extlinux: centralize file flags setting; add FAT support

Centralize the poking at file flags.
Add FAT support to file flags setting (S bit).

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

diff --git a/extlinux/main.c b/extlinux/main.c
index c6ac87d..d166671 100644 (file)
--- a/extlinux/main.c
+++ b/extlinux/main.c
@@ -1,7 +1,7 @@
 /* ----------------------------------------------------------------------- *
  *
  *   Copyright 1998-2008 H. Peter Anvin - All Rights Reserved
- *   Copyright 2009 Intel Corporation; author: H. Peter Anvin
+ *   Copyright 2009-2010 Intel Corporation; author: H. Peter Anvin
  *
  *   This program is free software; you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
@@ -45,7 +45,12 @@ typedef uint64_t u64;
 #include <linux/hdreg.h>       /* Hard disk geometry */
 #define statfs _kernel_statfs  /* HACK to deal with broken 2.4 distros */
 #include <linux/fs.h>          /* FIGETBSZ, FIBMAP */
+#include <linux/msdos_fs.h>    /* FAT_IOCTL_SET_ATTRIBUTES */
+#ifndef FAT_IOCTL_SET_ATTRIBUTES
+# define FAT_IOCTL_SET_ATTRIBUTES _IOW('r', 0x11, uint32_t)
+#endif
 #undef statfs
+#undef SECTOR_SIZE             /* Garbage from <linux/msdos_fs.h> */
 
 #include "ext2_fs.h"
 #include "btrfs.h"
@@ -61,10 +66,12 @@ typedef uint64_t u64;
 
 /* Global option handling */
 /* Global fs_type for handling fat, ext2/3/4 and btrfs */
-#define EXT2 1
-#define BTRFS 2
-#define VFAT 3
-int fs_type;
+static enum filesystem {
+    NONE,
+    EXT2,
+    BTRFS,
+    VFAT,
+} fs_type;
 
 const char *program;
 
@@ -228,6 +235,67 @@ ssize_t xpwrite(int fd, const void *buf, size_t count, off_t offset)
 }
 
 /*
+ * Set and clear file attributes
+ */
+static void clear_attributes(int fd)
+{
+    struct stat st;
+
+    if (!fstat(fd, &st)) {
+       switch (fs_type) {
+       case EXT2:
+       {
+           int flags;
+
+           if (!ioctl(fd, EXT2_IOC_GETFLAGS, &flags)) {
+               flags &= ~EXT2_IMMUTABLE_FL;
+               ioctl(fd, EXT2_IOC_SETFLAGS, &flags);
+           }
+           break;
+       }
+       case VFAT:
+       {
+           uint32_t attr = 0x00; /* Clear all attributes */
+           ioctl(fd, FAT_IOCTL_SET_ATTRIBUTES, &attr);
+           break;
+       }
+       default:
+           break;
+       }
+       fchmod(fd, st.st_mode | S_IWUSR);
+    }
+}
+
+static void set_attributes(int fd)
+{
+    struct stat st;
+
+    if (!fstat(fd, &st)) {
+       fchmod(fd, st.st_mode & (S_IRUSR | S_IRGRP | S_IROTH));
+       switch (fs_type) {
+       case EXT2:
+       {
+           int flags;
+
+           if (st.st_uid == 0 && !ioctl(fd, EXT2_IOC_GETFLAGS, &flags)) {
+               flags |= EXT2_IMMUTABLE_FL;
+               ioctl(fd, EXT2_IOC_SETFLAGS, &flags);
+           }
+           break;
+       }
+       case VFAT:
+       {
+           uint32_t attr = 0x07; /* Hidden+System+Readonly */
+           ioctl(fd, FAT_IOCTL_SET_ATTRIBUTES, &attr);
+           break;
+       }
+       default:
+           break;
+       }
+    }
+}
+
+/*
  * Produce file map
  */
 int sectmap(int fd, uint32_t * sectors, int nsectors)
@@ -589,7 +657,6 @@ int write_adv(const char *path, int devfd)
     int fd = -1;
     struct stat st, xst;
     int err = 0;
-    int flags, nflags;
 
     if (fs_type == BTRFS) { /* btrfs "extlinux.sys" is in 64k blank area */
        if (xpwrite(devfd, syslinux_adv, 2 * ADV_SIZE,
@@ -623,13 +690,7 @@ int write_adv(const char *path, int devfd)
        err = syslinux_validate_adv(advtmp) ? -2 : 0;
        if (!err) {
            /* Got a good one, write our own ADV here */
-           if (!ioctl(fd, EXT2_IOC_GETFLAGS, &flags)) {
-               nflags = flags & ~EXT2_IMMUTABLE_FL;
-               if (nflags != flags)
-                   ioctl(fd, EXT2_IOC_SETFLAGS, &nflags);
-           }
-           if (!(st.st_mode & S_IWUSR))
-               fchmod(fd, st.st_mode | S_IWUSR);
+           clear_attributes(fd);
 
            /* Need to re-open read-write */
            close(fd);
@@ -648,12 +709,7 @@ int write_adv(const char *path, int devfd)
            }
 
            sync();
-
-           if (!(st.st_mode & S_IWUSR))
-               fchmod(fd, st.st_mode);
-
-           if (nflags != flags)
-               ioctl(fd, EXT2_IOC_SETFLAGS, &flags);
+           set_attributes(fd);
        }
     }
 
@@ -751,8 +807,7 @@ int install_bootblock(int fd, const char *device)
 int ext2_fat_install_file(const char *path, int devfd, struct stat *rst)
 {
     char *file;
-    int fd = -1, dirfd = -1, flags;
-    struct stat st;
+    int fd = -1, dirfd = -1;
     int modbytes;
 
     asprintf(&file, "%s%sextlinux.sys",
@@ -774,15 +829,8 @@ int ext2_fat_install_file(const char *path, int devfd, struct stat *rst)
            perror(file);
            goto bail;
        }
-    } else if (fs_type == EXT2) {
-       /* If file exist, remove the immutable flag and set u+w mode */
-       if (!ioctl(fd, EXT2_IOC_GETFLAGS, &flags)) {
-           flags &= ~EXT2_IMMUTABLE_FL;
-           ioctl(fd, EXT2_IOC_SETFLAGS, &flags);
-       }
-       if (!fstat(fd, &st)) {
-           fchmod(fd, st.st_mode | S_IWUSR);
-       }
+    } else {
+       clear_attributes(fd);
     }
     close(fd);
 
@@ -813,13 +861,7 @@ int ext2_fat_install_file(const char *path, int devfd, struct stat *rst)
 
     /* Attempt to set immutable flag and remove all write access */
     /* Only set immutable flag if file is owned by root */
-    if (!fstat(fd, &st)) {
-       fchmod(fd, st.st_mode & (S_IRUSR | S_IRGRP | S_IROTH));
-       if (st.st_uid == 0 && !ioctl(fd, EXT2_IOC_GETFLAGS, &flags)) {
-           flags |= EXT2_IMMUTABLE_FL;
-           ioctl(fd, EXT2_IOC_SETFLAGS, &flags);
-       }
-    }
+    set_attributes(fd);
 
     if (fstat(fd, rst)) {
        perror(file);