char mtcp_readchar (int fd)
{
char c;
int rc;
do {
rc = mtcp_sys_read (fd, &c, 1);
} while ( rc == -1 && mtcp_sys_errno == EINTR );
if (rc <= 0) return (0);
return (c);
}
ssize_t mtcp_read_all(int fd, void *buf, size_t count)
{
int rc;
char *ptr = (char *) buf;
size_t num_read = 0;
for (num_read = 0; num_read < count;) {
rc = mtcp_sys_read (fd, ptr + num_read, count - num_read);
if (rc == -1) {
if (mtcp_sys_errno == EINTR || mtcp_sys_errno == EAGAIN)
continue;
else
return -1;
}
else if (rc == 0)
break;
else // else rc > 0
num_read += rc;
}
return num_read;
}
/**
* This function will return the first character of the given file. If the
* file is not readable, we will abort.
*
* @param filename the name of the file to read
* @return the first character of the given file
*/
static char first_char(char *filename)
{
int fd, rc;
char c;
fd = mtcp_sys_open(filename, O_RDONLY, 0);
if(fd < 0)
{
MTCP_PRINTF("ERROR: Cannot open file %s\n", filename);
mtcp_abort();
}
rc = mtcp_sys_read(fd, &c, 1);
if(rc != 1)
{
MTCP_PRINTF("ERROR: Error reading from file %s\n", filename);
mtcp_abort();
}
mtcp_sys_close(fd);
return c;
}
void mtcp_readfile(int fd, void *buf, size_t size)
{
ssize_t rc;
size_t ar = 0;
int tries = 0;
while(ar != size) {
rc = mtcp_sys_read(fd, (char*)buf + ar, size - ar);
if (rc < 0 && rc > -4096) { /* kernel could return large unsigned int */
MTCP_PRINTF("error %d reading checkpoint\n", mtcp_sys_errno);
mtcp_abort();
}
else if (rc == 0) {
MTCP_PRINTF("only read %u bytes instead of %u from checkpoint file\n",
(unsigned)ar, (unsigned)size);
if (tries++ >= 10) {
MTCP_PRINTF(" failed to read after 10 tries in a row.\n");
mtcp_abort();
}
}
ar += rc;
}
}
