shell.c

   1 #include "cache.h"
   2 #include "quote.h"
   3 #include "exec_cmd.h"
   4 #include "strbuf.h"
   5 #include "run-command.h"
   6
   7 #define COMMAND_DIR "git-shell-commands"
   8 #define HELP_COMMAND COMMAND_DIR "/help"
   9 #define NOLOGIN_COMMAND COMMAND_DIR "/no-interactive-login"
  10
  11 static int do_generic_cmd(const char *me, char *arg)
  12 {
  13         const char *my_argv[4];
  14
  15         setup_path();
  16         if (!arg || !(arg = sq_dequote(arg)))
  17                 die("bad argument");
  18         if (!starts_with(me, "git-"))
  19                 die("bad command");
  20
  21         my_argv[0] = me + 4;
  22         my_argv[1] = arg;
  23         my_argv[2] = NULL;
  24
  25         return execv_git_cmd(my_argv);
  26 }
  27
  28 static int do_cvs_cmd(const char *me, char *arg)
  29 {
  30         const char *cvsserver_argv[3] = {
  31                 "cvsserver", "server", NULL
  32         };
  33
  34         if (!arg || strcmp(arg, "server"))
  35                 die("git-cvsserver only handles server: %s", arg);
  36
  37         setup_path();
  38         return execv_git_cmd(cvsserver_argv);
  39 }
  40
  41 static int is_valid_cmd_name(const char *cmd)
  42 {
  43         /* Test command contains no . or / characters */
  44         return cmd[strcspn(cmd, "./")] == '\0';
  45 }
  46
  47 static char *make_cmd(const char *prog)
  48 {
  49         return xstrfmt("%s/%s", COMMAND_DIR, prog);
  50 }
  51
  52 static void cd_to_homedir(void)
  53 {
  54         const char *home = getenv("HOME");
  55         if (!home)
  56                 die("could not determine user's home directory; HOME is unset");
  57         if (chdir(home) == -1)
  58                 die("could not chdir to user's home directory");
  59 }
  60
  61 static void run_shell(void)
  62 {
  63         int done = 0;
  64         static const char *help_argv[] = { HELP_COMMAND, NULL };
  65
  66         if (!access(NOLOGIN_COMMAND, F_OK)) {
  67                 /* Interactive login disabled. */
  68                 const char *argv[] = { NOLOGIN_COMMAND, NULL };
  69                 int status;
  70
  71                 status = run_command_v_opt(argv, 0);
  72                 if (status < 0)
  73                         exit(127);
  74                 exit(status);
  75         }
  76
  77         /* Print help if enabled */
  78         run_command_v_opt(help_argv, RUN_SILENT_EXEC_FAILURE);
  79
  80         do {
  81                 struct strbuf line = STRBUF_INIT;
  82                 const char *prog;
  83                 char *full_cmd;
  84                 char *rawargs;
  85                 char *split_args;
  86                 const char **argv;
  87                 int code;
  88                 int count;
  89
  90                 fprintf(stderr, "git> ");
  91                 if (strbuf_getline(&line, stdin, '\n') == EOF) {
  92                         fprintf(stderr, "\n");
  93                         strbuf_release(&line);
  94                         break;
  95                 }
  96                 strbuf_trim(&line);
  97                 rawargs = strbuf_detach(&line, NULL);
  98                 split_args = xstrdup(rawargs);
  99                 count = split_cmdline(split_args, &argv);
 100                 if (count < 0) {
 101                         fprintf(stderr, "invalid command format '%s': %s\n", rawargs,
 102                                 split_cmdline_strerror(count));
 103                         free(split_args);
 104                         free(rawargs);
 105                         continue;
 106                 }
 107
 108                 prog = argv[0];
 109                 if (!strcmp(prog, "")) {
 110                 } else if (!strcmp(prog, "quit") || !strcmp(prog, "logout") ||
 111                            !strcmp(prog, "exit") || !strcmp(prog, "bye")) {
 112                         done = 1;
 113                 } else if (is_valid_cmd_name(prog)) {
 114                         full_cmd = make_cmd(prog);
 115                         argv[0] = full_cmd;
 116                         code = run_command_v_opt(argv, RUN_SILENT_EXEC_FAILURE);
 117                         if (code == -1 && errno == ENOENT) {
 118                                 fprintf(stderr, "unrecognized command '%s'\n", prog);
 119                         }
 120                         free(full_cmd);
 121                 } else {
 122                         fprintf(stderr, "invalid command format '%s'\n", prog);
 123                 }
 124
 125                 free(argv);
 126                 free(rawargs);
 127         } while (!done);
 128 }
 129
 130 static struct commands {
 131         const char *name;
 132         int (*exec)(const char *me, char *arg);
 133 } cmd_list[] = {
 134         { "git-receive-pack", do_generic_cmd },
 135         { "git-upload-pack", do_generic_cmd },
 136         { "git-upload-archive", do_generic_cmd },
 137         { "cvs", do_cvs_cmd },
 138         { NULL },
 139 };
 140
 141 int main(int argc, char **argv)
 142 {
 143         char *prog;
 144         const char **user_argv;
 145         struct commands *cmd;
 146         int count;
 147
 148         git_setup_gettext();
 149
 150         git_extract_argv0_path(argv[0]);
 151
 152         /*
 153          * Always open file descriptors 0/1/2 to avoid clobbering files
 154          * in die().  It also avoids messing up when the pipes are dup'ed
 155          * onto stdin/stdout/stderr in the child processes we spawn.
 156          */
 157         sanitize_stdfds();
 158
 159         /*
 160          * Special hack to pretend to be a CVS server
 161          */
 162         if (argc == 2 && !strcmp(argv[1], "cvs server")) {
 163                 argv--;
 164         } else if (argc == 1) {
 165                 /* Allow the user to run an interactive shell */
 166                 cd_to_homedir();
 167                 if (access(COMMAND_DIR, R_OK | X_OK) == -1) {
 168                         die("Interactive git shell is not enabled.\n"
 169                             "hint: ~/" COMMAND_DIR " should exist "
 170                             "and have read and execute access.");
 171                 }
 172                 run_shell();
 173                 exit(0);
 174         } else if (argc != 3 || strcmp(argv[1], "-c")) {
 175                 /*
 176                  * We do not accept any other modes except "-c" followed by
 177                  * "cmd arg", where "cmd" is a very limited subset of git
 178                  * commands or a command in the COMMAND_DIR
 179                  */
 180                 die("Run with no arguments or with -c cmd");
 181         }
 182
 183         prog = xstrdup(argv[2]);
 184         if (!strncmp(prog, "git", 3) && isspace(prog[3]))
 185                 /* Accept "git foo" as if the caller said "git-foo". */
 186                 prog[3] = '-';
 187
 188         for (cmd = cmd_list ; cmd->name ; cmd++) {
 189                 int len = strlen(cmd->name);
 190                 char *arg;
 191                 if (strncmp(cmd->name, prog, len))
 192                         continue;
 193                 arg = NULL;
 194                 switch (prog[len]) {
 195                 case '\0':
 196                         arg = NULL;
 197                         break;
 198                 case ' ':
 199                         arg = prog + len + 1;
 200                         break;
 201                 default:
 202                         continue;
 203                 }
 204                 exit(cmd->exec(cmd->name, arg));
 205         }
 206
 207         cd_to_homedir();
 208         count = split_cmdline(prog, &user_argv);
 209         if (count >= 0) {
 210                 if (is_valid_cmd_name(user_argv[0])) {
 211                         prog = make_cmd(user_argv[0]);
 212                         user_argv[0] = prog;
 213                         execv(user_argv[0], (char *const *) user_argv);
 214                 }
 215                 free(prog);
 216                 free(user_argv);
 217                 die("unrecognized command '%s'", argv[2]);
 218         } else {
 219                 free(prog);
 220                 die("invalid command format '%s': %s", argv[2],
 221                     split_cmdline_strerror(count));
 222         }
 223 }