char*, buf, off_t, count) /* open<65><6E><EFBFBD><EFBFBD><EFBFBD>ļ<EFBFBD><C4BC><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ļ<EFBFBD> */
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_syscall2(int, fstat, int, fildes, struct stat*, stat_buf) /* fstat<61><74><EFBFBD><EFBFBD><EFBFBD>ļ<EFBFBD><C4BC><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ȡ<EFBFBD>ļ<EFBFBD>״̬<D7B4><CCAC>Ϣ<EFBFBD><CFA2><EFBFBD><EFBFBD><EFBFBD><EFBFBD>statָ<74><D6B8>Ľṹ<C4BD><E1B9B9> */
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_syscall2(int, stat, const char*, filename, struct stat*, stat_buf) /* stat<61><74><EFBFBD><EFBFBD><EFBFBD>ļ<EFBFBD><C4BC><EFBFBD><EFBFBD><EFBFBD>ȡ<EFBFBD>ļ<EFBFBD>״̬<D7B4><CCAC>Ϣ<EFBFBD><CFA2><EFBFBD><EFBFBD><EFBFBD><EFBFBD>statָ<74><D6B8>Ľṹ<C4BD><E1B9B9> */
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_syscall1(int, chdir, const char*, filename) /* chdir<69>л<EFBFBD><D0BB><EFBFBD>filename<6D><65><EFBFBD><EFBFBD>Ŀ¼ */
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/* <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>c<EFBFBD><63><EFBFBD>е<EFBFBD>ʵ<EFBFBD><CAB5> */
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struct dirent* readdir(DIR* dir) /* <20><><EFBFBD>ز<EFBFBD><D8B2><EFBFBD>dirĿ¼<C4BF><C2BC><EFBFBD><EFBFBD><EFBFBD>¸<EFBFBD>Ŀ¼<C4BF><C2BC><EFBFBD><EFBFBD><EFBFBD> */
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{ /* <20><>ȡ<EFBFBD><C8A1>Ŀ¼<C4BF><C2BC>Ϣ<EFBFBD><CFA2><EFBFBD><EFBFBD><EFBFBD>ptrָ<72><D6B8><EFBFBD>Ŀ¼<C4BF>ṹ<EFBFBD><E1B9B9><EFBFBD>У<EFBFBD>ֻ<EFBFBD><D6BB>i<EFBFBD>ڵ<EFBFBD><DAB5>Ŀ¼<C4BF><C2BC> */
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struct direct* ptr; /* <20><>ȡ<EFBFBD><C8A1>ǰĿ¼<C4BF><C2BC>ͬʱ<CDAC><CAB1>ȡ<EFBFBD><C8A1><EFBFBD>¸<EFBFBD>Ŀ¼<C4BF><C2BC><EFBFBD><EFBFBD>Ϣ<EFBFBD><CFA2><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>result<6C><74> */
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/* <20><><EFBFBD><EFBFBD>ĩβ<C4A9><CEB2><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>NULL */
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if (!dir) {
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errno = EBADF;
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return NULL;
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}
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if (!dir->dd_buf)
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if (!(dir->dd_buf = malloc(DIRBUF)))
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return NULL;
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else
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dir->dd_size = dir->dd_loc = 0;
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while (1) {
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if (dir->dd_size <= dir->dd_loc) {
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dir->dd_loc = 0;
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dir->dd_size = read(dir->dd_fd, dir->dd_buf, DIRBUF);
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}
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if (dir->dd_size <= 0)
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return NULL;
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ptr = (struct direct*)(dir->dd_loc + dir->dd_buf);
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dir->dd_loc += sizeof(*ptr);
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if (!ptr->d_ino)
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continue;
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result.d_ino = ptr->d_ino;
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strncpy(result.d_name, ptr->d_name, NAME_MAX);
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result.d_name[NAME_MAX] = 0;
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result.d_reclen = strlen(result.d_name);
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return &result;
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}
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}
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int closedir(DIR* dir) /* <20>رղ<D8B1><D5B2><EFBFBD>dir<69><72>ָ<EFBFBD><D6B8><EFBFBD>Ŀ¼<C4BF><C2BC> */
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{
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int fd;
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if (!dir) {
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errno = EBADF;
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return -1;
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}
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fd = dir->dd_fd;
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free(dir->dd_buf);
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free(dir);
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return close(fd);
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}
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DIR* opendir(const char* dirname) /* <20><EFBFBD><F2BFAAB2><EFBFBD>dirnameָ<65><D6B8><EFBFBD><EFBFBD>Ŀ¼<C4BF><C2BC><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>DIR<49><52>̬<EFBFBD><CCAC>Ŀ¼<C4BF><C2BC><EFBFBD><EFBFBD>ʧ<EFBFBD>ܷ<EFBFBD><DCB7><EFBFBD>NULL */
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{
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int fd;
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struct stat stat_buf;
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DIR* ptr;
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if ((fd = open(dirname, O_RDONLY)) < 0) /* ִ<><D6B4>ϵͳ<CFB5><CDB3><EFBFBD><EFBFBD>read<61><64><EFBFBD><EFBFBD>ȡ<EFBFBD>ļ<EFBFBD><C4BC><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> */
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return NULL;
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if (fstat(fd, &stat_buf) < 0 || /* ִ<><D6B4>ϵͳ<CFB5><CDB3><EFBFBD><EFBFBD>fstat<61><74>ͨ<EFBFBD><CDA8><EFBFBD>ļ<EFBFBD><C4BC><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ȡ<EFBFBD>ļ<EFBFBD>״̬<D7B4><CCAC>Ϣ<EFBFBD><CFA2><EFBFBD><EFBFBD><EFBFBD>뻺<EFBFBD><EBBBBA><EFBFBD><EFBFBD>stat_buf */
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!S_ISDIR(stat_buf.st_mode) ||
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!(ptr = malloc(sizeof(*ptr)))) {
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close(fd);
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return NULL;
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}
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memset(ptr, 0, sizeof(*ptr));
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ptr->dd_fd = fd;
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return ptr;
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}
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/* ʵ<><CAB5>getcwd */
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char* sys_getcwd(char* buf, size_t size) {
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char through_name[BUF_MAX], cwd[BUF_MAX];
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DIR* pre_fstream;
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struct dirent* through_stream;
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struct stat current_direct_state, through_state, pre_direct_state;
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dev_t current_direct_dev;
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ino_t current_direct_inum;
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while (1) {
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if (stat(".", ¤t_direct_state == 0)) { /* <20><>ȡ<EFBFBD><C8A1>ǰĿ¼<C4BF><C2BC><EFBFBD>ļ<EFBFBD>״̬<D7B4><CCAC>Ϣ */
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current_direct_dev = current_direct_state.st_dev;
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current_direct_inum = current_direct_state.st_ino;
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}
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pre_fstream = opendir(".."); /* <20><>ȡ<EFBFBD><C8A1>ǰĿ¼<C4BF>ĸ<EFBFBD>Ŀ¼<C4BF><C2BC><EFBFBD>ļ<EFBFBD><C4BC><EFBFBD> */
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stat("..", &pre_direct_state); /* <20><>ȡ<EFBFBD><C8A1>ǰĿ¼<C4BF>ĸ<EFBFBD>Ŀ¼<C4BF><C2BC><EFBFBD>ļ<EFBFBD><C4BC><EFBFBD>Ϣ */
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if (pre_direct_state.st_dev == current_direct_dev && pre_direct_state.st_ino == current_direct_inum)
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break; /* <20><><EFBFBD><EFBFBD><EFBFBD>Ŀ¼<C4BF>͵<EFBFBD>ǰĿ¼<C4BF><C2BC>ͬ<EFBFBD><CDAC>˵<EFBFBD><CBB5><EFBFBD>Ѿ<EFBFBD><D1BE><EFBFBD><EFBFBD>˸<EFBFBD>Ŀ¼<C4BF><C2BC><EFBFBD><EFBFBD>ʱ<EFBFBD>˳<EFBFBD>ѭ<EFBFBD><D1AD> */
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while ((through_stream = readdir(pre_fstream)) != NULL) { /* <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ŀ¼<C4BF>µ<EFBFBD>Ŀ¼<C4BF><EFBFBD><EEA3AC><EFBFBD><EFBFBD>ƥ<EFBFBD><C6A5> */
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memcpy(through_name, through_stream->d_name, BUF_MAX); /* <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ŀ¼<C4BF><C2BC><EFBFBD><EFBFBD><EFBFBD><EFBFBD>֣<EFBFBD><D6A3><EFBFBD><EFBFBD><EFBFBD>ʹ<EFBFBD><CAB9>stat<61><74><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ȡ<EFBFBD><C8A1>״̬<D7B4><CCAC>Ϣ */
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stat(through_name, &through_state); /* <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ŀ¼<C4BF><C2BC><EFBFBD>״̬<D7B4><CCAC>Ϣ<EFBFBD><CFA2><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ƥ<EFBFBD><C6A5> */
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if (current_direct_dev == through_state.st_dev && current_direct_inum == through_state.st_ino) {
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memset(cwd, 0, sizeof(cwd)); /* ƥ<>䵽<EFBFBD>˵<EFBFBD>ǰĿ¼<C4BF><C2BC><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ӵ<EFBFBD>cwd<77><64> */
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strcat(cwd, "/");
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strcat(cwd, through_stream->d_name);
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strcat(cwd, buf); /* buf<75><66>¼<EFBFBD><C2BC><EFBFBD><EFBFBD><EFBFBD><EFBFBD>һ<EFBFBD><D2BB>ѭ<EFBFBD><D1AD><EFBFBD><EFBFBD>cwd<77><64><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ӹ<EFBFBD><D3B8><EFBFBD>ǰѭ<C7B0><D1AD><EFBFBD><EFBFBD>cwd */
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strncpy(buf, cwd, BUF_MAX); /* <20><>cwd<77><64><EFBFBD><EFBFBD><EFBFBD><EFBFBD>buf */
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break;
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}
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}
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closedir(pre_fstream);
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chdir(".."); /* <20>ı䵱ǰĿ¼Ϊ<C2BC>丸Ŀ¼ */
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}
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return buf;
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} |
