* [RESEND PATCH v4 1/2] Add grub_util_readlink()
@ 2020-01-17 16:10 Javier Martinez Canillas
2020-01-17 16:10 ` [RESEND PATCH v4 2/2] Make editenv chase symlinks including those across devices Javier Martinez Canillas
0 siblings, 1 reply; 3+ messages in thread
From: Javier Martinez Canillas @ 2020-01-17 16:10 UTC (permalink / raw)
To: grub-devel
Cc: Peter Jones, Adam Jackson, Javier Martinez Canillas, Daniel Kiper
From: Peter Jones <pjones@redhat.com>
Currently grub-editenv and related tools are not able to follow symbolic
links when finding their config file. For example the grub-editenv create
command will wrongly overwrite a symlink in /boot/grub2/grubenv with a new
regular file, instead of creating a file in the path the symlink points to.
A following patch will change that and add support in grub-editenv to
follow symbolic links when finding the grub environment variables file.
Add a grub_util_readlink() helper function that is just a wrapper around
the platform specific function to read the value of a symbolic link. This
helper function will be used by the following patch for grub-editenv.
The helper function is not added for Windows, since this operating system
doesn't have a primitive to read the contents of a symbolic link.
Signed-off-by: Peter Jones <pjones@redhat.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
Resending the patches rebased on top of the latest master branch so
they apply cleanly. Sorry for the noise.
Changes in v4:
- Don't add this helper for Windows OS since doesn't support it.
Changes in v3: None
Changes in v2:
- Add a better commit message explaining why the change is needed.
- Add Reviewed-by tag from Daniel Kiper.
include/grub/osdep/hostfile_aros.h | 6 ++++++
include/grub/osdep/hostfile_unix.h | 6 ++++++
2 files changed, 12 insertions(+)
diff --git a/include/grub/osdep/hostfile_aros.h b/include/grub/osdep/hostfile_aros.h
index a059c0fa40a..161fbb7bdfd 100644
--- a/include/grub/osdep/hostfile_aros.h
+++ b/include/grub/osdep/hostfile_aros.h
@@ -68,6 +68,12 @@ grub_util_rename (const char *from, const char *to)
return rename (from, to);
}
+static inline ssize_t
+grub_util_readlink (const char *name, char *buf, size_t bufsize)
+{
+ return readlink(name, buf, bufsize);
+}
+
#define grub_util_mkdir(a) mkdir ((a), 0755)
struct grub_util_fd
diff --git a/include/grub/osdep/hostfile_unix.h b/include/grub/osdep/hostfile_unix.h
index 9ffe46fa3ca..17cd3aa8b30 100644
--- a/include/grub/osdep/hostfile_unix.h
+++ b/include/grub/osdep/hostfile_unix.h
@@ -71,6 +71,12 @@ grub_util_rename (const char *from, const char *to)
return rename (from, to);
}
+static inline ssize_t
+grub_util_readlink (const char *name, char *buf, size_t bufsize)
+{
+ return readlink(name, buf, bufsize);
+}
+
#define grub_util_mkdir(a) mkdir ((a), 0755)
#if defined (__NetBSD__)
--
2.23.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [RESEND PATCH v4 2/2] Make editenv chase symlinks including those across devices
2020-01-17 16:10 [RESEND PATCH v4 1/2] Add grub_util_readlink() Javier Martinez Canillas
@ 2020-01-17 16:10 ` Javier Martinez Canillas
2020-02-11 21:04 ` Daniel Kiper
0 siblings, 1 reply; 3+ messages in thread
From: Javier Martinez Canillas @ 2020-01-17 16:10 UTC (permalink / raw)
To: grub-devel
Cc: Peter Jones, Jonathan Lebon, Adam Jackson, Javier Martinez Canillas
From: Peter Jones <pjones@redhat.com>
The grub-editenv create command will wrongly overwrite /boot/grub2/grubenv
with a regular file if grubenv is a symbolic link. But instead, it should
create a new file in the path the symlink points to.
This lets /boot/grub2/grubenv be a symlink to /boot/efi/EFI/fedora/grubenv
even when they're different mount points, which allows grub2-editenv to be
the same across platforms (i.e. UEFI vs BIOS).
For example, in Fedora the GRUB EFI builds have prefix set to /EFI/fedora
(on the EFI System Partition), but for BIOS machine it'll be /boot/grub2
(which may or may not be its own mountpoint).
With this patch, on EFI machines we can make /boot/grub2/grubenv a symlink
to /boot/efi/EFI/fedora/grubenv, and the same copy of grub-set-default will
work on both kinds of systems.
Windows doesn't implement a readlink primitive, so the current behaviour is
maintained for this operating system.
Signed-off-by: Peter Jones <pjones@redhat.com>
Signed-off-by: Jonathan Lebon <jlebon@redhat.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
---
Changes in v4:
- Only attempt following symlinks in operating sytems other than Windows.
Changes in v3:
- A couple of style cleanups.
Changes in v2:
- Address issues pointed out by Daniel Kiper in the previous version.
Makefile.util.def | 11 ++++++++
util/editenv.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 76 insertions(+)
diff --git a/Makefile.util.def b/Makefile.util.def
index 94336392b9e..51a254f1a6f 100644
--- a/Makefile.util.def
+++ b/Makefile.util.def
@@ -242,8 +242,19 @@ program = {
common = util/grub-editenv.c;
common = util/editenv.c;
+ common = util/grub-install-common.c;
common = grub-core/osdep/init.c;
+ common = grub-core/osdep/compress.c;
+ extra_dist = grub-core/osdep/unix/compress.c;
+ extra_dist = grub-core/osdep/basic/compress.c;
+ common = util/mkimage.c;
+ common = util/grub-mkimage32.c;
+ common = util/grub-mkimage64.c;
+ common = grub-core/osdep/config.c;
+ common = util/config.c;
+ common = util/resolve.c;
+ ldadd = '$(LIBLZMA)';
ldadd = libgrubmods.a;
ldadd = libgrubgcry.a;
ldadd = libgrubkern.a;
diff --git a/util/editenv.c b/util/editenv.c
index 81f68bd107b..c532b046f0e 100644
--- a/util/editenv.c
+++ b/util/editenv.c
@@ -28,6 +28,9 @@
#include <errno.h>
#include <string.h>
+#if !defined(_WIN32)
+#include <libgen.h>
+#endif
#define DEFAULT_ENVBLK_SIZE 1024
#define GRUB_ENVBLK_MESSAGE "# WARNING: Do not edit this file by tools other than "PACKAGE"-editenv!!!\n"
@@ -37,6 +40,11 @@ grub_util_create_envblk_file (const char *name)
{
FILE *fp;
char *buf, *pbuf, *namenew;
+#if !defined(_WIN32)
+ ssize_t size = 1;
+ char *rename_target = xstrdup (name);
+ int rc;
+#endif
buf = xmalloc (DEFAULT_ENVBLK_SIZE);
@@ -64,7 +72,64 @@ grub_util_create_envblk_file (const char *name)
free (buf);
fclose (fp);
+#if defined(_WIN32)
if (grub_util_rename (namenew, name) < 0)
grub_util_error (_("cannot rename the file %s to %s"), namenew, name);
+#else
+ while (1)
+ {
+ char *linkbuf;
+ ssize_t retsize;
+
+ linkbuf = xmalloc (size + 1);
+ retsize = grub_util_readlink (rename_target, linkbuf, size);
+ if (retsize < 0 && (errno == ENOENT || errno == EINVAL))
+ {
+ free (linkbuf);
+ break;
+ }
+ else if (retsize < 0)
+ {
+ free (linkbuf);
+ grub_util_error (_("cannot rename the file %s to %s: %m"), namenew, name);
+ }
+ else if (retsize == size)
+ {
+ free (linkbuf);
+ size += 128;
+ continue;
+ }
+
+ linkbuf[retsize] = '\0';
+ if (linkbuf[0] == '/')
+ {
+ free (rename_target);
+ rename_target = linkbuf;
+ }
+ else
+ {
+ char *dbuf = xstrdup (rename_target);
+ const char *dir = dirname (dbuf);
+
+ free (rename_target);
+ rename_target = xasprintf ("%s/%s", dir, linkbuf);
+ free (dbuf);
+ free (linkbuf);
+ }
+ }
+
+ rc = grub_util_rename (namenew, rename_target);
+ if (rc < 0 && errno == EXDEV)
+ {
+ rc = grub_install_copy_file (namenew, rename_target, 1);
+ grub_util_unlink (namenew);
+ }
+
+ free (rename_target);
+
+ if (rc < 0)
+ grub_util_error (_("cannot rename the file %s to %s: %m"), namenew, name);
+#endif
+
free (namenew);
}
--
2.23.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [RESEND PATCH v4 2/2] Make editenv chase symlinks including those across devices
2020-01-17 16:10 ` [RESEND PATCH v4 2/2] Make editenv chase symlinks including those across devices Javier Martinez Canillas
@ 2020-02-11 21:04 ` Daniel Kiper
0 siblings, 0 replies; 3+ messages in thread
From: Daniel Kiper @ 2020-02-11 21:04 UTC (permalink / raw)
To: Javier Martinez Canillas
Cc: grub-devel, Peter Jones, Jonathan Lebon, Adam Jackson
On Fri, Jan 17, 2020 at 05:10:43PM +0100, Javier Martinez Canillas wrote:
> From: Peter Jones <pjones@redhat.com>
>
> The grub-editenv create command will wrongly overwrite /boot/grub2/grubenv
> with a regular file if grubenv is a symbolic link. But instead, it should
> create a new file in the path the symlink points to.
>
> This lets /boot/grub2/grubenv be a symlink to /boot/efi/EFI/fedora/grubenv
> even when they're different mount points, which allows grub2-editenv to be
> the same across platforms (i.e. UEFI vs BIOS).
>
> For example, in Fedora the GRUB EFI builds have prefix set to /EFI/fedora
> (on the EFI System Partition), but for BIOS machine it'll be /boot/grub2
> (which may or may not be its own mountpoint).
>
> With this patch, on EFI machines we can make /boot/grub2/grubenv a symlink
> to /boot/efi/EFI/fedora/grubenv, and the same copy of grub-set-default will
> work on both kinds of systems.
>
> Windows doesn't implement a readlink primitive, so the current behaviour is
> maintained for this operating system.
>
> Signed-off-by: Peter Jones <pjones@redhat.com>
> Signed-off-by: Jonathan Lebon <jlebon@redhat.com>
> Reviewed-by: Adam Jackson <ajax@redhat.com>
> Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Daniel
^ permalink raw reply [flat|nested] 3+ messages in thread
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2020-01-17 16:10 [RESEND PATCH v4 1/2] Add grub_util_readlink() Javier Martinez Canillas
2020-01-17 16:10 ` [RESEND PATCH v4 2/2] Make editenv chase symlinks including those across devices Javier Martinez Canillas
2020-02-11 21:04 ` Daniel Kiper
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