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
59 lines
2.3 KiB
C
59 lines
2.3 KiB
C
#ifndef __VFS_GLO_H__
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#define __VFS_GLO_H__
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/* EXTERN should be extern except for the table file */
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#ifdef _TABLE
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#undef EXTERN
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#define EXTERN
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#endif
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/* File System global variables */
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EXTERN struct fproc *fp; /* pointer to caller's fproc struct */
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EXTERN int susp_count; /* number of procs suspended on pipe */
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EXTERN int nr_locks; /* number of locks currently in place */
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EXTERN int reviving; /* number of pipe processes to be revived */
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EXTERN int pending;
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EXTERN int sending;
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EXTERN dev_t ROOT_DEV; /* device number of the root device */
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EXTERN int ROOT_FS_E; /* kernel endpoint of the root FS proc */
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EXTERN u32_t system_hz; /* system clock frequency. */
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/* The parameters of the call are kept here. */
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EXTERN message m_in; /* the input message itself */
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EXTERN message m_out; /* the output message used for reply */
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# define who_p ((int) (fp - fproc))
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# define isokslot(p) (p >= 0 && \
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p < (int)(sizeof(fproc) / sizeof(struct fproc)))
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#if 0
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# define who_e (isokslot(who_p) ? fp->fp_endpoint : m_in.m_source)
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#else
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# define who_e (isokslot(who_p) && fp->fp_endpoint != NONE ? \
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fp->fp_endpoint : m_in.m_source)
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#endif
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# define call_nr (m_in.m_type)
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# define super_user (fp->fp_effuid == SU_UID ? 1 : 0)
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# define scratch(p) (scratchpad[((int) ((p) - fproc))])
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EXTERN struct worker_thread *self;
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EXTERN endpoint_t receive_from;/* endpoint with pending reply */
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EXTERN int force_sync; /* toggle forced synchronous communication */
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EXTERN int verbose;
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EXTERN int deadlock_resolving;
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EXTERN mutex_t exec_lock;
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EXTERN mutex_t bsf_lock;/* Global lock for access to block special files */
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EXTERN struct worker_thread workers[NR_WTHREADS];
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EXTERN struct worker_thread sys_worker;
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EXTERN struct worker_thread dl_worker;
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EXTERN char mount_label[LABEL_MAX]; /* label of file system to mount */
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/* The following variables are used for returning results to the caller. */
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EXTERN int err_code; /* temporary storage for error number */
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/* Data initialized elsewhere. */
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extern _PROTOTYPE (int (*call_vec[]), (void) ); /* sys call table */
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extern _PROTOTYPE (int (*pfs_call_vec[]), (void) ); /* pfs callback table */
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extern char dot1[2]; /* dot1 (&dot1[0]) and dot2 (&dot2[0]) have a special */
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extern char dot2[3]; /* meaning to search_dir: no access permission check. */
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extern char mode_map[]; /* mapping from O_ACCMODE mask to R_BIT/W_BIT flags */
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#endif
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