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/*
* A simple protocol for rdup, if you even want
* to call it a protocol
*
* When rdup output file contents it will do this in blocks.
*
* This removes the filesize race conditions
* and makes everything else somewhat simpler
*
* block header is VERSION BLOCK BLOCKSIZE as in
* 01BLOCK08192
* So a small 4 byte file becomes:
*
* 01BLOCK00004
* <4 bytes of the file>01BLOCK00000
*
* A stop block is a block with length zero 01BLOCK00000, this
* comes after each file.
*/
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <unistd.h>
#include <string.h>
#include <ctype.h>
#include "common.h"
#include "protocol.h"
extern gint opt_verbose;
extern int sig;
/* signal.c */
void got_sig(int);
void signal_abort(int);
/**
* output a block header
*/
gint
block_out_header(FILE *f, size_t size, int fp)
{
char *p;
p = g_strdup_printf("%c%c%s%05d\n", PROTO_VERSION_MAJOR,
PROTO_VERSION_MINOR, PROTO_BLOCK,(int)size);
if (sig != 0)
signal_abort(sig);
if (f) {
if (fwrite(p, sizeof(char), strlen(p), f) != strlen(p))
return -1;
} else if (fp != -1) {
if (write(fp, p, strlen(p)) == -1)
return -1;
}
g_free(p);
return 0;
}
/**
* output a block
*/
gint
block_out(FILE *f, size_t size, char *buf, int fp)
{
if (sig != 0)
signal_abort(sig);
if (f) {
if (fwrite(buf, sizeof(char), size, f) != size)
return -1;
} else if (fp != -1) {
if (write(fp, buf, size) == -1)
return -1;
}
return 0;
}
/**
* read a block from f
*/
gint
block_in(FILE *f, size_t size, char *buf)
{
if (sig != 0)
signal_abort(sig);
if (fread(buf, sizeof(char), size, f) != size) {
/* read less then expected */
return -1;
}
return 0;
}
/**
* parse a block header: 01BLOCK08192
* return the number of bytes to read
* 00000 signals the end (no more bytes to read
* -1 for parse errors
*/
size_t
block_in_header(FILE *f)
{
/* we are expecting a block header:
* 2 pos version; the word block; 5 digit number; newline
*/
char c[6];
int bytes;
/* I cannot think of anything smarter */
/* version check */
c[0] = fgetc(f);
if (sig != 0) signal_abort(sig);
c[1] = fgetc(f);
if (sig != 0) signal_abort(sig);
if (c[0] != PROTO_VERSION_MAJOR ||
c[1] != PROTO_VERSION_MINOR) {
msg(_("Wrong protocol version `%c%c\': want `%c%c'"),
c[0], c[1],
PROTO_VERSION_MAJOR,
PROTO_VERSION_MINOR);
return -1;
}
/* 'block' */
c[0] = fgetc(f); /* B */
if (sig != 0) signal_abort(sig);
c[1] = fgetc(f); /* L */
if (sig != 0) signal_abort(sig);
c[2] = fgetc(f); /* O */
if (sig != 0) signal_abort(sig);
c[3] = fgetc(f); /* C */
if (sig != 0) signal_abort(sig);
c[4] = fgetc(f); /* K */
if (sig != 0) signal_abort(sig);
if (c[0] != 'B' || c[1] != 'L' || c[2] != 'O' ||
c[3] != 'C' || c[4] != 'K') {
msg(_("BLOCK protocol seperator not found: `%c%c%c%c%c\'"),
c[0], c[1], c[2], c[3], c[4]);
return -1;
}
/* the bytes */
c[0] = fgetc(f);
if (sig != 0) signal_abort(sig);
c[1] = fgetc(f);
if (sig != 0) signal_abort(sig);
c[2] = fgetc(f);
if (sig != 0) signal_abort(sig);
c[3] = fgetc(f);
if (sig != 0) signal_abort(sig);
c[4] = fgetc(f);
if (sig != 0) signal_abort(sig);
c[5] = fgetc(f); /* \n */
if (sig != 0) signal_abort(sig);
if (!isdigit(c[0]) || !isdigit(c[1]) || !isdigit(c[2]) ||
!isdigit(c[3]) || !isdigit(c[4])) {
msg(_("Illegal block size"));
return -1;
}
gchar* out = g_strdup_printf("%c%c%c%c%c",
c[0], c[1], c[2], c[3], c[4]);
bytes = atoi(out);
g_free(out);
if (bytes > BUFSIZE) { /* out of bounds...? */
msg(_("Block size larger then BUFSIZE"));
return -1;
}
if (opt_verbose > 2)
msg(_("Block seen, start read of %d bytes"), bytes);
return bytes;
}
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