readproc.c

openmosix使用工具.mtop, mosmon, mps等。用于控制openmosix。openmosix 使用工具.mtop, mosmon, mps等。用于控制openmosix。openm

    rbuf = xrealloc(rbuf, tot + c + align);	/* make room for ptrs AT END */
    endbuf = rbuf + tot;			/* addr just past data buf */
    q = ret = (char**) (endbuf+align);		/* ==> free(*ret) to dealloc */
    *q++ = p = rbuf;				/* point ptrs to the strings */
    endbuf--;					/* do not traverse final NUL */
    while (++p < endbuf)
    	if (!*p)				/* NUL char implies that */
	    *q++ = p+1;				/* next string -> next char */

    *q = 0;					/* null ptr list terminator */
    return ret;
}


/* These are some nice GNU C expression subscope "inline" functions.
   The can be used with arbitrary types and evaluate their arguments
   exactly once.
*/

/* Test if item X of type T is present in the 0 terminated list L */
#   define XinL(T, X, L) ( {			\
	    T  x = (X), *l = (L);		\
	    while (*l && *l != x) l++;		\
	    *l == x;				\
	} )

/* Test if item X of type T is present in the list L of length N */
#   define XinLN(T, X, L, N) ( {		\
	    T x = (X), *l = (L);		\
	    int i = 0, n = (N);			\
	    while (i < n && l[i] != x) i++;	\
	    i < n && l[i] == x;			\
	} )

/* readproc: return a pointer to a proc_t filled with requested info about the
 * next process available matching the restriction set.  If no more such
 * processes are available, return a null pointer (boolean false).  Use the
 * passed buffer instead of allocating space if it is non-NULL.  */

/* This is optimized so that if a PID list is given, only those files are
 * searched for in /proc.  If other lists are given in addition to the PID list,
 * the same logic can follow through as for the no-PID list case.  This is
 * fairly complex, but it does try to not to do any unnecessary work.
 * Unfortunately, the reverse filtering option in which any PID *except* the
 * ones listed is pursued.
 */
#define flags (PT->flags)
proc_t* readproc(PROCTAB* PT, proc_t* rbuf) {
    static struct direct *ent;		/* dirent handle */
    static struct stat sb;		/* stat buffer */
    static char path[32], sbuf[256];	/* bufs for stat,statm */
    int allocated = 0, matched = 0;	/* flags */
    proc_t *p = NULL;

    /* loop until a proc matching restrictions is found or no more processes */
    /* I know this could be a while loop -- this way is easier to indent ;-) */
next_proc:				/* get next PID for consideration */
    if (Do(PID)) {
	if (!*PT->pids)			/* set to next item in pids */
	    return NULL;
	sprintf(path, "/proc/%d", *(PT->pids)++);
	matched = 1;
    } else {					/* get next numeric /proc ent */
	while ((ent = readdir(PT->procfs)) &&
	       (*ent->d_name < '0' || *ent->d_name > '9'))
	    ;
	if (!ent || !ent->d_name)
	    return NULL;
	sprintf(path, "/proc/%s", ent->d_name);
    }
    if (stat(path, &sb) == -1)		/* no such dirent (anymore) */
	goto next_proc;
    if (Do(UID) && !XinLN(uid_t, sb.st_uid, PT->uids, PT->nuid))
	goto next_proc;			/* not one of the requested uids */

    if (!allocated) {				 /* assign mem for return buf */
	p = rbuf ? rbuf : xcalloc(p, sizeof *p); /* passed buf or alloced mem */
	allocated = 1;				 /* remember space is set up */
    }
    p->uid = sb.st_uid;			/* need a way to get real uid */

    if ((file2str(path, "stat", sbuf, sizeof sbuf)) == -1)
	goto next_proc;			/* error reading /proc/#/stat */
    stat2proc(sbuf, p);				/* parse /proc/#/stat */

/* OMINFO { */
    p->where = readint( path , "where" );	/* parse /proc/#/where */
    p->nmigs = readint( path , "nmigs" );	/* parse /proc/#/nmigs */

    if ( oMout )	/* useless stuff for mtop, only mps set oMout to CL_fmt */
    {

       p->lock = readint( path , "lock"  );		/* parse /proc/#/lock */

       /*
       ** !!! dynamic allocation of readcantmove() is a memory leak if used by mtop !!!
       ** (ininfluent if used by mps since its output is page buffered)
       */
       p->cantmove = readcantmove( path , p->lock );	/* parse /proc/#/cantmove */

    }
    else
    {
       /*
       ** if mps && !oMout, avoid segfault on compare (--sort) of empty fields
       ** if mtop, nop nop (assigment but don't waste time and resources)
       */
       p->lock     = 0;
       p->cantmove = "";
    }
/* } OMINFO */

    if (!matched && Do(TTY) && !XinL(dev_t, p->tty, PT->ttys))
	goto next_proc;			/* not one of the requested ttys */

    if (!matched && Do(ANYTTY) && p->tty == -1)
	goto next_proc;			/* no controlling terminal */

    if (!matched && Do(STAT) && !strchr(PT->stats,p->state))
	goto next_proc;			/* not one of the requested states */

    if (Do(FILLMEM)) {				/* read, parse /proc/#/statm */
	if ((file2str(path, "statm", sbuf, sizeof sbuf)) != -1 )
	    statm2proc(sbuf, p);		/* ignore statm errors here */
    }						/* statm fields just zero */

    /* some number->text resolving which is time consuming */
    if (Do(FILLTTY))
	dev_to_tty(p->ttyc, p->tty);
    if (Do(FILLUSR))
	strncpy(p->user, user_from_uid(p->uid), sizeof p->user);

    if (Do(FILLCMD))				/* read+parse /proc/#/cmdline */
	p->cmdline = file2strvec(path, "cmdline");
    if (Do(FILLENV))				/* read+parse /proc/#/environ */
	p->environ = file2strvec(path, "environ");

    if (p->state == 'Z')			/* fixup cmd for zombies */
	strncat(p->cmd," <zombie>", sizeof p->cmd);

    return p;
}
#undef flags

/* Convenient wrapper around openproc and readproc to slurp in the whole process
 * tree subset satisfying the constraints of flags and the optional PID list.
 * Free allocated memory with freeproctree().  The tree structure is a classic
 * left-list children + right-list siblings.  The algorithm is a two-pass of the
 * process table.  Since most process trees will have children with strictly
 * increasing PIDs, most of the structure will be picked up in the first pass.
 * The second loop then cleans up any nodes which turn out to have preceeded
 * their parent in /proc order.
 */

/* Traverse tree 't' breadth-first looking for a process with pid p */
proc_t* LookupPID(proc_t* t, pid_t p) {
    proc_t* tmp = NULL;
    if (!t)
	return NULL;
    if (t->pid == p)				/* look here/terminate recursion */
	return t;
    if ((tmp = LookupPID(t->l, p)))		/* recurse over children */
	return tmp;
    for (; t; t=t->r)				/* recurse over siblings */
	if ((tmp = LookupPID(tmp, p)))
	    return tmp;
    return NULL;
}

proc_t* readproctree(int flags, ...) {
    static proc_t tree;
    PROCTAB* PT = NULL;
    proc_t *node, *tmp=NULL, *tmp2=NULL;
    va_list ap;

    /* pass through apropriate arguments to openproc */
    va_start(ap, flags);
    if (Do(UID)) {
	/* temporary variables to ensure that va_arg() instances
	 * are called in the right order
	 */
	uid_t* u;
	int i;

	u = va_arg(ap, uid_t*);
	i = va_arg(ap, int);
	PT = openproc(flags, u, i);
    }
    else if (Do(PID) || Do(TTY) || Do(STAT))
	PT = openproc(flags, va_arg(ap, void*));
    else
	PT = openproc(flags);
    va_end(ap);

    /* first pass: build tree, putting orphans on the first level */
    tree.l = tree.r = NULL;
    while ((node = readproc(PT,0)))
	if ((tmp = LookupPID(&tree, node->ppid))) {
	    node->r = tmp->l->r;	/* node --> left list of parent */
	    tmp->l->r = node;
	} else {
	    node->r = tree.r;		/* node --> right list of 'tree' */
	    tree.r = node;
	}
    /* second pass: scan tree for PPIDs of level-1 nodes moving links as necessary */
    for (node = &tree; node; node = node->r)
	if ((tmp = LookupPID(&tree, node->r->ppid))) {
	    tmp2 = node->r;			/* unlink from right list of 'tree' */
	    node->r = node->r->r;
	    tmp2->r = tmp->l->r;		/* insert as child of found node */
	    tmp->l->r = node;
	}
    closeproc(PT);
    return &tree;
}

/* Convenient wrapper around openproc and readproc to slurp in the whole process
 * table subset satisfying the constraints of flags and the optional PID list.
 * Free allocated memory with freeproctab().  Access via tab[N]->member.  The
 * pointer list is NULL terminated.
 */
proc_t** readproctab(int flags, ...) {
    PROCTAB* PT = NULL;
    proc_t** tab = NULL;
    int n = 0;
    va_list ap;

    va_start(ap, flags);		/* pass through args to openproc */
    if (Do(UID)) {
	/* temporary variables to ensure that va_arg() instances
	 * are called in the right order
	 */
	uid_t* u;
	int i;

	u = va_arg(ap, uid_t*);
	i = va_arg(ap, int);
	PT = openproc(flags, u, i);
    }
    else if (Do(PID) || Do(TTY) || Do(STAT))
	PT = openproc(flags, va_arg(ap, void*)); /* assume ptr sizes same */
    else
	PT = openproc(flags);
    va_end(ap);
    do {					/* read table: */
	tab = xrealloc(tab, (n+1)*sizeof(proc_t*));/* realloc as we go, using */
	tab[n] = readproc(PT, NULL);		  /* final null to terminate */
    } while (tab[n++]);				  /* stop when NULL reached */
    closeproc(PT);
    return tab;
}

/* deallocate a table of pointers to proc structures
 */
void freeproctab(proc_t** tab) {
    proc_t** p;
    for(p = tab; *p; p++)
	freeproc(*p);
    free(tab);
}