Read() stuck on trying to read file
I have a checkpoint file that receives a server state. This states represents serialized commands that pass trough my network.
I'm trying to read the file but the it gets stuck on the read while loop.
My read function:
struct message_t *pmanager_readop(int fd){
if (fd < 0) return NULL;
// Variables
char *buffer = NULL;
int result, msg_size;
struct message_t *msg;
// Check if file has data
lseek (fd, 0, SEEK_END);
int size_ckp = lseek(fd, 0, SEEK_CUR);
if (size_ckp <= 0)
return NULL;
// Read message size
result = read_all(fd, (char *) &msg_size, 4);
if (result < 0) {
return NULL;
}
msg_size = ntohl(msg_size);
// ............
My read_all() function:
int read_all(int sock, char *buf, int len){
int bufsize = len;
while(len > 0){
int res = read(sock,buf,len);
if(res < 0){
if (errno == EINTR) continue;
return res;
}
buf += res;
len -= res;
}
return bufsize;
}
I use this same function to read data from my server/client connection with the same serialization and format but with a socket descriptor, and it works perfectly.
c file io
asked Nov 25 '18 at 16:14
Filipe NóbregaFilipe Nóbrega
11318
add a comment |
I have a checkpoint file that receives a server state. This states represents serialized commands that pass trough my network.
I'm trying to read the file but the it gets stuck on the read while loop.
My read function:
struct message_t *pmanager_readop(int fd){
if (fd < 0) return NULL;
// Variables
char *buffer = NULL;
int result, msg_size;
struct message_t *msg;
// Check if file has data
lseek (fd, 0, SEEK_END);
int size_ckp = lseek(fd, 0, SEEK_CUR);
if (size_ckp <= 0)
return NULL;
// Read message size
result = read_all(fd, (char *) &msg_size, 4);
if (result < 0) {
return NULL;
}
msg_size = ntohl(msg_size);
// ............
My read_all() function:
int read_all(int sock, char *buf, int len){
int bufsize = len;
while(len > 0){
int res = read(sock,buf,len);
if(res < 0){
if (errno == EINTR) continue;
return res;
}
buf += res;
len -= res;
}
return bufsize;
}
I use this same function to read data from my server/client connection with the same serialization and format but with a socket descriptor, and it works perfectly.
c file io
asked Nov 25 '18 at 16:14
Filipe NóbregaFilipe Nóbrega
11318
1
Alsoread()returnsssize_tnotint.
– alk
Nov 25 '18 at 16:21
1
Andlseek()returnsoff_t, notint.
– Andrew Henle
Nov 25 '18 at 16:35
add a comment |
I have a checkpoint file that receives a server state. This states represents serialized commands that pass trough my network.
I'm trying to read the file but the it gets stuck on the read while loop.
My read function:
struct message_t *pmanager_readop(int fd){
if (fd < 0) return NULL;
// Variables
char *buffer = NULL;
int result, msg_size;
struct message_t *msg;
// Check if file has data
lseek (fd, 0, SEEK_END);
int size_ckp = lseek(fd, 0, SEEK_CUR);
if (size_ckp <= 0)
return NULL;
// Read message size
result = read_all(fd, (char *) &msg_size, 4);
if (result < 0) {
return NULL;
}
msg_size = ntohl(msg_size);
// ............
My read_all() function:
int read_all(int sock, char *buf, int len){
int bufsize = len;
while(len > 0){
int res = read(sock,buf,len);
if(res < 0){
if (errno == EINTR) continue;
return res;
}
buf += res;
len -= res;
}
return bufsize;
}
I use this same function to read data from my server/client connection with the same serialization and format but with a socket descriptor, and it works perfectly.
c file io
asked Nov 25 '18 at 16:14
Filipe NóbregaFilipe Nóbrega
11318
I have a checkpoint file that receives a server state. This states represents serialized commands that pass trough my network.
I'm trying to read the file but the it gets stuck on the read while loop.
My read function:
struct message_t *pmanager_readop(int fd){
if (fd < 0) return NULL;
// Variables
char *buffer = NULL;
int result, msg_size;
struct message_t *msg;
// Check if file has data
lseek (fd, 0, SEEK_END);
int size_ckp = lseek(fd, 0, SEEK_CUR);
if (size_ckp <= 0)
return NULL;
// Read message size
result = read_all(fd, (char *) &msg_size, 4);
if (result < 0) {
return NULL;
}
msg_size = ntohl(msg_size);
// ............
My read_all() function:
int read_all(int sock, char *buf, int len){
int bufsize = len;
while(len > 0){
int res = read(sock,buf,len);
if(res < 0){
if (errno == EINTR) continue;
return res;
}
buf += res;
len -= res;
}
return bufsize;
}
I use this same function to read data from my server/client connection with the same serialization and format but with a socket descriptor, and it works perfectly.
c file io
c file io
asked Nov 25 '18 at 16:14
Filipe NóbregaFilipe Nóbrega
11318
asked Nov 25 '18 at 16:14
Filipe NóbregaFilipe Nóbrega
11318
asked Nov 25 '18 at 16:14
Filipe NóbregaFilipe Nóbrega
11318
asked Nov 25 '18 at 16:14
Filipe NóbregaFilipe Nóbrega
11318
asked Nov 25 '18 at 16:14
Filipe NóbregaFilipe Nóbrega
11318
11318
1
Alsoread()returnsssize_tnotint.
– alk
Nov 25 '18 at 16:21
1
Andlseek()returnsoff_t, notint.
– Andrew Henle
Nov 25 '18 at 16:35
add a comment |
1
Alsoread()returnsssize_tnotint.
– alk
Nov 25 '18 at 16:21
1
Andlseek()returnsoff_t, notint.
– Andrew Henle
Nov 25 '18 at 16:35
1
1
Also
read() returns ssize_t not int.– alk
Nov 25 '18 at 16:21
Also
read() returns ssize_t not int.– alk
Nov 25 '18 at 16:21
1
1
And
lseek() returns off_t, not int.– Andrew Henle
Nov 25 '18 at 16:35
And
lseek() returns off_t, not int.– Andrew Henle
Nov 25 '18 at 16:35
add a comment |
1 Answer
1
active
oldest
votes
You ought to handle the case that read() returns 0, telling you that the other side shut-down the connection if reading from a socket descriptor, or EOF encountered if reading from a file descriptor.
answered Nov 25 '18 at 16:22
alkalk
58.6k763172
add a comment |
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1 Answer
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1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
You ought to handle the case that read() returns 0, telling you that the other side shut-down the connection if reading from a socket descriptor, or EOF encountered if reading from a file descriptor.
answered Nov 25 '18 at 16:22
alkalk
58.6k763172
add a comment |
You ought to handle the case that read() returns 0, telling you that the other side shut-down the connection if reading from a socket descriptor, or EOF encountered if reading from a file descriptor.
answered Nov 25 '18 at 16:22
alkalk
58.6k763172
add a comment |
You ought to handle the case that read() returns 0, telling you that the other side shut-down the connection if reading from a socket descriptor, or EOF encountered if reading from a file descriptor.
answered Nov 25 '18 at 16:22
alkalk
58.6k763172
You ought to handle the case that read() returns 0, telling you that the other side shut-down the connection if reading from a socket descriptor, or EOF encountered if reading from a file descriptor.
answered Nov 25 '18 at 16:22
alkalk
58.6k763172
edited Nov 26 '18 at 7:20
answered Nov 25 '18 at 16:22
alkalk
58.6k763172
answered Nov 25 '18 at 16:22
alkalk
58.6k763172
answered Nov 25 '18 at 16:22
alkalk
58.6k763172
58.6k763172
add a comment |
add a comment |
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1
Also
read()returnsssize_tnotint.– alk
Nov 25 '18 at 16:21
1
And
lseek()returnsoff_t, notint.– Andrew Henle
Nov 25 '18 at 16:35