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[/] [or1k_old/] [trunk/] [uclinux/] [uClinux-2.0.x/] [fs/] [proc/] [mem.c] - Blame information for rev 1782

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/*
 *  linux/fs/proc/mem.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 */
 
/*
 * uClinux revisions for NO_MM
 * Copyright (C) 1998  Kenneth Albanowski <kjahds@kjahds.com>,
 *                     The Silver Hammer Group, Ltd.
 */
 
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
 
#include <asm/page.h>
#include <asm/segment.h>
#include <asm/io.h>
#include <asm/pgtable.h>
 
#ifndef NO_MM
 
/*
 * mem_write isn't really a good idea right now. It needs
 * to check a lot more: if the process we try to write to
 * dies in the middle right now, mem_write will overwrite
 * kernel memory.. This disables it altogether.
 */
#define mem_write NULL
 
static int check_range(struct mm_struct * mm, unsigned long addr, int count)
{
        struct vm_area_struct *vma;
        int retval;
 
        vma = find_vma(mm, addr);
        if (!vma)
                return -EACCES;
        if (vma->vm_start > addr)
                return -EACCES;
        if (!(vma->vm_flags & VM_READ))
                return -EACCES;
        while ((retval = vma->vm_end - addr) < count) {
                struct vm_area_struct *next = vma->vm_next;
                if (!next)
                        break;
                if (vma->vm_end != next->vm_start)
                        break;
                if (!(next->vm_flags & VM_READ))
                        break;
                vma = next;
        }
        if (retval > count)
                retval = count;
        return retval;
}
 
static struct task_struct * get_task(int pid)
{
        struct task_struct * tsk = current;
 
        if (pid != tsk->pid) {
                int i;
                tsk = NULL;
                for (i = 1 ; i < NR_TASKS ; i++)
                        if (task[i] && task[i]->pid == pid) {
                                tsk = task[i];
                                break;
                        }
                /*
                 * allow accesses only under the same circumstances
                 * that we would allow ptrace to work
                 */
                if (tsk) {
                        if (!(tsk->flags & PF_PTRACED)
                            || tsk->state != TASK_STOPPED
                            || tsk->p_pptr != current)
                                tsk = NULL;
                }
        }
        return tsk;
}
 
static int mem_read(struct inode * inode, struct file * file,char * buf, int count)
{
        pgd_t *page_dir;
        pmd_t *page_middle;
        pte_t pte;
        char * page;
        struct task_struct * tsk;
        unsigned long addr;
        char *tmp;
        int i;
 
        if (count < 0)
                return -EINVAL;
        tsk = get_task(inode->i_ino >> 16);
        if (!tsk)
                return -ESRCH;
        addr = file->f_pos;
        count = check_range(tsk->mm, addr, count);
        if (count < 0)
                return count;
        tmp = buf;
        while (count > 0) {
                if (current->signal & ~current->blocked)
                        break;
                page_dir = pgd_offset(tsk->mm,addr);
                if (pgd_none(*page_dir))
                        break;
                if (pgd_bad(*page_dir)) {
                        printk("Bad page dir entry %08lx\n", pgd_val(*page_dir));
                        pgd_clear(page_dir);
                        break;
                }
                page_middle = pmd_offset(page_dir,addr);
                if (pmd_none(*page_middle))
                        break;
                if (pmd_bad(*page_middle)) {
                        printk("Bad page middle entry %08lx\n", pmd_val(*page_middle));
                        pmd_clear(page_middle);
                        break;
                }
                pte = *pte_offset(page_middle,addr);
                if (!pte_present(pte))
                        break;
                page = (char *) pte_page(pte) + (addr & ~PAGE_MASK);
                i = PAGE_SIZE-(addr & ~PAGE_MASK);
                if (i > count)
                        i = count;
                memcpy_tofs(tmp, page, i);
                addr += i;
                tmp += i;
                count -= i;
        }
        file->f_pos = addr;
        return tmp-buf;
}
 
#ifndef mem_write
 
static int mem_write(struct inode * inode, struct file * file,char * buf, int count)
{
        pgd_t *page_dir;
        pmd_t *page_middle;
        pte_t pte;
        char * page;
        struct task_struct * tsk;
        unsigned long addr;
        char *tmp;
        int i;
 
        if (count < 0)
                return -EINVAL;
        addr = file->f_pos;
        tsk = get_task(inode->i_ino >> 16);
        if (!tsk)
                return -ESRCH;
        tmp = buf;
        while (count > 0) {
                if (current->signal & ~current->blocked)
                        break;
                page_dir = pgd_offset(tsk,addr);
                if (pgd_none(*page_dir))
                        break;
                if (pgd_bad(*page_dir)) {
                        printk("Bad page dir entry %08lx\n", pgd_val(*page_dir));
                        pgd_clear(page_dir);
                        break;
                }
                page_middle = pmd_offset(page_dir,addr);
                if (pmd_none(*page_middle))
                        break;
                if (pmd_bad(*page_middle)) {
                        printk("Bad page middle entry %08lx\n", pmd_val(*page_middle));
                        pmd_clear(page_middle);
                        break;
                }
                pte = *pte_offset(page_middle,addr);
                if (!pte_present(pte))
                        break;
                if (!pte_write(pte))
                        break;
                page = (char *) pte_page(pte) + (addr & ~PAGE_MASK);
                i = PAGE_SIZE-(addr & ~PAGE_MASK);
                if (i > count)
                        i = count;
                memcpy_fromfs(page, tmp, i);
                addr += i;
                tmp += i;
                count -= i;
        }
        file->f_pos = addr;
        if (tmp != buf)
                return tmp-buf;
        if (current->signal & ~current->blocked)
                return -ERESTARTSYS;
        return 0;
}
 
#endif
 
static int mem_lseek(struct inode * inode, struct file * file, off_t offset, int orig)
{
        switch (orig) {
                case 0:
                        file->f_pos = offset;
                        return file->f_pos;
                case 1:
                        file->f_pos += offset;
                        return file->f_pos;
                default:
                        return -EINVAL;
        }
}
 
/*
 * This isn't really reliable by any means..
 */
int mem_mmap(struct inode * inode, struct file * file,
             struct vm_area_struct * vma)
{
        struct task_struct *tsk;
        pgd_t *src_dir, *dest_dir;
        pmd_t *src_middle, *dest_middle;
        pte_t *src_table, *dest_table;
        unsigned long stmp, dtmp, mapnr;
        struct vm_area_struct *src_vma = NULL;
 
        /* Get the source's task information */
 
        tsk = get_task(inode->i_ino >> 16);
 
        if (!tsk)
                return -ESRCH;
 
        /* Ensure that we have a valid source area.  (Has to be mmap'ed and
         have valid page information.)  We can't map shared memory at the
         moment because working out the vm_area_struct & nattach stuff isn't
         worth it. */
 
        src_vma = tsk->mm->mmap;
        stmp = vma->vm_offset;
        while (stmp < vma->vm_offset + (vma->vm_end - vma->vm_start)) {
                while (src_vma && stmp > src_vma->vm_end)
                        src_vma = src_vma->vm_next;
                if (!src_vma || (src_vma->vm_flags & VM_SHM))
                        return -EINVAL;
 
                src_dir = pgd_offset(tsk->mm, stmp);
                if (pgd_none(*src_dir))
                        return -EINVAL;
                if (pgd_bad(*src_dir)) {
                        printk("Bad source page dir entry %08lx\n", pgd_val(*src_dir));
                        return -EINVAL;
                }
                src_middle = pmd_offset(src_dir, stmp);
                if (pmd_none(*src_middle))
                        return -EINVAL;
                if (pmd_bad(*src_middle)) {
                        printk("Bad source page middle entry %08lx\n", pmd_val(*src_middle));
                        return -EINVAL;
                }
                src_table = pte_offset(src_middle, stmp);
                if (pte_none(*src_table))
                        return -EINVAL;
 
                if (stmp < src_vma->vm_start) {
                        if (!(src_vma->vm_flags & VM_GROWSDOWN))
                                return -EINVAL;
                        if (src_vma->vm_end - stmp > current->rlim[RLIMIT_STACK].rlim_cur)
                                return -EINVAL;
                }
                stmp += PAGE_SIZE;
        }
 
        src_vma = tsk->mm->mmap;
        stmp    = vma->vm_offset;
        dtmp    = vma->vm_start;
 
        flush_cache_range(vma->vm_mm, vma->vm_start, vma->vm_end);
        flush_cache_range(src_vma->vm_mm, src_vma->vm_start, src_vma->vm_end);
        while (dtmp < vma->vm_end) {
                while (src_vma && stmp > src_vma->vm_end)
                        src_vma = src_vma->vm_next;
 
                src_dir = pgd_offset(tsk->mm, stmp);
                src_middle = pmd_offset(src_dir, stmp);
                src_table = pte_offset(src_middle, stmp);
 
                dest_dir = pgd_offset(current->mm, dtmp);
                dest_middle = pmd_alloc(dest_dir, dtmp);
                if (!dest_middle)
                        return -ENOMEM;
                dest_table = pte_alloc(dest_middle, dtmp);
                if (!dest_table)
                        return -ENOMEM;
 
                if (!pte_present(*src_table))
                        do_no_page(tsk, src_vma, stmp, 1);
 
                if ((vma->vm_flags & VM_WRITE) && !pte_write(*src_table))
                        do_wp_page(tsk, src_vma, stmp, 1);
 
                set_pte(src_table, pte_mkdirty(*src_table));
                set_pte(dest_table, *src_table);
                mapnr = MAP_NR(pte_page(*src_table));
                if (mapnr < MAP_NR(high_memory))
                        mem_map[mapnr].count++;
 
                stmp += PAGE_SIZE;
                dtmp += PAGE_SIZE;
        }
 
        flush_tlb_range(vma->vm_mm, vma->vm_start, vma->vm_end);
        flush_tlb_range(src_vma->vm_mm, src_vma->vm_start, src_vma->vm_end);
        return 0;
}
 
static struct file_operations proc_mem_operations = {
        mem_lseek,
        mem_read,
        mem_write,
        NULL,           /* mem_readdir */
        NULL,           /* mem_select */
        NULL,           /* mem_ioctl */
        mem_mmap,       /* mmap */
        NULL,           /* no special open code */
        NULL,           /* no special release code */
        NULL            /* can't fsync */
};
 
struct inode_operations proc_mem_inode_operations = {
        &proc_mem_operations,   /* default base directory file-ops */
        NULL,                   /* create */
        NULL,                   /* lookup */
        NULL,                   /* link */
        NULL,                   /* unlink */
        NULL,                   /* symlink */
        NULL,                   /* mkdir */
        NULL,                   /* rmdir */
        NULL,                   /* mknod */
        NULL,                   /* rename */
        NULL,                   /* readlink */
        NULL,                   /* follow_link */
        NULL,                   /* readpage */
        NULL,                   /* writepage */
        NULL,                   /* bmap */
        NULL,                   /* truncate */
        NULL                    /* permission */
};
 
#else /* NO_MM */
 
/*
 * mem_write isn't really a good idea right now. It needs
 * to check a lot more: if the process we try to write to
 * dies in the middle right now, mem_write will overwrite
 * kernel memory.. This disables it altogether.
 */
#define mem_write NULL
 
static struct task_struct * get_task(int pid)
{
        struct task_struct * tsk = current;
 
        if (pid != tsk->pid) {
                int i;
                tsk = NULL;
                for (i = 1 ; i < NR_TASKS ; i++)
                        if (task[i] && task[i]->pid == pid) {
                                tsk = task[i];
                                break;
                        }
                /*
                 * allow accesses only under the same circumstances
                 * that we would allow ptrace to work
                 */
                if (tsk) {
                        if (!(tsk->flags & PF_PTRACED)
                            || tsk->state != TASK_STOPPED
                            || tsk->p_pptr != current)
                                tsk = NULL;
                }
        }
        return tsk;
}
 
static int mem_read(struct inode * inode, struct file * file,char * buf, int count)
{
        struct task_struct * tsk;
        unsigned long addr;
        char *tmp;
        int i;
 
        if (count < 0)
                return -EINVAL;
        tsk = get_task(inode->i_ino >> 16);
        if (!tsk)
                return -ESRCH;
        addr = file->f_pos;
        tmp = buf;
        while (count > 0) {
                if (current->signal & ~current->blocked)
                        break;
                i = count;
                memcpy_tofs(tmp, (void*)addr, i);
                addr += i;
                tmp += i;
                count -= i;
        }
        file->f_pos = addr;
        return tmp-buf;
}
 
#ifndef mem_write
 
static int mem_write(struct inode * inode, struct file * file,char * buf, int count)
{
        struct task_struct * tsk;
        unsigned long addr;
        char *tmp;
        int i;
 
        if (count < 0)
                return -EINVAL;
        addr = file->f_pos;
        tsk = get_task(inode->i_ino >> 16);
        if (!tsk)
                return -ESRCH;
        tmp = buf;
        while (count > 0) {
                if (current->signal & ~current->blocked)
                        break;
                i = count;
                memcpy_fromfs((void*)addr, tmp, i);
                addr += i;
                tmp += i;
                count -= i;
        }
        file->f_pos = addr;
        if (tmp != buf)
                return tmp-buf;
        if (current->signal & ~current->blocked)
                return -ERESTARTSYS;
        return 0;
}
 
#endif
 
int mem_mmap(struct inode * inode, struct file * file,
             struct vm_area_struct * vma)
{
        vma->vm_start = vma->vm_offset;
        return 0;
}
 
static int mem_lseek(struct inode * inode, struct file * file, off_t offset, int orig)
{
        switch (orig) {
                case 0:
                        file->f_pos = offset;
                        return file->f_pos;
                case 1:
                        file->f_pos += offset;
                        return file->f_pos;
                default:
                        return -EINVAL;
        }
}
 
static struct file_operations proc_mem_operations = {
        mem_lseek,
        mem_read,
        mem_write,
        NULL,           /* mem_readdir */
        NULL,           /* mem_select */
        NULL,           /* mem_ioctl */
        mem_mmap,       /* mmap */
        NULL,           /* no special open code */
        NULL,           /* no special release code */
        NULL            /* can't fsync */
};
 
struct inode_operations proc_mem_inode_operations = {
        &proc_mem_operations,   /* default base directory file-ops */
        NULL,                   /* create */
        NULL,                   /* lookup */
        NULL,                   /* link */
        NULL,                   /* unlink */
        NULL,                   /* symlink */
        NULL,                   /* mkdir */
        NULL,                   /* rmdir */
        NULL,                   /* mknod */
        NULL,                   /* rename */
        NULL,                   /* readlink */
        NULL,                   /* follow_link */
        NULL,                   /* readpage */
        NULL,                   /* writepage */
        NULL,                   /* bmap */
        NULL,                   /* truncate */
        NULL                    /* permission */
};
 
#endif /* NO_MM */

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[/] [or1k_old/] [trunk/] [uclinux/] [uClinux-2.0.x/] [fs/] [proc/] [mem.c] - Blame information for rev 1782

Line No.	Rev	Author	Line
1	199	simons	`/*`
2			`* linux/fs/proc/mem.c`
3			`*`
4			`* Copyright (C) 1991, 1992 Linus Torvalds`
5			`*/`
6
7			`/*`
8			`* uClinux revisions for NO_MM`
9			`* Copyright (C) 1998 Kenneth Albanowski <kjahds@kjahds.com>,`
10			`* The Silver Hammer Group, Ltd.`
11			`*/`
12
13			`#include <linux/types.h>`
14			`#include <linux/errno.h>`
15			`#include <linux/sched.h>`
16			`#include <linux/kernel.h>`
17			`#include <linux/mm.h>`
18
19			`#include <asm/page.h>`
20			`#include <asm/segment.h>`
21			`#include <asm/io.h>`
22			`#include <asm/pgtable.h>`
23
24			`#ifndef NO_MM`
25
26			`/*`
27			`* mem_write isn't really a good idea right now. It needs`
28			`* to check a lot more: if the process we try to write to`
29			`* dies in the middle right now, mem_write will overwrite`
30			`* kernel memory.. This disables it altogether.`
31			`*/`
32			`#define mem_write NULL`
33
34			`static int check_range(struct mm_struct * mm, unsigned long addr, int count)`
35			`{`
36			`struct vm_area_struct *vma;`
37			`int retval;`
38
39			`vma = find_vma(mm, addr);`
40			`if (!vma)`
41			`return -EACCES;`
42			`if (vma->vm_start > addr)`
43			`return -EACCES;`
44			`if (!(vma->vm_flags & VM_READ))`
45			`return -EACCES;`
46			`while ((retval = vma->vm_end - addr) < count) {`
47			`struct vm_area_struct *next = vma->vm_next;`
48			`if (!next)`
49			`break;`
50			`if (vma->vm_end != next->vm_start)`
51			`break;`
52			`if (!(next->vm_flags & VM_READ))`
53			`break;`
54			`vma = next;`
55			`}`
56			`if (retval > count)`
57			`retval = count;`
58			`return retval;`
59			`}`
60
61			`static struct task_struct * get_task(int pid)`
62			`{`
63			`struct task_struct * tsk = current;`
64
65			`if (pid != tsk->pid) {`
66			`int i;`
67			`tsk = NULL;`
68			`for (i = 1 ; i < NR_TASKS ; i++)`
69			`if (task[i] && task[i]->pid == pid) {`
70			`tsk = task[i];`
71			`break;`
72			`}`
73			`/*`
74			`* allow accesses only under the same circumstances`
75			`* that we would allow ptrace to work`
76			`*/`
77			`if (tsk) {`
78			`if (!(tsk->flags & PF_PTRACED)`
79			`\|\| tsk->state != TASK_STOPPED`
80			`\|\| tsk->p_pptr != current)`
81			`tsk = NULL;`
82			`}`
83			`}`
84			`return tsk;`
85			`}`
86
87			`static int mem_read(struct inode * inode, struct file * file,char * buf, int count)`
88			`{`
89			`pgd_t *page_dir;`
90			`pmd_t *page_middle;`
91			`pte_t pte;`
92			`char * page;`
93			`struct task_struct * tsk;`
94			`unsigned long addr;`
95			`char *tmp;`
96			`int i;`
97
98			`if (count < 0)`
99			`return -EINVAL;`
100			`tsk = get_task(inode->i_ino >> 16);`
101			`if (!tsk)`
102			`return -ESRCH;`
103			`addr = file->f_pos;`
104			`count = check_range(tsk->mm, addr, count);`
105			`if (count < 0)`
106			`return count;`
107			`tmp = buf;`
108			`while (count > 0) {`
109			`if (current->signal & ~current->blocked)`
110			`break;`
111			`page_dir = pgd_offset(tsk->mm,addr);`
112			`if (pgd_none(*page_dir))`
113			`break;`
114			`if (pgd_bad(*page_dir)) {`
115			`printk("Bad page dir entry %08lx\n", pgd_val(*page_dir));`
116			`pgd_clear(page_dir);`
117			`break;`
118			`}`
119			`page_middle = pmd_offset(page_dir,addr);`
120			`if (pmd_none(*page_middle))`
121			`break;`
122			`if (pmd_bad(*page_middle)) {`
123			`printk("Bad page middle entry %08lx\n", pmd_val(*page_middle));`
124			`pmd_clear(page_middle);`
125			`break;`
126			`}`
127			`pte = *pte_offset(page_middle,addr);`
128			`if (!pte_present(pte))`
129			`break;`
130			`page = (char *) pte_page(pte) + (addr & ~PAGE_MASK);`
131			`i = PAGE_SIZE-(addr & ~PAGE_MASK);`
132			`if (i > count)`
133			`i = count;`
134			`memcpy_tofs(tmp, page, i);`
135			`addr += i;`
136			`tmp += i;`
137			`count -= i;`
138			`}`
139			`file->f_pos = addr;`
140			`return tmp-buf;`
141			`}`
142
143			`#ifndef mem_write`
144
145			`static int mem_write(struct inode * inode, struct file * file,char * buf, int count)`
146			`{`
147			`pgd_t *page_dir;`
148			`pmd_t *page_middle;`
149			`pte_t pte;`
150			`char * page;`
151			`struct task_struct * tsk;`
152			`unsigned long addr;`
153			`char *tmp;`
154			`int i;`
155
156			`if (count < 0)`
157			`return -EINVAL;`
158			`addr = file->f_pos;`
159			`tsk = get_task(inode->i_ino >> 16);`
160			`if (!tsk)`
161			`return -ESRCH;`
162			`tmp = buf;`
163			`while (count > 0) {`
164			`if (current->signal & ~current->blocked)`
165			`break;`
166			`page_dir = pgd_offset(tsk,addr);`
167			`if (pgd_none(*page_dir))`
168			`break;`
169			`if (pgd_bad(*page_dir)) {`
170			`printk("Bad page dir entry %08lx\n", pgd_val(*page_dir));`
171			`pgd_clear(page_dir);`
172			`break;`
173			`}`
174			`page_middle = pmd_offset(page_dir,addr);`
175			`if (pmd_none(*page_middle))`
176			`break;`
177			`if (pmd_bad(*page_middle)) {`
178			`printk("Bad page middle entry %08lx\n", pmd_val(*page_middle));`
179			`pmd_clear(page_middle);`
180			`break;`
181			`}`
182			`pte = *pte_offset(page_middle,addr);`
183			`if (!pte_present(pte))`
184			`break;`
185			`if (!pte_write(pte))`
186			`break;`
187			`page = (char *) pte_page(pte) + (addr & ~PAGE_MASK);`
188			`i = PAGE_SIZE-(addr & ~PAGE_MASK);`
189			`if (i > count)`
190			`i = count;`
191			`memcpy_fromfs(page, tmp, i);`
192			`addr += i;`
193			`tmp += i;`
194			`count -= i;`
195			`}`
196			`file->f_pos = addr;`
197			`if (tmp != buf)`
198			`return tmp-buf;`
199			`if (current->signal & ~current->blocked)`
200			`return -ERESTARTSYS;`
201			`return 0;`
202			`}`
203
204			`#endif`
205
206			`static int mem_lseek(struct inode * inode, struct file * file, off_t offset, int orig)`
207			`{`
208			`switch (orig) {`
209			`case 0:`
210			`file->f_pos = offset;`
211			`return file->f_pos;`
212			`case 1:`
213			`file->f_pos += offset;`
214			`return file->f_pos;`
215			`default:`
216			`return -EINVAL;`
217			`}`
218			`}`
219
220			`/*`
221			`* This isn't really reliable by any means..`
222			`*/`
223			`int mem_mmap(struct inode * inode, struct file * file,`
224			`struct vm_area_struct * vma)`
225			`{`
226			`struct task_struct *tsk;`
227			`pgd_t src_dir, dest_dir;`
228			`pmd_t src_middle, dest_middle;`
229			`pte_t src_table, dest_table;`
230			`unsigned long stmp, dtmp, mapnr;`
231			`struct vm_area_struct *src_vma = NULL;`
232
233			`/* Get the source's task information */`
234
235			`tsk = get_task(inode->i_ino >> 16);`
236
237			`if (!tsk)`
238			`return -ESRCH;`
239
240			`/* Ensure that we have a valid source area. (Has to be mmap'ed and`
241			`have valid page information.) We can't map shared memory at the`
242			`moment because working out the vm_area_struct & nattach stuff isn't`
243			`worth it. */`
244
245			`src_vma = tsk->mm->mmap;`
246			`stmp = vma->vm_offset;`
247			`while (stmp < vma->vm_offset + (vma->vm_end - vma->vm_start)) {`
248			`while (src_vma && stmp > src_vma->vm_end)`
249			`src_vma = src_vma->vm_next;`
250			`if (!src_vma \|\| (src_vma->vm_flags & VM_SHM))`
251			`return -EINVAL;`
252
253			`src_dir = pgd_offset(tsk->mm, stmp);`
254			`if (pgd_none(*src_dir))`
255			`return -EINVAL;`
256			`if (pgd_bad(*src_dir)) {`
257			`printk("Bad source page dir entry %08lx\n", pgd_val(*src_dir));`
258			`return -EINVAL;`
259			`}`
260			`src_middle = pmd_offset(src_dir, stmp);`
261			`if (pmd_none(*src_middle))`
262			`return -EINVAL;`
263			`if (pmd_bad(*src_middle)) {`
264			`printk("Bad source page middle entry %08lx\n", pmd_val(*src_middle));`
265			`return -EINVAL;`
266			`}`
267			`src_table = pte_offset(src_middle, stmp);`
268			`if (pte_none(*src_table))`
269			`return -EINVAL;`
270
271			`if (stmp < src_vma->vm_start) {`
272			`if (!(src_vma->vm_flags & VM_GROWSDOWN))`
273			`return -EINVAL;`
274			`if (src_vma->vm_end - stmp > current->rlim[RLIMIT_STACK].rlim_cur)`
275			`return -EINVAL;`
276			`}`
277			`stmp += PAGE_SIZE;`
278			`}`
279
280			`src_vma = tsk->mm->mmap;`
281			`stmp = vma->vm_offset;`
282			`dtmp = vma->vm_start;`
283
284			`flush_cache_range(vma->vm_mm, vma->vm_start, vma->vm_end);`
285			`flush_cache_range(src_vma->vm_mm, src_vma->vm_start, src_vma->vm_end);`
286			`while (dtmp < vma->vm_end) {`
287			`while (src_vma && stmp > src_vma->vm_end)`
288			`src_vma = src_vma->vm_next;`
289
290			`src_dir = pgd_offset(tsk->mm, stmp);`
291			`src_middle = pmd_offset(src_dir, stmp);`
292			`src_table = pte_offset(src_middle, stmp);`
293
294			`dest_dir = pgd_offset(current->mm, dtmp);`
295			`dest_middle = pmd_alloc(dest_dir, dtmp);`
296			`if (!dest_middle)`
297			`return -ENOMEM;`
298			`dest_table = pte_alloc(dest_middle, dtmp);`
299			`if (!dest_table)`
300			`return -ENOMEM;`
301
302			`if (!pte_present(*src_table))`
303			`do_no_page(tsk, src_vma, stmp, 1);`
304
305			`if ((vma->vm_flags & VM_WRITE) && !pte_write(*src_table))`
306			`do_wp_page(tsk, src_vma, stmp, 1);`
307
308			`set_pte(src_table, pte_mkdirty(*src_table));`
309			`set_pte(dest_table, *src_table);`
310			`mapnr = MAP_NR(pte_page(*src_table));`
311			`if (mapnr < MAP_NR(high_memory))`
312			`mem_map[mapnr].count++;`
313
314			`stmp += PAGE_SIZE;`
315			`dtmp += PAGE_SIZE;`
316			`}`
317
318			`flush_tlb_range(vma->vm_mm, vma->vm_start, vma->vm_end);`
319			`flush_tlb_range(src_vma->vm_mm, src_vma->vm_start, src_vma->vm_end);`
320			`return 0;`
321			`}`
322
323			`static struct file_operations proc_mem_operations = {`
324			`mem_lseek,`
325			`mem_read,`
326			`mem_write,`
327			`NULL, /* mem_readdir */`
328			`NULL, /* mem_select */`
329			`NULL, /* mem_ioctl */`
330			`mem_mmap, /* mmap */`
331			`NULL, /* no special open code */`
332			`NULL, /* no special release code */`
333			`NULL /* can't fsync */`
334			`};`
335
336			`struct inode_operations proc_mem_inode_operations = {`
337			`&proc_mem_operations, /* default base directory file-ops */`
338			`NULL, /* create */`
339			`NULL, /* lookup */`
340			`NULL, /* link */`
341			`NULL, /* unlink */`
342			`NULL, /* symlink */`
343			`NULL, /* mkdir */`
344			`NULL, /* rmdir */`
345			`NULL, /* mknod */`
346			`NULL, /* rename */`
347			`NULL, /* readlink */`
348			`NULL, /* follow_link */`
349			`NULL, /* readpage */`
350			`NULL, /* writepage */`
351			`NULL, /* bmap */`
352			`NULL, /* truncate */`
353			`NULL /* permission */`
354			`};`
355
356			`#else /* NO_MM */`
357
358			`/*`
359			`* mem_write isn't really a good idea right now. It needs`
360			`* to check a lot more: if the process we try to write to`
361			`* dies in the middle right now, mem_write will overwrite`
362			`* kernel memory.. This disables it altogether.`
363			`*/`
364			`#define mem_write NULL`
365
366			`static struct task_struct * get_task(int pid)`
367			`{`
368			`struct task_struct * tsk = current;`
369
370			`if (pid != tsk->pid) {`
371			`int i;`
372			`tsk = NULL;`
373			`for (i = 1 ; i < NR_TASKS ; i++)`
374			`if (task[i] && task[i]->pid == pid) {`
375			`tsk = task[i];`
376			`break;`
377			`}`
378			`/*`
379			`* allow accesses only under the same circumstances`
380			`* that we would allow ptrace to work`
381			`*/`
382			`if (tsk) {`
383			`if (!(tsk->flags & PF_PTRACED)`
384			`\|\| tsk->state != TASK_STOPPED`
385			`\|\| tsk->p_pptr != current)`
386			`tsk = NULL;`
387			`}`
388			`}`
389			`return tsk;`
390			`}`
391
392			`static int mem_read(struct inode * inode, struct file * file,char * buf, int count)`
393			`{`
394			`struct task_struct * tsk;`
395			`unsigned long addr;`
396			`char *tmp;`
397			`int i;`
398
399			`if (count < 0)`
400			`return -EINVAL;`
401			`tsk = get_task(inode->i_ino >> 16);`
402			`if (!tsk)`
403			`return -ESRCH;`
404			`addr = file->f_pos;`
405			`tmp = buf;`
406			`while (count > 0) {`
407			`if (current->signal & ~current->blocked)`
408			`break;`
409			`i = count;`
410			`memcpy_tofs(tmp, (void*)addr, i);`
411			`addr += i;`
412			`tmp += i;`
413			`count -= i;`
414			`}`
415			`file->f_pos = addr;`
416			`return tmp-buf;`
417			`}`
418
419			`#ifndef mem_write`
420
421			`static int mem_write(struct inode * inode, struct file * file,char * buf, int count)`
422			`{`
423			`struct task_struct * tsk;`
424			`unsigned long addr;`
425			`char *tmp;`
426			`int i;`
427
428			`if (count < 0)`
429			`return -EINVAL;`
430			`addr = file->f_pos;`
431			`tsk = get_task(inode->i_ino >> 16);`
432			`if (!tsk)`
433			`return -ESRCH;`
434			`tmp = buf;`
435			`while (count > 0) {`
436			`if (current->signal & ~current->blocked)`
437			`break;`
438			`i = count;`
439			`memcpy_fromfs((void*)addr, tmp, i);`
440			`addr += i;`
441			`tmp += i;`
442			`count -= i;`
443			`}`
444			`file->f_pos = addr;`
445			`if (tmp != buf)`
446			`return tmp-buf;`
447			`if (current->signal & ~current->blocked)`
448			`return -ERESTARTSYS;`
449			`return 0;`
450			`}`
451
452			`#endif`
453
454			`int mem_mmap(struct inode * inode, struct file * file,`
455			`struct vm_area_struct * vma)`
456			`{`
457			`vma->vm_start = vma->vm_offset;`
458			`return 0;`
459			`}`
460
461			`static int mem_lseek(struct inode * inode, struct file * file, off_t offset, int orig)`
462			`{`
463			`switch (orig) {`
464			`case 0:`
465			`file->f_pos = offset;`
466			`return file->f_pos;`
467			`case 1:`
468			`file->f_pos += offset;`
469			`return file->f_pos;`
470			`default:`
471			`return -EINVAL;`
472			`}`
473			`}`
474
475			`static struct file_operations proc_mem_operations = {`
476			`mem_lseek,`
477			`mem_read,`
478			`mem_write,`
479			`NULL, /* mem_readdir */`
480			`NULL, /* mem_select */`
481			`NULL, /* mem_ioctl */`
482			`mem_mmap, /* mmap */`
483			`NULL, /* no special open code */`
484			`NULL, /* no special release code */`
485			`NULL /* can't fsync */`
486			`};`
487
488			`struct inode_operations proc_mem_inode_operations = {`
489			`&proc_mem_operations, /* default base directory file-ops */`
490			`NULL, /* create */`
491			`NULL, /* lookup */`
492			`NULL, /* link */`
493			`NULL, /* unlink */`
494			`NULL, /* symlink */`
495			`NULL, /* mkdir */`
496			`NULL, /* rmdir */`
497			`NULL, /* mknod */`
498			`NULL, /* rename */`
499			`NULL, /* readlink */`
500			`NULL, /* follow_link */`
501			`NULL, /* readpage */`
502			`NULL, /* writepage */`
503			`NULL, /* bmap */`
504			`NULL, /* truncate */`
505			`NULL /* permission */`
506			`};`
507
508			`#endif /* NO_MM */`