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