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      1 /*	$NetBSD: procfs_cmdline.c,v 1.33 2024/05/18 00:05:50 thorpej Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1999 Jaromir Dolecek <dolecek (at) ics.muni.cz>
      5  * Copyright (c) 1999 The NetBSD Foundation, Inc.
      6  * All rights reserved.
      7  *
      8  * This code is derived from software contributed to The NetBSD Foundation
      9  * by Jaromir Dolecek.
     10  *
     11  * Redistribution and use in source and binary forms, with or without
     12  * modification, are permitted provided that the following conditions
     13  * are met:
     14  * 1. Redistributions of source code must retain the above copyright
     15  *    notice, this list of conditions and the following disclaimer.
     16  * 2. Redistributions in binary form must reproduce the above copyright
     17  *    notice, this list of conditions and the following disclaimer in the
     18  *    documentation and/or other materials provided with the distribution.
     19  *
     20  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     22  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     23  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     24  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     25  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     26  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     29  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     30  * POSSIBILITY OF SUCH DAMAGE.
     31  */
     32 
     33 #include <sys/cdefs.h>
     34 __KERNEL_RCSID(0, "$NetBSD: procfs_cmdline.c,v 1.33 2024/05/18 00:05:50 thorpej Exp $");
     35 
     36 #include <sys/param.h>
     37 #include <sys/systm.h>
     38 #include <sys/syslimits.h>
     39 #include <sys/proc.h>
     40 #include <sys/vnode.h>
     41 #include <sys/exec.h>
     42 #include <sys/sysctl.h>
     43 #include <miscfs/procfs/procfs.h>
     44 
     45 #include <uvm/uvm_extern.h>
     46 
     47 static int
     48 procfs_doprocargs_helper(void *cookie, const void *src, size_t off, size_t len)
     49 {
     50 	struct uio *uio = cookie;
     51 	char *buf = __UNCONST(src);
     52 
     53 	buf += uio->uio_offset - off;
     54 	if (off + len <= (uintmax_t)uio->uio_offset)
     55 		return 0;
     56 	return uiomove(buf, off + len - uio->uio_offset, cookie);
     57 }
     58 
     59 /*
     60  * code for returning process's command line arguments/environment
     61  */
     62 int
     63 procfs_doprocargs(
     64     struct lwp *curl,
     65     struct proc *p,
     66     struct pfsnode *pfs,
     67     struct uio *uio,
     68     int oid
     69 )
     70 {
     71 	size_t len, start;
     72 	int error;
     73 
     74 	/* Don't allow writing. */
     75 	if (uio->uio_rw != UIO_READ)
     76 		return EOPNOTSUPP;
     77 
     78 	/*
     79 	 * Zombies don't have a stack, so we can't read their psstrings.
     80 	 * System processes also don't have a user stack.  This is what
     81 	 * ps(1) would display.
     82 	 */
     83 	if (P_ZOMBIE(p) || (p->p_flag & PK_SYSTEM) != 0) {
     84 		static char msg[] = "()";
     85 		error = 0;
     86 		if (0 == uio->uio_offset) {
     87 			error = uiomove(msg, 1, uio);
     88 			if (error)
     89 				return error;
     90 		}
     91 		len = strlen(p->p_comm);
     92 		if (len >= (uintmax_t)uio->uio_offset) {
     93 			start = uio->uio_offset - 1;
     94 			error = uiomove(p->p_comm + start, len - start, uio);
     95 			if (error)
     96 				return error;
     97 		}
     98 		if (len + 2 >= (uintmax_t)uio->uio_offset) {
     99 			start = uio->uio_offset - 1 - len;
    100 			error = uiomove(msg + 1 + start, 2 - start, uio);
    101 		}
    102 		return error;
    103 	}
    104 
    105 	len = uio->uio_offset + uio->uio_resid;
    106 	return copy_procargs(p, oid, &len, procfs_doprocargs_helper, uio);
    107 }
    108