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tar.c File Reference
#include "c.h"
#include <sys/stat.h>
#include "pgtar.h"
Include dependency graph for tar.c:

Go to the source code of this file.

Functions

void print_tar_number (char *s, int len, uint64 val)
 
uint64 read_tar_number (const char *s, int len)
 
int tarChecksum (char *header)
 
enum tarError tarCreateHeader (char *h, const char *filename, const char *linktarget, pgoff_t size, mode_t mode, uid_t uid, gid_t gid, time_t mtime)
 

Function Documentation

◆ print_tar_number()

void print_tar_number ( char *  s,
int  len,
uint64  val 
)

Definition at line 22 of file tar.c.

23{
24 if (val < (((uint64) 1) << ((len - 1) * 3)))
25 {
26 /* Use octal with trailing space */
27 s[--len] = ' ';
28 while (len)
29 {
30 s[--len] = (val & 7) + '0';
31 val >>= 3;
32 }
33 }
34 else
35 {
36 /* Use base-256 with leading \200 */
37 s[0] = '\200';
38 while (len > 1)
39 {
40 s[--len] = (val & 255);
41 val >>= 8;
42 }
43 }
44}
uint64_t uint64
Definition: c.h:489
long val
Definition: informix.c:689
const void size_t len

References len, and val.

Referenced by tar_close(), and tarCreateHeader().

◆ read_tar_number()

uint64 read_tar_number ( const char *  s,
int  len 
)

Definition at line 58 of file tar.c.

59{
60 uint64 result = 0;
61
62 if (*s == '\200')
63 {
64 /* base-256 */
65 while (--len)
66 {
67 result <<= 8;
68 result |= (unsigned char) (*++s);
69 }
70 }
71 else
72 {
73 /* octal */
74 while (len-- && *s >= '0' && *s <= '7')
75 {
76 result <<= 3;
77 result |= (*s - '0');
78 s++;
79 }
80 }
81 return result;
82}

References len.

Referenced by _tarGetHeader(), astreamer_tar_header(), and isValidTarHeader().

◆ tarChecksum()

int tarChecksum ( char *  header)

Definition at line 90 of file tar.c.

91{
92 int i,
93 sum;
94
95 /*
96 * Per POSIX, the checksum is the simple sum of all bytes in the header,
97 * treating the bytes as unsigned, and treating the checksum field (at
98 * offset 148) as though it contained 8 spaces.
99 */
100 sum = 8 * ' '; /* presumed value for checksum field */
101 for (i = 0; i < 512; i++)
102 if (i < 148 || i >= 156)
103 sum += 0xFF & header[i];
104 return sum;
105}
int i
Definition: isn.c:72

References i.

Referenced by _tarGetHeader(), isValidTarHeader(), tar_close(), and tarCreateHeader().

◆ tarCreateHeader()

enum tarError tarCreateHeader ( char *  h,
const char *  filename,
const char *  linktarget,
pgoff_t  size,
mode_t  mode,
uid_t  uid,
gid_t  gid,
time_t  mtime 
)

Definition at line 114 of file tar.c.

116{
117 if (strlen(filename) > 99)
118 return TAR_NAME_TOO_LONG;
119
120 if (linktarget && strlen(linktarget) > 99)
122
123 memset(h, 0, TAR_BLOCK_SIZE);
124
125 /* Name 100 */
127 if (linktarget != NULL || S_ISDIR(mode))
128 {
129 /*
130 * We only support symbolic links to directories, and this is
131 * indicated in the tar format by adding a slash at the end of the
132 * name, the same as for regular directories.
133 */
134 int flen = strlen(filename);
135
136 flen = Min(flen, 99);
137 h[flen] = '/';
138 h[flen + 1] = '\0';
139 }
140
141 /* Mode 8 - this doesn't include the file type bits (S_IFMT) */
142 print_tar_number(&h[TAR_OFFSET_MODE], 8, (mode & 07777));
143
144 /* User ID 8 */
145 print_tar_number(&h[TAR_OFFSET_UID], 8, uid);
146
147 /* Group 8 */
148 print_tar_number(&h[TAR_OFFSET_GID], 8, gid);
149
150 /* File size 12 */
151 if (linktarget != NULL || S_ISDIR(mode))
152 /* Symbolic link or directory has size zero */
154 else
156
157 /* Mod Time 12 */
158 print_tar_number(&h[TAR_OFFSET_MTIME], 12, mtime);
159
160 /* Checksum 8 cannot be calculated until we've filled all other fields */
161
162 if (linktarget != NULL)
163 {
164 /* Type - Symbolic link */
166 /* Link Name 100 */
167 strlcpy(&h[TAR_OFFSET_LINKNAME], linktarget, 100);
168 }
169 else if (S_ISDIR(mode))
170 {
171 /* Type - directory */
173 }
174 else
175 {
176 /* Type - regular file */
178 }
179
180 /* Magic 6 */
181 strcpy(&h[TAR_OFFSET_MAGIC], "ustar");
182
183 /* Version 2 */
184 memcpy(&h[TAR_OFFSET_VERSION], "00", 2);
185
186 /* User 32 */
187 /* XXX: Do we need to care about setting correct username? */
188 strlcpy(&h[TAR_OFFSET_UNAME], "postgres", 32);
189
190 /* Group 32 */
191 /* XXX: Do we need to care about setting correct group name? */
192 strlcpy(&h[TAR_OFFSET_GNAME], "postgres", 32);
193
194 /* Major Dev 8 */
196
197 /* Minor Dev 8 */
199
200 /* Prefix 155 - not used, leave as nulls */
201
202 /* Finally, compute and insert the checksum */
204
205 return TAR_OK;
206}
#define Min(x, y)
Definition: c.h:961
static PgChecksumMode mode
Definition: pg_checksums.c:55
static char * filename
Definition: pg_dumpall.c:119
@ TAR_FILETYPE_SYMLINK
Definition: pgtar.h:61
@ TAR_FILETYPE_DIRECTORY
Definition: pgtar.h:62
@ TAR_FILETYPE_PLAIN
Definition: pgtar.h:60
@ TAR_OFFSET_DEVMINOR
Definition: pgtar.h:53
@ TAR_OFFSET_MODE
Definition: pgtar.h:40
@ TAR_OFFSET_VERSION
Definition: pgtar.h:49
@ TAR_OFFSET_DEVMAJOR
Definition: pgtar.h:52
@ TAR_OFFSET_UID
Definition: pgtar.h:41
@ TAR_OFFSET_TYPEFLAG
Definition: pgtar.h:46
@ TAR_OFFSET_NAME
Definition: pgtar.h:39
@ TAR_OFFSET_SIZE
Definition: pgtar.h:43
@ TAR_OFFSET_GNAME
Definition: pgtar.h:51
@ TAR_OFFSET_CHECKSUM
Definition: pgtar.h:45
@ TAR_OFFSET_GID
Definition: pgtar.h:42
@ TAR_OFFSET_LINKNAME
Definition: pgtar.h:47
@ TAR_OFFSET_MTIME
Definition: pgtar.h:44
@ TAR_OFFSET_UNAME
Definition: pgtar.h:50
@ TAR_OFFSET_MAGIC
Definition: pgtar.h:48
@ TAR_SYMLINK_TOO_LONG
Definition: pgtar.h:23
@ TAR_OK
Definition: pgtar.h:21
@ TAR_NAME_TOO_LONG
Definition: pgtar.h:22
#define TAR_BLOCK_SIZE
Definition: pgtar.h:17
size_t strlcpy(char *dst, const char *src, size_t siz)
Definition: strlcpy.c:45
static pg_noinline void Size size
Definition: slab.c:607
int tarChecksum(char *header)
Definition: tar.c:90
void print_tar_number(char *s, int len, uint64 val)
Definition: tar.c:22
#define S_ISDIR(m)
Definition: win32_port.h:315

References filename, Min, mode, print_tar_number(), S_ISDIR, size, strlcpy(), TAR_BLOCK_SIZE, TAR_FILETYPE_DIRECTORY, TAR_FILETYPE_PLAIN, TAR_FILETYPE_SYMLINK, TAR_NAME_TOO_LONG, TAR_OFFSET_CHECKSUM, TAR_OFFSET_DEVMAJOR, TAR_OFFSET_DEVMINOR, TAR_OFFSET_GID, TAR_OFFSET_GNAME, TAR_OFFSET_LINKNAME, TAR_OFFSET_MAGIC, TAR_OFFSET_MODE, TAR_OFFSET_MTIME, TAR_OFFSET_NAME, TAR_OFFSET_SIZE, TAR_OFFSET_TYPEFLAG, TAR_OFFSET_UID, TAR_OFFSET_UNAME, TAR_OFFSET_VERSION, TAR_OK, TAR_SYMLINK_TOO_LONG, and tarChecksum().

Referenced by _tarWriteHeader(), astreamer_tar_archiver_content(), and tar_open_for_write().