Windows: Implement start_command().

On Windows, we have spawnv() variants to run a child process instead of
fork()/exec(). In order to attach pipe ends to stdin, stdout, and stderr,
we have to use this idiom:

    save1 = dup(1);
    dup2(pipe[1], 1);
    spawnv();
    dup2(save1, 1);
    close(pipe[1]);

assuming that the descriptors created by pipe() are not inheritable.

Signed-off-by: Johannes Sixt <johannes.sixt@telecom.at>

diff --git a/compat/mingw.c b/compat/mingw.c
index 31a9b9e2516ba04d04c147fb8d8da63a319c08ea..7f89a6cb87e4457c8ff017b25d4736732455aaa1 100644 (file)
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -315,6 +315,68 @@ void mingw_execvp(const char *cmd, char *const *argv)
        free_path_split(path);
 }
 
+char **copy_environ()
+{
+       char **env;
+       int i = 0;
+       while (environ[i])
+               i++;
+       env = xmalloc((i+1)*sizeof(*env));
+       for (i = 0; environ[i]; i++)
+               env[i] = xstrdup(environ[i]);
+       env[i] = NULL;
+       return env;
+}
+
+void free_environ(char **env)
+{
+       int i;
+       for (i = 0; env[i]; i++)
+               free(env[i]);
+       free(env);
+}
+
+static int lookup_env(char **env, const char *name, size_t nmln)
+{
+       int i;
+
+       for (i = 0; env[i]; i++) {
+               if (0 == strncmp(env[i], name, nmln)
+                   && '=' == env[i][nmln])
+                       /* matches */
+                       return i;
+       }
+       return -1;
+}
+
+/*
+ * If name contains '=', then sets the variable, otherwise it unsets it
+ */
+char **env_setenv(char **env, const char *name)
+{
+       char *eq = strchrnul(name, '=');
+       int i = lookup_env(env, name, eq-name);
+
+       if (i < 0) {
+               if (*eq) {
+                       for (i = 0; env[i]; i++)
+                               ;
+                       env = xrealloc(env, (i+2)*sizeof(*env));
+                       env[i] = xstrdup(name);
+                       env[i+1] = NULL;
+               }
+       }
+       else {
+               free(env[i]);
+               if (*eq)
+                       env[i] = xstrdup(name);
+               else
+                       for (; env[i]; i++)
+                               env[i] = env[i+1];
+       }
+       return env;
+}
+
 #undef rename
 int mingw_rename(const char *pold, const char *pnew)
 {

diff --git a/compat/mingw.h b/compat/mingw.h
index 0ce9c96f93a57d18588c4e0ba48957fa70ba1d71..0879894c68ace1954e262140d70c06a2df6387b8 100644 (file)
--- a/compat/mingw.h
+++ b/compat/mingw.h
@@ -165,3 +165,11 @@ sig_handler_t mingw_signal(int sig, sig_handler_t handler);
 #define is_dir_sep(c) ((c) == '/' || (c) == '\\')
 #define PATH_SEP ';'
 #define PRIuMAX "I64u"
+
+/*
+ * helpers
+ */
+
+char **copy_environ(void);
+void free_environ(char **env);
+char **env_setenv(char **env, const char *name);

diff --git a/run-command.c b/run-command.c
index 44100a749b09439121073e32e7a3143b54185d31..dd8b7751ceed0870c086f61766fecd50d4d1b176 100644 (file)
--- a/run-command.c
+++ b/run-command.c
@@ -65,21 +65,8 @@ int start_command(struct child_process *cmd)
                cmd->err = fderr[0];
        }
 
+#ifndef __MINGW32__
        cmd->pid = fork();
-       if (cmd->pid < 0) {
-               if (need_in)
-                       close_pair(fdin);
-               else if (cmd->in)
-                       close(cmd->in);
-               if (need_out)
-                       close_pair(fdout);
-               else if (cmd->out)
-                       close(cmd->out);
-               if (need_err)
-                       close_pair(fderr);
-               return -ERR_RUN_COMMAND_FORK;
-       }
-
        if (!cmd->pid) {
                if (cmd->no_stdin)
                        dup_devnull(0);
@@ -128,6 +115,88 @@ int start_command(struct child_process *cmd)
                }
                die("exec %s failed.", cmd->argv[0]);
        }
+#else
+       int s0 = -1, s1 = -1, s2 = -1;  /* backups of stdin, stdout, stderr */
+       const char *sargv0 = cmd->argv[0];
+       char **env = environ;
+       struct strbuf git_cmd;
+
+       if (cmd->no_stdin) {
+               s0 = dup(0);
+               dup_devnull(0);
+       } else if (need_in) {
+               s0 = dup(0);
+               dup2(fdin[0], 0);
+       } else if (cmd->in) {
+               s0 = dup(0);
+               dup2(cmd->in, 0);
+       }
+
+       if (cmd->no_stderr) {
+               s2 = dup(2);
+               dup_devnull(2);
+       } else if (need_err) {
+               s2 = dup(2);
+               dup2(fderr[1], 2);
+       }
+
+       if (cmd->no_stdout) {
+               s1 = dup(1);
+               dup_devnull(1);
+       } else if (cmd->stdout_to_stderr) {
+               s1 = dup(1);
+               dup2(2, 1);
+       } else if (need_out) {
+               s1 = dup(1);
+               dup2(fdout[1], 1);
+       } else if (cmd->out > 1) {
+               s1 = dup(1);
+               dup2(cmd->out, 1);
+       }
+
+       if (cmd->dir)
+               die("chdir in start_command() not implemented");
+       if (cmd->env) {
+               env = copy_environ();
+               for (; *cmd->env; cmd->env++)
+                       env = env_setenv(env, *cmd->env);
+       }
+
+       if (cmd->git_cmd) {
+               strbuf_init(&git_cmd, 0);
+               strbuf_addf(&git_cmd, "git-%s", cmd->argv[0]);
+               cmd->argv[0] = git_cmd.buf;
+       }
+
+       cmd->pid = spawnvpe(_P_NOWAIT, cmd->argv[0], cmd->argv, (const char **)env);
+
+       if (cmd->env)
+               free_environ(env);
+       if (cmd->git_cmd)
+               strbuf_release(&git_cmd);
+
+       cmd->argv[0] = sargv0;
+       if (s0 >= 0)
+               dup2(s0, 0), close(s0);
+       if (s1 >= 0)
+               dup2(s1, 1), close(s1);
+       if (s2 >= 0)
+               dup2(s2, 2), close(s2);
+#endif
+
+       if (cmd->pid < 0) {
+               if (need_in)
+                       close_pair(fdin);
+               else if (cmd->in)
+                       close(cmd->in);
+               if (need_out)
+                       close_pair(fdout);
+               else if (cmd->out)
+                       close(cmd->out);
+               if (need_err)
+                       close_pair(fderr);
+               return -ERR_RUN_COMMAND_FORK;
+       }
 
        if (need_in)
                close(fdin[0]);