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