/*
** Copyright (C) 2002 by Kevin L. Mitchell <klmitch@mit.edu>
**
** 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, write to the Free Software
** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
**
** @(#)$Id: ringlog.c,v 1.1.2.2 2002/02/06 06:21:53 kev Exp $
*/
/*
* This file contains two separate pieces, along with some common
* gunk. If RINGLOG_INSTRUMENT is defined, the two special functions
* __cyg_profile_func_enter() and __cyg_profile_func_exit() are
* defined; otherwise a main function is defined. The common gunk is
* init_log(), which opens and, if necessary, initializes a special
* binary log file that is treated as a ring buffer (to prevent the
* file from growing unboundedly).
*
* The object produced when compiled with RINGLOG_INSTRUMENT is
* designed to work with the special gcc option
* -finstrument-functions; this option causes the
* __cyg_profile_func_*() functions mentioned above to be called when
* a function is entered or exited. (Of course, ringlog.o should
* *not* be compiled with this option.) These functions will in turn
* call store_entry(), which will call init_log() as needed to open
* the log file, ensure that a start record is output, and then will
* store records for the function calls. The log file used is
* "call.ringlog" in the directory from which the program was
* started.
*
* When RINGLOG_INSTRUMENT is *not* defined while building, a main
* function is defined, and the result is an executable for
* interpretation of a ringlog. Usage is very simple: All arguments
* not beginning with '-' are treated as files to open, and all
* arguments beginning with '-' are treated as a specification for the
* number of entries new files should be created with. If this
* specification is 0 (which it is by default), files will not be
* created if they do not already exist.
*
* For every filename argument, at least one line will be printed
* out. If the file is not empty, the entries in the file will be
* printed out, one to a line. Each entry is numbered with a logical
* number. The entry numbers are followed by a two word description
* of the entry type ("Log start," "Function entry," "Function exit,"
* and "Invalid entry"), followed by a colon (":"), followed by the
* word "addr" and the address of the function, followed by the word
* "call" and the address from which the function was called. The
* ringlog program is not able to convert these addresses to symbols
* or file and line numbers--that can be done with a program like
* addr2line (part of the binutils package). The output has been
* carefully contrived to be parsable by a script.
*
* The file format is documented below. Note that data is stored in
* host byte order.
*
* 1 2 3
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Magic number |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | First entry | Last entry |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Records |
* \ \
* \ \
* | Records |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*
* Record format:
* 1 2 3
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Type code |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Function address |
* / /
* / /
* | Function address |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Calling location |
* / /
* / /
* | Calling location |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*
* Some systems may have pointers larger than 32 bits, which is why these
* fields are allowed to be variable width.
*/
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
/* /etc/magic rules:
*
* 0 belong 0x52e45fd4 RingLog call trace file, big endian
* >4 beshort x (First entry %u,
* >>6 beshort x last entry %u)
* 0 lelong 0x52e45fd4 RingLog call trace file, little endian
* >4 leshort x (First entry %u,
* >>6 leshort x last entry %u)
*/
#define RINGLOG_MAGIC 0x52e45fd4 /* verify file format */
#define RINGLOG_INIT 0x00000000 /* mark when a session was initiated */
#define RINGLOG_ENTER 0x01010101 /* record function entry */
#define RINGLOG_EXIT 0x02020202 /* record function exit */
#define RINGLOG_FNAME "call.ringlog" /* default file name */
#define RINGLOG_ILEN 2000 /* default number of entries */
/* length of the header and of individual entries */
#define HEAD_LEN (sizeof(u_int32_t) + 2 * sizeof(u_int16_t))
#define ENTRY_LEN (sizeof(u_int32_t) + 2 * sizeof(void *))
/* return an lvalue to the specified type stored at the specified location */
#define rl_ref(log, loc, type) (*((type *)((log) + (loc))))
/* access particular header fields */
#define rl_magic(log) rl_ref((log), 0, u_int32_t)
#define rl_first(log) rl_ref((log), 4, u_int16_t)
#define rl_last(log) rl_ref((log), 6, u_int16_t)
/* translate physical entry number to a file location */
#define rl_addr(loc) ((loc) * ENTRY_LEN + HEAD_LEN)
/* extract the type, function, and call fields of an entry */
#define rl_type(log, loc) rl_ref((log), rl_addr(loc), u_int32_t)
#define rl_func(log, loc) rl_ref((log), rl_addr(loc) + sizeof(u_int32_t), \
void *)
#define rl_call(log, loc) rl_ref((log), rl_addr(loc) + sizeof(u_int32_t) + \
sizeof(void *), void *)
static char *log = 0; /* the log has to be global data */
static size_t log_size = 0; /* remember the size of the log */
static int log_length = 0; /* remember how many entries it'll hold */
/* Open and initialize the log file */
static int
init_log(char *fname, size_t init_len)
{
char c = 0;
int fd, err = 0, size = -1;
struct stat buf;
/* open file */
if ((fd = open(fname, O_RDWR | (init_len > 0 ? O_CREAT : 0),
S_IRUSR | S_IWUSR)) < 0)
return errno; /* return error */
if (fstat(fd, &buf)) { /* get size */
err = errno; /* save errno... */
close(fd); /* close file descriptor */
return err; /* return error */
}
if (buf.st_size <= 8) /* too small */
size = HEAD_LEN + ENTRY_LEN * init_len;
else if ((buf.st_size - 8) % ENTRY_LEN) /* not a multiple of entry length */
size = ((buf.st_size - 8) / ENTRY_LEN + 1) * ENTRY_LEN + 8; /* round up */
if (size >= 0) { /* need to set the size */
if (lseek(fd, size - 1, SEEK_SET) < 0) { /* seek to the end of our file */
err = errno; /* save errno... */
close(fd); /* close file descriptor */
return err; /* return error */
}
if (write(fd, &c, 1) < 0) { /* write a zero to set the new size */
err = errno; /* save errno... */
close(fd); /* close file descriptor */
return err; /* return error */
}
log_size = size; /* record log size */
} else
log_size = buf.st_size; /* record log size */
/* map the file to memory */
if ((log = (char *)mmap(0, log_size, PROT_READ | PROT_WRITE,
MAP_SHARED, fd, 0)) == MAP_FAILED)
err = errno; /* save errno... */
close(fd); /* don't need the file descriptor anymore */
if (err) /* an error occurred while mapping the file; return it */
return err;
log_length = (log_size - HEAD_LEN) / ENTRY_LEN; /* store number of entries */
if (rl_magic(log) == 0) { /* initialize if necessary */
rl_magic(log) = RINGLOG_MAGIC;
rl_first(log) = -1;
rl_last(log) = -1;
}
if (rl_magic(log) != RINGLOG_MAGIC) { /* verify file format */
munmap(log, log_size); /* unmap file */
return -1; /* -1 indicates file format error */
}
return 0; /* return success */
}
#ifdef RINGLOG_INSTRUMENT
/* store an entry in the log file */
static void
store_entry(u_int32_t type, void *this_fn, void *call_site)
{
if (!log) { /* open the log file if necessary; die if unable */
assert(init_log(RINGLOG_FNAME, RINGLOG_ILEN) == 0);
store_entry(RINGLOG_INIT, 0, 0); /* mark start of logging */
}
if (++(rl_last(log)) >= log_length) /* select next entry to fill */
rl_last(log) = 0; /* wrap if needed */
if (rl_first(log) == rl_last(log)) { /* advance start pointer if collision */
if (++(rl_first(log)) >= log_length) /* wrap if necessary */
rl_first(log) = 0;
} else if (rl_first(log) == (u_int16_t)-1) /* no entries yet; enter one */
rl_first(log) = 0;
rl_type(log, rl_last(log)) = type; /* record the entry */
rl_func(log, rl_last(log)) = this_fn;
rl_call(log, rl_last(log)) = call_site;
}
/* called upon function entry */
void
__cyg_profile_func_enter(void *this_fn, void *call_site)
{
store_entry(RINGLOG_ENTER, this_fn, call_site);
}
/* called upon function exit */
void
__cyg_profile_func_exit(void *this_fn, void *call_site)
{
store_entry(RINGLOG_EXIT, this_fn, call_site);
}
#else /* !defined(RINGLOG_INSTRUMENT) */
/* converts a type to a printable string */
static char *
get_type(u_int32_t type)
{
switch (type) {
case RINGLOG_INIT:
return " Logging start";
break;
case RINGLOG_ENTER:
return "Function entry";
break;
case RINGLOG_EXIT:
return " Function exit";
break;
}
return " Invalid entry";
}
/* Print out entries from a starting point to an end point */
static void
extract(int *count, u_int16_t start, u_int16_t end)
{
for (; start <= end; start++)
printf("% 4d %s: addr %p call %p\n", (*count)++,
get_type(rl_type(log, start)), rl_func(log, start),
rl_call(log, start));
}
int
main(int argc, char **argv)
{
char *arg;
int i, err, size = 0;
while ((arg = *++argv)) {
if (arg[0] == '-') { /* -<number> turns into log file size */
size = atoi(arg + 1);
continue;
}
log = 0; /* initialize our data */
log_size = 0;
log_length = 0;
switch ((err = init_log(arg, size))) { /* initialize the log */
case -1: /* file is in an invalid format */
printf("File %s not a valid ringlog file\n", arg);
continue;
break;
case 0: /* file has opened and is ready to be read */
break;
default: /* some error occurred */
printf("Error %d opening file %s: %s\n", err, arg, strerror(err));
continue;
break;
}
if (rl_first(log) == (u_int16_t)-1) /* it's an empty file */
printf("File %s is empty\n", arg);
else { /* print out file contents */
printf("File %s contents:\n", arg);
i = 0; /* initialize counter */
if (rl_last(log) <= rl_first(log)) { /* print out log file */
extract(&i, rl_first(log), log_length - 1); /* end of buffer... */
extract(&i, 0, rl_last(log)); /* then beginning of buffer */
} else
extract(&i, rl_first(log), rl_last(log));
}
munmap(log, log_size); /* unmap the file */
}
return 0;
}
#endif /* !RINGLOG_INSTRUMENT */
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