compress .tar.gz using gzip as a filter

1 files changed, 37 insertions, 1 deletions

diff --git a/ui-snapshot.c b/ui-snapshot.c
index eb5f1cd..649569f 100644
--- a/ui-snapshot.c
+++ b/ui-snapshot.c
@@ -1,65 +1,101 @@
 /* ui-snapshot.c: generate snapshot of a commit
  *
  * Copyright (C) 2006 Lars Hjemli
  *
  * Licensed under GNU General Public License v2
  *   (see COPYING for full license text)
  */
 
 #include "cgit.h"
 
+static int write_tar_gzip_archive(struct archiver_args *args)
+{
+    int rw[2];
+    pid_t gzpid;
+    int stdout2;
+    int status;
+    int rv;
+
+    stdout2 = chk_non_negative(dup(STDIN_FILENO), "Preserving STDOUT before compressing");
+    chk_zero(pipe(rw), "Opening pipe from compressor subprocess");
+    gzpid = chk_non_negative(fork(), "Forking compressor subprocess");
+    if(gzpid==0) {
+	    /* child */
+	    chk_zero(close(rw[1]), "Closing write end of pipe in child");
+	    chk_zero(close(STDIN_FILENO), "Closing STDIN");
+	    chk_non_negative(dup2(rw[0],STDIN_FILENO), "Redirecting compressor input to stdin");
+	    execlp("gzip","gzip",NULL);
+	    _exit(-1);
+    }
+    /* parent */
+    chk_zero(close(rw[0]), "Closing read end of pipe");
+    chk_non_negative(dup2(rw[1],STDOUT_FILENO), "Redirecting output to compressor");
+    
+    rv = write_tar_archive(args);
+
+    chk_zero(close(STDOUT_FILENO), "Closing STDOUT redirected to compressor");
+    chk_non_negative(dup2(stdout2,STDOUT_FILENO), "Restoring uncompressed STDOUT");
+    chk_zero(close(stdout2), "Closing uncompressed STDOUT");
+    chk_zero(close(rw[1]), "Closing write end of pipe in parent");
+    chk_positive(waitpid(gzpid,&status,0), "Waiting on compressor process");
+    if(! ( WIFEXITED(status) && WEXITSTATUS(status)==0 ) )
+	    cgit_print_error("Failed to compress archive");
+
+    return rv;
+}
+
 static const struct snapshot_archive_t {
     	const char *suffix;
 	const char *mimetype;
 	write_archive_fn_t write_func;
 }	snapshot_archives[] = {
 	{ ".zip", "application/x-zip", write_zip_archive },
-	{ ".tar.gz", "application/x-gzip", write_tar_archive }
+	{ ".tar.gz", "application/x-gzip", write_tar_gzip_archive }
 };
 
 void cgit_print_snapshot(struct cacheitem *item, const char *hex, 
 			 const char *prefix, const char *filename)
 {
 	int fnl = strlen(filename);
 	int f;
     	for(f=0;f<(sizeof(snapshot_archives)/sizeof(*snapshot_archives));++f) {
 		const struct snapshot_archive_t* sat = &snapshot_archives[f];
 		int sl = strlen(sat->suffix);
 		if(fnl<sl || strcmp(&filename[fnl-sl],sat->suffix))
 			continue;
 
 		struct archiver_args args;
 		struct commit *commit;
 		unsigned char sha1[20];
 
 		if(get_sha1(hex, sha1)) {
 			cgit_print_error(fmt("Bad object id: %s", hex));
 			return;
 		}
 		commit = lookup_commit_reference(sha1);
 
 		if(!commit) {
 			cgit_print_error(fmt("Not a commit reference: %s", hex));
 			return;;
 		}
 
 		memset(&args,0,sizeof(args));
 		args.base = fmt("%s/", prefix);
 		args.tree = commit->tree;
 
 		cgit_print_snapshot_start(sat->mimetype, filename, item);
 		(*sat->write_func)(&args);
 		return;
 	}
 	cgit_print_error(fmt("Unsupported snapshot format: %s", filename));
 }
 
 void cgit_print_snapshot_links(const char *repo,const char *hex)
 {
     	char *filename;
 	int f;
     	for(f=0;f<(sizeof(snapshot_archives)/sizeof(*snapshot_archives));++f) {
 		const struct snapshot_archive_t* sat = &snapshot_archives[f];
 		filename = fmt("%s-%s%s",repo,hex,sat->suffix);
 		htmlf("<a href='%s'>%s</a><br/>",
 			cgit_pageurl(repo,"snapshot",