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/*++
/* NAME
/* write_buf 3
/* SUMMARY
/* write buffer or bust
/* SYNOPSIS
/* #include <iostuff.h>
/*
/* ssize_t write_buf(fd, buf, len, timeout)
/* int fd;
/* const char *buf;
/* ssize_t len;
/* int timeout;
/* DESCRIPTION
/* write_buf() writes a buffer to the named stream in as many
/* fragments as needed, and returns the number of bytes written,
/* which is always the number requested or an error indication.
/*
/* Arguments:
/* .IP fd
/* File descriptor in the range 0..FD_SETSIZE.
/* .IP buf
/* Address of data to be written.
/* .IP len
/* Amount of data to be written.
/* .IP timeout
/* Bounds the time in seconds to wait until \fIfd\fD becomes writable.
/* A value <= 0 means do not wait; this is useful only when \fIfd\fR
/* uses blocking I/O.
/* DIAGNOSTICS
/* write_buf() returns -1 in case of trouble. The global \fIerrno\fR
/* variable reflects the nature of the problem.
/* LICENSE
/* .ad
/* .fi
/* The Secure Mailer license must be distributed with this software.
/* AUTHOR(S)
/* Wietse Venema
/* IBM T.J. Watson Research
/* P.O. Box 704
/* Yorktown Heights, NY 10598, USA
/*--*/
/* System library. */
#include <sys_defs.h>
#include <unistd.h>
#include <errno.h>
#include <time.h>
/* Utility library. */
#include <msg.h>
#include <iostuff.h>
/* write_buf - write buffer or bust */
ssize_t write_buf(int fd, const char *buf, ssize_t len, int timeout)
{
const char *start = buf;
ssize_t count;
time_t expire;
int time_left = timeout;
if (time_left > 0)
expire = time((time_t *) 0) + time_left;
while (len > 0) {
if (time_left > 0 && write_wait(fd, time_left) < 0)
return (-1);
if ((count = write(fd, buf, len)) < 0) {
if ((errno == EAGAIN && time_left > 0) || errno == EINTR)
/* void */ ;
else
return (-1);
} else {
buf += count;
len -= count;
}
if (len > 0 && time_left > 0) {
time_left = expire - time((time_t *) 0);
if (time_left <= 0) {
errno = ETIMEDOUT;
return (-1);
}
}
}
return (buf - start);
}
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