1 files changed, 69 insertions, 0 deletions
diff --git a/vmcore-dmesg/vmcore-dmesg.c b/vmcore-dmesg/vmcore-dmesg.c
new file mode 100644
index 0000000..122e536
--- /dev/null
+++ b/vmcore-dmesg/vmcore-dmesg.c
@@ -0,0 +1,69 @@
+#include <elf_info.h>
+
+/* The 32bit and 64bit note headers make it clear we don't care */
+typedef Elf32_Nhdr Elf_Nhdr;
+
+extern const char *fname;
+
+/* stole this macro from kernel printk.c */
+#define LOG_BUF_LEN_MAX (uint32_t)(1U << 31)
+
+static void write_to_stdout(char *buf, unsigned int nr)
+{
+	ssize_t ret;
+	static uint32_t n_bytes = 0;
+
+	n_bytes += nr;
+	if (n_bytes > LOG_BUF_LEN_MAX) {
+		fprintf(stderr, "The vmcore-dmesg.txt over 2G in size is not supported.\n");
+		exit(53);
+	}
+
+	ret = write(STDOUT_FILENO, buf, nr);
+	if (ret != nr) {
+		fprintf(stderr, "Failed to write out the dmesg log buffer!:"
+			" %s\n", strerror(errno));
+		exit(54);
+	}
+}
+
+static int read_vmcore_dmesg(int fd, void (*handler)(char*, unsigned int))
+{
+	int ret;
+
+	ret = read_elf(fd);
+	if (ret > 0) {
+		fprintf(stderr, "Unable to read ELF information"
+			" from vmcore\n");
+		return ret;
+	}
+
+	dump_dmesg(fd, handler);
+
+	return 0;
+}
+
+int main(int argc, char **argv)
+{
+	ssize_t ret;
+	int fd;
+
+	if (argc != 2) {
+		fprintf(stderr, "usage: %s <kernel core file>\n", argv[0]);
+		return 1;
+	}
+	fname = argv[1];
+
+	fd = open(fname, O_RDONLY);
+	if (fd < 0) {
+		fprintf(stderr, "Cannot open %s: %s\n",
+			fname, strerror(errno));
+		return 2;
+	}
+
+	ret = read_vmcore_dmesg(fd, write_to_stdout);
+	
+	close(fd);
+
+	return ret;
+}