Introduce git_process class that invokes processes

src/util/process.h

+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+
+#ifndef INCLUDE_process_h__
+#define INCLUDE_process_h__
+
+typedef struct git_process git_process;
+
+typedef struct {
+	int capture_in  : 1,
+	    capture_out : 1,
+	    capture_err : 1,
+	    exclude_env : 1;
+
+	char *cwd;
+} git_process_options;
+
+typedef enum {
+	GIT_PROCESS_STATUS_NONE,
+	GIT_PROCESS_STATUS_NORMAL,
+	GIT_PROCESS_STATUS_ERROR
+} git_process_result_status;
+
+#define GIT_PROCESS_RESULT_INIT { GIT_PROCESS_STATUS_NONE }
+
+typedef struct {
+	git_process_result_status status;
+	int exitcode;
+	int signal;
+} git_process_result;
+
+#define GIT_PROCESS_OPTIONS_INIT { 0 }
+
+/**
+ * Create a new process.  The command to run should be specified as the
+ * element of the `arg` array.
+ *
+ * This function will add the given environment variables (in `env`)
+ * to the current environment.  Operations on environment variables
+ * are not thread safe, so you may not modify the environment during
+ * this call.  You can avoid this by setting `exclude_env` in the
+ * options and providing the entire environment yourself.
+ *
+ * @param out location to store the process
+ * @param args the command (with arguments) to run
+ * @param args_len the length of the args array
+ * @param env environment variables to add (or NULL)
+ * @param env_len the length of the env len
+ * @param opts the options for creating the process
+ * @return 0 or an error code
+ */
+extern int git_process_new(
+	git_process **out,
+	const char **args,
+	size_t args_len,
+	const char **env,
+	size_t env_len,
+	git_process_options *opts);
+
+#ifdef GIT_WIN32
+
+/* Windows path parsing is tricky; this helper function is for testing. */
+extern int git_process__cmdline(
+	git_str *out,
+	const char **in,
+	size_t in_len);
+
+#endif
+
+/**
+ * Start the process.
+ *
+ * @param process the process to start
+ * @return 0 or an error code
+ */
+extern int git_process_start(git_process *process);
+
+/**
+ * Read from the process's stdout.  The process must have been created with
+ * `capture_out` set to true.
+ *
+ * @param process the process to read from
+ * @param buf the buf to read into
+ * @param count maximum number of bytes to read
+ * @return number of bytes read or an error code
+ */
+extern ssize_t git_process_read(git_process *process, void *buf, size_t count);
+
+/**
+ * Write to the process's stdin.  The process must have been created with
+ * `capture_in` set to true.
+ *
+ * @param process the process to write to
+ * @param buf the buf to write
+ * @param count maximum number of bytes to write
+ * @return number of bytes written or an error code
+ */
+extern ssize_t git_process_write(git_process *process, const void *buf, size_t count);
+
+/**
+ * Wait for the process to finish.
+ *
+ * @param result the result of the process or NULL
+ * @param process the process to wait on
+ */
+extern int git_process_wait(git_process_result *result, git_process *process);
+
+/**
+ * Close the input pipe from the child.
+ *
+ * @param process the process to close the pipe on
+ */
+extern int git_process_close_in(git_process *process);
+
+/**
+ * Close the output pipe from the child.
+ *
+ * @param process the process to close the pipe on
+ */
+extern int git_process_close_out(git_process *process);
+
+/**
+ * Close the error pipe from the child.
+ *
+ * @param process the process to close the pipe on
+ */
+extern int git_process_close_err(git_process *process);
+
+/**
+ * Close all resources that are used by the process.  This does not
+ * wait for the process to complete.
+ *
+ * @parma process the process to close
+ */
+extern int git_process_close(git_process *process);
+
+/**
+ * Place a human-readable error message in the given git buffer.
+ *
+ * @param msg the buffer to store the message
+ * @param result the process result that produced an error
+ */
+extern int git_process_result_msg(git_str *msg, git_process_result *result);
+
+/**
+ * Free a process structure
+ *
+ * @param process the process to free
+ */
+extern void git_process_free(git_process *process);
+
+#endif

tests/resources/process/cat.bat

+@ECHO OFF
+FOR /F "tokens=*" %%a IN ('more') DO ECHO %%a

tests/resources/process/env.cmd

+@ECHO OFF
+SET

tests/resources/process/helloworld.sh

+#!/bin/sh
+
+echo "Hello, world."

tests/resources/process/pwd.bat

+@ECHO OFF
+ECHO %CD%

tests/util/process/env.c

+#include "clar_libgit2.h"
+#include "process.h"
+#include "vector.h"
+
+static git_str env_cmd = GIT_STR_INIT;
+static git_str accumulator = GIT_STR_INIT;
+static git_vector env_result = GIT_VECTOR_INIT;
+
+void test_process_env__initialize(void)
+{
+#ifdef GIT_WIN32
+	git_str_printf(&env_cmd, "%s/env.cmd", cl_fixture("process"));
+#else
+	git_str_puts(&env_cmd, "/usr/bin/env");
+#endif
+
+	cl_git_pass(git_vector_init(&env_result, 32, git__strcmp_cb));
+}
+
+void test_process_env__cleanup(void)
+{
+	git_vector_free(&env_result);
+	git_str_dispose(&accumulator);
+	git_str_dispose(&env_cmd);
+}
+
+static void run_env(const char **env_array, size_t env_len, bool exclude_env)
+{
+	const char *args_array[] = { env_cmd.ptr };
+
+	git_process *process;
+	git_process_options opts = GIT_PROCESS_OPTIONS_INIT;
+	git_process_result result = GIT_PROCESS_RESULT_INIT;
+
+	char buf[1024], *tok;
+	ssize_t ret;
+
+	opts.capture_out = 1;
+	opts.exclude_env = exclude_env;
+
+	cl_git_pass(git_process_new(&process, args_array, ARRAY_SIZE(args_array), env_array, env_len, &opts));
+	cl_git_pass(git_process_start(process));
+
+	while ((ret = git_process_read(process, buf, 1024)) > 0)
+		cl_git_pass(git_str_put(&accumulator, buf, (size_t)ret));
+
+	cl_assert_equal_i(0, ret);
+
+	cl_git_pass(git_process_wait(&result, process));
+
+	cl_assert_equal_i(GIT_PROCESS_STATUS_NORMAL, result.status);
+	cl_assert_equal_i(0, result.exitcode);
+	cl_assert_equal_i(0, result.signal);
+
+	for (tok = strtok(accumulator.ptr, "\n"); tok; tok = strtok(NULL, "\n")) {
+#ifdef GIT_WIN32
+		if (strlen(tok) && tok[strlen(tok) - 1] == '\r')
+			tok[strlen(tok) - 1] = '\0';
+#endif
+
+		cl_git_pass(git_vector_insert(&env_result, tok));
+	}
+
+	git_process_close(process);
+	git_process_free(process);
+}
+
+void test_process_env__can_add_env(void)
+{
+	const char *env_array[] = { "TEST_NEW_ENV=added", "TEST_OTHER_ENV=also_added" };
+	run_env(env_array, 2, false);
+
+	cl_git_pass(git_vector_search(NULL, &env_result, "TEST_NEW_ENV=added"));
+	cl_git_pass(git_vector_search(NULL, &env_result, "TEST_OTHER_ENV=also_added"));
+}
+
+void test_process_env__can_propagate_env(void)
+{
+	cl_setenv("TEST_NEW_ENV", "propagated");
+	run_env(NULL, 0, false);
+
+	cl_git_pass(git_vector_search(NULL, &env_result, "TEST_NEW_ENV=propagated"));
+}
+
+void test_process_env__can_remove_env(void)
+{
+	const char *env_array[] = { "TEST_NEW_ENV=" };
+	char *str;
+	size_t i;
+
+	cl_setenv("TEST_NEW_ENV", "propagated");
+	run_env(env_array, 1, false);
+
+	git_vector_foreach(&env_result, i, str)
+		cl_assert(git__prefixcmp(str, "TEST_NEW_ENV=") != 0);
+}
+
+void test_process_env__can_clear_env(void)
+{
+	const char *env_array[] = { "TEST_NEW_ENV=added", "TEST_OTHER_ENV=also_added" };
+
+	cl_setenv("SOME_EXISTING_ENV", "propagated");
+	run_env(env_array, 2, true);
+
+	/*
+	 * We can't simply test that the environment is precisely what we
+	 * provided.  Some systems (eg win32) will add environment variables
+	 * to all processes.
+	 */
+	cl_assert_equal_i(GIT_ENOTFOUND, git_vector_search(NULL, &env_result, "SOME_EXISTING_ENV=propagated"));
+}

tests/util/process/start.c

+#include "clar_libgit2.h"
+#include "process.h"
+#include "vector.h"
+
+#ifndef SIGPIPE
+# define SIGPIPE 42
+#endif
+
+static git_str helloworld_cmd = GIT_STR_INIT;
+static git_str cat_cmd = GIT_STR_INIT;
+static git_str pwd_cmd = GIT_STR_INIT;
+
+void test_process_start__initialize(void)
+{
+#ifdef GIT_WIN32
+	git_str_printf(&helloworld_cmd, "%s/helloworld.bat", cl_fixture("process"));
+	git_str_printf(&cat_cmd, "%s/cat.bat", cl_fixture("process"));
+	git_str_printf(&pwd_cmd, "%s/pwd.bat", cl_fixture("process"));
+#else
+	git_str_printf(&helloworld_cmd, "%s/helloworld.sh", cl_fixture("process"));
+#endif
+}
+
+void test_process_start__cleanup(void)
+{
+	git_str_dispose(&pwd_cmd);
+	git_str_dispose(&cat_cmd);
+	git_str_dispose(&helloworld_cmd);
+}
+
+void test_process_start__returncode(void)
+{
+#ifdef GIT_WIN32
+	const char *args_array[] = { "C:\\Windows\\System32\\cmd.exe", "/c", "exit", "1" };
+#elif __APPLE__
+	const char *args_array[] = { "/usr/bin/false" };
+#else
+	const char *args_array[] = { "/bin/false" };
+#endif
+
+	git_process *process;
+	git_process_options opts = GIT_PROCESS_OPTIONS_INIT;
+	git_process_result result = GIT_PROCESS_RESULT_INIT;
+
+	cl_git_pass(git_process_new(&process, args_array, ARRAY_SIZE(args_array), NULL, 0, &opts));
+	cl_git_pass(git_process_start(process));
+	cl_git_pass(git_process_wait(&result, process));
+
+	cl_assert_equal_i(GIT_PROCESS_STATUS_NORMAL, result.status);
+	cl_assert_equal_i(1, result.exitcode);
+	cl_assert_equal_i(0, result.signal);
+
+	git_process_free(process);
+}
+
+void test_process_start__not_found(void)
+{
+#ifdef GIT_WIN32
+	const char *args_array[] = { "C:\\a\\b\\z\\y\\not_found" };
+#else
+	const char *args_array[] = { "/a/b/z/y/not_found" };
+#endif
+
+	git_process *process;
+	git_process_options opts = GIT_PROCESS_OPTIONS_INIT;
+
+	cl_git_pass(git_process_new(&process, args_array, ARRAY_SIZE(args_array), NULL, 0, &opts));
+	cl_git_fail(git_process_start(process));
+	git_process_free(process);
+}
+
+static void write_all(git_process *process, char *buf)
+{
+	size_t buf_len = strlen(buf);
+	ssize_t ret;
+
+	while (buf_len) {
+		ret = git_process_write(process, buf, buf_len);
+		cl_git_pass(ret < 0 ? (int)ret : 0);
+
+		buf += ret;
+		buf_len -= ret;
+	}
+}
+
+static void read_all(git_str *out, git_process *process)
+{
+	char buf[32];
+	size_t buf_len = 32;
+	ssize_t ret;
+
+	while ((ret = git_process_read(process, buf, buf_len)) > 0)
+		cl_git_pass(git_str_put(out, buf, ret));
+
+	cl_git_pass(ret < 0 ? (int)ret : 0);
+}
+
+void test_process_start__redirect_stdio(void)
+{
+#ifdef GIT_WIN32
+	const char *args_array[] = { "C:\\Windows\\System32\\cmd.exe", "/c", cat_cmd.ptr };
+#else
+	const char *args_array[] = { "/bin/cat" };
+#endif
+
+	git_process *process;
+	git_process_options opts = GIT_PROCESS_OPTIONS_INIT;
+	git_process_result result = GIT_PROCESS_RESULT_INIT;
+	git_str buf = GIT_STR_INIT;
+
+	opts.capture_in = 1;
+	opts.capture_out = 1;
+
+	cl_git_pass(git_process_new(&process, args_array, ARRAY_SIZE(args_array), NULL, 0, &opts));
+	cl_git_pass(git_process_start(process));
+
+	write_all(process, "Hello, world.\r\nHello!\r\n");
+	cl_git_pass(git_process_close_in(process));
+
+	read_all(&buf, process);
+	cl_assert_equal_s("Hello, world.\r\nHello!\r\n", buf.ptr);
+
+	cl_git_pass(git_process_wait(&result, process));
+
+	cl_assert_equal_i(GIT_PROCESS_STATUS_NORMAL, result.status);
+	cl_assert_equal_i(0, result.exitcode);
+	cl_assert_equal_i(0, result.signal);
+
+	git_str_dispose(&buf);
+	git_process_free(process);
+}
+
+void test_process_start__catch_signal(void)
+{
+#ifndef GIT_WIN32
+	const char *args_array[] = { helloworld_cmd.ptr };
+
+	git_process *process;
+	git_process_options opts = GIT_PROCESS_OPTIONS_INIT;
+	git_process_result result = GIT_PROCESS_RESULT_INIT;
+
+	opts.capture_out = 1;
+
+	cl_git_pass(git_process_new(&process, args_array, ARRAY_SIZE(args_array), NULL, 0, &opts));
+	cl_git_pass(git_process_start(process));
+	cl_git_pass(git_process_close(process));
+	cl_git_pass(git_process_wait(&result, process));
+
+	cl_assert_equal_i(GIT_PROCESS_STATUS_ERROR, result.status);
+	cl_assert_equal_i(0, result.exitcode);
+	cl_assert_equal_i(SIGPIPE, result.signal);
+
+	git_process_free(process);
+#endif
+}
+
+void test_process_start__can_chdir(void)
+{
+#ifdef GIT_WIN32
+	const char *args_array[] = { "C:\\Windows\\System32\\cmd.exe", "/c", pwd_cmd.ptr };
+	char *startwd = "C:\\";
+#else
+	const char *args_array[] = { "/bin/pwd" };
+	char *startwd = "/";
+#endif
+
+	git_process *process;
+	git_process_options opts = GIT_PROCESS_OPTIONS_INIT;
+	git_process_result result = GIT_PROCESS_RESULT_INIT;
+	git_str buf = GIT_STR_INIT;
+
+	opts.cwd = startwd;
+	opts.capture_out = 1;
+
+	cl_git_pass(git_process_new(&process, args_array, ARRAY_SIZE(args_array), NULL, 0, &opts));
+	cl_git_pass(git_process_start(process));
+
+	read_all(&buf, process);
+	git_str_rtrim(&buf);
+
+	cl_assert_equal_s(startwd, buf.ptr);
+
+	cl_git_pass(git_process_wait(&result, process));
+
+	cl_assert_equal_i(GIT_PROCESS_STATUS_NORMAL, result.status);
+	cl_assert_equal_i(0, result.exitcode);
+	cl_assert_equal_i(0, result.signal);
+
+	git_str_dispose(&buf);
+	git_process_free(process);
+}
+
+void test_process_start__cannot_chdir_to_nonexistent_dir(void)
+{
+#ifdef GIT_WIN32
+	const char *args_array[] = { "C:\\Windows\\System32\\cmd.exe", "/c", pwd_cmd.ptr };
+	char *startwd = "C:\\a\\b\\z\\y\\not_found";
+#else
+	const char *args_array[] = { "/bin/pwd" };
+	char *startwd = "/a/b/z/y/not_found";
+#endif
+
+	git_process *process;
+	git_process_options opts = GIT_PROCESS_OPTIONS_INIT;
+
+	opts.cwd = startwd;
+	opts.capture_out = 1;
+
+	cl_git_pass(git_process_new(&process, args_array, ARRAY_SIZE(args_array), NULL, 0, &opts));
+	cl_git_fail(git_process_start(process));
+	git_process_free(process);
+}

tests/util/process/win32.c

+#include "clar_libgit2.h"
+#include "process.h"
+#include "vector.h"
+
+#ifdef GIT_WIN32
+static git_str result;
+
+# define assert_cmdline(expected, given) do { \
+		cl_git_pass(git_process__cmdline(&result, given, ARRAY_SIZE(given))); \
+		cl_assert_equal_s(expected, result.ptr); \
+		git_str_dispose(&result); \
+	} while(0)
+#endif
+
+void test_process_win32__cmdline_is_whitespace_delimited(void)
+{
+#ifdef GIT_WIN32
+	const char *one[] = { "one" };
+	const char *two[] = { "one", "two" };
+	const char *three[] = { "one", "two", "three" };
+	const char *four[] = { "one", "two", "three", "four" };
+
+	assert_cmdline("one", one);
+	assert_cmdline("one two", two);
+	assert_cmdline("one two three", three);
+	assert_cmdline("one two three four", four);
+#endif
+}
+
+void test_process_win32__cmdline_escapes_whitespace(void)
+{
+#ifdef GIT_WIN32
+	const char *spaces[] = { "one with spaces" };
+	const char *tabs[] = { "one\twith\ttabs" };
+	const char *multiple[] = { "one    with    many    spaces" };
+
+	assert_cmdline("one\" \"with\" \"spaces", spaces);
+	assert_cmdline("one\"\t\"with\"\t\"tabs", tabs);
+	assert_cmdline("one\"    \"with\"    \"many\"    \"spaces", multiple);
+#endif
+}
+
+void test_process_win32__cmdline_escapes_quotes(void)
+{
+#ifdef GIT_WIN32
+	const char *one[] = { "echo", "\"hello world\"" };
+
+	assert_cmdline("echo \\\"hello\" \"world\\\"", one);
+#endif
+}
+
+void test_process_win32__cmdline_escapes_backslash(void)
+{
+#ifdef GIT_WIN32
+	const char *one[] = { "foo\\bar", "foo\\baz" };
+	const char *two[] = { "c:\\program files\\foo bar\\foo bar.exe", "c:\\path\\to\\other\\", "/a", "/b" };
+
+	assert_cmdline("foo\\\\bar foo\\\\baz", one);
+	assert_cmdline("c:\\\\program\" \"files\\\\foo\" \"bar\\\\foo\" \"bar.exe c:\\\\path\\\\to\\\\other\\\\ /a /b", two);
+#endif
+}