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 (prefixcmp(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         char *prefix = xmalloc((strlen(prog) + strlen(COMMAND_DIR) + 2));
  50         strcpy(prefix, COMMAND_DIR);
  51         strcat(prefix, "/");
  52         strcat(prefix, prog);
  53         return prefix;
  54 }
  55
  56 static void cd_to_homedir(void)
  57 {
  58         const char *home = getenv("HOME");
  59         if (!home)
  60                 die("could not determine user's home directory; HOME is unset");
  61         if (chdir(home) == -1)
  62                 die("could not chdir to user's home directory");
  63 }
  64
  65 static void run_shell(void)
  66 {
  67         int done = 0;
  68         static const char *help_argv[] = { HELP_COMMAND, NULL };
  69
  70         if (!access(NOLOGIN_COMMAND, F_OK)) {
  71                 /* Interactive login disabled. */
  72                 const char *argv[] = { NOLOGIN_COMMAND, NULL };
  73                 int status;
  74
  75                 status = run_command_v_opt(argv, 0);
  76                 if (status < 0)
  77                         exit(127);
  78                 exit(status);
  79         }
  80
  81         /* Print help if enabled */
  82         run_command_v_opt(help_argv, RUN_SILENT_EXEC_FAILURE);
  83
  84         do {
  85                 struct strbuf line = STRBUF_INIT;
  86                 const char *prog;
  87                 char *full_cmd;
  88                 char *rawargs;
  89                 char *split_args;
  90                 const char **argv;
  91                 int code;
  92                 int count;
  93
  94                 fprintf(stderr, "git> ");
  95                 if (strbuf_getline(&line, stdin, '\n') == EOF) {
  96                         fprintf(stderr, "\n");
  97                         strbuf_release(&line);
  98                         break;
  99                 }
 100                 strbuf_trim(&line);
 101                 rawargs = strbuf_detach(&line, NULL);
 102                 split_args = xstrdup(rawargs);
 103                 count = split_cmdline(split_args, &argv);
 104                 if (count < 0) {
 105                         fprintf(stderr, "invalid command format '%s': %s\n", rawargs,
 106                                 split_cmdline_strerror(count));
 107                         free(split_args);
 108                         free(rawargs);
 109                         continue;
 110                 }
 111
 112                 prog = argv[0];
 113                 if (!strcmp(prog, "")) {
 114                 } else if (!strcmp(prog, "quit") || !strcmp(prog, "logout") ||
 115                            !strcmp(prog, "exit") || !strcmp(prog, "bye")) {
 116                         done = 1;
 117                 } else if (is_valid_cmd_name(prog)) {
 118                         full_cmd = make_cmd(prog);
 119                         argv[0] = full_cmd;
 120                         code = run_command_v_opt(argv, RUN_SILENT_EXEC_FAILURE);
 121                         if (code == -1 && errno == ENOENT) {
 122                                 fprintf(stderr, "unrecognized command '%s'\n", prog);
 123                         }
 124                         free(full_cmd);
 125                 } else {
 126                         fprintf(stderr, "invalid command format '%s'\n", prog);
 127                 }
 128
 129                 free(argv);
 130                 free(rawargs);
 131         } while (!done);
 132 }
 133
 134 static struct commands {
 135         const char *name;
 136         int (*exec)(const char *me, char *arg);
 137 } cmd_list[] = {
 138         { "git-receive-pack", do_generic_cmd },
 139         { "git-upload-pack", do_generic_cmd },
 140         { "git-upload-archive", do_generic_cmd },
 141         { "cvs", do_cvs_cmd },
 142         { NULL },
 143 };
 144
 145 int main(int argc, char **argv)
 146 {
 147         char *prog;
 148         const char **user_argv;
 149         struct commands *cmd;
 150         int devnull_fd;
 151         int count;
 152
 153         git_setup_gettext();
 154
 155         git_extract_argv0_path(argv[0]);
 156
 157         /*
 158          * Always open file descriptors 0/1/2 to avoid clobbering files
 159          * in die().  It also avoids not messing up when the pipes are
 160          * dup'ed onto stdin/stdout/stderr in the child processes we spawn.
 161          */
 162         devnull_fd = open("/dev/null", O_RDWR);
 163         while (devnull_fd >= 0 && devnull_fd <= 2)
 164                 devnull_fd = dup(devnull_fd);
 165         if (devnull_fd == -1)
 166                 die_errno("opening /dev/null failed");
 167         close (devnull_fd);
 168
 169         /*
 170          * Special hack to pretend to be a CVS server
 171          */
 172         if (argc == 2 && !strcmp(argv[1], "cvs server")) {
 173                 argv--;
 174         } else if (argc == 1) {
 175                 /* Allow the user to run an interactive shell */
 176                 cd_to_homedir();
 177                 if (access(COMMAND_DIR, R_OK | X_OK) == -1) {
 178                         die("Interactive git shell is not enabled.\n"
 179                             "hint: ~/" COMMAND_DIR " should exist "
 180                             "and have read and execute access.");
 181                 }
 182                 run_shell();
 183                 exit(0);
 184         } else if (argc != 3 || strcmp(argv[1], "-c")) {
 185                 /*
 186                  * We do not accept any other modes except "-c" followed by
 187                  * "cmd arg", where "cmd" is a very limited subset of git
 188                  * commands or a command in the COMMAND_DIR
 189                  */
 190                 die("Run with no arguments or with -c cmd");
 191         }
 192
 193         prog = xstrdup(argv[2]);
 194         if (!strncmp(prog, "git", 3) && isspace(prog[3]))
 195                 /* Accept "git foo" as if the caller said "git-foo". */
 196                 prog[3] = '-';
 197
 198         for (cmd = cmd_list ; cmd->name ; cmd++) {
 199                 int len = strlen(cmd->name);
 200                 char *arg;
 201                 if (strncmp(cmd->name, prog, len))
 202                         continue;
 203                 arg = NULL;
 204                 switch (prog[len]) {
 205                 case '\0':
 206                         arg = NULL;
 207                         break;
 208                 case ' ':
 209                         arg = prog + len + 1;
 210                         break;
 211                 default:
 212                         continue;
 213                 }
 214                 exit(cmd->exec(cmd->name, arg));
 215         }
 216
 217         cd_to_homedir();
 218         count = split_cmdline(prog, &user_argv);
 219         if (count >= 0) {
 220                 if (is_valid_cmd_name(user_argv[0])) {
 221                         prog = make_cmd(user_argv[0]);
 222                         user_argv[0] = prog;
 223                         execv(user_argv[0], (char *const *) user_argv);
 224                 }
 225                 free(prog);
 226                 free(user_argv);
 227                 die("unrecognized command '%s'", argv[2]);
 228         } else {
 229                 free(prog);
 230                 die("invalid command format '%s': %s", argv[2],
 231                     split_cmdline_strerror(count));
 232         }
 233 }