Re: [PATCH] When exec'ing sub-commands, fall back on execvp (thePATH)

> Yeah, that seems to work fine. The theoretical drawback to this approach
> is that it could possibly effect the order in which the paths are tried.
> For instance, if a user did "export GIT_EXEC_PATH=", then the
> builtin_exec_path wouldn't be tried before the PATH. (i doubt that it
> would be a problem, but thought i should note it)
> 
> sRp
> 
> 
> ----- Original Message -----
> Subject: Re: [PATCH] When exec'ing sub-commands, fall back on execvp
> (thePATH)
> Date: Sat, October 20, 2007 0:30
> From: "Johannes Schindelin" <Johannes.Schindelin@gmx.de>
> 
> > Hi,
> >
> > On Fri, 19 Oct 2007, Scott Parish wrote:
> >
> > > diff --git a/exec_cmd.c b/exec_cmd.c
> > > index 9b74ed2..674c9f3 100644
> > > --- a/exec_cmd.c
> > > +++ b/exec_cmd.c
> > > @@ -34,15 +34,15 @@ int execv_git_cmd(const char **argv)
> > >  {
> > >          char git_command[PATH_MAX + 1];
> > >          int i;
> > > +        int rc;
> > >          const char *paths[] = { current_exec_path,
> > >                                  getenv(EXEC_PATH_ENVIRONMENT),
> > >                                  builtin_exec_path };
> > > +        const char *tmp;
> > > +        size_t len;
> > >
> > >          for (i = 0; i < ARRAY_SIZE(paths); ++i) {
> > > -                size_t len;
> > > -                int rc;
> > >                  const char *exec_dir = paths[i];
> > > -                const char *tmp;
> > >
> > >                  if (!exec_dir || !*exec_dir) continue;
> > >
> > > @@ -106,8 +106,26 @@ int execv_git_cmd(const char **argv)
> > >
> > >                  argv[0] = tmp;
> > >          }
> > > -        return -1;
> > >
> > > +        rc = snprintf(git_command, sizeof(git_command), "git-%s",
> argv[0]);
> > > +        if (rc < 0 || rc >= sizeof(git_command) - len) {
> > > +                fprintf(stderr, "git: command name given is too
> long.\n");
> > > +                return -1;
> > > +        }
> > > +
> > > +        tmp = argv[0];
> > > +        argv[0] = git_command;
> > > +
> > > +        trace_argv_printf(argv, -1, "trace: exec:");
> > > +
> > > +        /* execve() can only ever return if it fails */
> > > +        execvp(git_command, (char **)argv);
> > > +
> > > +        trace_printf("trace: exec failed: %s\n", strerror(errno));
> > > +
> > > +        argv[0] = tmp;
> > > +
> > > +        return -1;
> > >  }
> >
> > I am not sure that this is elegant enough: Something like this (completely
> > untested) might be better:
> >
> > diff --git a/exec_cmd.c b/exec_cmd.c
> > index 9b74ed2..c928f37 100644
> > --- a/exec_cmd.c
> > +++ b/exec_cmd.c
> > @@ -36,7 +36,8 @@ int execv_git_cmd(const char **argv)
> >          int i;
> >          const char *paths[] = { current_exec_path,
> >                                  getenv(EXEC_PATH_ENVIRONMENT),
> > -                                builtin_exec_path };
> > +                                builtin_exec_path,
> > +                                "" };
> >
> >          for (i = 0; i < ARRAY_SIZE(paths); ++i) {
> >                  size_t len;
> > @@ -44,9 +45,12 @@ int execv_git_cmd(const char **argv)
> >                  const char *exec_dir = paths[i];
> >                  const char *tmp;
> >
> > -                if (!exec_dir || !*exec_dir) continue;
> > +                if (!exec_dir) continue;
> >
> > -                if (*exec_dir != '/') {
> > +                if (!*exec_dir)
> > +                        /* try PATH */
> > +                        *git_command = '\0';
> > +                else if (*exec_dir != '/') {
> >                          if (!getcwd(git_command, sizeof(git_command))) {
> >                                  fprintf(stderr, "git: cannot determine "
> >                                          "current directory: %s\n",
> > @@ -81,7 +85,7 @@ int execv_git_cmd(const char **argv)
> >
> >                  len = strlen(git_command);
> >                  rc = snprintf(git_command + len, sizeof(git_command) -
> len,
> > -                              "/git-%s", argv[0]);
> > +                              "%sgit-%s", *exec_dir ? "/" : "", argv[0]);
> >                  if (rc < 0 || rc >= sizeof(git_command) - len) {
> >                          fprintf(stderr,
> >                                  "git: command name given is too long.\n");
> >
> > Ciao,
> > Dscho
> >
> > -
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> >
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