diff options
Diffstat (limited to 'archive-tar.c')
| -rw-r--r-- | archive-tar.c | 502 |
1 files changed, 502 insertions, 0 deletions
diff --git a/archive-tar.c b/archive-tar.c new file mode 100644 index 0000000000..e16d3f756d --- /dev/null +++ b/archive-tar.c @@ -0,0 +1,502 @@ +/* + * Copyright (c) 2005, 2006 Rene Scharfe + */ +#include "cache.h" +#include "config.h" +#include "tar.h" +#include "archive.h" +#include "object-store.h" +#include "streaming.h" +#include "run-command.h" + +#define RECORDSIZE (512) +#define BLOCKSIZE (RECORDSIZE * 20) + +static char block[BLOCKSIZE]; +static unsigned long offset; + +static int tar_umask = 002; + +static int write_tar_filter_archive(const struct archiver *ar, + struct archiver_args *args); + +/* + * This is the max value that a ustar size header can specify, as it is fixed + * at 11 octal digits. POSIX specifies that we switch to extended headers at + * this size. + * + * Likewise for the mtime (which happens to use a buffer of the same size). + */ +#if ULONG_MAX == 0xFFFFFFFF +#define USTAR_MAX_SIZE ULONG_MAX +#else +#define USTAR_MAX_SIZE 077777777777UL +#endif +#if TIME_MAX == 0xFFFFFFFF +#define USTAR_MAX_MTIME TIME_MAX +#else +#define USTAR_MAX_MTIME 077777777777ULL +#endif + +/* writes out the whole block, but only if it is full */ +static void write_if_needed(void) +{ + if (offset == BLOCKSIZE) { + write_or_die(1, block, BLOCKSIZE); + offset = 0; + } +} + +/* + * queues up writes, so that all our write(2) calls write exactly one + * full block; pads writes to RECORDSIZE + */ +static void do_write_blocked(const void *data, unsigned long size) +{ + const char *buf = data; + + if (offset) { + unsigned long chunk = BLOCKSIZE - offset; + if (size < chunk) + chunk = size; + memcpy(block + offset, buf, chunk); + size -= chunk; + offset += chunk; + buf += chunk; + write_if_needed(); + } + while (size >= BLOCKSIZE) { + write_or_die(1, buf, BLOCKSIZE); + size -= BLOCKSIZE; + buf += BLOCKSIZE; + } + if (size) { + memcpy(block + offset, buf, size); + offset += size; + } +} + +static void finish_record(void) +{ + unsigned long tail; + tail = offset % RECORDSIZE; + if (tail) { + memset(block + offset, 0, RECORDSIZE - tail); + offset += RECORDSIZE - tail; + } + write_if_needed(); +} + +static void write_blocked(const void *data, unsigned long size) +{ + do_write_blocked(data, size); + finish_record(); +} + +/* + * The end of tar archives is marked by 2*512 nul bytes and after that + * follows the rest of the block (if any). + */ +static void write_trailer(void) +{ + int tail = BLOCKSIZE - offset; + memset(block + offset, 0, tail); + write_or_die(1, block, BLOCKSIZE); + if (tail < 2 * RECORDSIZE) { + memset(block, 0, offset); + write_or_die(1, block, BLOCKSIZE); + } +} + +/* + * queues up writes, so that all our write(2) calls write exactly one + * full block; pads writes to RECORDSIZE + */ +static int stream_blocked(const struct object_id *oid) +{ + struct git_istream *st; + enum object_type type; + unsigned long sz; + char buf[BLOCKSIZE]; + ssize_t readlen; + + st = open_istream(oid, &type, &sz, NULL); + if (!st) + return error(_("cannot stream blob %s"), oid_to_hex(oid)); + for (;;) { + readlen = read_istream(st, buf, sizeof(buf)); + if (readlen <= 0) + break; + do_write_blocked(buf, readlen); + } + close_istream(st); + if (!readlen) + finish_record(); + return readlen; +} + +/* + * pax extended header records have the format "%u %s=%s\n". %u contains + * the size of the whole string (including the %u), the first %s is the + * keyword, the second one is the value. This function constructs such a + * string and appends it to a struct strbuf. + */ +static void strbuf_append_ext_header(struct strbuf *sb, const char *keyword, + const char *value, size_t valuelen) +{ + size_t orig_len = sb->len; + size_t len, tmp; + + /* "%u %s=%s\n" */ + len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1; + for (tmp = 1; len / 10 >= tmp; tmp *= 10) + len++; + + strbuf_grow(sb, len); + strbuf_addf(sb, "%"PRIuMAX" %s=", (uintmax_t)len, keyword); + strbuf_add(sb, value, valuelen); + strbuf_addch(sb, '\n'); + + if (len != sb->len - orig_len) + BUG("pax extended header length miscalculated as %"PRIuMAX + ", should be %"PRIuMAX, + (uintmax_t)len, (uintmax_t)(sb->len - orig_len)); +} + +/* + * Like strbuf_append_ext_header, but for numeric values. + */ +static void strbuf_append_ext_header_uint(struct strbuf *sb, + const char *keyword, + uintmax_t value) +{ + char buf[40]; /* big enough for 2^128 in decimal, plus NUL */ + int len; + + len = xsnprintf(buf, sizeof(buf), "%"PRIuMAX, value); + strbuf_append_ext_header(sb, keyword, buf, len); +} + +static unsigned int ustar_header_chksum(const struct ustar_header *header) +{ + const unsigned char *p = (const unsigned char *)header; + unsigned int chksum = 0; + while (p < (const unsigned char *)header->chksum) + chksum += *p++; + chksum += sizeof(header->chksum) * ' '; + p += sizeof(header->chksum); + while (p < (const unsigned char *)header + sizeof(struct ustar_header)) + chksum += *p++; + return chksum; +} + +static size_t get_path_prefix(const char *path, size_t pathlen, size_t maxlen) +{ + size_t i = pathlen; + if (i > 1 && path[i - 1] == '/') + i--; + if (i > maxlen) + i = maxlen; + do { + i--; + } while (i > 0 && path[i] != '/'); + return i; +} + +static void prepare_header(struct archiver_args *args, + struct ustar_header *header, + unsigned int mode, unsigned long size) +{ + xsnprintf(header->mode, sizeof(header->mode), "%07o", mode & 07777); + xsnprintf(header->size, sizeof(header->size), "%011"PRIoMAX , S_ISREG(mode) ? (uintmax_t)size : (uintmax_t)0); + xsnprintf(header->mtime, sizeof(header->mtime), "%011lo", (unsigned long) args->time); + + xsnprintf(header->uid, sizeof(header->uid), "%07o", 0); + xsnprintf(header->gid, sizeof(header->gid), "%07o", 0); + strlcpy(header->uname, "root", sizeof(header->uname)); + strlcpy(header->gname, "root", sizeof(header->gname)); + xsnprintf(header->devmajor, sizeof(header->devmajor), "%07o", 0); + xsnprintf(header->devminor, sizeof(header->devminor), "%07o", 0); + + memcpy(header->magic, "ustar", 6); + memcpy(header->version, "00", 2); + + xsnprintf(header->chksum, sizeof(header->chksum), "%07o", ustar_header_chksum(header)); +} + +static void write_extended_header(struct archiver_args *args, + const struct object_id *oid, + const void *buffer, unsigned long size) +{ + struct ustar_header header; + unsigned int mode; + memset(&header, 0, sizeof(header)); + *header.typeflag = TYPEFLAG_EXT_HEADER; + mode = 0100666; + xsnprintf(header.name, sizeof(header.name), "%s.paxheader", oid_to_hex(oid)); + prepare_header(args, &header, mode, size); + write_blocked(&header, sizeof(header)); + write_blocked(buffer, size); +} + +static int write_tar_entry(struct archiver_args *args, + const struct object_id *oid, + const char *path, size_t pathlen, + unsigned int mode) +{ + struct ustar_header header; + struct strbuf ext_header = STRBUF_INIT; + unsigned int old_mode = mode; + unsigned long size, size_in_header; + void *buffer; + int err = 0; + + memset(&header, 0, sizeof(header)); + + if (S_ISDIR(mode) || S_ISGITLINK(mode)) { + *header.typeflag = TYPEFLAG_DIR; + mode = (mode | 0777) & ~tar_umask; + } else if (S_ISLNK(mode)) { + *header.typeflag = TYPEFLAG_LNK; + mode |= 0777; + } else if (S_ISREG(mode)) { + *header.typeflag = TYPEFLAG_REG; + mode = (mode | ((mode & 0100) ? 0777 : 0666)) & ~tar_umask; + } else { + return error(_("unsupported file mode: 0%o (SHA1: %s)"), + mode, oid_to_hex(oid)); + } + if (pathlen > sizeof(header.name)) { + size_t plen = get_path_prefix(path, pathlen, + sizeof(header.prefix)); + size_t rest = pathlen - plen - 1; + if (plen > 0 && rest <= sizeof(header.name)) { + memcpy(header.prefix, path, plen); + memcpy(header.name, path + plen + 1, rest); + } else { + xsnprintf(header.name, sizeof(header.name), "%s.data", + oid_to_hex(oid)); + strbuf_append_ext_header(&ext_header, "path", + path, pathlen); + } + } else + memcpy(header.name, path, pathlen); + + if (S_ISREG(mode) && !args->convert && + oid_object_info(args->repo, oid, &size) == OBJ_BLOB && + size > big_file_threshold) + buffer = NULL; + else if (S_ISLNK(mode) || S_ISREG(mode)) { + enum object_type type; + buffer = object_file_to_archive(args, path, oid, old_mode, &type, &size); + if (!buffer) + return error(_("cannot read %s"), oid_to_hex(oid)); + } else { + buffer = NULL; + size = 0; + } + + if (S_ISLNK(mode)) { + if (size > sizeof(header.linkname)) { + xsnprintf(header.linkname, sizeof(header.linkname), + "see %s.paxheader", oid_to_hex(oid)); + strbuf_append_ext_header(&ext_header, "linkpath", + buffer, size); + } else + memcpy(header.linkname, buffer, size); + } + + size_in_header = size; + if (S_ISREG(mode) && size > USTAR_MAX_SIZE) { + size_in_header = 0; + strbuf_append_ext_header_uint(&ext_header, "size", size); + } + + prepare_header(args, &header, mode, size_in_header); + + if (ext_header.len > 0) { + write_extended_header(args, oid, ext_header.buf, + ext_header.len); + } + strbuf_release(&ext_header); + write_blocked(&header, sizeof(header)); + if (S_ISREG(mode) && size > 0) { + if (buffer) + write_blocked(buffer, size); + else + err = stream_blocked(oid); + } + free(buffer); + return err; +} + +static void write_global_extended_header(struct archiver_args *args) +{ + const struct object_id *oid = args->commit_oid; + struct strbuf ext_header = STRBUF_INIT; + struct ustar_header header; + unsigned int mode; + + if (oid) + strbuf_append_ext_header(&ext_header, "comment", + oid_to_hex(oid), + the_hash_algo->hexsz); + if (args->time > USTAR_MAX_MTIME) { + strbuf_append_ext_header_uint(&ext_header, "mtime", + args->time); + args->time = USTAR_MAX_MTIME; + } + + if (!ext_header.len) + return; + + memset(&header, 0, sizeof(header)); + *header.typeflag = TYPEFLAG_GLOBAL_HEADER; + mode = 0100666; + xsnprintf(header.name, sizeof(header.name), "pax_global_header"); + prepare_header(args, &header, mode, ext_header.len); + write_blocked(&header, sizeof(header)); + write_blocked(ext_header.buf, ext_header.len); + strbuf_release(&ext_header); +} + +static struct archiver **tar_filters; +static int nr_tar_filters; +static int alloc_tar_filters; + +static struct archiver *find_tar_filter(const char *name, int len) +{ + int i; + for (i = 0; i < nr_tar_filters; i++) { + struct archiver *ar = tar_filters[i]; + if (!strncmp(ar->name, name, len) && !ar->name[len]) + return ar; + } + return NULL; +} + +static int tar_filter_config(const char *var, const char *value, void *data) +{ + struct archiver *ar; + const char *name; + const char *type; + int namelen; + + if (parse_config_key(var, "tar", &name, &namelen, &type) < 0 || !name) + return 0; + + ar = find_tar_filter(name, namelen); + if (!ar) { + ar = xcalloc(1, sizeof(*ar)); + ar->name = xmemdupz(name, namelen); + ar->write_archive = write_tar_filter_archive; + ar->flags = ARCHIVER_WANT_COMPRESSION_LEVELS; + ALLOC_GROW(tar_filters, nr_tar_filters + 1, alloc_tar_filters); + tar_filters[nr_tar_filters++] = ar; + } + + if (!strcmp(type, "command")) { + if (!value) + return config_error_nonbool(var); + free(ar->data); + ar->data = xstrdup(value); + return 0; + } + if (!strcmp(type, "remote")) { + if (git_config_bool(var, value)) + ar->flags |= ARCHIVER_REMOTE; + else + ar->flags &= ~ARCHIVER_REMOTE; + return 0; + } + + return 0; +} + +static int git_tar_config(const char *var, const char *value, void *cb) +{ + if (!strcmp(var, "tar.umask")) { + if (value && !strcmp(value, "user")) { + tar_umask = umask(0); + umask(tar_umask); + } else { + tar_umask = git_config_int(var, value); + } + return 0; + } + + return tar_filter_config(var, value, cb); +} + +static int write_tar_archive(const struct archiver *ar, + struct archiver_args *args) +{ + int err = 0; + + write_global_extended_header(args); + err = write_archive_entries(args, write_tar_entry); + if (!err) + write_trailer(); + return err; +} + +static int write_tar_filter_archive(const struct archiver *ar, + struct archiver_args *args) +{ + struct strbuf cmd = STRBUF_INIT; + struct child_process filter = CHILD_PROCESS_INIT; + const char *argv[2]; + int r; + + if (!ar->data) + BUG("tar-filter archiver called with no filter defined"); + + strbuf_addstr(&cmd, ar->data); + if (args->compression_level >= 0) + strbuf_addf(&cmd, " -%d", args->compression_level); + + argv[0] = cmd.buf; + argv[1] = NULL; + filter.argv = argv; + filter.use_shell = 1; + filter.in = -1; + + if (start_command(&filter) < 0) + die_errno(_("unable to start '%s' filter"), argv[0]); + close(1); + if (dup2(filter.in, 1) < 0) + die_errno(_("unable to redirect descriptor")); + close(filter.in); + + r = write_tar_archive(ar, args); + + close(1); + if (finish_command(&filter) != 0) + die(_("'%s' filter reported error"), argv[0]); + + strbuf_release(&cmd); + return r; +} + +static struct archiver tar_archiver = { + "tar", + write_tar_archive, + ARCHIVER_REMOTE +}; + +void init_tar_archiver(void) +{ + int i; + register_archiver(&tar_archiver); + + tar_filter_config("tar.tgz.command", "gzip -cn", NULL); + tar_filter_config("tar.tgz.remote", "true", NULL); + tar_filter_config("tar.tar.gz.command", "gzip -cn", NULL); + tar_filter_config("tar.tar.gz.remote", "true", NULL); + git_config(git_tar_config, NULL); + for (i = 0; i < nr_tar_filters; i++) { + /* omit any filters that never had a command configured */ + if (tar_filters[i]->data) + register_archiver(tar_filters[i]); + } +} |