Merge branch 'jk/gpg-interface-cleanup'

A new run-command API function pipe_command() is introduced to
sanely feed data to the standard input while capturing data from
the standard output and the standard error of an external process,
which is cumbersome to hand-roll correctly without deadlocking.

The codepath to sign data in a prepared buffer with GPG has been
updated to use this API to read from the status-fd to check for
errors (instead of relying on GPG's exit status).

* jk/gpg-interface-cleanup:
  gpg-interface: check gpg signature creation status
  sign_buffer: use pipe_command
  verify_signed_buffer: use pipe_command
  run-command: add pipe_command helper
  verify_signed_buffer: use tempfile object
  verify_signed_buffer: drop pbuf variable
  gpg-interface: use child_process.args

1 files changed, 35 insertions, 58 deletions

diff --git a/gpg-interface.c b/gpg-interface.c
index c4b1e8c78d..08356f92e7 100644
--- a/gpg-interface.c
+++ b/gpg-interface.c
@@ -3,6 +3,7 @@
 #include "strbuf.h"
 #include "gpg-interface.h"
 #include "sigchain.h"
+#include "tempfile.h"
 
 static char *configured_signing_key;
 static const char *gpg_program = "gpg";
@@ -150,42 +151,30 @@ const char *get_signing_key(void)
 int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key)
 {
 	struct child_process gpg = CHILD_PROCESS_INIT;
-	const char *args[4];
-	ssize_t len;
+	int ret;
 	size_t i, j, bottom;
+	struct strbuf gpg_status = STRBUF_INIT;
 
-	gpg.argv = args;
-	gpg.in = -1;
-	gpg.out = -1;
-	args[0] = gpg_program;
-	args[1] = "-bsau";
-	args[2] = signing_key;
-	args[3] = NULL;
+	argv_array_pushl(&gpg.args,
+			 gpg_program,
+			 "--status-fd=2",
+			 "-bsau", signing_key,
+			 NULL);
 
-	if (start_command(&gpg))
-		return error(_("could not run gpg."));
+	bottom = signature->len;
 
 	/*
 	 * When the username signingkey is bad, program could be terminated
 	 * because gpg exits without reading and then write gets SIGPIPE.
 	 */
 	sigchain_push(SIGPIPE, SIG_IGN);
-
-	if (write_in_full(gpg.in, buffer->buf, buffer->len) != buffer->len) {
-		close(gpg.in);
-		close(gpg.out);
-		finish_command(&gpg);
-		return error(_("gpg did not accept the data"));
-	}
-	close(gpg.in);
-
-	bottom = signature->len;
-	len = strbuf_read(signature, gpg.out, 1024);
-	close(gpg.out);
-
+	ret = pipe_command(&gpg, buffer->buf, buffer->len,
+			   signature, 1024, &gpg_status, 0);
 	sigchain_pop(SIGPIPE);
 
-	if (finish_command(&gpg) || !len || len < 0)
+	ret |= !strstr(gpg_status.buf, "\n[GNUPG:] SIG_CREATED ");
+	strbuf_release(&gpg_status);
+	if (ret)
 		return error(_("gpg failed to sign the data"));
 
 	/* Strip CR from the line endings, in case we are on Windows. */
@@ -210,50 +199,38 @@ int verify_signed_buffer(const char *payload, size_t payload_size,
 			 struct strbuf *gpg_output, struct strbuf *gpg_status)
 {
 	struct child_process gpg = CHILD_PROCESS_INIT;
-	const char *args_gpg[] = {NULL, "--status-fd=1", "--verify", "FILE", "-", NULL};
-	char path[PATH_MAX];
+	static struct tempfile temp;
 	int fd, ret;
 	struct strbuf buf = STRBUF_INIT;
-	struct strbuf *pbuf = &buf;
 
-	args_gpg[0] = gpg_program;
-	fd = git_mkstemp(path, PATH_MAX, ".git_vtag_tmpXXXXXX");
+	fd = mks_tempfile_t(&temp, ".git_vtag_tmpXXXXXX");
 	if (fd < 0)
-		return error_errno(_("could not create temporary file '%s'"), path);
-	if (write_in_full(fd, signature, signature_size) < 0)
-		return error_errno(_("failed writing detached signature to '%s'"), path);
+		return error_errno(_("could not create temporary file"));
+	if (write_in_full(fd, signature, signature_size) < 0) {
+		error_errno(_("failed writing detached signature to '%s'"),
+			    temp.filename.buf);
+		delete_tempfile(&temp);
+		return -1;
+	}
 	close(fd);
 
-	gpg.argv = args_gpg;
-	gpg.in = -1;
-	gpg.out = -1;
-	if (gpg_output)
-		gpg.err = -1;
-	args_gpg[3] = path;
-	if (start_command(&gpg)) {
-		unlink(path);
-		return error(_("could not run gpg."));
-	}
+	argv_array_pushl(&gpg.args,
+			 gpg_program,
+			 "--status-fd=1",
+			 "--verify", temp.filename.buf, "-",
+			 NULL);
 
-	sigchain_push(SIGPIPE, SIG_IGN);
-	write_in_full(gpg.in, payload, payload_size);
-	close(gpg.in);
+	if (!gpg_status)
+		gpg_status = &buf;
 
-	if (gpg_output) {
-		strbuf_read(gpg_output, gpg.err, 0);
-		close(gpg.err);
-	}
-	if (gpg_status)
-		pbuf = gpg_status;
-	strbuf_read(pbuf, gpg.out, 0);
-	close(gpg.out);
-
-	ret = finish_command(&gpg);
+	sigchain_push(SIGPIPE, SIG_IGN);
+	ret = pipe_command(&gpg, payload, payload_size,
+			   gpg_status, 0, gpg_output, 0);
 	sigchain_pop(SIGPIPE);
 
-	unlink_or_warn(path);
+	delete_tempfile(&temp);
 
-	ret |= !strstr(pbuf->buf, "\n[GNUPG:] GOODSIG ");
+	ret |= !strstr(gpg_status->buf, "\n[GNUPG:] GOODSIG ");
 	strbuf_release(&buf); /* no matter it was used or not */
 
 	return ret;