cregit-Linux how code gets into the kernel

Release 4.10 fs/seq_file.c

Directory: fs
/*
 * 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/export.h>
#include <linux/seq_file.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/cred.h>
#include <linux/mm.h>
#include <linux/printk.h>
#include <linux/string_helpers.h>

#include <linux/uaccess.h>
#include <asm/page.h>


static void seq_set_overflow(struct seq_file *m) { m->count = m->size; }

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kamezawa hiroyukikamezawa hiroyuki19100.00%1100.00%
Total19100.00%1100.00%


static void *seq_buf_alloc(unsigned long size) { void *buf; gfp_t gfp = GFP_KERNEL; /* * For high order allocations, use __GFP_NORETRY to avoid oom-killing - * it's better to fall back to vmalloc() than to kill things. For small * allocations, just use GFP_KERNEL which will oom kill, thus no need * for vmalloc fallback. */ if (size > PAGE_SIZE) gfp |= __GFP_NORETRY | __GFP_NOWARN; buf = kmalloc(size, gfp); if (!buf && size > PAGE_SIZE) buf = vmalloc(size); return buf; }

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PersonTokensPropCommitsCommitProp
heiko carstensheiko carstens4268.85%150.00%
greg thelengreg thelen1931.15%150.00%
Total61100.00%2100.00%

/** * 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. * Returning SEQ_SKIP means "discard this element and move on". * Note: seq_open() will allocate a struct seq_file and store its * pointer in @file->private_data. This pointer should not be modified. */
int seq_open(struct file *file, const struct seq_operations *op) { struct seq_file *p; WARN_ON(file->private_data); p = kzalloc(sizeof(*p), GFP_KERNEL); if (!p) return -ENOMEM; file->private_data = p; mutex_init(&p->lock); p->op = op; // No refcounting: the lifetime of 'p' is constrained // to the lifetime of the file. p->file = file; /* * Wrappers around seq_open(e.g. swaps_open) need to be * aware of this. If they set f_version themselves, they * should call seq_open first and then set f_version. */ file->f_version = 0; /* * seq_files support lseek() and pread(). They do not implement * write() at all, but we clear FMODE_PWRITE here for historical * reasons. * * If a client of seq_files a) implements file.write() and b) wishes to * support pwrite() then that client will need to implement its own * file.open() which calls seq_open() and then sets FMODE_PWRITE. */ file->f_mode &= ~FMODE_PWRITE; return 0; }

Contributors

PersonTokensPropCommitsCommitProp
linus torvaldslinus torvalds6264.58%330.00%
al viroal viro1212.50%110.00%
prasanna medaprasanna meda77.29%110.00%
eric w. biedermaneric w. biederman66.25%220.00%
yann droneaudyann droneaud66.25%110.00%
ingo molnaringo molnar22.08%110.00%
helge dellerhelge deller11.04%110.00%
Total96100.00%10100.00%

EXPORT_SYMBOL(seq_open);
static int traverse(struct seq_file *m, loff_t offset) { loff_t pos = 0, index; int error = 0; void *p; m->version = 0; index = 0; m->count = m->from = 0; if (!offset) { m->index = index; return 0; } if (!m->buf) { m->buf = seq_buf_alloc(m->size = PAGE_SIZE); if (!m->buf) return -ENOMEM; } p = m->op->start(m, &index); while (p) { error = PTR_ERR(p); if (IS_ERR(p)) break; error = m->op->show(m, p); if (error < 0) break; if (unlikely(error)) { error = 0; m->count = 0; } if (seq_has_overflowed(m)) goto Eoverflow; if (pos + m->count > offset) { m->from = offset - pos; m->count -= m->from; m->index = index; break; } pos += m->count; m->count = 0; if (pos == offset) { index++; m->index = index; break; } p = m->op->next(m, p, &index); } m->op->stop(m, p); m->index = index; return error; Eoverflow: m->op->stop(m, p); kvfree(m->buf); m->count = 0; m->buf = seq_buf_alloc(m->size <<= 1); return !m->buf ? -ENOMEM : -EAGAIN; }

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PersonTokensPropCommitsCommitProp
eric w. biedermaneric w. biederman13540.30%19.09%
linus torvaldslinus torvalds12637.61%19.09%
al viroal viro5215.52%436.36%
prasanna medaprasanna meda102.99%19.09%
alexey dobriyanalexey dobriyan61.79%19.09%
heiko carstensheiko carstens30.90%19.09%
kamezawa hiroyukikamezawa hiroyuki20.60%19.09%
joe perchesjoe perches10.30%19.09%
Total335100.00%11100.00%

/** * seq_read - ->read() method for sequential files. * @file: the file to read from * @buf: the buffer to read to * @size: the maximum number of bytes to read * @ppos: the current position in the file * * Ready-made ->f_op->read() */
ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos) { struct seq_file *m = file->private_data; size_t copied = 0; loff_t pos; size_t n; void *p; int err = 0; mutex_lock(&m->lock); /* * seq_file->op->..m_start/m_stop/m_next may do special actions * or optimisations based on the file->f_version, so we want to * pass the file->f_version to those methods. * * seq_file->version is just copy of f_version, and seq_file * methods can treat it simply as file version. * It is copied in first and copied out after all operations. * It is convenient to have it as part of structure to avoid the * need of passing another argument to all the seq_file methods. */ m->version = file->f_version; /* * if request is to read from zero offset, reset iterator to first * record as it might have been already advanced by previous requests */ if (*ppos == 0) m->index = 0; /* Don't assume *ppos is where we left it */ if (unlikely(*ppos != m->read_pos)) { while ((err = traverse(m, *ppos)) == -EAGAIN) ; if (err) { /* With prejudice... */ m->read_pos = 0; m->version = 0; m->index = 0; m->count = 0; goto Done; } else { m->read_pos = *ppos; } } /* grab buffer if we didn't have one */ if (!m->buf) { m->buf = seq_buf_alloc(m->size = PAGE_SIZE); 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->from = 0; m->index++; } if (!size) goto Done; } /* we need at least one record in buffer */ pos = m->index; p = m->op->start(m, &pos); while (1) { err = PTR_ERR(p); if (!p || IS_ERR(p)) break; err = m->op->show(m, p); if (err < 0) break; if (unlikely(err)) m->count = 0; if (unlikely(!m->count)) { p = m->op->next(m, p, &pos); m->index = pos; continue; } if (m->count < m->size) goto Fill; m->op->stop(m, p); kvfree(m->buf); m->count = 0; m->buf = seq_buf_alloc(m->size <<= 1); if (!m->buf) goto Enomem; m->version = 0; pos = m->index; p = m->op->start(m, &pos); } 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 (seq_has_overflowed(m) || err) { m->count = offs; if (likely(err <= 0)) 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; m->read_pos += copied; } file->f_version = m->version; mutex_unlock(&m->lock); return copied; Enomem: err = -ENOMEM; goto Done; Efault: err = -EFAULT; goto Done; }

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PersonTokensPropCommitsCommitProp
eric w. biedermaneric w. biederman46161.47%213.33%
linus torvaldslinus torvalds21228.27%213.33%
earl chewearl chew162.13%16.67%
al viroal viro152.00%213.33%
tomasz majchrzaktomasz majchrzak141.87%16.67%
alexey dobriyanalexey dobriyan101.33%16.67%
vegard nossumvegard nossum81.07%16.67%
prasanna medaprasanna meda50.67%16.67%
arnaldo carvalho de meloarnaldo carvalho de melo30.40%16.67%
heiko carstensheiko carstens30.40%16.67%
kamezawa hiroyukikamezawa hiroyuki20.27%16.67%
joe perchesjoe perches10.13%16.67%
Total750100.00%15100.00%

EXPORT_SYMBOL(seq_read); /** * seq_lseek - ->llseek() method for sequential files. * @file: the file in question * @offset: new position * @whence: 0 for absolute, 1 for relative position * * Ready-made ->f_op->llseek() */
loff_t seq_lseek(struct file *file, loff_t offset, int whence) { struct seq_file *m = file->private_data; loff_t retval = -EINVAL; mutex_lock(&m->lock); m->version = file->f_version; switch (whence) { case SEEK_CUR: offset += file->f_pos; case SEEK_SET: if (offset < 0) break; retval = offset; if (offset != m->read_pos) { while ((retval = traverse(m, offset)) == -EAGAIN) ; if (retval) { /* with extreme prejudice... */ file->f_pos = 0; m->read_pos = 0; m->version = 0; m->index = 0; m->count = 0; } else { m->read_pos = offset; retval = file->f_pos = offset; } } else { file->f_pos = offset; } } file->f_version = m->version; mutex_unlock(&m->lock); return retval; }

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PersonTokensPropCommitsCommitProp
linus torvaldslinus torvalds12467.03%218.18%
prasanna medaprasanna meda2211.89%19.09%
eric w. biedermaneric w. biederman147.57%19.09%
gu zhenggu zheng94.86%19.09%
alexey dobriyanalexey dobriyan84.32%19.09%
cyrill gorcunovcyrill gorcunov21.08%19.09%
andrew mortonandrew morton21.08%19.09%
ingo molnaringo molnar21.08%19.09%
randy dunlaprandy dunlap10.54%19.09%
david sterbadavid sterba10.54%19.09%
Total185100.00%11100.00%

EXPORT_SYMBOL(seq_lseek); /** * seq_release - free the structures associated with sequential file. * @file: file in question * @inode: its 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 = file->private_data; kvfree(m->buf); kfree(m); return 0; }

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linus torvaldslinus torvalds3897.44%150.00%
heiko carstensheiko carstens12.56%150.00%
Total39100.00%2100.00%

EXPORT_SYMBOL(seq_release); /** * 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. * Use seq_has_overflowed() to check for errors. */
void seq_escape(struct seq_file *m, const char *s, const char *esc) { char *buf; size_t size = seq_get_buf(m, &buf); int ret; ret = string_escape_str(s, buf, size, ESCAPE_OCTAL, esc); seq_commit(m, ret < size ? ret : -1); }

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linus torvaldslinus torvalds3450.75%125.00%
andy shevchenkoandy shevchenko3146.27%125.00%
kamezawa hiroyukikamezawa hiroyuki11.49%125.00%
joe perchesjoe perches11.49%125.00%
Total67100.00%4100.00%

EXPORT_SYMBOL(seq_escape);
void seq_vprintf(struct seq_file *m, const char *f, va_list args) { int len; if (m->count < m->size) { len = vsnprintf(m->buf + m->count, m->size - m->count, f, args); if (m->count + len < m->size) { m->count += len; return; } } seq_set_overflow(m); }

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linus torvaldslinus torvalds7690.48%125.00%
steven whitehousesteven whitehouse33.57%125.00%
kamezawa hiroyukikamezawa hiroyuki33.57%125.00%
joe perchesjoe perches22.38%125.00%
Total84100.00%4100.00%

EXPORT_SYMBOL(seq_vprintf);
void seq_printf(struct seq_file *m, const char *f, ...) { va_list args; va_start(args, f); seq_vprintf(m, f, args); va_end(args); }

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steven whitehousesteven whitehouse4097.56%150.00%
joe perchesjoe perches12.44%150.00%
Total41100.00%2100.00%

EXPORT_SYMBOL(seq_printf); /** * mangle_path - mangle and copy path to buffer beginning * @s: buffer start * @p: beginning of path in above buffer * @esc: set of characters that need escaping * * Copy the path from @p to @s, replacing each occurrence of character from * @esc with usual octal escape. * Returns pointer past last written character in @s, or NULL in case of * failure. */
char *mangle_path(char *s, const char *p, const char *esc) { while (s <= p) { char c = *p++; if (!c) { return s; } 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); } } return NULL; }

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al viroal viro12191.67%266.67%
ram pairam pai118.33%133.33%
Total132100.00%3100.00%

EXPORT_SYMBOL(mangle_path); /** * seq_path - seq_file interface to print a pathname * @m: the seq_file handle * @path: the struct path to print * @esc: set of characters to escape in the output * * return the absolute path of 'path', as represented by the * dentry / mnt pair in the path parameter. */
int seq_path(struct seq_file *m, const struct path *path, const char *esc) { char *buf; size_t size = seq_get_buf(m, &buf); int res = -1; if (size) { char *p = d_path(path, buf, size); if (!IS_ERR(p)) { char *end = mangle_path(buf, p, esc); if (end) res = end - buf; } } seq_commit(m, res); return res; }

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PersonTokensPropCommitsCommitProp
ram pairam pai6057.69%125.00%
miklos szeredimiklos szeredi3634.62%125.00%
al viroal viro87.69%250.00%
Total104100.00%4100.00%

EXPORT_SYMBOL(seq_path); /** * seq_file_path - seq_file interface to print a pathname of a file * @m: the seq_file handle * @file: the struct file to print * @esc: set of characters to escape in the output * * return the absolute path to the file. */
int seq_file_path(struct seq_file *m, struct file *file, const char *esc) { return seq_path(m, &file->f_path, esc); }

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miklos szeredimiklos szeredi33100.00%1100.00%
Total33100.00%1100.00%

EXPORT_SYMBOL(seq_file_path); /* * Same as seq_path, but relative to supplied root. */
int seq_path_root(struct seq_file *m, const struct path *path, const struct path *root, const char *esc) { char *buf; size_t size = seq_get_buf(m, &buf); int res = -ENAMETOOLONG; if (size) { char *p; p = __d_path(path, root, buf, size); if (!p) return SEQ_SKIP; res = PTR_ERR(p); if (!IS_ERR(p)) { char *end = mangle_path(buf, p, esc); if (end) res = end - buf; else res = -ENAMETOOLONG; } } seq_commit(m, res); return res < 0 && res != -ENAMETOOLONG ? res : 0; }

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miklos szeredimiklos szeredi12686.30%240.00%
al viroal viro1610.96%240.00%
tetsuo handatetsuo handa42.74%120.00%
Total146100.00%5100.00%

/* * returns the path of the 'dentry' from the root of its filesystem. */
int seq_dentry(struct seq_file *m, struct dentry *dentry, const char *esc) { char *buf; size_t size = seq_get_buf(m, &buf); int res = -1; if (size) { char *p = dentry_path(dentry, buf, size); if (!IS_ERR(p)) { char *end = mangle_path(buf, p, esc); if (end) res = end - buf; } } seq_commit(m, res); return res; }

Contributors

PersonTokensPropCommitsCommitProp
ram pairam pai6664.08%133.33%
miklos szeredimiklos szeredi3634.95%133.33%
al viroal viro10.97%133.33%
Total103100.00%3100.00%

EXPORT_SYMBOL(seq_dentry);
static void *single_start(struct seq_file *p, loff_t *pos) { return NULL + (*pos == 0); }

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al viroal viro26100.00%1100.00%
Total26100.00%1100.00%


static void *single_next(struct seq_file *p, void *v, loff_t *pos) { ++*pos; return NULL; }

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al viroal viro27100.00%1100.00%
Total27100.00%1100.00%


static void single_stop(struct seq_file *p, void *v) { }

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al viroal viro14100.00%1100.00%
Total14100.00%1100.00%


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; }

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PersonTokensPropCommitsCommitProp
al viroal viro118100.00%1100.00%
Total118100.00%1100.00%

EXPORT_SYMBOL(single_open);
int single_open_size(struct file *file, int (*show)(struct seq_file *, void *), void *data, size_t size) { char *buf = seq_buf_alloc(size); int ret; if (!buf) return -ENOMEM; ret = single_open(file, show, data); if (ret) { kvfree(buf); return ret; } ((struct seq_file *)file->private_data)->buf = buf; ((struct seq_file *)file->private_data)->size = size; return 0; }

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al viroal viro10898.18%150.00%
heiko carstensheiko carstens21.82%150.00%
Total110100.00%2100.00%

EXPORT_SYMBOL(single_open_size);
int single_release(struct inode *inode, struct file *file) { const struct seq_operations *op = ((struct seq_file *)file->private_data)->op; int res = seq_release(inode, file); kfree(op); return res; }

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al viroal viro5198.08%150.00%
helge dellerhelge deller11.92%150.00%
Total52100.00%2100.00%

EXPORT_SYMBOL(single_release);
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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steven whitehousesteven whitehouse45100.00%1100.00%
Total45100.00%1100.00%

EXPORT_SYMBOL(seq_release_private);
void *__seq_open_private(struct file *f, const struct seq_operations *ops, int psize) { int rc; void *private; struct seq_file *seq; private = kzalloc(psize, GFP_KERNEL); if (private == NULL) goto out; rc = seq_open(f, ops); if (rc < 0) goto out_free; seq = f->private_data; seq->private = private; return private; out_free: kfree(private); out: return NULL; }

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pavel emelianovpavel emelianov95100.00%1100.00%
Total95100.00%1100.00%

EXPORT_SYMBOL(__seq_open_private);
int seq_open_private(struct file *filp, const struct seq_operations *ops, int psize) { return __seq_open_private(filp, ops, psize) ? 0 : -ENOMEM; }

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pavel emelianovpavel emelianov34100.00%1100.00%
Total34100.00%1100.00%

EXPORT_SYMBOL(seq_open_private);
void seq_putc(struct seq_file *m, char c) { if (m->count >= m->size) return; m->buf[m->count++] = c; }

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andrew mortonandrew morton3391.67%150.00%
joe perchesjoe perches38.33%150.00%
Total36100.00%2100.00%

EXPORT_SYMBOL(seq_putc);
void seq_puts(struct seq_file *m, const char *s) { int len = strlen(s); if (m->count + len >= m->size) { seq_set_overflow(m)