/*
 crash shared object for retrieving systemtap buffer
 Copyright (c) 2007, Hitachi, Ltd.,
 Copyright (C) 2009-2011, Red Hat Inc.
 Created by Satoru Moriya <satoru.moriya.br@hitachi.com>
 Updated by Masami Hiramatsu <mhiramat@redhat.com>

 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; either version 2 of the License, or
 (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/


/* crash/defs.h defines NR_CPUS based upon architecture macros
   X86, X86_64, etc.  See crash/configure.c (!). */
#if !defined(X86) && !defined(X86_64) && !defined(ALPHA) && !defined(PPC) && \
    !defined(IA64) && !defined(PPC64) && !defined(S390) && !defined(S390X) && \
    !defined(ARM) && !defined(ARM64)

#if defined(__alpha__)
#define ALPHA
#elif defined(__x86_64__)
#define X86_64
#elif defined(__i386__)
#define X86
#elif defined(__powerpc64__)
#define PPC64
#elif defined(__powerpc__)
#define PPC
#elif defined(__ia64__)
#define IA64
#elif defined(__s390x__)
#define S390X
#elif defined(__s390__)
#define S390
#elif defined(__aarch64__)
#define ARM64
#elif defined(__arm__)
#define ARM
#else
#warn "unknown architecture for crash/staplog support"
#endif

#endif

#include <crash/defs.h>

struct rchan_offsets {
	long	subbuf_size;
	long	n_subbufs;
	long	buf;
	long	buf_start;
	long	buf_offset;
	long	buf_subbufs_produced;
	long	buf_padding;
};

struct fake_rchan_buf {
	void	*start;
	size_t	offset;
	size_t	subbufs_produced;
	size_t	*padding;
};

struct fake_rchan {
	size_t	subbuf_size;
	size_t	n_subbufs;
};

struct per_cpu_data {
	struct fake_rchan_buf	buf;
};

static struct rchan_offsets rchan_offsets;
static struct fake_rchan chan;
static struct per_cpu_data per_cpu[NR_CPUS];
static FILE *outfp = NULL;
static char *subbuf = NULL;
static int is_global = 0;
static int old_format = 0;
static int retrieve_all = 0;

void cmd_staplog(void);
void cmd_staplog_cleanup(void);
char *help_staplog[];
char *help_staplog_cleanup[];

static struct command_table_entry command_table[] = {
	{"staplog", cmd_staplog, help_staplog, 0},
	{"staplog_cleanup", cmd_staplog_cleanup, help_staplog_cleanup, CLEANUP},
	{NULL, NULL, NULL, 0},
};

static void get_rchan_offsets(void)
{
	rchan_offsets.subbuf_size = MEMBER_OFFSET("rchan", "subbuf_size");
	if (rchan_offsets.subbuf_size < 0)
		goto ERR;
	rchan_offsets.n_subbufs = MEMBER_OFFSET("rchan", "n_subbufs");
	if (rchan_offsets.n_subbufs < 0)
		goto ERR;
	rchan_offsets.buf = MEMBER_OFFSET("rchan", "buf");
	if (rchan_offsets.buf < 0)
		goto ERR;
	rchan_offsets.buf_start = MEMBER_OFFSET("rchan_buf", "start");
	if (rchan_offsets.buf_start < 0)
		goto ERR;
	rchan_offsets.buf_offset = MEMBER_OFFSET("rchan_buf", "offset");
	if (rchan_offsets.buf_offset < 0)
		goto ERR;
	rchan_offsets.buf_subbufs_produced
		= MEMBER_OFFSET("rchan_buf", "subbufs_produced");
	if (rchan_offsets.buf_subbufs_produced < 0)
		goto ERR;
	rchan_offsets.buf_padding = MEMBER_OFFSET("rchan_buf", "padding");
	if (rchan_offsets.buf_padding < 0)
		goto ERR;
	return;
ERR:
	error(FATAL, "cannot get rchan offset\n");
}

/*
 * Here's a description of 'readmem()' from crash:
 *
 * ====
 * readmem() is by far *the* workhorse of this whole program.  It
 * reads memory from /dev/kmem, /dev/mem the dumpfile or /proc/kcore,
 * whichever is appropriate:
 *
 *         addr  a user, kernel or physical memory address.
 *      memtype  addr type: UVADDR, KVADDR, PHYSADDR, XENMACHADDR or
 *               FILEADDR
 *       buffer  supplied buffer to read the data into.
 *         size  number of bytes to read.
 *         type  string describing the request -- helpful when the
 *               read fails.
 * error_handle  what to do if the read fails: FAULT_ON_ERROR kills
 *               the command immediately; RETURN_ON_ERROR returns
 *               FALSE; QUIET suppresses the error message. 
 * ====  
 */

static ulong get_rchan(ulong rchan_addr)
{
	ulong rchan;

	readmem(rchan_addr, KVADDR, &rchan, sizeof(void*),
		"rchan", FAULT_ON_ERROR);
	if (old_format == 1) {
		readmem(rchan + rchan_offsets.subbuf_size,
			KVADDR, &chan.subbuf_size, sizeof(unsigned),
			"rchan.subbuf_size", FAULT_ON_ERROR);
		readmem(rchan + rchan_offsets.n_subbufs,
			KVADDR, &chan.n_subbufs, sizeof(unsigned),
			"rchan.n_subbufs", FAULT_ON_ERROR);
	} else {
		readmem(rchan + rchan_offsets.subbuf_size,
			KVADDR, &chan.subbuf_size, sizeof(size_t),
			"rchan.subbuf_size", FAULT_ON_ERROR);
		readmem(rchan + rchan_offsets.n_subbufs,
			KVADDR, &chan.n_subbufs, sizeof(size_t),
			"rchan.n_subbufs", FAULT_ON_ERROR);
	}

	return rchan;
}

static void get_rchan_buf(int cpu, ulong rchan)
{
	ulong rchan_buf;
	struct per_cpu_data *pcd;

	pcd = &per_cpu[cpu];
	readmem(rchan + rchan_offsets.buf + sizeof(void*) * cpu,
		KVADDR, &rchan_buf, sizeof(void*),
		"rchan.buf", FAULT_ON_ERROR);
	readmem(rchan_buf + rchan_offsets.buf_start,
		KVADDR, &pcd->buf.start, sizeof(void*),
		"rchan.buf.start", FAULT_ON_ERROR);
	if (old_format == 1) {
		readmem(rchan_buf + rchan_offsets.buf_offset,
			KVADDR, &pcd->buf.offset, sizeof(unsigned),
			"rchan.buf.offset", FAULT_ON_ERROR);
		readmem(rchan_buf + rchan_offsets.buf_subbufs_produced,
			KVADDR, &pcd->buf.subbufs_produced, sizeof(int32_t),
			"rchan.buf.subbufs_produced", FAULT_ON_ERROR);
		readmem(rchan_buf + rchan_offsets.buf_padding,
			KVADDR, &pcd->buf.padding, sizeof(unsigned*),
			"rchan.buf.padding", FAULT_ON_ERROR);
	} else {
		readmem(rchan_buf + rchan_offsets.buf_offset,
			KVADDR, &pcd->buf.offset, sizeof(size_t),
			"rchan.buf.offset", FAULT_ON_ERROR);
		readmem(rchan_buf + rchan_offsets.buf_subbufs_produced,
			KVADDR, &pcd->buf.subbufs_produced, sizeof(size_t),
			"rchan.buf.subbufs_produced", FAULT_ON_ERROR);
		readmem(rchan_buf + rchan_offsets.buf_padding,
			KVADDR, &pcd->buf.padding, sizeof(size_t*),
			"rchan.buf.padding", FAULT_ON_ERROR);
	}
	return;
}

static ulong get_rchan_addr(ulong stp_relay_data)
{
	long offset;

	/*
	 * If we can get the member offset of struct
	 * stp_relay_data.flushing, we'll assume this is a system
	 * using STP_TRANSPORT_VERSION 1.  Note that this will fail if
	 * the debuginfo of the trace module isn't available.
         *
         * NB: STP_TRANSPORT_VERSION 1 code has been removed from the
         * bulk of the runtime in 2020-09, so this will always be false.
	 */
	if ((offset = MEMBER_OFFSET("_stp_relay_data_type", "flushing")) > 0) {
		old_format = 1;
	}

	/*
	 * If we can't get the member offset of struct
	 * stp_relay_data.rchan, i.e. the debuginfo of the trace
	 * module isn't available, we use 0 as the offset
	 * instead. Currently struct _stp_relay_data_type is defined
	 * as below:
	 *
	 *     struct _stp_relay_data_type {
	 *             struct rchan *rchan;
	 *             ...
	 *     }
	 *
	 * If the definision of struct _stp_relay_data_type changes,
	 * we must check if this code is correct.
	 */
	if ((offset = MEMBER_OFFSET("_stp_relay_data_type", "rchan")) < 0) {
		error(WARNING, "The debuginfo of the trace module hasn't been loaded.\n"
		      "You may not be able to retrieve the correct trace data.\n");
		offset = 0;
	}

	return (stp_relay_data + (ulong)offset);
}

static int check_global_buffer(ulong rchan)
{
	int cpu;
	ulong rchan_buf[2];

	for (cpu = 0; cpu < 2; cpu++) {
		readmem(rchan + rchan_offsets.buf + sizeof(void*) * cpu,
			KVADDR, &rchan_buf[cpu], sizeof(void*),
			"rchan.buf", FAULT_ON_ERROR);
	}
	if (rchan_buf[0] == rchan_buf[1])
		return 1;
	return 0;
}

static void setup_global_data(char *module)
{
	int i;
	ulong stp_relay_data = 0;
	ulong stp_rchan_addr = 0;
 	ulong rchan;

	stp_relay_data = symbol_value_module("_stp_relay_data", module);
	if (stp_relay_data == 0) {
		error(FATAL,
		      "Failed to find _stp_relay_data in module '%s'.\n",
		      module);
	}

	stp_rchan_addr = get_rchan_addr(stp_relay_data);
	if (stp_rchan_addr == 0) {
		error(FATAL,
		      "Failed to find '_stp_relay_data' in module '%s'.\n",
		      module);
	}

	rchan = get_rchan(stp_rchan_addr);
	for (i = 0; i < kt->cpus; i++)
		get_rchan_buf(i, rchan);

	if (kt->cpus > 1) {
		is_global = check_global_buffer(rchan);
	}
	return;
}

static void create_output_filename(char *buf, int len, int cpu)
{
	if (is_global) {
		snprintf(buf, len, "global");
	} else {
		snprintf(buf, len, "cpu%d", cpu);
	}
}

static void create_output_dir(const char *dirname)
{
	DIR *dir;
	dir = opendir(dirname);
	if (dir) {
		closedir(dir);
	} else {
		if (mkdir(dirname, S_IRWXU) < 0) {
			error(FATAL, "cannot create log directory '%s\n'", dirname);
		}
	}
}

static FILE *open_output_file(const char *dname, const char *fname)
{
	FILE *filp = NULL;
	char *output_file;

	output_file = GETBUF(sizeof(char) * (strlen(dname) + strlen(fname) + 2));
	if (output_file == NULL) {
		error(FATAL,
		      "cannot allocate memory for logfile name '%s%s'\n",
		      dname, fname);
	}

	create_output_dir(dname);
	sprintf(output_file,"%s/%s", dname, fname);

	filp = fopen(output_file, "w");
	if (!filp) {
		error(FATAL, "cannot create log file '%s'\n", output_file);
	}
	FREEBUF(output_file);

	return filp;
}

#define MAX_FNAME 128

static void output_cpu_logs(char *dirname)
{
	int i;
	struct per_cpu_data *pcd;
	size_t n, idx, start, end, len;
	size_t padding;
	char *source, fname[MAX_FNAME + 1];

	/* allocate subbuf memory */
	subbuf = GETBUF(chan.subbuf_size);
	if (!subbuf) {
		error(FATAL, "cannot allocate memory\n");
	}

	for (i = 0; i < kt->cpus; i++) {
		pcd = &per_cpu[i];

		if (pcd->buf.subbufs_produced == 0 && pcd->buf.offset == 0) {
			if (is_global == 1) {
				error(WARNING, "There is no data in the relay buffer.\n");
				break;
			} else {
				error(WARNING, "[cpu:%d]There is no data in the relay buffer.\n", i);
				continue;
			}
		}

		end = pcd->buf.subbufs_produced + 1;
		if (pcd->buf.subbufs_produced >= chan.n_subbufs) {
			start = end - chan.n_subbufs;
		} else {
			start = 0;
		}

		create_output_filename(fname, MAX_FNAME, i);
		fprintf(fp, "--- generating '%s/%s' ---\n", dirname, fname);
		fprintf(fp, "  subbufs ready on relayfs:%ld\n", (long)end);
		fprintf(fp, "  n_subbufs:%ld, read subbuf from:%ld(%ld) "
			"to:%ld(%ld) (offset:0-%ld)\n\n",
			(long)chan.n_subbufs,
			(long)start,
			(long)(start % chan.n_subbufs),
			(long)end-1,
			(long)((end-1) % chan.n_subbufs),
			(long) pcd->buf.offset);
		outfp = open_output_file(dirname, fname);

		for (n = start; n < end; n++) {
			/* read relayfs subbufs and write to log file */
			idx = n % chan.n_subbufs;
			source = pcd->buf.start + idx * chan.subbuf_size;
			if (old_format == 1) {
				readmem((ulong)pcd->buf.padding + sizeof(unsigned) * idx,
					KVADDR, &padding, sizeof(unsigned),
					"padding", FAULT_ON_ERROR);
			} else {
				readmem((ulong)pcd->buf.padding + sizeof(padding) * idx,
					KVADDR, &padding, sizeof(padding),
					"padding", FAULT_ON_ERROR);
			}
			if (n == end - 1) {
				len = pcd->buf.offset;
			} else {
				len = chan.subbuf_size;
			}

			if (old_format == 1) {
				source += sizeof(unsigned int);
				len -= sizeof(unsigned int) + padding;
			} else {
				len -= padding;
			}
			if (len > 0) {
				readmem((ulong)source, KVADDR, subbuf, len,
					"subbuf", FAULT_ON_ERROR);
				if (fwrite(subbuf, len, 1, outfp) != 1) {
					error(FATAL, "cannot write log data\n");
				}
			}
		}
		fclose(outfp);
		outfp = NULL;

		/*
		 * -a option retrieve the old data of subbuffer where the
		 * probe record is written at that time.
		 */
		if (retrieve_all == 1 && start != 0) {
			strncat(fname, ".may_broken", MAX_FNAME - 1);
			fprintf(fp, "--- generating '%s/%s' ---\n", dirname, fname);
			fprintf(fp, "  read subbuf %ld(%ld) (offset:%ld-%ld)\n",
				(long)start-1,
				(long)((start-1) % chan.n_subbufs),
				(long)pcd->buf.offset,
				(long)chan.subbuf_size);
			outfp = open_output_file(dirname, fname);

			idx = (start - 1) % chan.n_subbufs;
			source = pcd->buf.start + idx * chan.subbuf_size +
				 pcd->buf.offset;
			len = chan.subbuf_size - pcd->buf.offset;
			if (len) {
				readmem((ulong)source, KVADDR, subbuf, len,
					"may_broken_subbuf", FAULT_ON_ERROR);
				if (fwrite(subbuf, len, 1, outfp) != 1) {
					error(FATAL,
					      "cannot write log data(may_broken)\n");
				}
			}
			fclose(outfp);
			outfp = NULL;
		}
		if (is_global == 1)
			break;
	}
	if (subbuf) {
		FREEBUF(subbuf);
		subbuf = NULL;
	}
	return;
}

void cmd_staplog(void)
{

	int c;
	char *module = NULL;
	char *dirname = NULL;

	while ((c = getopt(argcnt, args, "+ao:")) != EOF) {
		switch (c) {
		case 'a':
			retrieve_all = 1;
			break;
		case 'o':
			dirname = optarg;
			break;
		default:
			argerrs++;
			break;
		}
	}
	module = args[optind];

	if (!module || argerrs)
		cmd_usage(pc->curcmd, SYNOPSIS);

	if (dirname == NULL && module != NULL)
		dirname = module;

	setup_global_data(module);
	assert(dirname);
	output_cpu_logs(dirname);
	return;
}

void cmd_staplog_cleanup(void)
{
	if (outfp) {
		fclose(outfp);
		outfp = NULL;
	}
	return;
}

char *help_staplog[] = {
	"systemtaplog",
	"Retrieve SystemTap log data",
	"[-a] [-o dir_name] module_name",
	"  Retrieve SystemTap's log data and write them to files.\n",
	"  All valid SystemTap's log data made by the trace module which name",
	"  is 'module_name' are written into log files. This command starts",
	"  to retrieve log data from the subbuffer which is next to current",
	"  written subbuffer. Therefore some old data in the current written",
	"  subbuffer may not be retrieved. But -a option retrieves these data",
	"  and write them into another log file which have the special ",
	"  postfix `.may_broken`.",
	"  If you don't use -o option, the log files are created in",
	"  `module_name` directory. The name of each log file is cpu0, cpu1..",
	"  ...cpuN. This command doesn't change the log data format, but remove",
 	"  only padding.",
	"",
	"              -a    Retrieve the old data which is recorded in",
	"                    current written subbuffer and create another files",
	"                    which have the special postfix `.may_broken`",
	"                    for these data.",
	"    -o file_name    Specify the output directory.",
	NULL,
};

char *help_staplog_cleanup[] = {
	"systemtaplog cleanup (hidden)",
	"Cleanup command for staplog",
	"",
	"  This command is called during restore_sanity() prior to each ",
	"  command prompt to close the files which was opened and failed to",
	"  close by staplog command.",
	NULL,
};

static void __attribute__ ((constructor)) _init(void)
{
	get_rchan_offsets();
	register_extension(command_table);
	return;
}


static void __attribute__ ((destructor)) _fini(void)
{
	return;
}