de5a9a3e8b
Some code relies on having the file descriptor in m_in.fd. Consequently,
m_in is not only used to provide syscall parameters from user space to
VFS, but also as a global variable to store temporary data within VFS.
This has the ugly side effect that m_in gets overwritten during core
dumping.*
To work around this problem VFS now uses a so called "scratchpad" to
store temporary data that has to be globally accessible. This is a simple
table indexed by process number, just like fproc. The scratchpad allows
us to store the buffer pointer and buffer size for suspended system calls
(i.e., read, write, open, lock) instead of using fproc. This makes fproc
a bit smaller and fproc iterators a bit faster. Moreover, suspension of
processes becomes simpler altogether and suspended operations on pipes
are now less of a special case.
* This patch fixes a bug where due to unexpected m_in overwriting a
coredump would fail, and consequently resources are leaked. The coredump
was triggered with:
$ a() { a; }
$ a
72 lines
2.7 KiB
C
72 lines
2.7 KiB
C
#ifndef __VFS_FPROC_H__
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#define __VFS_FPROC_H__
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#include "threads.h"
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#include <sys/select.h>
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#include <minix/safecopies.h>
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/* This is the per-process information. A slot is reserved for each potential
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* process. Thus NR_PROCS must be the same as in the kernel. It is not
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* possible or even necessary to tell when a slot is free here.
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*/
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#define LOCK_DEBUG 0
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EXTERN struct fproc {
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unsigned fp_flags;
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pid_t fp_pid; /* process id */
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endpoint_t fp_endpoint; /* kernel endpoint number of this process */
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struct vnode *fp_wd; /* working directory; NULL during reboot */
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struct vnode *fp_rd; /* root directory; NULL during reboot */
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struct filp *fp_filp[OPEN_MAX];/* the file descriptor table */
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fd_set fp_filp_inuse; /* which fd's are in use? */
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fd_set fp_cloexec_set; /* bit map for POSIX Table 6-2 FD_CLOEXEC */
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dev_t fp_tty; /* major/minor of controlling tty */
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int fp_blocked_on; /* what is it blocked on */
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int fp_block_callnr; /* blocked call if rd/wr can't finish */
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int fp_cum_io_partial; /* partial byte count if rd/wr can't finish */
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endpoint_t fp_task; /* which task is proc suspended on */
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endpoint_t fp_ioproc; /* proc no. in suspended-on i/o message */
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cp_grant_id_t fp_grant; /* revoke this grant on unsuspend if > -1 */
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uid_t fp_realuid; /* real user id */
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uid_t fp_effuid; /* effective user id */
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gid_t fp_realgid; /* real group id */
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gid_t fp_effgid; /* effective group id */
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int fp_ngroups; /* number of supplemental groups */
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gid_t fp_sgroups[NGROUPS_MAX];/* supplemental groups */
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mode_t fp_umask; /* mask set by umask system call */
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message *fp_sendrec; /* request/reply to/from FS/driver */
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mutex_t fp_lock; /* mutex to lock fproc object */
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struct job fp_job; /* pending job */
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thread_t fp_wtid; /* Thread ID of worker */
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#if LOCK_DEBUG
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int fp_vp_rdlocks; /* number of read-only locks on vnodes */
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int fp_vmnt_rdlocks; /* number of read-only locks on vmnts */
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#endif
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} fproc[NR_PROCS];
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/* fp_flags */
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#define FP_NOFLAGS 00
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#define FP_SUSP_REOPEN 01 /* Process is suspended until the reopens are
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* completed (after the restart of a driver).
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*/
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#define FP_REVIVED 0002 /* Indicates process is being revived */
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#define FP_SESLDR 0004 /* Set if process is session leader */
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#define FP_PENDING 0010 /* Set if process has pending work */
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#define FP_EXITING 0020 /* Set if process is exiting */
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#define FP_PM_PENDING 0040 /* Set if process has pending PM request */
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#define FP_SYS_PROC 0100 /* Set if process is a driver or FS */
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/* Field values. */
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#define NOT_REVIVING 0xC0FFEEE /* process is not being revived */
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#define REVIVING 0xDEEAD /* process is being revived from suspension */
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#define PID_FREE 0 /* process slot free */
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#endif /* __VFS_FPROC_H__ */
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