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[/] [or1k/] [trunk/] [linux/] [linux-2.4/] [fs/] [seq_file.c] - Blame information for rev 1765

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/*
 * linux/fs/seq_file.c
 *
 * helper functions for making synthetic files from sequences of records.
 * initial implementation -- AV, Oct 2001.
 */
 
#include <linux/fs.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
 
#include <asm/uaccess.h>
#include <asm/page.h>
 
/**
 *      seq_open -      initialize sequential file
 *      @file: file we initialize
 *      @op: method table describing the sequence
 *
 *      seq_open() sets @file, associating it with a sequence described
 *      by @op.  @op->start() sets the iterator up and returns the first
 *      element of sequence. @op->stop() shuts it down.  @op->next()
 *      returns the next element of sequence.  @op->show() prints element
 *      into the buffer.  In case of error ->start() and ->next() return
 *      ERR_PTR(error).  In the end of sequence they return %NULL. ->show()
 *      returns 0 in case of success and negative number in case of error.
 */
int seq_open(struct file *file, struct seq_operations *op)
{
        struct seq_file *p = kmalloc(sizeof(*p), GFP_KERNEL);
        if (!p)
                return -ENOMEM;
        memset(p, 0, sizeof(*p));
        sema_init(&p->sem, 1);
        p->op = op;
        file->private_data = p;
        return 0;
}
 
/**
 *      seq_read -      ->read() method for sequential files.
 *      @file, @buf, @size, @ppos: see file_operations method
 *
 *      Ready-made ->f_op->read()
 */
ssize_t seq_read(struct file *file, char *buf, size_t size, loff_t *ppos)
{
        struct seq_file *m = (struct seq_file *)file->private_data;
        size_t copied = 0;
        loff_t pos;
        size_t n;
        void *p;
        int err = 0;
 
        if (ppos != &file->f_pos)
                return -EPIPE;
 
        down(&m->sem);
        /* grab buffer if we didn't have one */
        if (!m->buf) {
                m->buf = kmalloc(m->size = PAGE_SIZE, GFP_KERNEL);
                if (!m->buf)
                        goto Enomem;
        }
        /* if not empty - flush it first */
        if (m->count) {
                n = min(m->count, size);
                err = copy_to_user(buf, m->buf + m->from, n);
                if (err)
                        goto Efault;
                m->count -= n;
                m->from += n;
                size -= n;
                buf += n;
                copied += n;
                if (!m->count)
                        m->index++;
                if (!size)
                        goto Done;
        }
        /* we need at least one record in buffer */
        while (1) {
                pos = m->index;
                p = m->op->start(m, &pos);
                err = PTR_ERR(p);
                if (!p || IS_ERR(p))
                        break;
                err = m->op->show(m, p);
                if (err)
                        break;
                if (m->count < m->size)
                        goto Fill;
                m->op->stop(m, p);
                kfree(m->buf);
                m->buf = kmalloc(m->size <<= 1, GFP_KERNEL);
                if (!m->buf)
                        goto Enomem;
                m->count = 0;
        }
        m->op->stop(m, p);
        m->count = 0;
        goto Done;
Fill:
        /* they want more? let's try to get some more */
        while (m->count < size) {
                size_t offs = m->count;
                loff_t next = pos;
                p = m->op->next(m, p, &next);
                if (!p || IS_ERR(p)) {
                        err = PTR_ERR(p);
                        break;
                }
                err = m->op->show(m, p);
                if (err || m->count == m->size) {
                        m->count = offs;
                        break;
                }
                pos = next;
        }
        m->op->stop(m, p);
        n = min(m->count, size);
        err = copy_to_user(buf, m->buf, n);
        if (err)
                goto Efault;
        copied += n;
        m->count -= n;
        if (m->count)
                m->from = n;
        else
                pos++;
        m->index = pos;
Done:
        if (!copied)
                copied = err;
        else
                *ppos += copied;
        up(&m->sem);
        return copied;
Enomem:
        err = -ENOMEM;
        goto Done;
Efault:
        err = -EFAULT;
        goto Done;
}
 
static int traverse(struct seq_file *m, loff_t offset)
{
        loff_t pos = 0;
        int error = 0;
        void *p;
 
        m->index = 0;
        m->count = m->from = 0;
        if (!offset)
                return 0;
        if (!m->buf) {
                m->buf = kmalloc(m->size = PAGE_SIZE, GFP_KERNEL);
                if (!m->buf)
                        return -ENOMEM;
        }
        p = m->op->start(m, &m->index);
        while (p) {
                error = PTR_ERR(p);
                if (IS_ERR(p))
                        break;
                error = m->op->show(m, p);
                if (error)
                        break;
                if (m->count == m->size)
                        goto Eoverflow;
                if (pos + m->count > offset) {
                        m->from = offset - pos;
                        m->count -= m->from;
                        break;
                }
                pos += m->count;
                m->count = 0;
                if (pos == offset) {
                        m->index++;
                        break;
                }
                p = m->op->next(m, p, &m->index);
        }
        m->op->stop(m, p);
        return error;
 
Eoverflow:
        m->op->stop(m, p);
        kfree(m->buf);
        m->buf = kmalloc(m->size <<= 1, GFP_KERNEL);
        return !m->buf ? -ENOMEM : -EAGAIN;
}
 
/**
 *      seq_lseek -     ->llseek() method for sequential files.
 *      @file, @offset, @origin: see file_operations method
 *
 *      Ready-made ->f_op->llseek()
 */
loff_t seq_lseek(struct file *file, loff_t offset, int origin)
{
        struct seq_file *m = (struct seq_file *)file->private_data;
        long long retval = -EINVAL;
 
        down(&m->sem);
        switch (origin) {
                case 1:
                        offset += file->f_pos;
                case 0:
                        if (offset < 0)
                                break;
                        retval = offset;
                        if (offset != file->f_pos) {
                                while ((retval=traverse(m, offset)) == -EAGAIN)
                                        ;
                                if (retval) {
                                        /* with extreme prejudice... */
                                        file->f_pos = 0;
                                        m->index = 0;
                                        m->count = 0;
                                } else {
                                        retval = file->f_pos = offset;
                                }
                        }
        }
        up(&m->sem);
        return retval;
}
 
/**
 *      seq_release -   free the structures associated with sequential file.
 *      @file: file in question
 *      @inode: file->f_dentry->d_inode
 *
 *      Frees the structures associated with sequential file; can be used
 *      as ->f_op->release() if you don't have private data to destroy.
 */
int seq_release(struct inode *inode, struct file *file)
{
        struct seq_file *m = (struct seq_file *)file->private_data;
        kfree(m->buf);
        kfree(m);
        return 0;
}
 
/**
 *      seq_escape -    print string into buffer, escaping some characters
 *      @m:     target buffer
 *      @s:     string
 *      @esc:   set of characters that need escaping
 *
 *      Puts string into buffer, replacing each occurrence of character from
 *      @esc with usual octal escape.  Returns 0 in case of success, -1 - in
 *      case of overflow.
 */
int seq_escape(struct seq_file *m, const char *s, const char *esc)
{
        char *end = m->buf + m->size;
        char *p;
        char c;
 
        for (p = m->buf + m->count; (c = *s) != '\0' && p < end; s++) {
                if (!strchr(esc, c)) {
                        *p++ = c;
                        continue;
                }
                if (p + 3 < end) {
                        *p++ = '\\';
                        *p++ = '0' + ((c & 0300) >> 6);
                        *p++ = '0' + ((c & 070) >> 3);
                        *p++ = '0' + (c & 07);
                        continue;
                }
                m->count = m->size;
                return -1;
        }
        m->count = p - m->buf;
        return 0;
}
 
int seq_printf(struct seq_file *m, const char *f, ...)
{
        va_list args;
        int len;
 
        if (m->count < m->size) {
                va_start(args, f);
                len = vsnprintf(m->buf + m->count, m->size - m->count, f, args);
                va_end(args);
                if (m->count + len < m->size) {
                        m->count += len;
                        return 0;
                }
        }
        m->count = m->size;
        return -1;
}
 
int seq_path(struct seq_file *m,
                struct vfsmount *mnt, struct dentry *dentry,
                char *esc)
{
        if (m->count < m->size) {
                char *s = m->buf + m->count;
                char *p = d_path(dentry, mnt, s, m->size - m->count);
                if (!IS_ERR(p)) {
                        while (s <= p) {
                                char c = *p++;
                                if (!c) {
                                        p = m->buf + m->count;
                                        m->count = s - m->buf;
                                        return s - p;
                                } else if (!strchr(esc, c)) {
                                        *s++ = c;
                                } else if (s + 4 > p) {
                                        break;
                                } else {
                                        *s++ = '\\';
                                        *s++ = '0' + ((c & 0300) >> 6);
                                        *s++ = '0' + ((c & 070) >> 3);
                                        *s++ = '0' + (c & 07);
                                }
                        }
                }
        }
        m->count = m->size;
        return -1;
}
 
static void *single_start(struct seq_file *p, loff_t *pos)
{
        return NULL + (*pos == 0);
}
 
static void *single_next(struct seq_file *p, void *v, loff_t *pos)
{
        ++*pos;
        return NULL;
}
 
static void single_stop(struct seq_file *p, void *v)
{
}
 
int single_open(struct file *file, int (*show)(struct seq_file *, void*), void *data)
{
        struct seq_operations *op = kmalloc(sizeof(*op), GFP_KERNEL);
        int res = -ENOMEM;
 
        if (op) {
                op->start = single_start;
                op->next = single_next;
                op->stop = single_stop;
                op->show = show;
                res = seq_open(file, op);
                if (!res)
                        ((struct seq_file *)file->private_data)->private = data;
                else
                        kfree(op);
        }
        return res;
}
 
int single_release(struct inode *inode, struct file *file)
{
        struct seq_operations *op = ((struct seq_file *)file->private_data)->op;
        int res = seq_release(inode, file);
        kfree(op);
        return res;
}
 
int seq_release_private(struct inode *inode, struct file *file)
{
        struct seq_file *seq = file->private_data;
 
        kfree(seq->private);
        seq->private = NULL;
        return seq_release(inode, file);
}
 

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[/] [or1k/] [trunk/] [linux/] [linux-2.4/] [fs/] [seq_file.c] - Blame information for rev 1765

Line No.	Rev	Author	Line
1	1275	phoenix	`/*`
2			`* linux/fs/seq_file.c`
3			`*`
4			`* helper functions for making synthetic files from sequences of records.`
5			`* initial implementation -- AV, Oct 2001.`
6			`*/`
7
8			`#include <linux/fs.h>`
9			`#include <linux/seq_file.h>`
10			`#include <linux/slab.h>`
11
12			`#include <asm/uaccess.h>`
13			`#include <asm/page.h>`
14
15			`/**`
16			`* seq_open - initialize sequential file`
17			`* @file: file we initialize`
18			`* @op: method table describing the sequence`
19			`*`
20			`* seq_open() sets @file, associating it with a sequence described`
21			`* by @op. @op->start() sets the iterator up and returns the first`
22			`* element of sequence. @op->stop() shuts it down. @op->next()`
23			`* returns the next element of sequence. @op->show() prints element`
24			`* into the buffer. In case of error ->start() and ->next() return`
25			`* ERR_PTR(error). In the end of sequence they return %NULL. ->show()`
26			`* returns 0 in case of success and negative number in case of error.`
27			`*/`
28			`int seq_open(struct file file, struct seq_operations op)`
29			`{`
30			`struct seq_file p = kmalloc(sizeof(p), GFP_KERNEL);`
31			`if (!p)`
32			`return -ENOMEM;`
33			`memset(p, 0, sizeof(*p));`
34			`sema_init(&p->sem, 1);`
35			`p->op = op;`
36			`file->private_data = p;`
37			`return 0;`
38			`}`
39
40			`/**`
41			`* seq_read - ->read() method for sequential files.`
42			`* @file, @buf, @size, @ppos: see file_operations method`
43			`*`
44			`* Ready-made ->f_op->read()`
45			`*/`
46			`ssize_t seq_read(struct file file, char buf, size_t size, loff_t *ppos)`
47			`{`
48			`struct seq_file m = (struct seq_file )file->private_data;`
49			`size_t copied = 0;`
50			`loff_t pos;`
51			`size_t n;`
52			`void *p;`
53			`int err = 0;`
54
55			`if (ppos != &file->f_pos)`
56			`return -EPIPE;`
57
58			`down(&m->sem);`
59			`/* grab buffer if we didn't have one */`
60			`if (!m->buf) {`
61			`m->buf = kmalloc(m->size = PAGE_SIZE, GFP_KERNEL);`
62			`if (!m->buf)`
63			`goto Enomem;`
64			`}`
65			`/* if not empty - flush it first */`
66			`if (m->count) {`
67			`n = min(m->count, size);`
68			`err = copy_to_user(buf, m->buf + m->from, n);`
69			`if (err)`
70			`goto Efault;`
71			`m->count -= n;`
72			`m->from += n;`
73			`size -= n;`
74			`buf += n;`
75			`copied += n;`
76			`if (!m->count)`
77			`m->index++;`
78			`if (!size)`
79			`goto Done;`
80			`}`
81			`/* we need at least one record in buffer */`
82			`while (1) {`
83			`pos = m->index;`
84			`p = m->op->start(m, &pos);`
85			`err = PTR_ERR(p);`
86			`if (!p \|\| IS_ERR(p))`
87			`break;`
88			`err = m->op->show(m, p);`
89			`if (err)`
90			`break;`
91			`if (m->count < m->size)`
92			`goto Fill;`
93			`m->op->stop(m, p);`
94			`kfree(m->buf);`
95			`m->buf = kmalloc(m->size <<= 1, GFP_KERNEL);`
96			`if (!m->buf)`
97			`goto Enomem;`
98			`m->count = 0;`
99			`}`
100			`m->op->stop(m, p);`
101			`m->count = 0;`
102			`goto Done;`
103			`Fill:`
104			`/* they want more? let's try to get some more */`
105			`while (m->count < size) {`
106			`size_t offs = m->count;`
107			`loff_t next = pos;`
108			`p = m->op->next(m, p, &next);`
109			`if (!p \|\| IS_ERR(p)) {`
110			`err = PTR_ERR(p);`
111			`break;`
112			`}`
113			`err = m->op->show(m, p);`
114			`if (err \|\| m->count == m->size) {`
115			`m->count = offs;`
116			`break;`
117			`}`
118			`pos = next;`
119			`}`
120			`m->op->stop(m, p);`
121			`n = min(m->count, size);`
122			`err = copy_to_user(buf, m->buf, n);`
123			`if (err)`
124			`goto Efault;`
125			`copied += n;`
126			`m->count -= n;`
127			`if (m->count)`
128			`m->from = n;`
129			`else`
130			`pos++;`
131			`m->index = pos;`
132			`Done:`
133			`if (!copied)`
134			`copied = err;`
135			`else`
136			`*ppos += copied;`
137			`up(&m->sem);`
138			`return copied;`
139			`Enomem:`
140			`err = -ENOMEM;`
141			`goto Done;`
142			`Efault:`
143			`err = -EFAULT;`
144			`goto Done;`
145			`}`
146
147			`static int traverse(struct seq_file *m, loff_t offset)`
148			`{`
149			`loff_t pos = 0;`
150			`int error = 0;`
151			`void *p;`
152
153			`m->index = 0;`
154			`m->count = m->from = 0;`
155			`if (!offset)`
156			`return 0;`
157			`if (!m->buf) {`
158			`m->buf = kmalloc(m->size = PAGE_SIZE, GFP_KERNEL);`
159			`if (!m->buf)`
160			`return -ENOMEM;`
161			`}`
162			`p = m->op->start(m, &m->index);`
163			`while (p) {`
164			`error = PTR_ERR(p);`
165			`if (IS_ERR(p))`
166			`break;`
167			`error = m->op->show(m, p);`
168			`if (error)`
169			`break;`
170			`if (m->count == m->size)`
171			`goto Eoverflow;`
172			`if (pos + m->count > offset) {`
173			`m->from = offset - pos;`
174			`m->count -= m->from;`
175			`break;`
176			`}`
177			`pos += m->count;`
178			`m->count = 0;`
179			`if (pos == offset) {`
180			`m->index++;`
181			`break;`
182			`}`
183			`p = m->op->next(m, p, &m->index);`
184			`}`
185			`m->op->stop(m, p);`
186			`return error;`
187
188			`Eoverflow:`
189			`m->op->stop(m, p);`
190			`kfree(m->buf);`
191			`m->buf = kmalloc(m->size <<= 1, GFP_KERNEL);`
192			`return !m->buf ? -ENOMEM : -EAGAIN;`
193			`}`
194
195			`/**`
196			`* seq_lseek - ->llseek() method for sequential files.`
197			`* @file, @offset, @origin: see file_operations method`
198			`*`
199			`* Ready-made ->f_op->llseek()`
200			`*/`
201			`loff_t seq_lseek(struct file *file, loff_t offset, int origin)`
202			`{`
203			`struct seq_file m = (struct seq_file )file->private_data;`
204			`long long retval = -EINVAL;`
205
206			`down(&m->sem);`
207			`switch (origin) {`
208			`case 1:`
209			`offset += file->f_pos;`
210			`case 0:`
211			`if (offset < 0)`
212			`break;`
213			`retval = offset;`
214			`if (offset != file->f_pos) {`
215			`while ((retval=traverse(m, offset)) == -EAGAIN)`
216			`;`
217			`if (retval) {`
218			`/* with extreme prejudice... */`
219			`file->f_pos = 0;`
220			`m->index = 0;`
221			`m->count = 0;`
222			`} else {`
223			`retval = file->f_pos = offset;`
224			`}`
225			`}`
226			`}`
227			`up(&m->sem);`
228			`return retval;`
229			`}`
230
231			`/**`
232			`* seq_release - free the structures associated with sequential file.`
233			`* @file: file in question`
234			`* @inode: file->f_dentry->d_inode`
235			`*`
236			`* Frees the structures associated with sequential file; can be used`
237			`* as ->f_op->release() if you don't have private data to destroy.`
238			`*/`
239			`int seq_release(struct inode inode, struct file file)`
240			`{`
241			`struct seq_file m = (struct seq_file )file->private_data;`
242			`kfree(m->buf);`
243			`kfree(m);`
244			`return 0;`
245			`}`
246
247			`/**`
248			`* seq_escape - print string into buffer, escaping some characters`
249			`* @m: target buffer`
250			`* @s: string`
251			`* @esc: set of characters that need escaping`
252			`*`
253			`* Puts string into buffer, replacing each occurrence of character from`
254			`* @esc with usual octal escape. Returns 0 in case of success, -1 - in`
255			`* case of overflow.`
256			`*/`
257			`int seq_escape(struct seq_file m, const char s, const char *esc)`
258			`{`
259			`char *end = m->buf + m->size;`
260			`char *p;`
261			`char c;`
262
263			`for (p = m->buf + m->count; (c = *s) != '\0' && p < end; s++) {`
264			`if (!strchr(esc, c)) {`
265			`*p++ = c;`
266			`continue;`
267			`}`
268			`if (p + 3 < end) {`
269			`*p++ = '\\';`
270			`*p++ = '0' + ((c & 0300) >> 6);`
271			`*p++ = '0' + ((c & 070) >> 3);`
272			`*p++ = '0' + (c & 07);`
273			`continue;`
274			`}`
275			`m->count = m->size;`
276			`return -1;`
277			`}`
278			`m->count = p - m->buf;`
279			`return 0;`
280			`}`
281
282			`int seq_printf(struct seq_file m, const char f, ...)`
283			`{`
284			`va_list args;`
285			`int len;`
286
287			`if (m->count < m->size) {`
288			`va_start(args, f);`
289			`len = vsnprintf(m->buf + m->count, m->size - m->count, f, args);`
290			`va_end(args);`
291			`if (m->count + len < m->size) {`
292			`m->count += len;`
293			`return 0;`
294			`}`
295			`}`
296			`m->count = m->size;`
297			`return -1;`
298			`}`
299
300			`int seq_path(struct seq_file *m,`
301			`struct vfsmount mnt, struct dentry dentry,`
302			`char *esc)`
303			`{`
304			`if (m->count < m->size) {`
305			`char *s = m->buf + m->count;`
306			`char *p = d_path(dentry, mnt, s, m->size - m->count);`
307			`if (!IS_ERR(p)) {`
308			`while (s <= p) {`
309			`char c = *p++;`
310			`if (!c) {`
311			`p = m->buf + m->count;`
312			`m->count = s - m->buf;`
313			`return s - p;`
314			`} else if (!strchr(esc, c)) {`
315			`*s++ = c;`
316			`} else if (s + 4 > p) {`
317			`break;`
318			`} else {`
319			`*s++ = '\\';`
320			`*s++ = '0' + ((c & 0300) >> 6);`
321			`*s++ = '0' + ((c & 070) >> 3);`
322			`*s++ = '0' + (c & 07);`
323			`}`
324			`}`
325			`}`
326			`}`
327			`m->count = m->size;`
328			`return -1;`
329			`}`
330
331			`static void single_start(struct seq_file p, loff_t *pos)`
332			`{`
333			`return NULL + (*pos == 0);`
334			`}`
335
336			`static void single_next(struct seq_file p, void v, loff_t pos)`
337			`{`
338			`++*pos;`
339			`return NULL;`
340			`}`
341
342			`static void single_stop(struct seq_file p, void v)`
343			`{`
344			`}`
345
346			`int single_open(struct file file, int (show)(struct seq_file , void), void *data)`
347			`{`
348			`struct seq_operations op = kmalloc(sizeof(op), GFP_KERNEL);`
349			`int res = -ENOMEM;`
350
351			`if (op) {`
352			`op->start = single_start;`
353			`op->next = single_next;`
354			`op->stop = single_stop;`
355			`op->show = show;`
356			`res = seq_open(file, op);`
357			`if (!res)`
358			`((struct seq_file *)file->private_data)->private = data;`
359			`else`
360			`kfree(op);`
361			`}`
362			`return res;`
363			`}`
364
365			`int single_release(struct inode inode, struct file file)`
366			`{`
367			`struct seq_operations op = ((struct seq_file )file->private_data)->op;`
368			`int res = seq_release(inode, file);`
369			`kfree(op);`
370			`return res;`
371			`}`
372
373			`int seq_release_private(struct inode inode, struct file file)`
374			`{`
375			`struct seq_file *seq = file->private_data;`
376
377			`kfree(seq->private);`
378			`seq->private = NULL;`
379			`return seq_release(inode, file);`
380			`}`
381