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procfs_cmdline.c revision 1.7
      1 /*	$NetBSD: procfs_cmdline.c,v 1.7 2000/05/16 13:45:25 simonb 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  * 3. All advertising materials mentioning features or use of this software
     20  *    must display the following acknowledgement:
     21  *	This product includes software developed by the NetBSD
     22  *	Foundation, Inc. and its contributors.
     23  * 4. Neither the name of The NetBSD Foundation nor the names of its
     24  *    contributors may be used to endorse or promote products derived
     25  *    from this software without specific prior written permission.
     26  *
     27  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     28  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     29  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     30  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     31  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     32  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     33  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     34  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     35  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     36  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     37  * POSSIBILITY OF SUCH DAMAGE.
     38  */
     39 
     40 #include <sys/param.h>
     41 #include <sys/types.h>
     42 #include <sys/systm.h>
     43 #include <sys/syslimits.h>
     44 #include <sys/proc.h>
     45 #include <sys/vnode.h>
     46 #include <sys/exec.h>
     47 #include <sys/malloc.h>
     48 #include <miscfs/procfs/procfs.h>
     49 
     50 #include <vm/vm.h>
     51 
     52 #include <uvm/uvm_extern.h>
     53 
     54 /*
     55  * code for returning process's command line arguments
     56  */
     57 int
     58 procfs_docmdline(curp, p, pfs, uio)
     59 	struct proc *curp;
     60 	struct proc *p;
     61 	struct pfsnode *pfs;
     62 	struct uio *uio;
     63 {
     64 	struct ps_strings pss;
     65 	int count, error, i;
     66 	size_t len, xlen, upper_bound;
     67 	struct uio auio;
     68 	struct iovec aiov;
     69 	vaddr_t argv;
     70 	char *arg;
     71 
     72 	/* Don't allow writing. */
     73 	if (uio->uio_rw != UIO_READ)
     74 		return (EOPNOTSUPP);
     75 
     76 	/*
     77 	 * Allocate a temporary buffer to hold the arguments.
     78 	 */
     79 	arg = malloc(PAGE_SIZE, M_TEMP, M_WAITOK);
     80 
     81 	/*
     82 	 * Zombies don't have a stack, so we can't read their psstrings.
     83 	 * System processes also don't have a user stack.  This is what
     84 	 * ps(1) would display.
     85 	 */
     86 	if (P_ZOMBIE(p) || (p->p_flag & P_SYSTEM) != 0) {
     87 		len = snprintf(arg, PAGE_SIZE, "(%s)", p->p_comm);
     88 		xlen = len - uio->uio_offset;
     89 		if (xlen <= 0)
     90 			error = 0;
     91 		else
     92 			error = uiomove(arg, xlen, uio);
     93 
     94 		free(arg, M_TEMP);
     95 		return (error);
     96 	}
     97 
     98 	/*
     99 	 * NOTE: Don't bother doing a procfs_checkioperm() here
    100 	 * because the psstrings info is available by using ps(1),
    101 	 * so it's not like there's anything to protect here.
    102 	 */
    103 
    104 	/*
    105 	 * Lock the process down in memory.
    106 	 */
    107 	/* XXXCDC: how should locking work here? */
    108 	if ((p->p_flag & P_WEXIT) || (p->p_vmspace->vm_refcnt < 1))
    109 		return (EFAULT);
    110 	PHOLD(p);
    111 	p->p_vmspace->vm_refcnt++;	/* XXX */
    112 
    113 	/*
    114 	 * Read in the ps_strings structure.
    115 	 */
    116 	aiov.iov_base = &pss;
    117 	aiov.iov_len = sizeof(pss);
    118 	auio.uio_iov = &aiov;
    119 	auio.uio_iovcnt = 1;
    120 	auio.uio_offset = (vaddr_t)PS_STRINGS;
    121 	auio.uio_resid = sizeof(pss);
    122 	auio.uio_segflg = UIO_SYSSPACE;
    123 	auio.uio_rw = UIO_READ;
    124 	auio.uio_procp = NULL;
    125 	error = uvm_io(&p->p_vmspace->vm_map, &auio);
    126 	if (error)
    127 		goto bad;
    128 
    129 	/*
    130 	 * Now read the address of the argument vector.
    131 	 */
    132 	aiov.iov_base = &argv;
    133 	aiov.iov_len = sizeof(argv);
    134 	auio.uio_iov = &aiov;
    135 	auio.uio_iovcnt = 1;
    136 	auio.uio_offset = (vaddr_t)pss.ps_argvstr;
    137 	auio.uio_resid = sizeof(argv);
    138 	auio.uio_segflg = UIO_SYSSPACE;
    139 	auio.uio_rw = UIO_READ;
    140 	auio.uio_procp = NULL;
    141 	error = uvm_io(&p->p_vmspace->vm_map, &auio);
    142 	if (error)
    143 		goto bad;
    144 
    145 	/*
    146 	 * Now copy in the actual argument vector, one page at a time,
    147 	 * since we don't know how long the vector is (though, we do
    148 	 * know how many NUL-terminated strings are in the vector).
    149 	 */
    150 	len = 0;
    151 	count = pss.ps_nargvstr;
    152 	upper_bound = round_page(uio->uio_offset + uio->uio_resid);
    153 	for (; count && len < upper_bound; len += xlen) {
    154 		aiov.iov_base = arg;
    155 		aiov.iov_len = PAGE_SIZE;
    156 		auio.uio_iov = &aiov;
    157 		auio.uio_iovcnt = 1;
    158 		auio.uio_offset = argv + len;
    159 		xlen = PAGE_SIZE - ((argv + len) & PAGE_MASK);
    160 		auio.uio_resid = xlen;
    161 		auio.uio_segflg = UIO_SYSSPACE;
    162 		auio.uio_rw = UIO_READ;
    163 		auio.uio_procp = NULL;
    164 		error = uvm_io(&p->p_vmspace->vm_map, &auio);
    165 		if (error)
    166 			goto bad;
    167 
    168 		for (i = 0; i < xlen && count != 0; i++) {
    169 			if (arg[i] == '\0')
    170 				count--;	/* one full string */
    171 		}
    172 
    173 		if (count == 0)
    174 			i--;		/* exclude the final NUL */
    175 
    176 		if (len + i > uio->uio_offset) {
    177 			/* Have data in this page, copy it out */
    178 			error = uiomove(arg + uio->uio_offset - len,
    179 			    i + len - uio->uio_offset, uio);
    180 			if (error || uio->uio_resid <= 0)
    181 				break;
    182 		}
    183 	}
    184 
    185  bad:
    186 	/*
    187 	 * Release the process.
    188 	 */
    189 	PRELE(p);
    190 	uvmspace_free(p->p_vmspace);
    191 
    192 	free(arg, M_TEMP);
    193 	return (error);
    194 }
    195