Merge branch 'mm/gc-safety-doc' into next
[git] / 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_lf(&line, stdin) == 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 cmd_main(int argc, const char **argv)
142 {
143         char *prog;
144         const char **user_argv;
145         struct commands *cmd;
146         int count;
147
148         /*
149          * Special hack to pretend to be a CVS server
150          */
151         if (argc == 2 && !strcmp(argv[1], "cvs server")) {
152                 argv--;
153         } else if (argc == 1) {
154                 /* Allow the user to run an interactive shell */
155                 cd_to_homedir();
156                 if (access(COMMAND_DIR, R_OK | X_OK) == -1) {
157                         die("Interactive git shell is not enabled.\n"
158                             "hint: ~/" COMMAND_DIR " should exist "
159                             "and have read and execute access.");
160                 }
161                 run_shell();
162                 exit(0);
163         } else if (argc != 3 || strcmp(argv[1], "-c")) {
164                 /*
165                  * We do not accept any other modes except "-c" followed by
166                  * "cmd arg", where "cmd" is a very limited subset of git
167                  * commands or a command in the COMMAND_DIR
168                  */
169                 die("Run with no arguments or with -c cmd");
170         }
171
172         prog = xstrdup(argv[2]);
173         if (!strncmp(prog, "git", 3) && isspace(prog[3]))
174                 /* Accept "git foo" as if the caller said "git-foo". */
175                 prog[3] = '-';
176
177         for (cmd = cmd_list ; cmd->name ; cmd++) {
178                 int len = strlen(cmd->name);
179                 char *arg;
180                 if (strncmp(cmd->name, prog, len))
181                         continue;
182                 arg = NULL;
183                 switch (prog[len]) {
184                 case '\0':
185                         arg = NULL;
186                         break;
187                 case ' ':
188                         arg = prog + len + 1;
189                         break;
190                 default:
191                         continue;
192                 }
193                 exit(cmd->exec(cmd->name, arg));
194         }
195
196         cd_to_homedir();
197         count = split_cmdline(prog, &user_argv);
198         if (count >= 0) {
199                 if (is_valid_cmd_name(user_argv[0])) {
200                         prog = make_cmd(user_argv[0]);
201                         user_argv[0] = prog;
202                         execv(user_argv[0], (char *const *) user_argv);
203                 }
204                 free(prog);
205                 free(user_argv);
206                 die("unrecognized command '%s'", argv[2]);
207         } else {
208                 free(prog);
209                 die("invalid command format '%s': %s", argv[2],
210                     split_cmdline_strerror(count));
211         }
212 }