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phunix/servers/ipc/shm.c
David van Moolenbroek 80bd109cd3 libsys: various updates 
- move system calls for use by services from libminlib into libsys;
- move srv_fork(2) and srv_kill(2) from RS and into libsys;
- replace getprocnr(2) with sef_self(3);
- rename previous getnprocnr(2) to getprocnr(2);
- clean up getepinfo(2);
- change all libsys calls that used _syscall to use _taskcall, so as
  to avoid going through errno to pass errors; this is already how
  most calls work anyway, and many of the calls previously using
  _syscall were already assumed to return the actual error;
- initialize request messages to zero, for future compatibility
  (note that this does not include PCI calls, which are in need of a
  much bigger overhaul, nor kernel calls);
- clean up more of dead DS code as a side effect.

Change-Id: I8788f54c68598fcf58e23486e270c2d749780ebb
2014-03-01 09:05:00 +01:00

349 lines
8.4 KiB
C
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#include "inc.h"
#define MAX_SHM_NR 1024
struct shm_struct {
key_t key;
int id;
struct shmid_ds shmid_ds;
vir_bytes page;
int vm_id;
};
static struct shm_struct shm_list[MAX_SHM_NR];
static int shm_list_nr = 0;
static struct shm_struct *shm_find_key(key_t key)
{
int i;
if (key == IPC_PRIVATE)
return NULL;
for (i = 0; i < shm_list_nr; i++)
if (shm_list[i].key == key)
return shm_list+i;
return NULL;
}
static struct shm_struct *shm_find_id(int id)
{
int i;
for (i = 0; i < shm_list_nr; i++)
if (shm_list[i].id == id)
return shm_list+i;
return NULL;
}
/*===========================================================================*
* do_shmget *
*===========================================================================*/
int do_shmget(message *m)
{
struct shm_struct *shm;
long key, size, old_size;
int flag;
int id;
key = m->SHMGET_KEY;
old_size = size = m->SHMGET_SIZE;
flag = m->SHMGET_FLAG;
if ((shm = shm_find_key(key))) {
if (!check_perm(&shm->shmid_ds.shm_perm, who_e, flag))
return EACCES;
if ((flag & IPC_CREAT) && (flag & IPC_EXCL))
return EEXIST;
if (size && shm->shmid_ds.shm_segsz < size)
return EINVAL;
id = shm->id;
} else { /* no key found */
if (!(flag & IPC_CREAT))
return ENOENT;
if (size <= 0)
return EINVAL;
/* round up to a multiple of PAGE_SIZE */
if (size % PAGE_SIZE)
size += PAGE_SIZE - size % PAGE_SIZE;
if (size <= 0)
return EINVAL;
if (shm_list_nr == MAX_SHM_NR)
return ENOMEM;
/* TODO: shmmni should be changed... */
if (identifier == SHMMNI)
return ENOSPC;
shm = &shm_list[shm_list_nr];
memset(shm, 0, sizeof(struct shm_struct));
shm->page = (vir_bytes) minix_mmap(0, size,
PROT_READ|PROT_WRITE, MAP_ANON, -1, 0);
if (shm->page == (vir_bytes) MAP_FAILED)
return ENOMEM;
shm->vm_id = vm_getphys(sef_self(), (void *) shm->page);
memset((void *)shm->page, 0, size);
shm->shmid_ds.shm_perm.cuid =
shm->shmid_ds.shm_perm.uid = getnuid(who_e);
shm->shmid_ds.shm_perm.cgid =
shm->shmid_ds.shm_perm.gid = getngid(who_e);
shm->shmid_ds.shm_perm.mode = flag & 0777;
shm->shmid_ds.shm_segsz = old_size;
shm->shmid_ds.shm_atime = 0;
shm->shmid_ds.shm_dtime = 0;
shm->shmid_ds.shm_ctime = time(NULL);
shm->shmid_ds.shm_cpid = getnpid(who_e);
shm->shmid_ds.shm_lpid = 0;
shm->shmid_ds.shm_nattch = 0;
shm->id = id = identifier++;
shm->key = key;
shm_list_nr++;
}
m->SHMGET_RETID = id;
return OK;
}
/*===========================================================================*
* do_shmat *
*===========================================================================*/
int do_shmat(message *m)
{
int id, flag;
vir_bytes addr;
void *ret;
struct shm_struct *shm;
id = m->SHMAT_ID;
addr = (vir_bytes) m->SHMAT_ADDR;
flag = m->SHMAT_FLAG;
if (addr && (addr % PAGE_SIZE)) {
if (flag & SHM_RND)
addr -= (addr % PAGE_SIZE);
else
return EINVAL;
}
if (!(shm = shm_find_id(id)))
return EINVAL;
if (flag & SHM_RDONLY)
flag = 0444;
else
flag = 0666;
if (!check_perm(&shm->shmid_ds.shm_perm, who_e, flag))
return EACCES;
ret = vm_remap(who_e, sef_self(), (void *)addr, (void *)shm->page,
shm->shmid_ds.shm_segsz);
if (ret == MAP_FAILED)
return ENOMEM;
shm->shmid_ds.shm_atime = time(NULL);
shm->shmid_ds.shm_lpid = getnpid(who_e);
/* nattach is updated lazily */
m->SHMAT_RETADDR = (long) ret;
return OK;
}
/*===========================================================================*
* update_refcount_and_destroy *
*===========================================================================*/
void update_refcount_and_destroy(void)
{
int i, j;
for (i = 0, j = 0; i < shm_list_nr; i++) {
u8_t rc;
rc = vm_getrefcount(sef_self(), (void *) shm_list[i].page);
if (rc == (u8_t) -1) {
printf("IPC: can't find physical region.\n");
continue;
}
shm_list[i].shmid_ds.shm_nattch = rc - 1;
if (shm_list[i].shmid_ds.shm_nattch ||
!(shm_list[i].shmid_ds.shm_perm.mode & SHM_DEST)) {
if (i != j)
shm_list[j] = shm_list[i];
j++;
} else {
int size = shm_list[i].shmid_ds.shm_segsz;
if (size % PAGE_SIZE)
size += PAGE_SIZE - size % PAGE_SIZE;
minix_munmap((void *)shm_list[i].page, size);
}
}
shm_list_nr = j;
}
/*===========================================================================*
* do_shmdt *
*===========================================================================*/
int do_shmdt(message *m)
{
vir_bytes addr;
phys_bytes vm_id;
int i;
addr = m->SHMDT_ADDR;
if ((vm_id = vm_getphys(who_e, (void *) addr)) == 0)
return EINVAL;
for (i = 0; i < shm_list_nr; i++) {
if (shm_list[i].vm_id == vm_id) {
struct shm_struct *shm = &shm_list[i];
shm->shmid_ds.shm_atime = time(NULL);
shm->shmid_ds.shm_lpid = getnpid(who_e);
/* nattch is updated lazily */
vm_unmap(who_e, (void *) addr);
break;
}
}
if (i == shm_list_nr)
printf("IPC: do_shmdt impossible error! could not find id %lu to unmap\n",
vm_id);
update_refcount_and_destroy();
return OK;
}
/*===========================================================================*
* do_shmctl *
*===========================================================================*/
int do_shmctl(message *m)
{
int id = m->SHMCTL_ID;
int cmd = m->SHMCTL_CMD;
struct shmid_ds *ds = (struct shmid_ds *)m->SHMCTL_BUF;
struct shmid_ds tmp_ds;
struct shm_struct *shm = NULL;
struct shminfo sinfo;
struct shm_info s_info;
uid_t uid;
int r, i;
if (cmd == IPC_STAT)
update_refcount_and_destroy();
if ((cmd == IPC_STAT ||
cmd == IPC_SET ||
cmd == IPC_RMID) &&
!(shm = shm_find_id(id)))
return EINVAL;
switch (cmd) {
case IPC_STAT:
if (!ds)
return EFAULT;
/* check whether it has read permission */
if (!check_perm(&shm->shmid_ds.shm_perm, who_e, 0444))
return EACCES;
r = sys_datacopy(SELF, (vir_bytes)&shm->shmid_ds,
who_e, (vir_bytes)ds, sizeof(struct shmid_ds));
if (r != OK)
return EFAULT;
break;
case IPC_SET:
uid = getnuid(who_e);
if (uid != shm->shmid_ds.shm_perm.cuid &&
uid != shm->shmid_ds.shm_perm.uid &&
uid != 0)
return EPERM;
r = sys_datacopy(who_e, (vir_bytes)ds,
SELF, (vir_bytes)&tmp_ds, sizeof(struct shmid_ds));
if (r != OK)
return EFAULT;
shm->shmid_ds.shm_perm.uid = tmp_ds.shm_perm.uid;
shm->shmid_ds.shm_perm.gid = tmp_ds.shm_perm.gid;
shm->shmid_ds.shm_perm.mode &= ~0777;
shm->shmid_ds.shm_perm.mode |= tmp_ds.shm_perm.mode & 0666;
shm->shmid_ds.shm_ctime = time(NULL);
break;
case IPC_RMID:
uid = getnuid(who_e);
if (uid != shm->shmid_ds.shm_perm.cuid &&
uid != shm->shmid_ds.shm_perm.uid &&
uid != 0)
return EPERM;
shm->shmid_ds.shm_perm.mode |= SHM_DEST;
/* destroy if possible */
update_refcount_and_destroy();
break;
case IPC_INFO:
if (!ds)
return EFAULT;
sinfo.shmmax = (unsigned long) -1;
sinfo.shmmin = 1;
sinfo.shmmni = MAX_SHM_NR;
sinfo.shmseg = (unsigned long) -1;
sinfo.shmall = (unsigned long) -1;
r = sys_datacopy(SELF, (vir_bytes)&sinfo,
who_e, (vir_bytes)ds, sizeof(struct shminfo));
if (r != OK)
return EFAULT;
m->SHMCTL_RET = shm_list_nr - 1;
if (m->SHMCTL_RET < 0)
m->SHMCTL_RET = 0;
break;
case SHM_INFO:
if (!ds)
return EFAULT;
s_info.used_ids = shm_list_nr;
s_info.shm_tot = 0;
for (i = 0; i < shm_list_nr; i++)
s_info.shm_tot +=
shm_list[i].shmid_ds.shm_segsz/PAGE_SIZE;
s_info.shm_rss = s_info.shm_tot;
s_info.shm_swp = 0;
s_info.swap_attempts = 0;
s_info.swap_successes = 0;
r = sys_datacopy(SELF, (vir_bytes)&s_info,
who_e, (vir_bytes)ds, sizeof(struct shm_info));
if (r != OK)
return EFAULT;
m->SHMCTL_RET = shm_list_nr - 1;
if (m->SHMCTL_RET < 0)
m->SHMCTL_RET = 0;
break;
case SHM_STAT:
if (id < 0 || id >= shm_list_nr)
return EINVAL;
shm = &shm_list[id];
r = sys_datacopy(SELF, (vir_bytes)&shm->shmid_ds,
who_e, (vir_bytes)ds, sizeof(struct shmid_ds));
if (r != OK)
return EFAULT;
m->SHMCTL_RET = shm->id;
break;
default:
return EINVAL;
}
return OK;
}
#if 0
static void list_shm_ds(void)
{
int i;
printf("key\tid\tpage\n");
for (i = 0; i < shm_list_nr; i++)
printf("%ld\t%d\t%lx\n",
shm_list[i].key,
shm_list[i].id,
shm_list[i].page);
}
#endif
/*===========================================================================*
* is_shm_nil *
*===========================================================================*/
int is_shm_nil(void)
{
return (shm_list_nr == 0);
}
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