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/* $OpenBSD: misc.c,v 1.2 2001/08/13 20:19:33 camield Exp $ */
/*
* Miscellaneous syscall wrappers. See misc.h for the descriptions.
*/
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <errno.h>
#include <sys/time.h>
#include <sys/file.h>
#include "params.h"
int sleep_select(int sec, int usec)
{
struct timeval timeout;
timeout.tv_sec = sec;
timeout.tv_usec = usec;
return select(0, NULL, NULL, NULL, &timeout);
}
int lock_fd(int fd, int shared)
{
#if LOCK_FCNTL
struct flock l;
memset(&l, 0, sizeof(l));
l.l_whence = SEEK_SET;
l.l_type = shared ? F_RDLCK : F_WRLCK;
while (fcntl(fd, F_SETLKW, &l)) {
if (errno != EBUSY) return -1;
sleep_select(1, 0);
}
#endif
#if LOCK_FLOCK
while (flock(fd, shared ? LOCK_SH : LOCK_EX)) {
if (errno != EBUSY) return -1;
sleep_select(1, 0);
}
#endif
return 0;
}
int unlock_fd(int fd)
{
#if LOCK_FCNTL
struct flock l;
memset(&l, 0, sizeof(l));
l.l_whence = SEEK_SET;
l.l_type = F_UNLCK;
if (fcntl(fd, F_SETLK, &l)) return -1;
#endif
#if LOCK_FLOCK
if (flock(fd, LOCK_UN)) return -1;
#endif
return 0;
}
int write_loop(int fd, char *buffer, int count)
{
int offset, block;
offset = 0;
while (count > 0) {
block = write(fd, &buffer[offset], count);
/* If any write(2) fails, we consider that the entire write_loop() has
* failed to do its job. We don't even ignore EINTR here. We also don't
* retry when a write(2) returns zero, as we could start eating up the
* CPU if we did. */
if (block < 0) return block;
if (!block) return offset;
offset += block;
count -= block;
}
/* Should be equal to the requested size, unless our kernel got crazy. */
return offset;
}
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