[Libguestfs] [PATCH supermin 2/2] helper: Implement --dtb / device tree search.
Richard W.M. Jones
rjones at redhat.com
Fri Sep 6 15:45:07 UTC 2013
From: "Richard W.M. Jones" <rjones at redhat.com>
For architectures such as ARM which require a device tree, this
implements a supermin-helper --dtb option which can be used to search
for a device tree file matching a wildcard.
Usage example:
supermin-helper -f ext2 --dtb 'vexpress-*a9' supermin-d -o /tmp
would find a suitable dtb and symlink it as /tmp/dtb (or exit with an
error is none could be found).
---
helper/helper.h | 2 +-
helper/kernel.c | 115 +++++++++++++++++++++++++++++++++++++++++++++++++-------
helper/main.c | 33 +++++++++++-----
3 files changed, 126 insertions(+), 24 deletions(-)
diff --git a/helper/helper.h b/helper/helper.h
index 281cec9..94ad9e1 100644
--- a/helper/helper.h
+++ b/helper/helper.h
@@ -65,7 +65,7 @@ extern struct writer cpio_writer;
extern struct writer ext2_writer;
/* kernel.c */
-extern const char *create_kernel (const char *hostcpu, const char *kernel);
+extern const char *create_kernel (const char *hostcpu, const char *kernel, const char *dtb_wildcard, const char *dtb);
/* utils.c */
extern void print_timestamped_message (const char *fs, ...);
diff --git a/helper/kernel.c b/helper/kernel.c
index 7957b25..4ff207b 100644
--- a/helper/kernel.c
+++ b/helper/kernel.c
@@ -26,6 +26,7 @@
#include <unistd.h>
#include <errno.h>
#include <sys/utsname.h>
+#include <assert.h>
#include "error.h"
#include "xvasprintf.h"
@@ -44,8 +45,8 @@
#define MODULESDIR "/lib/modules"
static char* get_kernel_version (char* filename);
-static const char *create_kernel_from_env (const char *hostcpu, const char *kernel, const char *kernel_env, const char *modpath_env);
-static void copy_or_symlink_kernel (const char *from, const char *to);
+static const char *create_kernel_from_env (const char *hostcpu, const char *kernel, const char *kernel_env, const char *modpath_env, const char *dtb_wildcard, const char *dtb);
+static void copy_or_symlink_file (const char *what, const char *from, const char *to);
static char *
get_modpath (const char *kernel_name)
@@ -109,8 +110,85 @@ has_modpath (const char *kernel_name)
}
}
-/* Create the kernel. This chooses an appropriate kernel and makes a
- * symlink to it (or copies it if --copy-kernel was passed).
+/* Try to find a device tree file in the kernel's dtb directory which
+ * matches the 'dtb_wildcard' pattern. Copy the file (or symlink it) to
+ * 'dtb'.
+ *
+ * The dtb directory is formed by replacing "vmlinuz-" at the
+ * beginning of the 'kernel' filename with "dtb-".
+ *
+ * We can override the whole lot by setting $SUPERMIN_DTB.
+ */
+static void
+get_dtb (const char *kernel, const char *dtb_wildcard, const char *dtb)
+{
+ char *dtb_env = getenv ("SUPERMIN_DTB");
+ if (dtb_env) {
+ copy_or_symlink_file ("dtb", dtb_env, dtb);
+ return;
+ }
+
+ if (!dtb_wildcard)
+ return;
+
+ assert (dtb); /* command line arg parsing should ensure this */
+ assert (kernel != NULL);
+
+ /* Replace /vmlinuz- with /dtb- */
+ if (strncmp (kernel, "vmlinuz-", 8) != 0) {
+ no_dtb_dir:
+ fprintf (stderr,
+ "supermin-helper: failed to find a dtb (device tree) directory.\n"
+ "I expected to take '%s'\n"
+ "and replace vmlinuz- with dtb- to form a directory.\n"
+ "You can set SUPERMIN_DTB to point to the dtb *file* that should\n"
+ "be used.\n",
+ kernel);
+ exit (EXIT_FAILURE);
+ }
+
+ char *dtb_dir;
+ if (asprintf (&dtb_dir, KERNELDIR "/dtb-%s", &kernel[8]) == -1) {
+ perror ("asprintf");
+ exit (EXIT_FAILURE);
+ }
+
+ /* It should be a directory. */
+ if (!isdir (dtb_dir))
+ goto no_dtb_dir;
+
+ if (verbose)
+ fprintf (stderr, "looking for dtb matching %s in %s\n",
+ dtb_wildcard, dtb_dir);
+
+ /* Look for the wildcard match.
+ * XXX Should probably do some sorting here and/or worry if there
+ * are multiple matches.
+ */
+ char **all_files = read_dir (dtb_dir);
+ char **candidates = filter_fnmatch (all_files, dtb_wildcard, FNM_NOESCAPE);
+
+ if (candidates[0] == NULL) {
+ fprintf (stderr,
+ "supermin-helper: failed to find a matching device tree.\n"
+ "I looked for a file matching '%s' in directory '%s'\n"
+ "You can set SUPERMIN_DTB to point to the dtb file that should\n"
+ "be used.\n",
+ dtb_wildcard, dtb_dir);
+ exit (EXIT_FAILURE);
+ }
+
+ if (verbose)
+ fprintf (stderr, "picked dtb %s\n", candidates[0]);
+
+ char *tmp = xasprintf ("%s/%s", dtb_dir, candidates[0]);
+ copy_or_symlink_file ("dtb", tmp, dtb);
+ free (tmp);
+}
+
+/* Create the kernel and device tree files. This chooses an
+ * appropriate kernel, and optionally a device tree, and makes a
+ * symlink to them (or copies them if --copy-kernel was passed).
*
* Look for the most recent kernel named vmlinuz-*.<arch>* which has a
* corresponding directory in /lib/modules/. If the architecture is
@@ -124,7 +202,8 @@ has_modpath (const char *kernel_name)
* This function returns the module path (ie. /lib/modules/<version>).
*/
const char *
-create_kernel (const char *hostcpu, const char *kernel)
+create_kernel (const char *hostcpu, const char *kernel,
+ const char *dtb_wildcard, const char *dtb)
{
int is_x86; /* x86 but not x86-64 */
int is_arm; /* arm */
@@ -138,7 +217,8 @@ create_kernel (const char *hostcpu, const char *kernel)
char *kernel_env = getenv ("SUPERMIN_KERNEL");
if (kernel_env) {
char *modpath_env = getenv ("SUPERMIN_MODULES");
- return create_kernel_from_env (hostcpu, kernel, kernel_env, modpath_env);
+ return create_kernel_from_env (hostcpu, kernel, kernel_env, modpath_env,
+ dtb_wildcard, dtb);
}
/* In original: ls -1dvr /boot/vmlinuz-*.$arch* 2>/dev/null | grep -v xen */
@@ -176,15 +256,18 @@ create_kernel (const char *hostcpu, const char *kernel)
sort (candidates, reverse_filevercmp);
if (verbose)
- fprintf (stderr, "picked %s\n", candidates[0]);
+ fprintf (stderr, "picked kernel %s\n", candidates[0]);
if (kernel) {
/* Choose the first candidate. */
char *tmp = xasprintf (KERNELDIR "/%s", candidates[0]);
- copy_or_symlink_kernel (tmp, kernel);
+ copy_or_symlink_file ("kernel", tmp, kernel);
free (tmp);
}
+ /* Device tree. */
+ get_dtb (candidates[0], dtb_wildcard, dtb);
+
return get_modpath (candidates[0]);
/* Print more diagnostics here than the old script did. */
@@ -205,7 +288,8 @@ create_kernel (const char *hostcpu, const char *kernel)
*/
static const char *
create_kernel_from_env (const char *hostcpu, const char *kernel,
- const char *kernel_env, const char *modpath_env)
+ const char *kernel_env, const char *modpath_env,
+ const char *dtb_wildcard, const char *dtb)
{
if (verbose) {
fprintf (stderr,
@@ -250,25 +334,28 @@ create_kernel_from_env (const char *hostcpu, const char *kernel,
/* Create the symlink. */
if (kernel)
- copy_or_symlink_kernel (kernel_env, kernel);
+ copy_or_symlink_file ("kernel", kernel_env, kernel);
+
+ /* Device tree. */
+ get_dtb (kernel, dtb_wildcard, dtb);
return modpath_env;
}
static void
-copy_or_symlink_kernel (const char *from, const char *to)
+copy_or_symlink_file (const char *what, const char *from, const char *to)
{
int fd1, fd2;
char buf[BUFSIZ];
ssize_t r;
if (verbose >= 2)
- fprintf (stderr, "%s kernel %s -> %s\n",
- !copy_kernel ? "symlink" : "copy", from, to);
+ fprintf (stderr, "%s %s %s -> %s\n",
+ !copy_kernel ? "symlink" : "copy", what, from, to);
if (!copy_kernel) {
if (symlink (from, to) == -1)
- error (EXIT_FAILURE, errno, "creating kernel symlink %s %s", from, to);
+ error (EXIT_FAILURE, errno, "creating %s symlink %s %s", what, from, to);
}
else {
fd1 = open (from, O_RDONLY | O_CLOEXEC);
diff --git a/helper/main.c b/helper/main.c
index 5632b9f..a4c33dc 100644
--- a/helper/main.c
+++ b/helper/main.c
@@ -187,9 +187,12 @@ main (int argc, char *argv[])
const char *hostcpu = host_cpu;
/* Output files. */
- char *kernel = NULL, *initrd = NULL, *appliance = NULL;
+ char *kernel = NULL, *dtb = NULL, *initrd = NULL, *appliance = NULL;
const char *output_dir = NULL;
+ /* Device tree wildcard (--dtb argument). */
+ const char *dtb_wildcard = NULL;
+
uid_t euid = geteuid ();
gid_t egid = getegid ();
@@ -211,8 +214,8 @@ main (int argc, char *argv[])
copy_kernel = 1;
}
else if (strcmp (long_options[option_index].name, "dtb") == 0) {
- fprintf (stderr, "%s: error: --dtb is not implemented yet\n", argv[0]);
- exit (EXIT_FAILURE);
+ dtb_wildcard = optarg;
+ old_style = false; /* --dtb + old-style wouldn't work anyway */
}
else if (strcmp (long_options[option_index].name, "host-cpu") == 0) {
hostcpu = optarg;
@@ -223,13 +226,8 @@ main (int argc, char *argv[])
old_style = false;
}
else if (strcmp (long_options[option_index].name, "output-dtb") == 0) {
- /*
dtb = optarg;
old_style = false;
- */
- fprintf (stderr, "%s: error: --output-dtb is not implemented yet\n",
- argv[0]);
- exit (EXIT_FAILURE);
}
else if (strcmp (long_options[option_index].name, "output-initrd") == 0) {
initrd = optarg;
@@ -287,6 +285,8 @@ main (int argc, char *argv[])
bool needs_initrd;
bool needs_appliance;
+ bool needs_dtb = dtb_wildcard != NULL;
+
if (strcmp (format, "cpio") == 0) {
writer = &cpio_writer;
needs_kernel = true;
@@ -357,6 +357,15 @@ main (int argc, char *argv[])
}
}
+ if (needs_dtb && !dtb) {
+ if (!output_dir)
+ goto no_output_dir;
+ if (asprintf (&dtb, "%s/dtb", output_dir) == -1) {
+ perror ("asprintf");
+ exit (EXIT_FAILURE);
+ }
+ }
+
if (needs_initrd && !initrd) {
if (!output_dir)
goto no_output_dir;
@@ -387,12 +396,16 @@ main (int argc, char *argv[])
if (verbose) {
print_timestamped_message ("whitelist = %s, "
"host_cpu = %s, "
+ "dtb_wildcard = %s, "
"kernel = %s, "
+ "dtb = %s, "
"initrd = %s, "
"appliance = %s",
whitelist ? : "(not specified)",
hostcpu,
+ dtb_wildcard ? : "(not specified)",
kernel ? : "(none)",
+ dtb ? : "(none)",
initrd ? : "(none)",
appliance ? : "(none)");
int i;
@@ -441,13 +454,15 @@ main (int argc, char *argv[])
/* Remove the output files if they exist. */
if (kernel)
unlink (kernel);
+ if (dtb)
+ unlink (dtb);
if (initrd)
unlink (initrd);
if (appliance)
unlink (appliance);
/* Create kernel output file. */
- const char *modpath = create_kernel (hostcpu, kernel);
+ const char *modpath = create_kernel (hostcpu, kernel, dtb_wildcard, dtb);
if (verbose)
print_timestamped_message ("finished creating kernel");
--
1.8.3.1
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