core/fs/chdir.c

   1 #include <stdio.h>
   2 #include <stdbool.h>
   3 #include <string.h>
   4 #include "fs.h"
   5 #include "cache.h"
   6
   7 /*
   8  * Convert a relative pathname to an absolute pathname
   9  * In the future this might also resolve symlinks...
  10  */
  11 void pm_realpath(com32sys_t *regs)
  12 {
  13     const char *src = MK_PTR(regs->ds, regs->esi.w[0]);
  14     char       *dst = MK_PTR(regs->es, regs->edi.w[0]);
  15
  16     realpath(dst, src, FILENAME_MAX);
  17 }
  18
  19 size_t realpath(char *dst, const char *src, size_t bufsize)
  20 {
  21     if (this_fs->fs_ops->realpath) {
  22         return this_fs->fs_ops->realpath(this_fs, dst, src, bufsize);
  23     } else {
  24         /* Filesystems with "common" pathname resolution */
  25         return snprintf(dst, bufsize, "%s%s",
  26                         src[0] == '/' ? "" : this_fs->cwd_name,
  27                         src);
  28     }
  29 }
  30
  31 int chdir(const char *src)
  32 {
  33     int rv;
  34     struct file *file;
  35     char *p;
  36
  37     if (this_fs->fs_ops->chdir)
  38         return this_fs->fs_ops->chdir(this_fs, src);
  39
  40     /* Otherwise it is a "conventional filesystem" */
  41     rv = searchdir(src);
  42     if (rv < 0)
  43         return rv;
  44
  45     file = handle_to_file(rv);
  46     if (file->inode->mode != DT_DIR) {
  47         _close_file(file);
  48         return -1;
  49     }
  50
  51     put_inode(this_fs->cwd);
  52     this_fs->cwd = get_inode(file->inode);
  53     _close_file(file);
  54
  55     /* Save the current working directory */
  56     realpath(this_fs->cwd_name, src, CURRENTDIR_MAX);
  57     p = strchr(this_fs->cwd_name, '\0');
  58
  59     /* Make sure the cwd_name ends in a slash, it's supposed to be a prefix */
  60     if (p < this_fs->cwd_name + CURRENTDIR_MAX - 1 &&
  61         (p == this_fs->cwd_name || p[1] != '/')) {
  62         p[0] = '/';
  63         p[1] = '\0';
  64     }
  65     return 0;
  66 }