From 87fec8fc9e790fedbee0c9fc810dbd1bf006d7b6 Mon Sep 17 00:00:00 2001 From: Rene Scharfe Date: Fri, 29 Apr 2005 19:51:04 -0700 Subject: [PATCH] [PATCH] GIT: Create tar archives of tree on the fly Write commit ID to global extended pax header at the beginning of the tar file, if possible. get-tar-commit-id.c is an example program to get the ID back out of such a tar archive. Signed-off-by: Rene Scharfe Signed-off-by: Linus Torvalds --- get-tar-commit-id.c | 27 +++++++++++++++++++++++++++ tar-tree.c | 43 +++++++++++++++++++++++++++---------------- 2 files changed, 54 insertions(+), 16 deletions(-) create mode 100644 get-tar-commit-id.c diff --git a/get-tar-commit-id.c b/get-tar-commit-id.c new file mode 100644 index 000000000..a1a17e53d --- /dev/null +++ b/get-tar-commit-id.c @@ -0,0 +1,27 @@ +#include +#include +#include + +#define HEADERSIZE 1024 + +int main(int argc, char **argv) +{ + char buffer[HEADERSIZE]; + ssize_t n; + + n = read(0, buffer, HEADERSIZE); + if (n < HEADERSIZE) { + fprintf(stderr, "read error\n"); + return 3; + } + if (buffer[156] != 'g') + return 1; + if (memcmp(&buffer[512], "52 comment=", 11)) + return 1; + n = write(1, &buffer[523], 41); + if (n < 41) { + fprintf(stderr, "write error\n"); + return 2; + } + return 0; +} diff --git a/tar-tree.c b/tar-tree.c index 5cc7cfef6..ea7ea91ad 100644 --- a/tar-tree.c +++ b/tar-tree.c @@ -160,7 +160,7 @@ static unsigned int path_len(int is_dir, const char *basepath, return len; } -static void write_header(const char *, const char *, struct path_prefix *, +static void write_header(const char *, char, const char *, struct path_prefix *, const char *, unsigned int, unsigned long); /* stores a pax extended header directly in the block buffer */ @@ -169,7 +169,7 @@ static void write_extended_header(const char *headerfilename, int is_dir, struct path_prefix *prefix, const char *path, unsigned int namelen) { - char *records, *p; + char *p; unsigned int size = 1 + 6 + namelen + 1; if (size > 9) size++; @@ -177,12 +177,10 @@ static void write_extended_header(const char *headerfilename, int is_dir, size++; if (size > RECORDSIZE) die("tar-tree: extended header too big, wtf?"); - write_header(NULL, NULL, NULL, headerfilename, 0100600, size); - - records = block + offset; - memset(records, 0, RECORDSIZE); + write_header(NULL, 'x', NULL, NULL, headerfilename, 0100600, size); + p = block + offset; + memset(p, 0, RECORDSIZE); offset += RECORDSIZE; - p = records; append_long(&p, size); append_string(&p, " path="); append_path(&p, is_dir, basepath, prefix, path); @@ -190,8 +188,22 @@ static void write_extended_header(const char *headerfilename, int is_dir, write_if_needed(); } +static void write_global_extended_header(const char *sha1) +{ + char *p; + write_header(NULL, 'g', NULL, NULL, "pax_global_header", 0, 52); + p = block + offset; + memset(p, 0, RECORDSIZE); + offset += RECORDSIZE; + append_long(&p, 52); /* 2 + 9 + 40 + 1 */ + append_string(&p, " comment="); + append_string(&p, sha1_to_hex(sha1)); + append_char(&p, '\n'); + write_if_needed(); +} + /* stores a ustar header directly in the block buffer */ -static void write_header(const char *sha1, const char *basepath, +static void write_header(const char *sha1, char typeflag, const char *basepath, struct path_prefix *prefix, const char *path, unsigned int mode, unsigned long size) { @@ -236,11 +248,7 @@ static void write_header(const char *sha1, const char *basepath, sprintf(&header[124], "%011lo", S_ISDIR(mode) ? 0 : size); sprintf(&header[136], "%011lo", archive_time); - /* typeflag */ - if (!sha1) - header[156] = 'x'; /* extended header */ - else - header[156] = S_ISDIR(mode) ? '5' : '0'; + header[156] = typeflag; memcpy(&header[257], "ustar", 6); memcpy(&header[263], "00", 2); @@ -279,7 +287,8 @@ static void traverse_tree(void *buffer, unsigned long size, eltbuf = read_sha1_file(sha1, elttype, &eltsize); if (!eltbuf) die("cannot read %s", sha1_to_hex(sha1)); - write_header(sha1, basedir, prefix, path, mode, eltsize); + write_header(sha1, S_ISDIR(mode) ? '5' : '0', basedir, + prefix, path, mode, eltsize); if (!strcmp(elttype, "tree")) { this_prefix.name = path; traverse_tree(eltbuf, eltsize, &this_prefix); @@ -320,6 +329,7 @@ time_t commit_time(void * buffer, unsigned long size) int main(int argc, char **argv) { unsigned char sha1[20]; + unsigned char commit_sha1[20]; void *buffer; unsigned long size; @@ -339,8 +349,9 @@ int main(int argc, char **argv) if (!sha1_file_directory) sha1_file_directory = DEFAULT_DB_ENVIRONMENT; - buffer = read_object_with_reference(sha1, "commit", &size, NULL); + buffer = read_object_with_reference(sha1, "commit", &size, commit_sha1); if (buffer) { + write_global_extended_header(commit_sha1); archive_time = commit_time(buffer, size); free(buffer); } @@ -351,7 +362,7 @@ int main(int argc, char **argv) if (!archive_time) archive_time = time(NULL); if (basedir) - write_header("0", NULL, NULL, basedir, 040755, 0); + write_header("0", '5', NULL, NULL, basedir, 040755, 0); traverse_tree(buffer, size, NULL); free(buffer); write_trailer(); -- 2.30.2