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Merge "Full backup tweaks"

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Christopher Tate 2011-05-13 15:41:32 -07:00 committed by Android (Google) Code Review
commit 21a357e114
1 changed files with 20 additions and 12 deletions
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32
libs/utils/BackupHelpers.cpp
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@ -468,6 +468,19 @@ static void calc_tar_checksum(char* buf) {
sprintf(buf + 148, "%06o", sum); // the trailing space is already in place
}
// Returns number of bytes written
static int write_pax_header_entry(char* buf, const char* key, const char* value) {
// start with the size of "1 key=value\n"
int len = strlen(key) + strlen(value) + 4;
if (len > 9) len++;
if (len > 99) len++;
if (len > 999) len++;
// since PATH_MAX is 4096 we don't expect to have to generate any single
// header entry longer than 9999 characters
return sprintf(buf, "%d %s=%s\n", len, key, value);
}
int write_tarfile(const String8& packageName, const String8& domain,
const String8& rootpath, const String8& filepath, BackupDataWriter* writer)
{
@ -525,8 +538,7 @@ int write_tarfile(const String8& packageName, const String8& domain,
}
// Good to go -- first construct the standard tar header at the start of the buffer
memset(buf, 0, 512); // tar header is 512 bytes
memset(paxHeader, 0, 512);
memset(buf, 0, BUFSIZE);
// Magic fields for the ustar file format
strcat(buf + 257, "ustar");
@ -602,24 +614,20 @@ int write_tarfile(const String8& packageName, const String8& domain,
// If we're using a pax extended header, build & write that here; lengths are
// already preflighted
if (needExtended) {
char sizeStr[32]; // big enough for a 64-bit unsigned value in decimal
char* p = paxData;
// construct the pax extended header data block
memset(paxData, 0, BUFSIZE - (paxData - buf));
char* p = paxData;
int len;
// size header -- calc len in digits by actually rendering the number
// to a string - brute force but simple
len = sprintf(p, "%lld", s.st_size) + 8; // 8 for "1 size=" and final LF
if (len >= 10) len++;
memset(p, 0, 512);
p += sprintf(p, "%d size=%lld\n", len, s.st_size);
snprintf(sizeStr, sizeof(sizeStr), "%lld", s.st_size);
p += write_pax_header_entry(p, "size", sizeStr);
// fullname was generated above with the ustar paths
len = fullname.length() + 8; // 8 for "1 path=" and final LF
if (len >= 10) len++;
if (len >= 100) len++;
p += sprintf(p, "%d path=%s\n", len, fullname.string());
p += write_pax_header_entry(p, "path", fullname.string());
// Now we know how big the pax data is
int paxLen = p - paxData;