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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 | /* * linux/fs/readdir.c * * Copyright (C) 1995 Linus Torvalds */ #include <linux/types.h> #include <linux/errno.h> #include <linux/stat.h> #include <linux/kernel.h> #include <linux/sched.h> #include <linux/mm.h> #include <asm/segment.h> /* * Traditional linux readdir() handling.. * * "count=1" is a special case, meaning that the buffer is one * dirent-structure in size and that the code can't handle more * anyway. Thus the special "fillonedir()" function for that * case (the low-level handlers don't need to care about this). */ #define NAME_OFFSET(de) ((int) ((de)->d_name - (char *) (de))) #define ROUND_UP(x) (((x)+sizeof(long)-1) & ~(sizeof(long)-1)) struct old_linux_dirent { unsigned long d_ino; unsigned long d_offset; unsigned short d_namlen; char d_name[1]; }; struct readdir_callback { struct old_linux_dirent * dirent; int count; }; static int fillonedir(void * __buf, const char * name, int namlen, off_t offset, ino_t ino) { struct readdir_callback * buf = (struct readdir_callback *) __buf; struct old_linux_dirent * dirent; if (buf->count) return -EINVAL; buf->count++; dirent = buf->dirent; put_user(ino, &dirent->d_ino); put_user(offset, &dirent->d_offset); put_user(namlen, &dirent->d_namlen); memcpy_tofs(dirent->d_name, name, namlen); put_user(0, dirent->d_name + namlen); return 0; } asmlinkage int old_readdir(unsigned int fd, void * dirent, unsigned int count) { int error; struct file * file; struct readdir_callback buf; if (fd >= NR_OPEN || !(file = current->files->fd[fd])) return -EBADF; if (!file->f_op || !file->f_op->readdir) return -ENOTDIR; error = verify_area(VERIFY_WRITE, dirent, sizeof(struct old_linux_dirent)); if (error) return error; buf.count = 0; buf.dirent = dirent; error = file->f_op->readdir(file->f_inode, file, &buf, fillonedir); if (error < 0) return error; return buf.count; } /* * New, all-improved, singing, dancing, iBCS2-compliant getdents() * interface. */ struct linux_dirent { unsigned long d_ino; unsigned long d_off; unsigned short d_reclen; char d_name[1]; }; struct getdents_callback { struct linux_dirent * current; struct linux_dirent * previous; int count; int error; }; static int filldir(void * __buf, const char * name, int namlen, off_t offset, ino_t ino) { struct linux_dirent * dirent; struct getdents_callback * buf = (struct getdents_callback *) __buf; int reclen = ROUND_UP(NAME_OFFSET(dirent) + namlen + 1); buf->error = -EINVAL; /* only used if we fail.. */ if (reclen > buf->count) return -EINVAL; dirent = buf->previous; if (dirent) put_user(offset, &dirent->d_off); dirent = buf->current; buf->previous = dirent; put_user(ino, &dirent->d_ino); put_user(reclen, &dirent->d_reclen); memcpy_tofs(dirent->d_name, name, namlen); put_user(0, dirent->d_name + namlen); ((char *) dirent) += reclen; buf->current = dirent; buf->count -= reclen; return 0; } asmlinkage int sys_getdents(unsigned int fd, void * dirent, unsigned int count) { struct file * file; struct linux_dirent * lastdirent; struct getdents_callback buf; int error; if (fd >= NR_OPEN || !(file = current->files->fd[fd])) return -EBADF; if (!file->f_op || !file->f_op->readdir) return -ENOTDIR; error = verify_area(VERIFY_WRITE, dirent, count); if (error) return error; buf.current = (struct linux_dirent *) dirent; buf.previous = NULL; buf.count = count; buf.error = 0; error = file->f_op->readdir(file->f_inode, file, &buf, filldir); if (error < 0) return error; lastdirent = buf.previous; if (!lastdirent) return buf.error; put_user(file->f_pos, &lastdirent->d_off); return count - buf.count; } |