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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 | /* * linux/fs/proc/sysvipc.c * * Copyright (c) 1999 Dragos Acostachioaie * * This code is derived from linux/fs/proc/generic.c, * which is Copyright (C) 1991, 1992 Linus Torvalds. * * /proc/sysvipc directory handling functions */ #include <linux/errno.h> #include <linux/sched.h> #include <linux/proc_fs.h> #include <linux/stat.h> #include <linux/mm.h> #include <asm/uaccess.h> #ifndef MIN #define MIN(a,b) (((a) < (b)) ? (a) : (b)) #endif /* 4K page size but our output routines use some slack for overruns */ #define PROC_BLOCK_SIZE (3*1024) static ssize_t proc_sysvipc_read(struct file * file, char * buf, size_t nbytes, loff_t *ppos) { struct inode * inode = file->f_dentry->d_inode; char *page; ssize_t retval=0; int eof=0; ssize_t n, count; char *start; struct proc_dir_entry * dp; dp = (struct proc_dir_entry *) inode->u.generic_ip; if (!(page = (char*) __get_free_page(GFP_KERNEL))) return -ENOMEM; while ((nbytes > 0) && !eof) { count = MIN(PROC_BLOCK_SIZE, nbytes); start = NULL; if (dp->get_info) { /* * Handle backwards compatibility with the old net * routines. * * XXX What gives with the file->f_flags & O_ACCMODE * test? Seems stupid to me.... */ n = dp->get_info(page, &start, *ppos, count, (file->f_flags & O_ACCMODE) == O_RDWR); if (n < count) eof = 1; } else if (dp->read_proc) { n = dp->read_proc(page, &start, *ppos, count, &eof, dp->data); } else break; if (!start) { /* * For proc files that are less than 4k */ start = page + *ppos; n -= *ppos; if (n <= 0) break; if (n > count) n = count; } if (n == 0) break; /* End of file */ if (n < 0) { if (retval == 0) retval = n; break; } /* This is a hack to allow mangling of file pos independent * of actual bytes read. Simply place the data at page, * return the bytes, and set `start' to the desired offset * as an unsigned int. - Paul.Russell@rustcorp.com.au */ n -= copy_to_user(buf, start < page ? page : start, n); if (n == 0) { if (retval == 0) retval = -EFAULT; break; } *ppos += start < page ? (long)start : n; /* Move down the file */ nbytes -= n; buf += n; retval += n; } free_page((unsigned long) page); return retval; } static struct file_operations proc_sysvipc_operations = { NULL, /* lseek */ proc_sysvipc_read, /* read */ NULL, /* write */ NULL, /* readdir */ NULL, /* poll */ NULL, /* ioctl */ NULL, /* mmap */ NULL, /* no special open code */ NULL, /* no special release code */ NULL /* can't fsync */ }; /* * proc directories can do almost nothing.. */ struct inode_operations proc_sysvipc_inode_operations = { &proc_sysvipc_operations, /* default net 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, /* get_block */ NULL, /* readpage */ NULL, /* writepage */ NULL, /* flushpage */ NULL, /* truncate */ NULL, /* permission */ NULL, /* smap */ NULL /* revalidate */ }; |