Created
July 17, 2020 01:24
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figuring out some things regarding directories
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| #include <err.h> | |
| #include <errno.h> | |
| #include <stdio.h> | |
| #include <stdlib.h> | |
| #include <fcntl.h> | |
| #include <sys/stat.h> | |
| #include <unistd.h> | |
| int main(void) | |
| { | |
| const char *outer_path = "tmpdir"; | |
| const char *inner_path = "inner"; | |
| const char *file_path = "file"; | |
| struct stat sb = {}; | |
| int dirfd = 0; | |
| int error = 0; | |
| error = stat(outer_path, &sb); | |
| if(error != 0 && errno == ENOENT) | |
| { | |
| fprintf(stderr, "stat: ENOENT\n"); | |
| if(mkdir(outer_path, 0750)) | |
| { | |
| err(1, "mkdir"); | |
| } | |
| fprintf(stderr, "mkdir: ok\n"); | |
| error = stat(outer_path, &sb); | |
| } | |
| if(error != 0) | |
| { | |
| err(1, "stat"); | |
| } | |
| fprintf(stderr, "stat: ok\n"); | |
| if(!(sb.st_mode&S_IFDIR)) | |
| { | |
| errx(1, "dir is not a directory: %s", outer_path); | |
| } | |
| fprintf(stderr, "directory: ok\n"); | |
| dirfd = open(outer_path, O_DIRECTORY); | |
| if(dirfd < 0) | |
| { | |
| err(1, "open"); | |
| } | |
| fprintf(stderr, "open: ok\n"); | |
| /* | |
| // if this is enabled the unlinkat call fails with "directory not empty" on this box | |
| if((error = openat(dirfd, file_path, O_CREAT|O_APPEND)) < 0) | |
| { | |
| err(1, "creat"); | |
| } | |
| close(error); | |
| fprintf(stderr, "creat: ok\n"); | |
| //*/ | |
| if(unlinkat(AT_FDCWD, outer_path, AT_REMOVEDIR)) | |
| { | |
| err(1, "unlink"); | |
| } | |
| fprintf(stderr, "unlink: ok\n"); | |
| printf("waiting, press enter to continue\n"); | |
| getchar(); | |
| //* | |
| // this fails with "no such file or directory" | |
| // likely because the directory does have neither `.` nor `..` after the unlinkat, therefore ceasing to exist | |
| if(mkdirat(dirfd, inner_path, 0)) | |
| { | |
| err(1,"mkdirat"); | |
| } | |
| fprintf(stderr, "mkdirat: ok\n"); | |
| //*/ | |
| printf("waiting, press enter to continue\n"); | |
| getchar(); | |
| return 0; | |
| } |
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