summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorErik Nolte <erik_nolte@acm.org>2011-10-06 14:47:26 -0600
committerRichard W.M. Jones <rjones@redhat.com>2011-10-14 10:58:24 +0100
commit65125379903231f1b0c2ccd0929123317c80bcc2 (patch)
tree3c19abc8fe77a3fc60789a0f0c2777e835503f12
parenta98be5ba1deea4f0b46eb4273ea278e3e0eb87ea (diff)
downloadfebootstrap-65125379903231f1b0c2ccd0929123317c80bcc2.zip
febootstrap-65125379903231f1b0c2ccd0929123317c80bcc2.tar.gz
febootstrap-65125379903231f1b0c2ccd0929123317c80bcc2.tar.xz
Replace ArchLinux module detection with generic method.
ArchLinux used to keep its kernel in /boot/vmlinuz26 but, with Linux 3.0, now uses /boot/vmlinuz-linux. Instead of just changing the kernel filename and module directory, this change removes the ArchLinux specific code, lets febootstrap find a kernel, and then computes the module directory from the version string extracted from the actual kernel file.
-rw-r--r--helper/kernel.c156
1 files changed, 96 insertions, 60 deletions
diff --git a/helper/kernel.c b/helper/kernel.c
index 6a68e55..88dc940 100644
--- a/helper/kernel.c
+++ b/helper/kernel.c
@@ -24,6 +24,7 @@
#include <fnmatch.h>
#include <unistd.h>
#include <errno.h>
+#include <sys/utsname.h>
#include "error.h"
#include "xvasprintf.h"
@@ -36,6 +37,9 @@
#define KERNELDIR "/boot"
#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 char *
get_modpath (const char *kernel_name)
{
@@ -49,6 +53,27 @@ get_modpath (const char *kernel_name)
exit (EXIT_FAILURE);
}
+ if (! isdir (modpath)) {
+ char* path;
+ char* version;
+ path = xasprintf (KERNELDIR "/%s", kernel_name);
+ if (!path) {
+ perror ("xasprintf");
+ exit (EXIT_FAILURE);
+ }
+ version = get_kernel_version (path);
+ free (path);
+ if (version != NULL) {
+ free (modpath);
+ modpath = xasprintf (MODULESDIR "/%s", version);
+ free (version);
+ if (!path) {
+ perror ("xasprintf");
+ exit (EXIT_FAILURE);
+ }
+ }
+ }
+
return modpath;
}
@@ -78,9 +103,6 @@ has_modpath (const char *kernel_name)
}
}
-static const char *create_kernel_archlinux (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);
-
/* Create the kernel. This chooses an appropriate kernel and makes a
* symlink to it.
*
@@ -105,10 +127,6 @@ create_kernel (const char *hostcpu, const char *kernel)
return create_kernel_from_env (hostcpu, kernel, kernel_env, modpath_env);
}
- /* In ArchLinux, kernel is always named /boot/vmlinuz26. */
- if (access ("/boot/vmlinuz26", F_OK) == 0)
- return create_kernel_archlinux (hostcpu, kernel);
-
/* In original: ls -1dvr /boot/vmlinuz-*.$arch* 2>/dev/null | grep -v xen */
const char *patt;
if (hostcpu[0] == 'i' && hostcpu[2] == '8' && hostcpu[3] == '6' &&
@@ -163,59 +181,6 @@ create_kernel (const char *hostcpu, const char *kernel)
exit (EXIT_FAILURE);
}
-/* In ArchLinux, kernel is always named /boot/vmlinuz26, and we have
- * to use the 'file' command to work out what version it is.
- */
-static const char *
-create_kernel_archlinux (const char *hostcpu, const char *kernel)
-{
- const char *file_cmd = "file /boot/vmlinuz26 | awk '{print $9}'";
- FILE *pp;
- char modversion[256];
- char *modpath;
- size_t len;
-
- pp = popen (file_cmd, "r");
- if (pp == NULL) {
- error:
- fprintf (stderr, "febootstrap-supermin-helper: %s: command failed\n",
- file_cmd);
- exit (EXIT_FAILURE);
- }
-
- if (fgets (modversion, sizeof modversion, pp) == NULL)
- goto error;
-
- if (pclose (pp) == -1)
- goto error;
-
- /* Chomp final \n */
- len = strlen (modversion);
- if (len > 0 && modversion[len-1] == '\n') {
- modversion[len-1] = '\0';
- len--;
- }
-
- /* Generate module path. */
- modpath = xasprintf (MODULESDIR "/%s", modversion);
-
- /* Check module path is a directory. */
- if (!isdir (modpath)) {
- fprintf (stderr, "febootstrap-supermin-helper: /boot/vmlinuz26 kernel exists but %s is not a valid module path\n",
- modpath);
- exit (EXIT_FAILURE);
- }
-
- if (kernel) {
- /* Symlink from kernel to /boot/vmlinuz26. */
- if (symlink ("/boot/vmlinuz26", kernel) == -1)
- error (EXIT_FAILURE, errno, "symlink kernel");
- }
-
- /* Return module path. */
- return modpath;
-}
-
/* Select the kernel from environment variables set by the user.
* modpath_env may be NULL, in which case we attempt to work it out
* from kernel_env.
@@ -276,3 +241,74 @@ create_kernel_from_env (const char *hostcpu, const char *kernel,
return modpath_env;
}
+
+/* Read an unsigned little endian short at a specified offset in a file.
+ * Returns a non-negative int on success or -1 on failure.
+ */
+static int
+read_leshort (FILE* fp, int offset)
+{
+ char buf[2];
+ if (fseek (fp, offset, SEEK_SET) != 0 ||
+ fread (buf, sizeof(char), 2, fp) != 2)
+ {
+ return -1;
+ }
+ return ((buf[1] & 0xFF) << 8) | (buf[0] & 0xFF);
+}
+
+/* Extract the kernel version from a Linux kernel file.
+ * Returns a malloc'd string containing the version or NULL if the
+ * file can't be read, is not a Linux kernel, or the version can't
+ * be found.
+ *
+ * See ftp://ftp.astron.com/pub/file/file-<ver>.tar.gz
+ * (file-<ver>/magic/Magdir/linux) for the rules used to find the
+ * version number:
+ * 514 string HdrS Linux kernel
+ * >518 leshort >0x1ff
+ * >>(526.s+0x200) string >\0 version %s,
+ *
+ * Bugs: probably limited to x86 kernels.
+ */
+static char*
+get_kernel_version (char* filename)
+{
+ FILE* fp;
+ int size = 132;
+ char buf[size];
+ int offset;
+
+ fp = fopen (filename, "rb");
+
+ if (fseek (fp, 514, SEEK_SET) != 0 ||
+ fgets (buf, size, fp) == NULL ||
+ strncmp (buf, "HdrS", 4) != 0 ||
+ read_leshort (fp, 518) < 0x1FF)
+ {
+ /* not a Linux kernel */
+ fclose (fp);
+ return NULL;
+ }
+
+ offset = read_leshort (fp, 526);
+ if (offset == -1)
+ {
+ /* can't read version offset */
+ fclose (fp);
+ return NULL;
+ }
+
+ if (fseek (fp, offset + 0x200, SEEK_SET) != 0 ||
+ fgets (buf, size, fp) == NULL)
+ {
+ /* can't read version string */
+ fclose (fp);
+ return NULL;
+ }
+
+ fclose (fp);
+
+ buf[strcspn (buf, " \t\n")] = '\0';
+ return strdup (buf);
+}