From f082218c18f9ccedcb6e5ec87920a79c548c03f6 Mon Sep 17 00:00:00 2001 From: Peter Wemm Date: Sun, 20 Feb 2000 13:36:26 +0000 Subject: [PATCH] Fix select(2) for the Alpha. (!!) It was never returning true for fd's in the range of 32-63, 96-127 etc. The first problem was the FD_*() macros were shifting a 32 bit integer "1" left by more than 32 bits. The same problem happened in selscan(). ffs() also takes an int argument and causes failure. For cases where int == long (ie: the usual case for x86, but not always as gcc can have long being a 64 bit quantity) ffs() could be used. Reported by: Marian Stagarescu Reviewed by: dfr, gallatin (sys/types.h only) Approved by: jkh --- sys/kern/sys_generic.c | 14 ++++++++------ sys/sys/types.h | 7 ++++--- 2 files changed, 12 insertions(+), 9 deletions(-) diff --git a/sys/kern/sys_generic.c b/sys/kern/sys_generic.c index 59628110f13..5ef9059e5de 100644 --- a/sys/kern/sys_generic.c +++ b/sys/kern/sys_generic.c @@ -730,9 +730,9 @@ selscan(p, ibits, obits, nfd) fd_mask **ibits, **obits; int nfd; { - register struct filedesc *fdp = p->p_fd; - register int msk, i, j, fd; - register fd_mask bits; + struct filedesc *fdp = p->p_fd; + int msk, i, fd; + fd_mask bits; struct file *fp; int n = 0; /* Note: backend also returns POLLHUP/POLLERR if appropriate. */ @@ -743,14 +743,16 @@ selscan(p, ibits, obits, nfd) continue; for (i = 0; i < nfd; i += NFDBITS) { bits = ibits[msk][i/NFDBITS]; - while ((j = ffs(bits)) && (fd = i + --j) < nfd) { - bits &= ~(1 << j); + /* ffs(int mask) not portable, fd_mask is long */ + for (fd = i; bits && fd < nfd; fd++, bits >>= 1) { + if (!(bits & 1)) + continue; fp = fdp->fd_ofiles[fd]; if (fp == NULL) return (EBADF); if (fo_poll(fp, flag[msk], fp->f_cred, p)) { obits[msk][(fd)/NFDBITS] |= - (1 << ((fd) % NFDBITS)); + ((fd_mask)1 << ((fd) % NFDBITS)); n++; } } diff --git a/sys/sys/types.h b/sys/sys/types.h index 34a115409de..fadbb7de09d 100644 --- a/sys/sys/types.h +++ b/sys/sys/types.h @@ -178,9 +178,10 @@ typedef struct fd_set { fd_mask fds_bits[howmany(FD_SETSIZE, NFDBITS)]; } fd_set; -#define FD_SET(n, p) ((p)->fds_bits[(n)/NFDBITS] |= (1 << ((n) % NFDBITS))) -#define FD_CLR(n, p) ((p)->fds_bits[(n)/NFDBITS] &= ~(1 << ((n) % NFDBITS))) -#define FD_ISSET(n, p) ((p)->fds_bits[(n)/NFDBITS] & (1 << ((n) % NFDBITS))) +#define _fdset_mask(n) ((fd_mask)1 << ((n) % NFDBITS)) +#define FD_SET(n, p) ((p)->fds_bits[(n)/NFDBITS] |= _fdset_mask(n)) +#define FD_CLR(n, p) ((p)->fds_bits[(n)/NFDBITS] &= ~_fdset_mask(n)) +#define FD_ISSET(n, p) ((p)->fds_bits[(n)/NFDBITS] & _fdset_mask(n)) #define FD_COPY(f, t) bcopy(f, t, sizeof(*(f))) #define FD_ZERO(p) bzero(p, sizeof(*(p)))