In SANE (scanner project), the backend for snapscan failed to call
shmget() with error EACCES (Permission denied) if the current user isn't
administrator.
When I'am logged as windows administrator, shmget() is called successfully
In both case, the env. variable CYGWIN exists and this value is
CYGWIN=server
cygserver is installed and runs
Is it possible to call shmget() without administrator's privileges ?
In this case, what kind of privileges a user must have ? and how to set
those privileges ?
Thanks
extract from snapscan backend
#ifndef SHM_R
#define SHM_R 0
#endif
#ifndef SHM_W
#define SHM_W 0
#endif
struct urb_counters_t {
unsigned long read_urbs;
unsigned long write_urbs;
};
static struct urb_counters_t* urb_counters = NULL;
static SANE_Status snapscani_usb_shm_init(void)
{
unsigned int shm_size = sizeof(struct urb_counters_t);
void* shm_area = NULL;
int shm_id = shmget (IPC_PRIVATE, shm_size, IPC_CREAT | SHM_R | SHM_W);
if (shm_id == -1)
{
DBG ("snapscani_usb_shm_init: cannot create shared memory
segment: %s\n",
strerror (errno));
return 1;
}
a log from strace
92 19220 [main] testshmget 2944 shmget: shmget (key = 0, size = 8,
shmflg = 0x200)
1627 20847 [main] testshmget 2944 shmat: shmat (shmid = 327680,
shmaddr = 0x0, shmflg = 0x0)
732 21579 [main] testshmget 2944 shmat: -1 [13] = shmat ()
65 21644 [main] testshmget 2944 __set_errno: void* shmat(int, const
void*, int):224 val 13
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