1 #include "stdinc.h"
2 #include "dat.h"
3 #include "fns.h"
4 
5 u32int	maxblocksize;
6 int	readonly;
7 
8 Part*
9 initpart(char *name, int writable)
10 {
11 	Part *part;
12 	Dir *dir;
13 	int how;
14 
15 	part = MK(Part);
16 	part->name = estrdup(name);
17 	if(!writable && readonly)
18 		how = OREAD;
19 	else
20 		how = ORDWR;
21 	part->fd = open(name, how);
22 	if(part->fd < 0){
23 		if(how == ORDWR)
24 			part->fd = open(name, OREAD);
25 		if(part->fd < 0){
26 			freepart(part);
27 			seterr(EOk, "can't open partition='%s': %r", name);
28 			return nil;
29 		}
30 		fprint(2, "warning: %s opened for reading only\n", name);
31 	}
32 	dir = dirfstat(part->fd);
33 	if(dir == nil){
34 		freepart(part);
35 		seterr(EOk, "can't stat partition='%s': %r", name);
36 		return nil;
37 	}
38 	part->size = dir->length;
39 	part->blocksize = 0;
40 	free(dir);
41 	return part;
42 }
43 
44 void
45 freepart(Part *part)
46 {
47 	if(part == nil)
48 		return;
49 	close(part->fd);
50 	free(part->name);
51 	free(part);
52 }
53 
54 void
55 partblocksize(Part *part, u32int blocksize)
56 {
57 	if(part->blocksize)
58 		sysfatal("resetting partition=%s's block size", part->name);
59 	part->blocksize = blocksize;
60 	if(blocksize > maxblocksize)
61 		maxblocksize = blocksize;
62 }
63 
64 int
65 writepart(Part *part, u64int addr, u8int *buf, u32int n)
66 {
67 	long m, mm, nn;
68 
69 	qlock(&stats.lock);
70 	stats.diskwrites++;
71 	stats.diskbwrites += n;
72 	qunlock(&stats.lock);
73 
74 	if(addr > part->size || addr + n > part->size){
75 		seterr(ECorrupt, "out of bounds write to partition='%s'", part->name);
76 		return -1;
77 	}
78 	print("write %s %lud at %llud\n", part->name, n, addr);
79 	for(nn = 0; nn < n; nn += m){
80 		mm = n - nn;
81 		if(mm > MaxIo)
82 			mm = MaxIo;
83 		m = pwrite(part->fd, &buf[nn], mm, addr + nn);
84 		if(m != mm){
85 			if(m < 0){
86 				seterr(EOk, "can't write partition='%s': %r", part->name);
87 				return -1;
88 			}
89 			logerr(EOk, "truncated write to partition='%s' n=%ld wrote=%ld", part->name, mm, m);
90 		}
91 	}
92 	return 0;
93 }
94 
95 int
96 readpart(Part *part, u64int addr, u8int *buf, u32int n)
97 {
98 	long m, mm, nn;
99 	int i;
100 
101 	qlock(&stats.lock);
102 	stats.diskreads++;
103 	stats.diskbreads += n;
104 	qunlock(&stats.lock);
105 
106 	if(addr > part->size || addr + n > part->size){
107 		seterr(ECorrupt, "out of bounds read from partition='%s': addr=%lld n=%d size=%lld", part->name, addr, n, part->size);
108 		return -1;
109 	}
110 	print("read %s %lud at %llud\n", part->name, n, addr);
111 	for(nn = 0; nn < n; nn += m){
112 		mm = n - nn;
113 		if(mm > MaxIo)
114 			mm = MaxIo;
115 		m = -1;
116 		for(i=0; i<4; i++) {
117 			m = pread(part->fd, &buf[nn], mm, addr + nn);
118 			if(m == mm)
119 				break;
120 		}
121 		if(m != mm){
122 			if(m < 0){
123 				seterr(EOk, "can't read partition='%s': %r", part->name);
124 				return -1;
125 			}
126 			logerr(EOk, "warning: truncated read from partition='%s' n=%ld read=%ld", part->name, mm, m);
127 		}
128 	}
129 	return 0;
130 }