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/*
* (c) Copyright 2001 - 2004 -- Anders Torger
*
* This program is open source. For license terms, see the LICENSE file.
*
*/
#include "defs.h"
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <errno.h>
#ifdef __OS_LINUX__
#include <malloc.h>
#else
#include <stddef.h>
#endif
#include "shmalloc.h"
static void
print_shmget_error(size_t size)
{
switch (errno) {
case EINVAL:
fprintf(stderr, "shmget() failed when requesting %d bytes.\n"
" The OS shmmax parameter must be increased.\n", (int)size);
break;
case ENOSPC:
fprintf(stderr, "shmget() failed due to exceeded id limit.\n"
" The OS shmmni parameter must be increased.\n");
break;
case ENOMEM:
fprintf(stderr, "shmget() failed when requesting %d bytes.\n"
"Out of memory, or the OS parameters shmmax and/or shmmni "
"may be too small.\n", (int)size);
break;
default:
fprintf(stderr, "shmget() failed when requesting %d bytes: %s.\n",
(int)size, strerror(errno));
break;
}
}
void *
shmalloc(size_t size)
{
struct shmid_ds shmid_ds;
void *p;
int n;
if ((n = shmget(IPC_PRIVATE, size, IPC_CREAT | SHM_R | SHM_W)) == -1) {
print_shmget_error(size);
return NULL;
}
memset(&shmid_ds, 0, sizeof(shmid_ds)); /* to get rid of valgrind warning */
if ((p = shmat(n, 0, 0)) == (char *)-1 ||
shmctl(n, IPC_RMID, &shmid_ds) == -1)
{
return NULL;
}
if (((ptrdiff_t)p & (ALIGNMENT - 1)) != 0) {
fprintf(stderr, "alignment error\n");
}
return p;
}
void *
shmalloc_id(int *shmid,
size_t size)
{
static key_t key = 1;
struct shmid_ds shmid_ds;
void *p;
int n;
if (shmid != NULL) {
*shmid = -1;
}
while ((n = shmget(key, size, IPC_CREAT | IPC_EXCL |
SHM_R | SHM_W)) == -1 && errno == EEXIST)
{
key++;
}
if (n == -1) {
print_shmget_error(size);
return NULL;
}
if ((p = shmat(n, 0, 0)) == (char *)-1) {
fprintf(stderr, "Failed to attach to shared memory (shmid %d): %s.\n",
n, strerror(errno));
return NULL;
}
memset(&shmid_ds, 0, sizeof(shmid_ds));
if (shmctl(n, IPC_RMID, &shmid_ds) == -1) {
fprintf(stderr, "Failed to set IPC_RMID (shmid %d): %s.\n", n,
strerror(errno));
return NULL;
}
key++;
if (shmid != NULL) {
*shmid = n;
}
return p;
}
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