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author | Jeff Johnston <jjohnstn@redhat.com> | 2002-06-19 22:17:33 +0000 |
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committer | Jeff Johnston <jjohnstn@redhat.com> | 2002-06-19 22:17:33 +0000 |
commit | ef467338e4a290b0f8978a0701b404e17c5bb048 (patch) | |
tree | 94570e7616b92bab0db3acef31bcf53dd6ce7a24 /newlib/libc/sys/linux/mq_receive.c | |
parent | 676a64b87d76d8c0a518dbcb2e03d8ae4c59ced4 (diff) | |
download | cygnal-ef467338e4a290b0f8978a0701b404e17c5bb048.tar.gz cygnal-ef467338e4a290b0f8978a0701b404e17c5bb048.tar.bz2 cygnal-ef467338e4a290b0f8978a0701b404e17c5bb048.zip |
2002-06-19 Jeff Johnston <jjohnstn@redhat.com>
* libc/sys/linux/Makefile.am: Add support for message queue routines,
ipc routines, and ftok.
* libc/sys/linux/Makefile.in: Regenerated.
* libc/sys/linux/ftok.c: New file.
* libc/sys/linux/ipc.c: Ditto.
* libc/sys/linux/mq_close.c: Ditto.
* libc/sys/linux/mq_getattr.c: Ditto.
* libc/sys/linux/mq_notify.c: Ditto.
* libc/sys/linux/mq_open.c: Ditto.
* libc/sys/linux/mq_receive.c: Ditto.
* libc/sys/linux/mq_send.c: Ditto.
* libc/sys/linux/mq_setattr.c: Ditto.
* libc/sys/linux/mq_unlink.c: Ditto.
* libc/sys/linux/mqlocal.h: Ditto.
* libc/sys/linux/include/mqueue.h: Ditto.
* libc/sys/linux/sys/types.h: Define __gid_t_defined and
__uid_t_defined.
Diffstat (limited to 'newlib/libc/sys/linux/mq_receive.c')
-rw-r--r-- | newlib/libc/sys/linux/mq_receive.c | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/newlib/libc/sys/linux/mq_receive.c b/newlib/libc/sys/linux/mq_receive.c new file mode 100644 index 000000000..1aa7b9fb3 --- /dev/null +++ b/newlib/libc/sys/linux/mq_receive.c @@ -0,0 +1,67 @@ +/* Copyright 2002, Red Hat Inc. */ + +#include <mqueue.h> +#include <fcntl.h> +#include <errno.h> +#include <sys/ipc.h> +#include <sys/sem.h> +#include <string.h> +#define _LIBC +#include <sys/lock.h> +#undef _LIBC + +#include "mqlocal.h" + +__LOCK_INIT(static, mq_rdbuf_lock); + +ssize_t +mq_receive (mqd_t msgid, char *msg, size_t msg_len, unsigned int *msg_prio) +{ + struct libc_mq *info; + struct sembuf sb2 = {2, 1, 0}; + struct sembuf sb3 = {3, -1, IPC_NOWAIT}; + struct sembuf sb5 = {5, 1, IPC_NOWAIT}; + ssize_t num_bytes; + int ipcflag; + + info = __find_mq (msgid); + + if (info == NULL || (info->oflag & O_ACCMODE) == O_WRONLY) + { + errno = EBADF; + return -1; + } + + if (msg_len < info->attr->mq_msgsize) + { + errno = EMSGSIZE; + return -1; + } + + __lock_acquire (mq_rdbuf_lock); + + ipcflag = (info->attr->mq_flags & O_NONBLOCK) ? IPC_NOWAIT : 0; + + semop (info->semid, &sb5, 1); /* increase number of readers */ + num_bytes = msgrcv (info->msgqid, info->rdbuf, msg_len, -MQ_PRIO_MAX, ipcflag); + sb5.sem_op = -1; + semop (info->semid, &sb5, 1); /* decrease number of readers */ + + if (num_bytes != (ssize_t)-1) + { + semop (info->semid, &sb2, 1); /* add one to messages left to write */ + semop (info->semid, &sb3, 1); /* subtract one from messages to read */ + memcpy (msg, info->rdbuf->text, num_bytes); + if (msg_prio != NULL) + *msg_prio = MQ_PRIO_MAX - info->rdbuf->type; + } + + __lock_release (mq_rdbuf_lock); + return num_bytes; +} + + + + + + |