ramoops: scripts/ramoops.c for extracting oopses

new file mode 100644
index 0000000..25cc7c5
@@ -0,0 +1,175 @@
+/*
+ * ramoops: Extract ramoops images from /dev/mem.
+ *
+ * Copyright (C) 2011 Thomas Tuttle <[email protected]>
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file COPYING in the main directory of the Linux
+ * distribution for more details.
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+static char *progn;
+
+static void read_long(char *name, unsigned long *out)
+{
+	FILE *f = fopen(name, "r");
+	if (!f) {
+		fprintf(stderr, "%s: %s: %s\n",
+			progn, name, strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	if (fscanf(f, "%lu", out) < 1) {
+		fprintf(stderr, "%s: %s: couldn't read a number\n",
+			progn, name);
+		exit(EXIT_FAILURE);
+	}
+
+	fclose(f);
+}
+
+static const char *MEM_NAME = "/dev/mem";
+
+static FILE *open_mem(void)
+{
+	FILE *mem = fopen(MEM_NAME, "r");
+	if (!mem) {
+		fprintf(stderr, "%s: open %s: %s\n",
+			progn, MEM_NAME, strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+	return mem;
+}
+
+static void seek_mem(FILE *mem, unsigned long off)
+{
+	if (fseek(mem, off, SEEK_SET) < 0) {
+		fprintf(stderr, "%s: seek %s: %s\n",
+			progn, MEM_NAME, strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+}
+
+static void read_mem(FILE *mem, char *buf, unsigned long len)
+{
+	size_t res;
+
+	res = fread(buf, 1, len, mem);
+	if (res == 0 && ferror(mem)) {
+		fprintf(stderr, "%s: read %s: %s\n",
+			progn, MEM_NAME, strerror(errno));
+		exit(EXIT_FAILURE);
+	} else if (res < len) {
+		fprintf(stderr, "%s: read %s: short read\n",
+			progn, MEM_NAME);
+		exit(EXIT_FAILURE);
+	}
+}
+
+static void putsn(const char *s, size_t n)
+{
+	while (*s && n-- > 0)
+		putchar(*s++);
+}
+
+static int check_record(char *buf, char *time_out, size_t time_len)
+{
+	static const char *MAGIC = "====";
+	static const size_t MAGIC_LEN = 4;
+
+	char *s;
+
+	if (memcmp(buf, MAGIC, MAGIC_LEN))
+		return 0;
+
+	s = buf + MAGIC_LEN;
+	while (*s != '\n' && --time_len > 0)
+		*time_out++ = *s++;
+	*time_out = '\0';
+
+	return 1;
+}
+
+static const int REC_LIST = -1;
+
+#define RAMOOPS_PARAM "/sys/module/ramoops/parameters/"
+
+static int print_record(int record, int contents, FILE *mem,
+			unsigned long record_size, char *buf)
+{
+	static const size_t TIME_LEN = 64;
+
+	char time[TIME_LEN];
+
+	read_mem(mem, buf, record_size);
+	fprintf(stderr, "ramoops record %d: ", record);
+	if (check_record(buf, time, TIME_LEN)) {
+		fprintf(stderr, "valid, timestamp %s\n", time);
+		if (contents)
+			putsn(buf, record_size);
+		return 0;
+	} else {
+		fprintf(stderr, "invalid\n");
+		return 1;
+	}
+}
+
+static int print_records(int record)
+{
+	unsigned long mem_address, mem_size, record_size, num_records;
+	FILE *mem;
+	int i;
+	int ret = 0;
+
+	read_long(RAMOOPS_PARAM "mem_address", &mem_address);
+	read_long(RAMOOPS_PARAM "mem_size",    &mem_size);
+	read_long(RAMOOPS_PARAM "record_size", &record_size);
+	num_records = mem_size / record_size;
+
+	if (record != REC_LIST &&
+	    (record < 0 || (unsigned long)record >= num_records)) {
+		fprintf(stderr, "%s: record number %d out of range [0, %ld)\n",
+			progn, record, num_records);
+		return 1;
+	}
+
+	buf = malloc(record_size);
+	if (!buf) {
+		fprintf(stderr, "%s: failed to allocate record buffer\n",
+			progn);
+		return 1;
+	}
+
+	mem = open_mem();
+	if (record == REC_LIST) {
+		seek_mem(mem, mem_address);
+		for (i = 0; i < (int)num_records; i++)
+			print_record(i, 0, mem, record_size, buf);
+	} else {
+		seek_mem(mem, mem_address + record * record_size);
+		ret = print_record(record, 1, mem, record_size, buf);
+	}
+	fclose(mem);
+
+	return ret;
+}
+
+int main(int argc, char *argv[])
+{
+	progn = argv[0];
+
+	switch (argc) {
+	case 1:
+		return print_records(REC_LIST);
+	case 2:
+		return print_records(atoi(argv[1]));
+	default:
+		fprintf(stderr, "Usage: %s [record]\n", progn);
+		return 1;
+	}
+}