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Make the file backup helper not crash if a file you requested 

can't be stated.  This means you don't need to know if the files
you are backing up exist or not -- we'll figure it out for you.
This commit is contained in:
Joe Onorato 2009-06-11 11:27:16 -07:00 committed by Alex Ray
parent 0d1d7ae49a
commit 9becbac780
2 changed files with 109 additions and 45 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
include/utils/BackupHelpers.h
View File

@ -128,6 +128,7 @@ int backup_helper_test_empty();
int backup_helper_test_four();
int backup_helper_test_files();
int backup_helper_test_null_base();
int backup_helper_test_missing_file();
int backup_helper_test_data_writer();
int backup_helper_test_data_reader();
#endif

153
libs/utils/BackupHelpers.cpp
View File

@ -64,6 +64,7 @@ struct FileState {
struct FileRec {
char const* file; // this object does not own this string
bool deleted;
FileState s;
};
@ -135,18 +136,23 @@ read_snapshot_file(int fd, KeyedVector<String8,FileState>* snapshot)
static int
write_snapshot_file(int fd, const KeyedVector<String8,FileRec>& snapshot)
{
int fileCount = 0;
int bytesWritten = sizeof(SnapshotHeader);
// preflight size
const int N = snapshot.size();
for (int i=0; i<N; i++) {
const String8& name = snapshot.keyAt(i);
bytesWritten += sizeof(FileState) + round_up(name.length());
const FileRec& g = snapshot.valueAt(i);
if (!g.deleted) {
const String8& name = snapshot.keyAt(i);
bytesWritten += sizeof(FileState) + round_up(name.length());
fileCount++;
}
}
LOGP("write_snapshot_file fd=%d\n", fd);
int amt;
SnapshotHeader header = { MAGIC0, N, MAGIC1, bytesWritten };
SnapshotHeader header = { MAGIC0, fileCount, MAGIC1, bytesWritten };
amt = write(fd, &header, sizeof(header));
if (amt != sizeof(header)) {
@ -154,32 +160,34 @@ write_snapshot_file(int fd, const KeyedVector<String8,FileRec>& snapshot)
return errno;
}
for (int i=0; i<header.fileCount; i++) {
const String8& name = snapshot.keyAt(i);
for (int i=0; i<N; i++) {
FileRec r = snapshot.valueAt(i);
int nameLen = r.s.nameLen = name.length();
if (!r.deleted) {
const String8& name = snapshot.keyAt(i);
int nameLen = r.s.nameLen = name.length();
amt = write(fd, &r.s, sizeof(FileState));
if (amt != sizeof(FileState)) {
LOGW("write_snapshot_file error writing header %s", strerror(errno));
return 1;
}
// filename is not NULL terminated, but it is padded
amt = write(fd, name.string(), nameLen);
if (amt != nameLen) {
LOGW("write_snapshot_file error writing filename %s", strerror(errno));
return 1;
}
int paddingLen = ROUND_UP[nameLen % 4];
if (paddingLen != 0) {
int padding = 0xabababab;
amt = write(fd, &padding, paddingLen);
if (amt != paddingLen) {
LOGW("write_snapshot_file error writing %d bytes of filename padding %s",
paddingLen, strerror(errno));
amt = write(fd, &r.s, sizeof(FileState));
if (amt != sizeof(FileState)) {
LOGW("write_snapshot_file error writing header %s", strerror(errno));
return 1;
}
// filename is not NULL terminated, but it is padded
amt = write(fd, name.string(), nameLen);
if (amt != nameLen) {
LOGW("write_snapshot_file error writing filename %s", strerror(errno));
return 1;
}
int paddingLen = ROUND_UP[nameLen % 4];
if (paddingLen != 0) {
int padding = 0xabababab;
amt = write(fd, &padding, paddingLen);
if (amt != paddingLen) {
LOGW("write_snapshot_file error writing %d bytes of filename padding %s",
paddingLen, strerror(errno));
return 1;
}
}
}
}
@ -308,18 +316,19 @@ back_up_files(int oldSnapshotFD, BackupDataWriter* dataStream, int newSnapshotFD
err = stat(file, &st);
if (err != 0) {
LOGW("Error stating file %s", file);
continue;
}
r.deleted = true;
} else {
r.deleted = false;
r.s.modTime_sec = st.st_mtime;
r.s.modTime_nsec = 0; // workaround sim breakage
//r.s.modTime_nsec = st.st_mtime_nsec;
r.s.size = st.st_size;
// we compute the crc32 later down below, when we already have the file open.
r.s.modTime_sec = st.st_mtime;
r.s.modTime_nsec = 0; // workaround sim breakage
//r.s.modTime_nsec = st.st_mtime_nsec;
r.s.size = st.st_size;
// we compute the crc32 later down below, when we already have the file open.
if (newSnapshot.indexOfKey(key) >= 0) {
LOGP("back_up_files key already in use '%s'", key.string());
return -1;
if (newSnapshot.indexOfKey(key) >= 0) {
LOGP("back_up_files key already in use '%s'", key.string());
return -1;
}
}
newSnapshot.add(key, r);
}
@ -331,24 +340,24 @@ back_up_files(int oldSnapshotFD, BackupDataWriter* dataStream, int newSnapshotFD
while (n<N && m<fileCount) {
const String8& p = oldSnapshot.keyAt(n);
const String8& q = newSnapshot.keyAt(m);
FileRec& g = newSnapshot.editValueAt(m);
int cmp = p.compare(q);
if (cmp > 0) {
if (g.deleted || cmp < 0) {
// file removed
LOGP("file removed: %s", p.string());
g.deleted = true; // They didn't mention the file, but we noticed that it's gone.
dataStream->WriteEntityHeader(p, -1);
n++;
}
else if (cmp > 0) {
// file added
const FileRec& g = newSnapshot.valueAt(m);
LOGP("file added: %s", g.file);
write_update_file(dataStream, q, g.file);
m++;
}
else if (cmp < 0) {
// file removed
LOGP("file removed: %s", p.string());
dataStream->WriteEntityHeader(p, -1);
n++;
}
else {
// both files exist, check them
const FileState& f = oldSnapshot.valueAt(n);
FileRec& g = newSnapshot.editValueAt(m);
int fd = open(g.file, O_RDONLY);
if (fd < 0) {
@ -550,6 +559,7 @@ backup_helper_test_four()
String8 filenames[4];
FileState states[4];
FileRec r;
r.deleted = false;
r.file = NULL;
states[0].modTime_sec = 0xfedcba98;
@ -1149,6 +1159,59 @@ backup_helper_test_null_base()
return 0;
}
int
backup_helper_test_missing_file()
{
int err;
int oldSnapshotFD;
int dataStreamFD;
int newSnapshotFD;
system("rm -r " SCRATCH_DIR);
mkdir(SCRATCH_DIR, 0777);
mkdir(SCRATCH_DIR "data", 0777);
write_text_file(SCRATCH_DIR "data/b", "b\nbb\n");
char const* files[] = {
SCRATCH_DIR "data/a",
SCRATCH_DIR "data/b",
SCRATCH_DIR "data/c",
};
char const* keys[] = {
"a",
"b",
"c",
};
dataStreamFD = creat(SCRATCH_DIR "null_base.data", 0666);
if (dataStreamFD == -1) {
fprintf(stderr, "error creating: %s\n", strerror(errno));
return errno;
}
newSnapshotFD = creat(SCRATCH_DIR "null_base.snap", 0666);
if (newSnapshotFD == -1) {
fprintf(stderr, "error creating: %s\n", strerror(errno));
return errno;
}
{
BackupDataWriter dataStream(dataStreamFD);
err = back_up_files(-1, &dataStream, newSnapshotFD, files, keys, 1);
if (err != 0) {
return err;
}
}
close(dataStreamFD);
close(newSnapshotFD);
return 0;
}
#endif // TEST_BACKUP_HELPERS