treewide: remove SPDX "WITH Linux-syscall-note" from kernel-space headers
[sfrench/cifs-2.6.git] / block / partitions / cmdline.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2013 HUAWEI
4  * Author: Cai Zhiyong <caizhiyong@huawei.com>
5  *
6  * Read block device partition table from the command line.
7  * Typically used for fixed block (eMMC) embedded devices.
8  * It has no MBR, so saves storage space. Bootloader can be easily accessed
9  * by absolute address of data on the block device.
10  * Users can easily change the partition.
11  *
12  * The format for the command line is just like mtdparts.
13  *
14  * For further information, see "Documentation/block/cmdline-partition.txt"
15  *
16  */
17
18 #include <linux/cmdline-parser.h>
19
20 #include "check.h"
21 #include "cmdline.h"
22
23 static char *cmdline;
24 static struct cmdline_parts *bdev_parts;
25
26 static int add_part(int slot, struct cmdline_subpart *subpart, void *param)
27 {
28         int label_min;
29         struct partition_meta_info *info;
30         char tmp[sizeof(info->volname) + 4];
31         struct parsed_partitions *state = (struct parsed_partitions *)param;
32
33         if (slot >= state->limit)
34                 return 1;
35
36         put_partition(state, slot, subpart->from >> 9,
37                       subpart->size >> 9);
38
39         info = &state->parts[slot].info;
40
41         label_min = min_t(int, sizeof(info->volname) - 1,
42                           sizeof(subpart->name));
43         strncpy(info->volname, subpart->name, label_min);
44         info->volname[label_min] = '\0';
45
46         snprintf(tmp, sizeof(tmp), "(%s)", info->volname);
47         strlcat(state->pp_buf, tmp, PAGE_SIZE);
48
49         state->parts[slot].has_info = true;
50
51         return 0;
52 }
53
54 static int __init cmdline_parts_setup(char *s)
55 {
56         cmdline = s;
57         return 1;
58 }
59 __setup("blkdevparts=", cmdline_parts_setup);
60
61 static bool has_overlaps(sector_t from, sector_t size,
62                          sector_t from2, sector_t size2)
63 {
64         sector_t end = from + size;
65         sector_t end2 = from2 + size2;
66
67         if (from >= from2 && from < end2)
68                 return true;
69
70         if (end > from2 && end <= end2)
71                 return true;
72
73         if (from2 >= from && from2 < end)
74                 return true;
75
76         if (end2 > from && end2 <= end)
77                 return true;
78
79         return false;
80 }
81
82 static inline void overlaps_warns_header(void)
83 {
84         pr_warn("Overlapping partitions are used in command line partitions.");
85         pr_warn("Don't use filesystems on overlapping partitions:");
86 }
87
88 static void cmdline_parts_verifier(int slot, struct parsed_partitions *state)
89 {
90         int i;
91         bool header = true;
92
93         for (; slot < state->limit && state->parts[slot].has_info; slot++) {
94                 for (i = slot+1; i < state->limit && state->parts[i].has_info;
95                      i++) {
96                         if (has_overlaps(state->parts[slot].from,
97                                          state->parts[slot].size,
98                                          state->parts[i].from,
99                                          state->parts[i].size)) {
100                                 if (header) {
101                                         header = false;
102                                         overlaps_warns_header();
103                                 }
104                                 pr_warn("%s[%llu,%llu] overlaps with "
105                                         "%s[%llu,%llu].",
106                                         state->parts[slot].info.volname,
107                                         (u64)state->parts[slot].from << 9,
108                                         (u64)state->parts[slot].size << 9,
109                                         state->parts[i].info.volname,
110                                         (u64)state->parts[i].from << 9,
111                                         (u64)state->parts[i].size << 9);
112                         }
113                 }
114         }
115 }
116
117 /*
118  * Purpose: allocate cmdline partitions.
119  * Returns:
120  * -1 if unable to read the partition table
121  *  0 if this isn't our partition table
122  *  1 if successful
123  */
124 int cmdline_partition(struct parsed_partitions *state)
125 {
126         sector_t disk_size;
127         char bdev[BDEVNAME_SIZE];
128         struct cmdline_parts *parts;
129
130         if (cmdline) {
131                 if (bdev_parts)
132                         cmdline_parts_free(&bdev_parts);
133
134                 if (cmdline_parts_parse(&bdev_parts, cmdline)) {
135                         cmdline = NULL;
136                         return -1;
137                 }
138                 cmdline = NULL;
139         }
140
141         if (!bdev_parts)
142                 return 0;
143
144         bdevname(state->bdev, bdev);
145         parts = cmdline_parts_find(bdev_parts, bdev);
146         if (!parts)
147                 return 0;
148
149         disk_size = get_capacity(state->bdev->bd_disk) << 9;
150
151         cmdline_parts_set(parts, disk_size, 1, add_part, (void *)state);
152         cmdline_parts_verifier(1, state);
153
154         strlcat(state->pp_buf, "\n", PAGE_SIZE);
155
156         return 1;
157 }