1 #include "stdinc.h"
2 #include "dat.h"
3 #include "fns.h"
4 
5 #define trace 1
6 
7 u32int	maxblocksize;
8 int	readonly;
9 
10 Part*
11 initpart(char *name, int writable)
12 {
13 	Part *part;
14 	Dir *dir;
15 	int how;
16 
17 	part = MKZ(Part);
18 	part->name = estrdup(name);
19 	if(!writable && readonly)
20 		how = OREAD;
21 	else
22 		how = ORDWR;
23 	part->fd = open(name, how);
24 	if(part->fd < 0){
25 		if(how == ORDWR)
26 			part->fd = open(name, OREAD);
27 		if(part->fd < 0){
28 			freepart(part);
29 			seterr(EOk, "can't open partition='%s': %r", name);
30 			return nil;
31 		}
32 		fprint(2, "warning: %s opened for reading only\n", name);
33 	}
34 	dir = dirfstat(part->fd);
35 	if(dir == nil){
36 		freepart(part);
37 		seterr(EOk, "can't stat partition='%s': %r", name);
38 		return nil;
39 	}
40 	part->size = dir->length;
41 	part->blocksize = 0;
42 	free(dir);
43 	return part;
44 }
45 
46 void
47 freepart(Part *part)
48 {
49 	if(part == nil)
50 		return;
51 	close(part->fd);
52 	free(part->name);
53 	free(part);
54 }
55 
56 void
57 partblocksize(Part *part, u32int blocksize)
58 {
59 	if(part->blocksize)
60 		sysfatal("resetting partition=%s's block size", part->name);
61 	part->blocksize = blocksize;
62 	if(blocksize > maxblocksize)
63 		maxblocksize = blocksize;
64 }
65 
66 int
67 writepart(Part *part, u64int addr, u8int *buf, u32int n)
68 {
69 	long m, mm, nn;
70 
71 	qlock(&stats.lock);
72 	stats.diskwrites++;
73 	stats.diskbwrites += n;
74 	qunlock(&stats.lock);
75 
76 	if(addr > part->size || addr + n > part->size){
77 		seterr(ECorrupt, "out of bounds write to partition='%s'", part->name);
78 		return -1;
79 	}
80 if(trace) print("write %s %lud at %llud\n", part->name, n, addr);
81 	for(nn = 0; nn < n; nn += m){
82 		mm = n - nn;
83 		if(mm > MaxIo)
84 			mm = MaxIo;
85 		m = pwrite(part->fd, &buf[nn], mm, addr + nn);
86 		if(m != mm){
87 			if(m < 0){
88 				seterr(EOk, "can't write partition='%s': %r", part->name);
89 				return -1;
90 			}
91 			logerr(EOk, "truncated write to partition='%s' n=%ld wrote=%ld", part->name, mm, m);
92 		}
93 	}
94 	return 0;
95 }
96 
97 int
98 readpart(Part *part, u64int addr, u8int *buf, u32int n)
99 {
100 	long m, mm, nn;
101 	int i;
102 
103 	qlock(&stats.lock);
104 	stats.diskreads++;
105 	stats.diskbreads += n;
106 	qunlock(&stats.lock);
107 
108 	if(addr > part->size || addr + n > part->size){
109 		seterr(ECorrupt, "out of bounds read from partition='%s': addr=%lld n=%d size=%lld", part->name, addr, n, part->size);
110 		return -1;
111 	}
112 if(trace) print("read %s %lud at %llud\n", part->name, n, addr);
113 	for(nn = 0; nn < n; nn += m){
114 		mm = n - nn;
115 		if(mm > MaxIo)
116 			mm = MaxIo;
117 		m = -1;
118 		for(i=0; i<4; i++) {
119 			m = pread(part->fd, &buf[nn], mm, addr + nn);
120 			if(m == mm)
121 				break;
122 		}
123 		if(m != mm){
124 			if(m < 0){
125 				seterr(EOk, "can't read partition='%s': %r", part->name);
126 				return -1;
127 			}
128 			logerr(EOk, "warning: truncated read from partition='%s' n=%ld read=%ld", part->name, mm, m);
129 		}
130 	}
131 	return 0;
132 }