Say when --track is useful in the git-checkout docs.

diff --git a/run-command.c b/run-command.c
index bef9775e0807200e07c9780c69e3e1bda0c6c874..7e779d33ee9ea5f7d2e6aedc8c3a0a0476e87135 100644 (file)
--- a/run-command.c
+++ b/run-command.c
@@ -8,11 +8,19 @@ static inline void close_pair(int fd[2])
        close(fd[1]);
 }
 
+static inline void dup_devnull(int to)
+{
+       int fd = open("/dev/null", O_RDWR);
+       dup2(fd, to);
+       close(fd);
+}
+
 int start_command(struct child_process *cmd)
 {
-       int need_in = !cmd->no_stdin && cmd->in < 0;
-       int fdin[2];
+       int need_in, need_out;
+       int fdin[2], fdout[2];
 
+       need_in = !cmd->no_stdin && cmd->in < 0;
        if (need_in) {
                if (pipe(fdin) < 0)
                        return -ERR_RUN_COMMAND_PIPE;
@@ -20,19 +28,32 @@ int start_command(struct child_process *cmd)
                cmd->close_in = 1;
        }
 
+       need_out = !cmd->no_stdout
+               && !cmd->stdout_to_stderr
+               && cmd->out < 0;
+       if (need_out) {
+               if (pipe(fdout) < 0) {
+                       if (need_in)
+                               close_pair(fdin);
+                       return -ERR_RUN_COMMAND_PIPE;
+               }
+               cmd->out = fdout[0];
+               cmd->close_out = 1;
+       }
+
        cmd->pid = fork();
        if (cmd->pid < 0) {
                if (need_in)
                        close_pair(fdin);
+               if (need_out)
+                       close_pair(fdout);
                return -ERR_RUN_COMMAND_FORK;
        }
 
        if (!cmd->pid) {
-               if (cmd->no_stdin) {
-                       int fd = open("/dev/null", O_RDWR);
-                       dup2(fd, 0);
-                       close(fd);
-               } else if (need_in) {
+               if (cmd->no_stdin)
+                       dup_devnull(0);
+               else if (need_in) {
                        dup2(fdin[0], 0);
                        close_pair(fdin);
                } else if (cmd->in) {
@@ -40,8 +61,29 @@ int start_command(struct child_process *cmd)
                        close(cmd->in);
                }
 
-               if (cmd->stdout_to_stderr)
+               if (cmd->no_stdout)
+                       dup_devnull(1);
+               else if (cmd->stdout_to_stderr)
                        dup2(2, 1);
+               else if (need_out) {
+                       dup2(fdout[1], 1);
+                       close_pair(fdout);
+               } else if (cmd->out > 1) {
+                       dup2(cmd->out, 1);
+                       close(cmd->out);
+               }
+
+               if (cmd->dir && chdir(cmd->dir))
+                       die("exec %s: cd to %s failed (%s)", cmd->argv[0],
+                           cmd->dir, strerror(errno));
+               if (cmd->env) {
+                       for (; *cmd->env; cmd->env++) {
+                               if (strchr(*cmd->env, '='))
+                                       putenv((char*)*cmd->env);
+                               else
+                                       unsetenv(*cmd->env);
+                       }
+               }
                if (cmd->git_cmd) {
                        execv_git_cmd(cmd->argv);
                } else {
@@ -55,6 +97,11 @@ int start_command(struct child_process *cmd)
        else if (cmd->in)
                close(cmd->in);
 
+       if (need_out)
+               close(fdout[1]);
+       else if (cmd->out > 1)
+               close(cmd->out);
+
        return 0;
 }
 
@@ -62,6 +109,8 @@ int finish_command(struct child_process *cmd)
 {
        if (cmd->close_in)
                close(cmd->in);
+       if (cmd->close_out)
+               close(cmd->out);
 
        for (;;) {
                int status, code;
@@ -95,13 +144,37 @@ int run_command(struct child_process *cmd)
        return finish_command(cmd);
 }
 
+static void prepare_run_command_v_opt(struct child_process *cmd,
+                                     const char **argv,
+                                     int opt)
+{
+       memset(cmd, 0, sizeof(*cmd));
+       cmd->argv = argv;
+       cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
+       cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
+       cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
+}
+
 int run_command_v_opt(const char **argv, int opt)
 {
        struct child_process cmd;
-       memset(&cmd, 0, sizeof(cmd));
-       cmd.argv = argv;
-       cmd.no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
-       cmd.git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
-       cmd.stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
+       prepare_run_command_v_opt(&cmd, argv, opt);
+       return run_command(&cmd);
+}
+
+int run_command_v_opt_cd(const char **argv, int opt, const char *dir)
+{
+       struct child_process cmd;
+       prepare_run_command_v_opt(&cmd, argv, opt);
+       cmd.dir = dir;
+       return run_command(&cmd);
+}
+
+int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
+{
+       struct child_process cmd;
+       prepare_run_command_v_opt(&cmd, argv, opt);
+       cmd.dir = dir;
+       cmd.env = env;
        return run_command(&cmd);
 }