ch4. file & directory

◆ stat

 

#include<sys/stat.h>

 int stat(const char *restrict pathname, struct stat *restrict buf);

(ret)  success :  0

                       failed : -1

 

◆ fstat

 

#include<sys/stat.h>

 int fstat(int filedes, struct stat *buf);

(ret)  success :  0

                       failed : -1

 

◆ lstat

 

#include<sys/stat.h>

 int lstat(const char *restrict pathname, struct stat *restrict buf);

(ret)  success :  0

                       failed : -1

 

 

 

#include<stdio.h> #include<stdlib.h> #include<sys/stat.h> int main(int argc, char *argv[]) { int i; struct stat buf; char *ptr; for( i = 1 ; i < argc ; i++) { printf("%s: ",argv[i]); if(lstat(argv[i], &buf)<0) { printf("lstat error\n"); continue; } if(S_ISREG(buf.st_mode)) ptr = "regular"; else if(S_ISDIR(buf.st_mode)) ptr = "directory"; else if(S_ISCHR(buf.st_mode)) ptr = "character special"; else if(S_ISBLK(buf.st_mode)) ptr = "block special"; else if(S_ISFIFO(buf.st_mode)) ptr = "fifo"; else if(S_ISLNK(buf.st_mode)) ptr = "symbolic link"; else if(S_ISSOCK(buf.st_mode)) ptr = "socket"; else ptr = " ** unknown mode ** "; printf( "%s\n", ptr); } exit(0); }

 

 

◆ access

 

#include<unistd.h>

 int access(const char *pathname, int mode);

(ret)  success :  0

                       failed : -1

 

 

 

#include<stdio.h> #include<stdlib.h> #include<fcntl.h> int main(int argc, char *argv[]) { if (argc != 2) { printf("usage : a.out <pathname>\n"); exit(1); } if (access(argv[1], R_OK) < 0) printf("access error for %s\n", argv[1]); else printf("read access OK\n"); if(open(argv[1], O_RDONLY) < 0) printf("open error for %s\n", argv[1]); else printf("open for reading OK\n"); exit(0); }

 

 

◆ umask

 

#include<sys/stat.h>

 mode_t umask(mode_t cmask);

(ret)   이전의 파일 모드 생성 마스크

                       

 

 

◆ chmod

 

#include<sys/stat.h>

 int chmod(const char *pathname, mode_t mode);

(ret)  success :  0

                       failed : -1

 

 

◆ fchmod

 

#include<sys/stat.h>

 int fchmod(int filedes, mode_t mode);

(ret)  success :  0

                       failed : -1

 

 

 

#include<stdio.h> #include<stdlib.h> #include<sys/stat.h> int main(void) { struct stat statbuf; /* turn on set-group-ID and turn off group-execute */ if ( stat("foo", &statbuf) < 0 ) printf("stat error for foo\n"); if(chmod("foo", (statbuf.st_mode & ~S_IXGRP) | S_ISGID) < 0) printf("chmod error for foo\n"); /* set absolute mode to "rw-r--r--" */ if(chmod("bar", S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH) < 0 ) { printf("chmod error for bar\n"); } exit(0); }

 

 

◆ chown

 

#include<unistd.h>

 int chown(const char *pathname, uid_t owner, gid_t group);

(ret)  success :  0

                       failed : -1

 

 

◆ fchown

 

#include<unistd.h>

 int fchown(int filedes, uid_t owner, gid_t group);

(ret)  success :  0

                       failed : -1

 

 

◆ lchown

 

#include<unistd.h>

 int lchown(const char *pathname, uid_t owner, gid_t group);

(ret)  success :  0

                       failed : -1

 

 

◆ truncate

 

#include<unistd.h>

 int truncate(const char *pathname, off_t length);

(ret)  success :  0

                       failed : -1

 

 

◆ ftruncate

 

#include<unistd.h>

 int ftruncate(int filedes, off_t length);

(ret)  success :  0

                       failed : -1

 

 

 

◆ link

 

#include<unistd.h>

 int link(const char *existingpath, const char *newpath);

(ret)  success :  0

                       failed : -1

 

 

◆ unlink

 

#include<unistd.h>

 int unlink(const char *pathname);

(ret)  success :  0

                       failed : -1

 

 

 

#include<stdio.h> #include<stdlib.h> #include<fcntl.h> int main(void) { if( open("tempfile", O_RDWR) < 0) { printf("open error\n"); exit(1); } if( unlink("tempfile") < 0) { printf("unlink error\n"); exit(1); } printf("file unlinked\n"); sleep(15); printf("done\n"); exit(0); }

 

 

 

 

◆ remove

 

#include<stdio.h>

 int remove(const char *pathname);

(ret)  success :  0

                       failed : -1

 

 

◆ rename

 

#include<stdio.h>

 int rename(const char *oldname, const char *newname);

(ret)  success :  0

                       failed : -1

 

 

◆ symlink

 

#include<unistd.h>

 int symlink(const char *actualpath, const char *sympath);

(ret)  success :  0

                       failed : -1

 

 

 

◆ readlink

 

#include<unistd.h>

 int readlink(const char *restrict pathname, char *restrict buf, size_t bufsize);

(ret)  success :  읽은 바이트 수

                       failed : -1

 

 

◆ utime

 

#include<utime.h>

 int utime(const char *pathname, const struct utimbuf *times);

(ret)  success :  0

                       failed : -1

#include<stdio.h> #include<stdlib.h> #include<sys/stat.h> #include<fcntl.h> #include<utime.h> int main(int argc, char *argv[]) { int i, fd; struct stat statbuf; struct utimbuf timebuf; for( i = 1 ; i < argc ; i++ ) { if(stat(argv[i], &statbuf) < 0) { printf("%s : stat error\n", argv[i]); continue; } if( (fd = open(argv[i], O_RDWR | O_TRUNC)) < 0) { printf("%s : open error\n", argv[i]); continue; } close(fd); timebuf.actime = statbuf.st_atime; timebuf.modtime = statbuf.st_mtime; if(utime(argv[i], &timebuf) < 0) { printf("%s : utime error\n", argv[i]); continue; } } exit(0); }

 

 

 

 

 

◆ mkdir

 

#include<sys/stat.h>

 int mkdir(const char *pathname, mode_t mode);

(ret)  success :  0

                       failed :  -1

 

 

◆ rmdir

 

#include<sys/stat.h>

 int rmdir(const char *pathname);

(ret)  success :  0

                       failed :  -1

 

 

 

 

◆ opendir

 

#include<dirent.h>

DIR*  opendir(const char *pathname);

(ret)  success :  포인터

                       failed :  NULL

 

 

◆ readdir

 

#include<dirent.h>

 struct dirent* readdir(DIR *dp);

(ret)  success : 포인터, 디렉토리의 끝일 경우 NULL

                       failed : NULL

 

 

◆ closedir

 

#include<dirent.h>

 int closedir(DIR *dp);

(ret)  success :  0

                       failed : -1

 

 

◆ rewinddir

 

#include<dirent.h>

 void rewinddir(DIR *dp);

 

 

◆ telldir

 

#include<dirent.h>

 long telldir(DIR *dp);

(ret)  dp에 해당하는 디렉토리 안의 현재 위치

 

 

◆ seekdir

 

#include<dirent.h>

 void seekdir(DIR *dp, long loc);

 

#include<stdio.h> #include<stdlib.h> #include<string.h> #include<sys/stat.h> #include<dirent.h> #include<limits.h> #ifndef PATH_MAX #define PATH_MAX 1024 #endif /*function type that is called for each filename*/ typedef int Myfunc(const char *, const struct stat *, int); static Myfunc myfunc; static int myftw(char *, Myfunc *); static int dopath(Myfunc *); static long nreg, ndir, nblk, nchr, nfifo, nslink, nsock, ntot; int main(int argc, char *argv[]) { int ret; if(argc != 2) { printf("usage : ftw <starting-pathname>\n"); exit(1); } ret = myftw(argv[1], myfunc); ntot = nreg + ndir + nblk + nchr + nfifo + nslink + nsock ; if(ntot == 0) ntot=1; printf("regular files = %7ld, %5.2f %%\n", nreg, nreg*100.0/ntot); printf("directories = %7ld, %5.2f %%\n", ndir, ndir*100.0/ntot); printf("block special = %7ld, %5.2f %%\n", nblk, nblk*100.0/ntot); printf("char special = %7ld, %5.2f %%\n", nchr, nchr*100.0/ntot); printf("FIFOs = %7ld, %5.2f %%\n", nfifo, nfifo*100.0/ntot); printf("symbolic links = %7ld, %5.2f %%\n", nslink, nslink*100.0/ntot); printf("sockets = %7ld, %5.2f %%\n", nsock, nsock*100.0/ntot); exit(ret); } #define FTW_F 1 #define FTW_D 2 #define FTW_DNR 3 #define FTW_NS 4 static char *fullpath; static int myftw(char *pathname, Myfunc *func) { fullpath = malloc(PATH_MAX + 1); strncpy(fullpath, pathname, PATH_MAX); fullpath[PATH_MAX - 1] = 0; return (dopath(func)); } static int dopath(Myfunc *func) { struct stat statbuf; struct dirent *dirp; DIR *dp; int ret; char *ptr; if(lstat(fullpath, &statbuf) < 0) return(func(fullpath, &statbuf, FTW_NS)); if(S_ISDIR(statbuf.st_mode) == 0) return(func(fullpath, &statbuf, FTW_F)); if((ret = func(fullpath, &statbuf, FTW_D)) != 0) return(ret); ptr = fullpath + strlen(fullpath); *ptr++ = '/'; *ptr = 0; if( (dp = opendir(fullpath)) == NULL ) return (func(fullpath, &statbuf, FTW_DNR)); while ((dirp = readdir(dp)) != NULL) { if(strcmp(dirp->d_name, ".") == 0 || strcmp(dirp->d_name,"..")== 0) continue; strcpy(ptr, dirp->d_name); if( (ret = dopath(func)) != 0) break; } ptr[-1] = 0; if(closedir(dp) < 0) { printf("can't close directory %s\n", fullpath); exit(0); } return (ret); } static int myfunc(const char *pathname, const struct stat *statptr, int type) { switch(type) { case FTW_F : switch(statptr->st_mode & S_IFMT) { case S_IFREG : nreg++; break; case S_IFBLK : nblk++; break; case S_IFCHR : nchr++; break; case S_IFIFO : nfifo++; break; case S_IFLNK : nslink++; break; case S_IFSOCK : nsock++; break; case S_IFDIR : printf("for S_IFDIR for %s\n", pathname); exit(1); } break; case FTW_D : ndir++; break; case FTW_DNR : printf("can't read directory %s\n", pathname); break; case FTW_NS : printf("stat error for %s\n", pathname); break; default : printf("unknown type %d for pathname %s\n", type, pathname); exit(1); } return (0); }

 

 

 

 

◆ chdir

 

#include<unistd.h>

 int chdir(const char *pathname);

(ret)  success :   0

                       failed :  -1

 

 

◆ fchdir

 

#include<unistd.h>

int fchdir(int filedes);

(ret)  success :  0

                       failed : -1

 

 

 

#include<stdio.h> #include<stdlib.h> #include<unistd.h> int main(void) { if( chdir("/tmp") < 0 ) { printf("chdir failed\n"); exit(1); } printf("chdir to /tmp succeeded\n"); exit(0); }

 

 

 

◆ getcwd

 

#include<unistd.h>

 char* getcwd(char *buf, size_t size);

(ret)  success :  buf

                       failed : NULL

 

 

◆ get_current_dir_name

 

#include<unistd.h>

 char* get_current_dir_name(void);

(ret)  success :  buf

                       failed : NULL

 

 

#include<stdio.h> #include<stdlib.h> #include<unistd.h> #define PATH_MAX 1024 int main(void) { char *ptr; if(chdir("/home/4th_ssu") < 0) { printf("chdir failed\n"); exit(1); } ptr = malloc(PATH_MAX); if(getcwd(ptr, PATH_MAX) == NULL) { printf("getcwd failed\n"); exit(1); } printf("cwd = %s\n", ptr); exit(0); }