sunus_jos/lib/ipc.c at master · sunuslee/sunus_jos · GitHub

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// User-level IPC library routines

#include <inc/lib.h>

// Receive a value via IPC and return it.
// If 'pg' is nonnull, then any page sent by the sender will be mapped at
//	that address.
// If 'from_env_store' is nonnull, then store the IPC sender's envid in
//	*from_env_store.
// If 'perm_store' is nonnull, then store the IPC sender's page permission
//	in *perm_store (this is nonzero iff a page was successfully
//	transferred to 'pg').
// If the system call fails, then store 0 in *fromenv and *perm (if
//	they're nonnull) and return the error.
// Otherwise, return the value sent by the sender
//
// Hint:
//   Use 'env' to discover the value and who sent it.
//   If 'pg' is null, pass sys_ipc_recv a value that it will understand
//   as meaning "no page".  (Zero is not the right value, since that's
//   a perfectly valid place to map a page.)   SUNUS : THAT VALUE IS UTOP!

int32_t
ipc_recv(envid_t *from_env_store, void *pg, int *perm_store)
{
        // LAB 4: Your code here.
        // Fab 9,2011 SUNUS
        int r;
        if(!pg)
                pg = (void *)UTOP;
        if((r = sys_ipc_recv(pg)) < 0)
        {
                sunus_dbg(1 ,1, ipc_recv,"r = %e\n",r);
                return r;
        }
        if(from_env_store)
                *from_env_store = env->env_ipc_from;
        if(perm_store)
                *perm_store = env->env_ipc_perm;
        return env->env_ipc_value;
}
/*
int32_t
ipc_recv(envid_t *from_env_store, void *pg, int *perm_store)
{
        // LAB 4: Your code here.
        int r;

        if (pg == NULL)
                pg = (void *) UTOP;

        r = sys_ipc_recv(pg);
        if (r < 0) {
                if (from_env_store)
                        *from_env_store = 0;
                if (perm_store)
                        *perm_store = 0;
                return r;
        }

        if (from_env_store)
                *from_env_store = env->env_ipc_from;
        if (perm_store)
                *perm_store = env->env_ipc_perm;

        return env->env_ipc_value;
}
*/
// Send 'val' (and 'pg' with 'perm', if 'pg' is nonnull) to 'toenv'.
// This function keeps trying until it succeeds.
// It should panic() on any error other than -E_IPC_NOT_RECV.
//
// Hint:
//   Use sys_yield() to be CPU-friendly.
//   If 'pg' is null, pass sys_ipc_recv a value that it will understand
//   as meaning "no page".  (Zero is not the right value.)

void
ipc_send(envid_t to_env, uint32_t val, void *pg, int perm)
{
        // LAB 4: Your code here.
        // Fab 9,2011 SUNUS
        int r;
        int newperm = perm;
        if(!pg)
        {
                pg = (void *)UTOP;
                newperm = 0;
        }
        while((r = sys_ipc_try_send(to_env, val, pg, newperm)) < 0)
        {

                if(r != -E_IPC_NOT_RECV)
                {
                        sunus_dbg(1,1,ipc_send,"r = %e(%d)\n",r,r);
                        panic("%e\n",r);
                }
                sys_yield();
        }
        sys_yield();
}
/*
void
ipc_send(envid_t to_env, uint32_t val, void *pg, int perm)
{
        // LAB 4: Your code here.
        int r;

        if (pg == NULL)
                pg = (void *) UTOP;

        while ((r = sys_ipc_try_send(to_env, val, pg, perm))) {
                if (r != -E_IPC_NOT_RECV)
                        panic("sys_ipc_try_send: %e", r);
        }
}
*/