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mariadb/storage/archive/archive_reader.c
Davi Arnaut bb036c93b4 Bug#42733: Type-punning warnings when compiling MySQL --
strict aliasing violations.

Essentially, the problem is that large parts of the server were
developed in simpler times (last decades, pre C99 standard) when
strict aliasing and compilers supporting such optimizations were
rare to non-existent. Thus, when compiling the server with a modern
compiler that uses strict aliasing rules to perform optimizations,
there are several places in the code that might trigger undefined
behavior.

As evinced by some recent bugs, GCC does a somewhat good of job
misoptimizing such code, but on the other hand also gives warnings
about suspicious code. One problem is that the warnings aren't
always accurate, yet we can't afford to just shut them off as we
might miss real cases. False-positive cases are aggravated mostly
by casts that are likely to trigger undefined behavior.

The solution is to start a cleanup process focused on fixing and
reducing the amount of strict-aliasing related warnings produced
by GCC and others compilers. A good deal of noise reduction can
be achieved by just removing useless casts that are product of
historical cruft and are likely to trigger undefined behavior if
dereferenced.
2010-06-10 17:16:43 -03:00

405 lines
11 KiB
C

#include "azlib.h"
#include <string.h>
#include <assert.h>
#include <stdio.h>
#include <stdarg.h>
#include <m_ctype.h>
#include <m_string.h>
#include <my_getopt.h>
#include <mysql_version.h>
#define BUFFER_LEN 1024
#define ARCHIVE_ROW_HEADER_SIZE 4
#define SHOW_VERSION "0.1"
static void get_options(int *argc,char * * *argv);
static void print_version(void);
static void usage(void);
static const char *opt_tmpdir;
static const char *new_auto_increment;
unsigned long long new_auto_increment_value;
static const char *load_default_groups[]= { "archive_reader", 0 };
static char **default_argv;
int opt_check, opt_force, opt_quiet, opt_backup= 0, opt_extract_frm;
int opt_autoincrement;
int main(int argc, char *argv[])
{
unsigned int ret;
azio_stream reader_handle;
MY_INIT(argv[0]);
get_options(&argc, &argv);
if (argc < 1)
{
printf("No file specified. \n");
return 0;
}
if (!(ret= azopen(&reader_handle, argv[0], O_RDONLY|O_BINARY)))
{
printf("Could not open Archive file\n");
return 0;
}
if (opt_autoincrement)
{
azio_stream writer_handle;
if (new_auto_increment_value)
{
if (reader_handle.auto_increment >= new_auto_increment_value)
{
printf("Value is lower then current value\n");
goto end;
}
}
else
{
new_auto_increment_value= reader_handle.auto_increment + 1;
}
if (!(ret= azopen(&writer_handle, argv[0], O_CREAT|O_RDWR|O_BINARY)))
{
printf("Could not open file for update: %s\n", argv[0]);
goto end;
}
writer_handle.auto_increment= new_auto_increment_value;
azclose(&writer_handle);
azflush(&reader_handle, Z_SYNC_FLUSH);
}
printf("Version %u\n", reader_handle.version);
if (reader_handle.version > 2)
{
printf("\tMinor version %u\n", reader_handle.minor_version);
printf("\tStart position %llu\n", (unsigned long long)reader_handle.start);
printf("\tBlock size %u\n", reader_handle.block_size);
printf("\tRows %llu\n", reader_handle.rows);
printf("\tAutoincrement %llu\n", reader_handle.auto_increment);
printf("\tCheck Point %llu\n", reader_handle.check_point);
printf("\tForced Flushes %llu\n", reader_handle.forced_flushes);
printf("\tLongest Row %u\n", reader_handle.longest_row);
printf("\tShortest Row %u\n", reader_handle.shortest_row);
printf("\tState %s\n", ( reader_handle.dirty ? "dirty" : "clean"));
printf("\tFRM stored at %u\n", reader_handle.frm_start_pos);
printf("\tComment stored at %u\n", reader_handle.comment_start_pos);
printf("\tData starts at %u\n", (unsigned int)reader_handle.start);
if (reader_handle.frm_start_pos)
printf("\tFRM length %u\n", reader_handle.frm_length);
if (reader_handle.comment_start_pos)
{
char *comment =
(char *) malloc(sizeof(char) * reader_handle.comment_length);
azread_comment(&reader_handle, comment);
printf("\tComment length %u\n\t\t%.*s\n", reader_handle.comment_length,
reader_handle.comment_length, comment);
free(comment);
}
}
else
{
goto end;
}
printf("\n");
if (opt_check)
{
uchar size_buffer[ARCHIVE_ROW_HEADER_SIZE];
int error;
unsigned int x;
unsigned int read;
unsigned int row_len;
unsigned long long row_count= 0;
char buffer;
while ((read= azread(&reader_handle, (uchar *)size_buffer,
ARCHIVE_ROW_HEADER_SIZE, &error)))
{
if (error == Z_STREAM_ERROR || (read && read < ARCHIVE_ROW_HEADER_SIZE))
{
printf("Table is damaged\n");
goto end;
}
/* If we read nothing we are at the end of the file */
if (read == 0 || read != ARCHIVE_ROW_HEADER_SIZE)
break;
row_len= uint4korr(size_buffer);
row_count++;
if (row_len > reader_handle.longest_row)
{
printf("Table is damaged, row %llu is invalid\n",
row_count);
goto end;
}
for (read= x= 0; x < row_len ; x++)
{
read+= (unsigned int)azread(&reader_handle, &buffer, sizeof(char), &error);
if (!read)
break;
}
if (row_len != read)
{
printf("Row length did not match row (at %llu). %u != %u \n",
row_count, row_len, read);
goto end;
}
}
if (0)
{
printf("Table is damaged\n");
goto end;
}
else
{
printf("Found %llu rows\n", row_count);
}
}
if (opt_backup)
{
uchar size_buffer[ARCHIVE_ROW_HEADER_SIZE];
int error;
unsigned int read;
unsigned int row_len;
unsigned long long row_count= 0;
char *buffer;
azio_stream writer_handle;
buffer= (char *)malloc(reader_handle.longest_row);
if (buffer == NULL)
{
printf("Could not allocate memory for row %llu\n", row_count);
goto end;
}
if (!(ret= azopen(&writer_handle, argv[1], O_CREAT|O_RDWR|O_BINARY)))
{
printf("Could not open file for backup: %s\n", argv[1]);
goto end;
}
writer_handle.auto_increment= reader_handle.auto_increment;
if (reader_handle.frm_length)
{
char *ptr;
ptr= (char *)my_malloc(sizeof(char) * reader_handle.frm_length, MYF(0));
azread_frm(&reader_handle, ptr);
azwrite_frm(&writer_handle, ptr, reader_handle.frm_length);
my_free(ptr, MYF(0));
}
if (reader_handle.comment_length)
{
char *ptr;
ptr= (char *)my_malloc(sizeof(char) * reader_handle.comment_length, MYF(0));
azread_comment(&reader_handle, ptr);
azwrite_comment(&writer_handle, ptr, reader_handle.comment_length);
my_free(ptr, MYF(0));
}
while ((read= azread(&reader_handle, (uchar *)size_buffer,
ARCHIVE_ROW_HEADER_SIZE, &error)))
{
if (error == Z_STREAM_ERROR || (read && read < ARCHIVE_ROW_HEADER_SIZE))
{
printf("Table is damaged\n");
goto end;
}
/* If we read nothing we are at the end of the file */
if (read == 0 || read != ARCHIVE_ROW_HEADER_SIZE)
break;
row_len= uint4korr(size_buffer);
row_count++;
memcpy(buffer, size_buffer, ARCHIVE_ROW_HEADER_SIZE);
read= (unsigned int)azread(&reader_handle, buffer + ARCHIVE_ROW_HEADER_SIZE,
row_len, &error);
DBUG_ASSERT(read == row_len);
azwrite(&writer_handle, buffer, row_len + ARCHIVE_ROW_HEADER_SIZE);
if (row_len != read)
{
printf("Row length did not match row (at %llu). %u != %u \n",
row_count, row_len, read);
goto end;
}
if (reader_handle.rows == writer_handle.rows)
break;
}
free(buffer);
azclose(&writer_handle);
}
if (opt_extract_frm)
{
File frm_file;
char *ptr;
frm_file= my_open(argv[1], O_CREAT|O_RDWR|O_BINARY, MYF(0));
ptr= (char *)my_malloc(sizeof(char) * reader_handle.frm_length, MYF(0));
azread_frm(&reader_handle, ptr);
my_write(frm_file, (uchar*) ptr, reader_handle.frm_length, MYF(0));
my_close(frm_file, MYF(0));
my_free(ptr, MYF(0));
}
end:
printf("\n");
azclose(&reader_handle);
return 0;
}
static my_bool
get_one_option(int optid,
const struct my_option *opt __attribute__((unused)),
char *argument)
{
switch (optid) {
case 'b':
opt_backup= 1;
break;
case 'c':
opt_check= 1;
break;
case 'e':
opt_extract_frm= 1;
break;
case 'f':
opt_force= 1;
printf("Not implemented yet\n");
break;
case 'q':
opt_quiet= 1;
printf("Not implemented yet\n");
break;
case 'V':
print_version();
exit(0);
case 't':
printf("Not implemented yet\n");
break;
case 'A':
opt_autoincrement= 1;
if (argument)
new_auto_increment_value= strtoull(argument, NULL, 0);
else
new_auto_increment_value= 0;
break;
case '?':
usage();
exit(0);
case '#':
if (argument == disabled_my_option)
{
DBUG_POP();
}
else
{
DBUG_PUSH(argument ? argument : "d:t:o,/tmp/archive_reader.trace");
}
break;
}
return 0;
}
static struct my_option my_long_options[] =
{
{"backup", 'b',
"Make a backup of an archive table.",
0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0},
{"check", 'c', "Check table for errors.",
0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0},
#ifndef DBUG_OFF
{"debug", '#',
"Output debug log. Often this is 'd:t:o,filename'.",
0, 0, 0, GET_STR, OPT_ARG, 0, 0, 0, 0, 0, 0},
#endif
{"extract-frm", 'e',
"Extract the frm file.",
0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0},
{"force", 'f',
"Restart with -r if there are any errors in the table.",
0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0},
{"help", '?',
"Display this help and exit.",
0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0},
{"quick", 'q', "Faster repair by not modifying the data file.",
0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0},
{"repair", 'r', "Repair a damaged Archive version 3 or above file.",
0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0},
{"set-auto-increment", 'A',
"Force auto_increment to start at this or higher value. If no value is given, then sets the next auto_increment value to the highest used value for the auto key + 1.",
&new_auto_increment, &new_auto_increment,
0, GET_ULL, OPT_ARG, 0, 0, 0, 0, 0, 0},
{"silent", 's',
"Only print errors. One can use two -s to make archive_reader very silent.",
0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0},
{"tmpdir", 't',
"Path for temporary files.",
&opt_tmpdir,
0, 0, GET_STR, REQUIRED_ARG, 0, 0, 0, 0, 0, 0},
{"version", 'V',
"Print version and exit.",
0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0},
{ 0, 0, 0, 0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0}
};
static void usage(void)
{
print_version();
puts("Copyright 2007-2008 MySQL AB, 2008 Sun Microsystems, Inc.");
puts("This software comes with ABSOLUTELY NO WARRANTY. This is free software,\nand you are welcome to modify and redistribute it under the GPL license\n");
puts("Read and modify Archive files directly\n");
printf("Usage: %s [OPTIONS] file_to_be_looked_at [file_for_backup]\n", my_progname);
print_defaults("my", load_default_groups);
my_print_help(my_long_options);
}
static void print_version(void)
{
printf("%s Ver %s Distrib %s, for %s (%s)\n", my_progname, SHOW_VERSION,
MYSQL_SERVER_VERSION, SYSTEM_TYPE, MACHINE_TYPE);
}
static void get_options(int *argc, char ***argv)
{
load_defaults("my", load_default_groups, argc, argv);
default_argv= *argv;
handle_options(argc, argv, my_long_options, get_one_option);
if (*argc == 0)
{
usage();
exit(-1);
}
return;
} /* get options */