(read_filesystem_list):

Don't leak memory on failure.
Don't create a dummy struct mount_entry entry;
use the address-of-the-tail-address method instead.
Preserve errno if possible on failure, setting it to 0 if inapplicable.
Close file descriptor leak if the F_SETLKW failed.
Report an error if SVR4 lock file cannot be opened for some reason
other than a nonexistent lock file.

diff --git a/lib/mountlist.c b/lib/mountlist.c
index 58ac26df4e5d1d1be79dd7f0d55574ede1bea0cb..044a77055b0b4f38cc20b80aa3c58ceaba1e0ce3 100644 (file)
--- a/lib/mountlist.c
+++ b/lib/mountlist.c
@@ -292,12 +292,7 @@ read_filesystem_list (need_fs_type, all_fs)
 {
   struct mount_entry *mount_list;
   struct mount_entry *me;
-  struct mount_entry *mtail;
-
-  /* Start the list off with a dummy entry. */
-  me = (struct mount_entry *) xmalloc (sizeof (struct mount_entry));
-  me->me_next = NULL;
-  mount_list = mtail = me;
+  struct mount_entry **mtail = &mount_list;
 
 #ifdef MOUNTED_LISTMNTENT
   {
@@ -320,9 +315,8 @@ read_filesystem_list (need_fs_type, all_fs)
       me->me_mountdir = xstrdup(mnt->mnt_dir);
       me->me_type = xstrdup(mnt->mnt_type);
       me->me_dev = -1;
-      me->me_next = NULL;
-      mtail->me_next = me;
-      mtail = me;
+      *mtail = me;
+      mtail = &me->me_next;
       p = p->next;
     }
     freemntlist(mntlist);
@@ -360,15 +354,14 @@ read_filesystem_list (need_fs_type, all_fs)
          }
        else
          me->me_dev = (dev_t) -1;      /* Magic; means not known yet. */
-       me->me_next = NULL;
 
        /* Add to the linked list. */
-       mtail->me_next = me;
-       mtail = me;
+       *mtail = me;
+       mtail = &me->me_next;
       }
 
     if (endmntent (fp) == 0)
-      return NULL;
+      goto free_then_fail;
   }
 #endif /* MOUNTED_GETMNTENT1. */
 
@@ -387,11 +380,10 @@ read_filesystem_list (need_fs_type, all_fs)
        me->me_mountdir = xstrdup (fsp->f_mntonname);
        me->me_type = fsp_to_string (fsp);
        me->me_dev = (dev_t) -1;        /* Magic; means not known yet. */
-       me->me_next = NULL;
 
        /* Add to the linked list. */
-       mtail->me_next = me;
-       mtail = me;
+       *mtail = me;
+       mtail = &me->me_next;
        fsp++;
       }
   }
@@ -403,22 +395,22 @@ read_filesystem_list (need_fs_type, all_fs)
     int val;
     struct fs_data fsd;
 
-    while ((val = getmnt (&offset, &fsd, sizeof (fsd), NOSTAT_MANY,
-                         (char *) 0)) > 0)
+    while (errno = 0,
+          0 <= (val = getmnt (&offset, &fsd, sizeof (fsd), NOSTAT_MANY,
+                              (char *) 0)))
       {
        me = (struct mount_entry *) xmalloc (sizeof (struct mount_entry));
        me->me_devname = xstrdup (fsd.fd_req.devname);
        me->me_mountdir = xstrdup (fsd.fd_req.path);
        me->me_type = gt_names[fsd.fd_req.fstype];
        me->me_dev = fsd.fd_req.dev;
-       me->me_next = NULL;
 
        /* Add to the linked list. */
-       mtail->me_next = me;
-       mtail = me;
+       *mtail = me;
+       mtail = &me->me_next;
       }
     if (val < 0)
-      return NULL;
+      goto free_then_fail;
   }
 #endif /* MOUNTED_GETMNT. */
 
@@ -448,11 +440,10 @@ read_filesystem_list (need_fs_type, all_fs)
        me->me_mountdir = xstrdup (stats[counter].f_mntonname);
        me->me_type = mnt_names[stats[counter].f_type];
        me->me_dev = (dev_t) -1;        /* Magic; means not known yet. */
-       me->me_next = NULL;
 
        /* Add to the linked list. */
-       mtail->me_next = me;
-       mtail = me;
+       *mtail = me;
+       mtail = &me->me_next;
       }
 
     free (stats);
@@ -493,15 +484,22 @@ read_filesystem_list (need_fs_type, all_fs)
              me->me_type = xstrdup (typebuf);
          }
 # endif
-       me->me_next = NULL;
 
        /* Add to the linked list. */
-       mtail->me_next = me;
-       mtail = me;
+       *mtail = me;
+       mtail = &me->me_next;
+      }
+
+    if (ferror (fp))
+      {
+       int saved_errno = errno;
+       fclose (fp);
+       errno = saved_errno;
+       goto free_then_fail;
       }
 
     if (fclose (fp) == EOF)
-      return NULL;
+      goto free_then_fail;
   }
 #endif /* MOUNTED_FREAD || MOUNTED_FREAD_FSTYP.  */
 
@@ -515,11 +513,10 @@ read_filesystem_list (need_fs_type, all_fs)
        me->me_mountdir = xstrdup( (*ent)->mt_directory);
        me->me_type =  xstrdup ((*ent)->mt_fstype);
        me->me_dev = (dev_t) -1;        /* Magic; means not known yet. */
-       me->me_next = NULL;
 
        /* Add to the linked list. */
-       mtail->me_next = me;
-       mtail = me;
+       *mtail = me;
+       mtail = &me->me_next;
       }
     endmnttbl();
   }
@@ -551,13 +548,21 @@ read_filesystem_list (need_fs_type, all_fs)
        flock.l_len = 0;
        while (fcntl (lockfd, F_SETLKW, &flock) == -1)
          if (errno != EINTR)
-           return NULL;
+           {
+             int saved_errno = errno;
+             close (lockfd);
+             errno = saved_errno;
+             return NULL;
+           }
       }
+    else if (errno != ENOENT)
+      return NULL;
 # endif
 
+    errno = 0;
     fp = fopen (table, "r");
     if (fp == NULL)
-      ret = 1;
+      ret = errno;
     else
       {
        while ((ret = getmntent (fp, &mnt)) == 0)
@@ -571,22 +576,23 @@ read_filesystem_list (need_fs_type, all_fs)
            me->me_mountdir = xstrdup (mnt.mnt_mountp);
            me->me_type = xstrdup (mnt.mnt_fstype);
            me->me_dev = (dev_t) -1;    /* Magic; means not known yet. */
-           me->me_next = NULL;
 
            /* Add to the linked list. */
-           mtail->me_next = me;
-           mtail = me;
+           *mtail = me;
+           mtail = &me->me_next;
          }
 
-       if (fclose (fp) == EOF)
-         ret = 1;
+       ret = fclose (fp) == EOF ? errno : 0 < ret ? 0 : -1;
       }
 
     if (0 <= lockfd && close (lockfd) != 0)
-      return NULL;
+      ret = errno;
 
-    if (ret > 0)
-      return NULL;
+    if (0 <= ret)
+      {
+       errno = ret;
+       goto free_then_fail;
+      }
   }
 #endif /* MOUNTED_GETMNTENT2.  */
 
@@ -628,19 +634,32 @@ read_filesystem_list (need_fs_type, all_fs)
        me->me_mountdir = xstrdup (thisent + vmp->vmt_data[VMT_STUB].vmt_off);
        me->me_type = xstrdup (fstype_to_string (vmp->vmt_gfstype));
        me->me_dev = (dev_t) -1; /* vmt_fsid might be the info we want.  */
-       me->me_next = NULL;
 
        /* Add to the linked list. */
-       mtail->me_next = me;
-       mtail = me;
+       *mtail = me;
+       mtail = &me->me_next;
       }
     free (entries);
   }
 #endif /* MOUNTED_VMOUNT. */
 
-  /* Free the dummy head. */
-  me = mount_list;
-  mount_list = mount_list->me_next;
-  free (me);
+  *mtail = NULL;
   return mount_list;
+
+
+ free_then_fail:
+  {
+    int saved_errno = errno;
+    *mtail = NULL;
+    
+    while (mount_list)
+      {
+       me = mount_list->me_next;
+       free (mount_list);
+       mount_list = me;
+      }
+
+    errno = saved_errno;
+    return NULL;
+  }
 }