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1.1 root 1: /*
2: * linux/fs/proc/base.c
3: *
4: * Copyright (C) 1991, 1992 Linus Torvalds
5: *
6: * proc base directory handling functions
7: */
8:
9: #include <asm/segment.h>
10:
11: #include <linux/errno.h>
12: #include <linux/sched.h>
13: #include <linux/proc_fs.h>
14: #include <linux/stat.h>
15:
16: static int proc_readbase(struct inode *, struct file *, struct dirent *, int);
17: static int proc_lookupbase(struct inode *,const char *,int,struct inode **);
18:
19: static struct file_operations proc_base_operations = {
20: NULL, /* lseek - default */
21: NULL, /* read - bad */
22: NULL, /* write - bad */
23: proc_readbase, /* readdir */
24: NULL, /* select - default */
25: NULL, /* ioctl - default */
26: NULL, /* no special open code */
27: NULL /* no special release code */
28: };
29:
30: /*
31: * proc directories can do almost nothing..
32: */
33: struct inode_operations proc_base_inode_operations = {
34: &proc_base_operations, /* default base directory file-ops */
35: NULL, /* create */
36: proc_lookupbase, /* lookup */
37: NULL, /* link */
38: NULL, /* unlink */
39: NULL, /* symlink */
40: NULL, /* mkdir */
41: NULL, /* rmdir */
42: NULL, /* mknod */
43: NULL, /* rename */
44: NULL, /* readlink */
45: NULL, /* follow_link */
46: NULL, /* bmap */
47: NULL /* truncate */
48: };
49:
50: struct proc_dir_entry {
51: unsigned short low_ino;
52: unsigned short namelen;
53: char * name;
54: };
55:
56: static struct proc_dir_entry base_dir[] = {
57: { 1,2,".." },
58: { 2,1,"." },
59: { 3,3,"mem" },
60: { 4,3,"cwd" },
61: { 5,4,"root" },
62: { 6,3,"exe" },
63: { 7,2,"fd" },
64: { 8,3,"lib" }
65: };
66:
67: #define NR_BASE_DIRENTRY ((sizeof (base_dir))/(sizeof (base_dir[0])))
68:
69: static int proc_match(int len,const char * name,struct proc_dir_entry * de)
70: {
71: register int same __asm__("ax");
72:
73: if (!de || !de->low_ino)
74: return 0;
75: /* "" means "." ---> so paths like "/usr/lib//libc.a" work */
76: if (!len && (de->name[0]=='.') && (de->name[1]=='\0'))
77: return 1;
78: if (de->namelen != len)
79: return 0;
80: __asm__("cld\n\t"
81: "fs ; repe ; cmpsb\n\t"
82: "setz %%al"
83: :"=a" (same)
84: :"0" (0),"S" ((long) name),"D" ((long) de->name),"c" (len)
85: :"cx","di","si");
86: return same;
87: }
88:
89: static int proc_lookupbase(struct inode * dir,const char * name, int len,
90: struct inode ** result)
91: {
92: unsigned int pid;
93: int i, ino;
94:
95: *result = NULL;
96: if (!dir)
97: return -ENOENT;
98: if (!S_ISDIR(dir->i_mode)) {
99: iput(dir);
100: return -ENOENT;
101: }
102: ino = dir->i_ino;
103: pid = ino >> 16;
104: i = NR_BASE_DIRENTRY;
105: while (i-- > 0 && !proc_match(len,name,base_dir+i))
106: /* nothing */;
107: if (i < 0) {
108: iput(dir);
109: return -ENOENT;
110: }
111: if (base_dir[i].low_ino == 1)
112: ino = 1;
113: else
114: ino = (pid << 16) + base_dir[i].low_ino;
115: for (i = 0 ; i < NR_TASKS ; i++)
116: if (task[i] && task[i]->pid == pid)
117: break;
118: if (!pid || i >= NR_TASKS) {
119: iput(dir);
120: return -ENOENT;
121: }
122: if (!(*result = iget(dir->i_dev,ino))) {
123: iput(dir);
124: return -ENOENT;
125: }
126: iput(dir);
127: return 0;
128: }
129:
130: static int proc_readbase(struct inode * inode, struct file * filp,
131: struct dirent * dirent, int count)
132: {
133: struct proc_dir_entry * de;
134: unsigned int pid, ino;
135: int i,j;
136:
137: if (!inode || !S_ISDIR(inode->i_mode))
138: return -EBADF;
139: ino = inode->i_ino;
140: pid = ino >> 16;
141: for (i = 0 ; i < NR_TASKS ; i++)
142: if (task[i] && task[i]->pid == pid)
143: break;
144: if (!pid || i >= NR_TASKS)
145: return 0;
146: if (((unsigned) filp->f_pos) < NR_BASE_DIRENTRY) {
147: de = base_dir + filp->f_pos;
148: filp->f_pos++;
149: i = de->namelen;
150: ino = de->low_ino;
151: if (ino != 1)
152: ino |= (pid << 16);
153: put_fs_long(ino, &dirent->d_ino);
154: put_fs_word(i,&dirent->d_reclen);
155: put_fs_byte(0,i+dirent->d_name);
156: j = i;
157: while (i--)
158: put_fs_byte(de->name[i], i+dirent->d_name);
159: return j;
160: }
161: return 0;
162: }
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