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Christoph-Anton Schwierz
EmbeddedLinuxProject
Commits
c247814a
Commit
c247814a
authored
4 months ago
by
Felix Moser
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addedCRC
parent
82deeeff
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1 changed file
main.c
+86
-51
86 additions, 51 deletions
main.c
with
86 additions
and
51 deletions
main.c
+
86
−
51
View file @
c247814a
...
@@ -12,25 +12,64 @@
...
@@ -12,25 +12,64 @@
static
const
char
*
CHAR_DEV
=
"/dev/packet_receiver"
;
static
const
char
*
CHAR_DEV
=
"/dev/packet_receiver"
;
static
const
char
*
SENDER_ID
=
"0x91"
;
// static const char *SENDER_ID = "0x91";
ssize_t
read_pipe
(
int
*
fd
,
char
*
buf
,
size_t
bufSize
,
const
char
*
pipeName
)
{
// Alles mit 0 füllen, um es später einfach als String verarbeiten zu können.
memset
(
buf
,
0
,
bufSize
);
// Blocking read
ssize_t
bytesRead
=
read
(
*
fd
,
buf
,
bufSize
-
1
);
if
(
bytesRead
>
0
)
{
// buf[bytesRead] = '\0'; // Schon durch memset garantiert
return
bytesRead
;
}
if
(
bytesRead
==
0
)
{
// EOF -> Schreibseite geschlossen
printf
(
"Pipe '%s' closed by writer. Reopening...
\n
"
,
pipeName
);
close
(
*
fd
);
// Neu öffnen (blockierend)
*
fd
=
open
(
pipeName
,
O_RDONLY
);
if
(
*
fd
==
-
1
)
{
perror
(
"Reopen pipe"
);
}
// bytesRead = 0 bedeutet hier: wir haben keine Daten
return
0
;
}
char
*
build_crc_checksum
(
const
char
*
payload
)
{
// Fehlerfall (bytesRead < 0)
uLong
crc
=
crc32
(
0L
,
Z_NULL
,
0
);
perror
(
"read pipe"
);
crc
=
crc32
(
crc
,
payload
,
strlen
(
payload
));
return
-
1
;
}
char
*
crc_checksum
=
(
"0x%08lX"
,
crc
);
void
build_package
(
char
*
package
,
size_t
package_size
,
const
char
*
payload
,
int
value_id
)
{
// Zwischenspeicher für die neue Komponente
char
tmp
[
128
];
// VALUE_ID=<id> VALUE=<payload>
snprintf
(
tmp
,
sizeof
(
tmp
),
" VALUE_ID=%d VALUE=%s"
,
value_id
,
payload
);
return
crc_checksum
;
// Hänge tmp an package
strncat
(
package
,
tmp
,
package_size
-
strlen
(
package
)
-
1
);
}
}
char
*
build_package
(
char
const
*
payload
)
{
void
build_crc_checksum
(
char
*
package
,
size_t
package_size
)
{
char
*
crc_checksum
=
build_crc_checksum
(
payload
);
// CRC berechnen
uLong
c
=
crc32
(
0L
,
Z_NULL
,
0
);
c
=
crc32
(
c
,
(
const
Bytef
*
)
package
,
strlen
(
package
));
char
tmp
[
32
];
// z.B. " CRC=0x1A2B3C4D"
snprintf
(
tmp
,
sizeof
(
tmp
),
" CRC=0x%08lX"
,
(
unsigned
long
)
c
);
return
"SENDER=%s %s %s"
,
SENDER_ID
,
payload
,
crc_checksum
;
// ans package anhängen
strncat
(
package
,
tmp
,
package_size
-
strlen
(
package
)
-
1
);
}
}
void
send_package
(
const
char
*
package
,
const
int
fdCharDev
)
{
void
send_package
(
const
char
*
package
,
const
int
fdCharDev
)
{
char
transmitBuf
[
256
]
=
{
0
};
char
transmitBuf
[
256
]
=
{
0
};
// Kopiere Package in transmitBuf
snprintf
(
transmitBuf
,
sizeof
(
transmitBuf
),
package
);
snprintf
(
transmitBuf
,
sizeof
(
transmitBuf
),
package
);
const
ssize_t
written
=
write
(
fdCharDev
,
transmitBuf
,
strlen
(
transmitBuf
));
const
ssize_t
written
=
write
(
fdCharDev
,
transmitBuf
,
strlen
(
transmitBuf
));
...
@@ -41,53 +80,31 @@ void send_package(const char *package, const int fdCharDev) {
...
@@ -41,53 +80,31 @@ void send_package(const char *package, const int fdCharDev) {
}
}
}
}
char
*
read_pipe
(
int
fd
,
char
const
*
pipeName
,
char
*
payload
)
{
char
buf
[
128
]
=
{
0
};
// =========== Lesevorgang Pipe ===========
// read() kann blockieren, wenn noch keine Daten da sind,
// da wir blockierendes I/O verwenden.
// Wenn die Schreibseite offen bleibt, kommen periodisch neue Daten.
const
ssize_t
bytesReadOne
=
read
(
fd
,
buf
,
sizeof
(
buf
));
if
(
bytesReadOne
>
0
)
{
// Gültige Daten -> ausgeben
printf
(
"Value: %s
\n
"
,
buf
);
}
else
if
(
bytesReadOne
==
0
)
{
// EOF -> Schreibseite hat geschlossen
// -> ggf. Pipe erneut öffnen
printf
(
"Pipe closed by writer. Reopening...
\n
"
);
close
(
fd
);
// Neu öffnen
fd
=
open
(
pipeName
,
O_RDONLY
);
if
(
fd
==
-
1
)
{
perror
(
"Reopen pipe"
);
}
}
else
{
// bytesReadOne < 0 => Fehler
if
(
errno
==
EINTR
)
{
// Signal unterbrochen, einfach weiter
return
;
}
perror
(
"read pipe"
);
}
}
// argc = Anzahl Pipes *argv[] Pipe Pfade
// argc = Anzahl Pipes *argv[] Pipe Pfade
int
main
(
const
int
argc
,
char
*
argv
[])
{
int
main
(
const
int
argc
,
char
*
argv
[])
{
int
fds
[
argc
]
;
const
int
num_pipes
=
argc
-
1
;
for
(
int
i
=
0
;
i
<
argc
;
i
++
)
{
int
*
fds
=
calloc
(
num_pipes
,
sizeof
(
int
));
if
(
!
fds
)
{
perror
(
"calloc fds"
);
return
1
;
}
for
(
int
i
=
0
;
i
<
num_pipes
;
i
++
)
{
const
char
*
pipeName
=
argv
[
i
+
1
];
// mkfifo() nur ausführen, wenn die Pipes noch nicht existieren,
// mkfifo() nur ausführen, wenn die Pipes noch nicht existieren,
// bzw. Fehler ignorieren, falls schon existiert:
// bzw. Fehler ignorieren, falls schon existiert:
if
(
mkfifo
(
argv
[
i
]
,
0666
)
<
0
&&
errno
!=
EEXIST
)
{
if
(
mkfifo
(
pipeName
,
0666
)
<
0
&&
errno
!=
EEXIST
)
{
perror
(
"mkfifo pipe"
);
perror
(
"mkfifo pipe"
);
free
(
fds
);
return
1
;
return
1
;
}
}
// Pipes blockierend öffnen
// Pipes blockierend öffnen
fds
[
i
]
=
open
(
argv
[
i
]
,
O_RDONLY
);
fds
[
i
]
=
open
(
pipeName
,
O_RDONLY
);
if
(
fds
[
i
]
==
-
1
)
{
if
(
fds
[
i
]
==
-
1
)
{
perror
(
"open pipeOne for reading"
);
perror
(
"open pipe for reading"
);
free
(
fds
);
return
1
;
return
1
;
}
}
}
}
...
@@ -96,22 +113,40 @@ int main(const int argc, char *argv[]) {
...
@@ -96,22 +113,40 @@ int main(const int argc, char *argv[]) {
const
int
fdCharDev
=
open
(
CHAR_DEV
,
O_WRONLY
);
const
int
fdCharDev
=
open
(
CHAR_DEV
,
O_WRONLY
);
if
(
fdCharDev
==
-
1
)
{
if
(
fdCharDev
==
-
1
)
{
perror
(
"open /dev/packet_receiver"
);
perror
(
"open /dev/packet_receiver"
);
for
(
int
i
=
0
;
i
<
argc
;
i
++
)
{
// Aufräumen
for
(
int
i
=
0
;
i
<
num_pipes
;
i
++
)
{
close
(
fds
[
i
]);
close
(
fds
[
i
]);
}
}
free
(
fds
);
return
1
;
return
1
;
}
}
printf
(
"Opened %s for writing.
\n
"
,
CHAR_DEV
);
printf
(
"Opened %s for writing.
\n
"
,
CHAR_DEV
);
// Dauerhafte Lese-Schleife
// Dauerhafte Lese-Schleife
while
(
1
)
{
while
(
1
)
{
// =========== Lesevorgang Pipes ===========
char
package
[
256
];
for
(
int
i
=
0
;
i
<
argc
;
i
++
)
{
snprintf
(
package
,
sizeof
(
package
),
"SENDER=0x91"
);
read_pipe
(
fds
[
i
],
argv
[
i
]);
// Lese von jeder Pipe und ergänze das Package
for
(
int
i
=
0
;
i
<
num_pipes
;
i
++
)
{
char
pipeBuf
[
128
];
const
ssize_t
ret
=
read_pipe
(
&
fds
[
i
],
pipeBuf
,
sizeof
(
pipeBuf
),
argv
[
i
+
1
]);
if
(
ret
>
0
)
{
// ret Bytes gelesen in pipeBuf -> package anhängen
build_package
(
package
,
sizeof
(
package
),
pipeBuf
,
i
);
}
else
if
(
ret
==
-
1
)
{
// Fehler beim Lesen
fprintf
(
stderr
,
"Error reading from pipe
\n
"
);
free
(
fds
);
return
1
;
}
}
}
// =========== Zum cdev schreiben ===========
// Jetzt an /dev/packet_receiver schicken
if
(
strlen
(
package
)
>
0
)
{
send_package
(
package
,
fdCharDev
);
send_package
(
package
,
fdCharDev
);
}
// Kurze Pause, damit CPU-Last nicht durch
// Kurze Pause, damit CPU-Last nicht durch
// Dauerschleife hochgetrieben wird
// Dauerschleife hochgetrieben wird
...
...
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