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Commit 1a9e19a7 authored by Joe Onorato's avatar Joe Onorato
Browse files

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.
parent 0ad6120d

include/utils/BackupHelpers.h

+1 −0
Original line number Diff line number Diff line
@@ -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

libs/utils/BackupHelpers.cpp

+108 −45
Original line number Diff line number Diff line
@@ -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 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)) {
@@ -154,9 +160,10 @@ 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);

        if (!r.deleted) {

            const String8& name = snapshot.keyAt(i);

            int nameLen = r.s.nameLen = name.length();



            amt = write(fd, &r.s, sizeof(FileState));
@@ -182,6 +189,7 @@ write_snapshot_file(int fd, const KeyedVector<String8,FileRec>& snapshot) 
                }

            }

        }

    }



    return 0;

}
@@ -308,9 +316,9 @@ 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;
@@ -321,6 +329,7 @@ back_up_files(int oldSnapshotFD, BackupDataWriter* dataStream, int newSnapshotFD 
                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) {

            // 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) {

        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

            LOGP("file added: %s", g.file);

            write_update_file(dataStream, q, g.file);

            m++;

        }

        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