/**
* gammad -- Cooperative gamma server
* Copyright (C) 2016 Mattias Andrée (maandree@kth.se)
*
* This library is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
#include "util.h"
#include <sys/stat.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
/**
* Duplicate a memory segment
*
* @param src The memory segment, must not be `NULL`
* @param n The size of the memory segment, must not be zero
* @return The duplicate of the memory segment,
* `NULL` on error
*/
void* memdup(const void* src, size_t n)
{
void* dest = malloc(n);
if (dest == NULL)
return NULL;
memcpy(dest, src, n);
return dest;
}
/**
* Read an entire file
*
* @param fd The file descriptor
* @param n Output for the size of the file
* @return The read content, plus a NUL byte at
* the end (not counted in `*n`)
*/
void* nread(int fd, size_t* n)
{
size_t size = 32;
ssize_t got;
struct stat st;
char* buf = NULL;
char* new;
int saved_errno;
*n = 0;
if (!fstat(fd, &st))
size = st.st_size <= 0 ? 32 : (size_t)(st.st_size);
buf = malloc(size + 1);
if (buf == NULL)
return NULL;
for (;;)
{
if (*n == size)
{
new = realloc(buf, (size <<= 1) + 1);
if (new == NULL)
goto fail;
buf = new;
}
got = read(fd, buf + *n, size - *n);
if (got < 0)
goto fail;
if (got == 0)
break;
*n += (size_t)got;
}
buf[*n] = '\0';
return buf;
fail:
saved_errno = errno;
free(buf);
errno = saved_errno;
return NULL;
}
/**
* Duplicate a file descriptor an make sure
* the new file descriptor's index as a
* specified minimum value
*
* @param fd The file descriptor
* @param atleast The least acceptable new file descriptor
* @return The new file descriptor, -1 on error
*/
int dup2atleast(int fd, int atleast)
{
int* stack = malloc((size_t)(atleast + 1) * sizeof(int));
size_t stack_ptr = 0;
int new = -1, saved_errno;
if (stack == NULL)
goto fail;
for (;;)
{
new = dup(fd);
if (new < 0)
goto fail;
if (new >= atleast)
break;
}
fail:
saved_errno = errno;
while (stack_ptr--)
close(stack[stack_ptr]);
free(stack);
errno = saved_errno;
return new;
}
/**
* Perform a timed suspention of the process.
* The process resumes when the timer expires,
* or when it is interrupted.
*
* @param ms The number of milliseconds to sleep,
* must be less than 1000
*/
void msleep(int ms)
{
struct timespec ts;
ts.tv_sec = 0;
ts.tv_nsec = (long)ms * 1000000L;
if (clock_nanosleep(CLOCK_MONOTONIC, 0, &ts, NULL) == ENOTSUP)
nanosleep(&ts, NULL);
}
