Subversion Repositories planix.SVN

Rev

Rev 2 | Details | Compare with Previous | Last modification | View Log | RSS feed

Rev Author Line No. Line
2 - 1 
/*
2 
 * tar archive manipulation functions
3 
 */
4 
 
5 
#include <u.h>
6 
#include <libc.h>
7 
#include <ctype.h>
8 
#include "tar.h"
9 
 
10 
enum {
11 
	Blocksxfr = 32,
12 
};
13 
 
14 
/* exports */
15 
char *thisnm, *lastnm;
16 
 
17 
/* private data */
18 
static uvlong outoff = 0;		/* maintained by newarch, writetar */
19 
 
20 
unsigned
21 
checksum(Hblock *hp)
22 
{
23 
	int i;
24 
	uchar *cp, *csum, *end;
25 
 
26 
	i = ' ' * sizeof hp->chksum;	/* pretend blank chksum field */
27 
	csum = (uchar *)hp->chksum;
28 
	end = &hp->dummy[Tblock];
29 
	/*
30 
	 * Unixware gets this wrong; it adds *signed* chars.
31 
	 *	i += (Uflag? *(schar *)cp: *cp);
32 
	 */
33 
	for (cp = hp->dummy; cp < csum; )
34 
		i += *cp++;
35 
	/* skip checksum field */
36 
	for (cp += sizeof hp->chksum; cp < end; )
37 
		i += *cp++;
38 
	return i;
39 
}
40 
 
41 
void
42 
readtar(int in, char *buffer, long size)
43 
{
44 
	int i;
45 
	unsigned bytes;
46 
 
47 
	bytes = i = readn(in, buffer, size);
48 
	if (i <= 0)
49 
		sysfatal("archive read error: %r");
50 
	if (bytes % Tblock != 0)
51 
		sysfatal("archive blocksize error");
52 
	if (bytes != size) {
53 
		/*
54 
		 * buffering would be screwed up by only partially
55 
		 * filling tbuf, yet this might be the last (short)
56 
		 * record in a tar disk archive, so just zero the rest.
57 
		 */
58 
		fprint(2, "%s: warning: short archive block\n", argv0);
59 
		memset(buffer + bytes, '\0', size - bytes);
60 
	}
61 
}
62 
 
63 
void
64 
newarch(void)
65 
{
66 
	outoff = 0;
67 
}
68 
 
69 
uvlong
70 
writetar(int outf, char *buffer, ulong size)
71 
{
72 
	if (write(outf, buffer, size) < size) {
73 
		fprint(2, "%s: archive write error: %r\n", argv0);
74 
		fprint(2, "%s: archive seek offset: %llud\n", argv0, outoff);
75 
		exits("write");
76 
	}
77 
	outoff += size;
78 
	return outoff;
79 
}
80 
 
81 
ulong
82 
otoi(char *s)
83 
{
84 
	int c;
85 
	ulong ul = 0;
86 
 
87 
	while (isascii(*s) && isspace(*s))
88 
		s++;
89 
	while ((c = *s++) >= '0' && c <= '7') {
90 
		ul <<= 3;
91 
		ul |= c - '0';
92 
	}
93 
	return ul;
94 
}
95 
 
96 
int
97 
getdir(Hblock *hp, int in, vlong *lenp)
98 
{
99 
	*lenp = 0;
100 
	readtar(in, (char*)hp, Tblock);
101 
	if (hp->name[0] == '\0') { /* zero block indicates end-of-archive */
102 
		lastnm = strdup(thisnm);
103 
		return 0;
104 
	}
105 
	*lenp = otoi(hp->size);
106 
	if (otoi(hp->chksum) != checksum(hp))
107 
		sysfatal("directory checksum error");
108 
	if (lastnm != nil)
109 
		free(lastnm);
110 
	lastnm = thisnm;
111 
	thisnm = strdup(hp->name);
112 
	return 1;
113 
}
114 
 
115 
uvlong
116 
passtar(Hblock *hp, int in, int outf, vlong len)
117 
{
118 
	ulong bytes;
119 
	vlong off;
120 
	uvlong blks;
121 
	char bigbuf[Blocksxfr*Tblock];		/* 2*(8192 == MAXFDATA) */
122 
 
123 
	off = outoff;
124 
	if (islink(hp->linkflag))
125 
		return off;
126 
	for (blks = TAPEBLKS((uvlong)len); blks >= Blocksxfr;
127 
	    blks -= Blocksxfr) {
128 
		readtar(in, bigbuf, sizeof bigbuf);
129 
		off = writetar(outf, bigbuf, sizeof bigbuf);
130 
	}
131 
	if (blks > 0) {
132 
		bytes = blks*Tblock;
133 
		readtar(in, bigbuf, bytes);
134 
		off = writetar(outf, bigbuf, bytes);
135 
	}
136 
	return off;
137 
}
138 
 
139 
void
140 
putempty(int out)
141 
{
142 
	static char buf[Tblock];
143 
 
144 
	writetar(out, buf, sizeof buf);
145 
}
146 
 
147 
/* emit zero blocks at end */
148 
int
149 
closeout(int outf, char *, int prflag)
150 
{
151 
	if (outf < 0)
152 
		return -1;
153 
	putempty(outf);
154 
	putempty(outf);
155 
	if (lastnm && prflag)
156 
		fprint(2, " %s\n", lastnm);
157 
	close(outf);		/* guaranteed to succeed on plan 9 */
158 
	return -1;
159 
}