Merge branch 'tg/maint-cache-name-compare'
[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
10 static int do_generic_cmd(const char *me, char *arg)
11 {
12         const char *my_argv[4];
13
14         setup_path();
15         if (!arg || !(arg = sq_dequote(arg)))
16                 die("bad argument");
17         if (prefixcmp(me, "git-"))
18                 die("bad command");
19
20         my_argv[0] = me + 4;
21         my_argv[1] = arg;
22         my_argv[2] = NULL;
23
24         return execv_git_cmd(my_argv);
25 }
26
27 static int do_cvs_cmd(const char *me, char *arg)
28 {
29         const char *cvsserver_argv[3] = {
30                 "cvsserver", "server", NULL
31         };
32
33         if (!arg || strcmp(arg, "server"))
34                 die("git-cvsserver only handles server: %s", arg);
35
36         setup_path();
37         return execv_git_cmd(cvsserver_argv);
38 }
39
40 static int is_valid_cmd_name(const char *cmd)
41 {
42         /* Test command contains no . or / characters */
43         return cmd[strcspn(cmd, "./")] == '\0';
44 }
45
46 static char *make_cmd(const char *prog)
47 {
48         char *prefix = xmalloc((strlen(prog) + strlen(COMMAND_DIR) + 2));
49         strcpy(prefix, COMMAND_DIR);
50         strcat(prefix, "/");
51         strcat(prefix, prog);
52         return prefix;
53 }
54
55 static void cd_to_homedir(void)
56 {
57         const char *home = getenv("HOME");
58         if (!home)
59                 die("could not determine user's home directory; HOME is unset");
60         if (chdir(home) == -1)
61                 die("could not chdir to user's home directory");
62 }
63
64 static void run_shell(void)
65 {
66         int done = 0;
67         static const char *help_argv[] = { HELP_COMMAND, NULL };
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         { "cvs", do_cvs_cmd },
129         { NULL },
130 };
131
132 int main(int argc, char **argv)
133 {
134         char *prog;
135         const char **user_argv;
136         struct commands *cmd;
137         int devnull_fd;
138         int count;
139
140         git_setup_gettext();
141
142         git_extract_argv0_path(argv[0]);
143
144         /*
145          * Always open file descriptors 0/1/2 to avoid clobbering files
146          * in die().  It also avoids not messing up when the pipes are
147          * dup'ed onto stdin/stdout/stderr in the child processes we spawn.
148          */
149         devnull_fd = open("/dev/null", O_RDWR);
150         while (devnull_fd >= 0 && devnull_fd <= 2)
151                 devnull_fd = dup(devnull_fd);
152         if (devnull_fd == -1)
153                 die_errno("opening /dev/null failed");
154         close (devnull_fd);
155
156         /*
157          * Special hack to pretend to be a CVS server
158          */
159         if (argc == 2 && !strcmp(argv[1], "cvs server")) {
160                 argv--;
161         } else if (argc == 1) {
162                 /* Allow the user to run an interactive shell */
163                 cd_to_homedir();
164                 if (access(COMMAND_DIR, R_OK | X_OK) == -1) {
165                         die("Interactive git shell is not enabled.\n"
166                             "hint: ~/" COMMAND_DIR " should exist "
167                             "and have read and execute access.");
168                 }
169                 run_shell();
170                 exit(0);
171         } else if (argc != 3 || strcmp(argv[1], "-c")) {
172                 /*
173                  * We do not accept any other modes except "-c" followed by
174                  * "cmd arg", where "cmd" is a very limited subset of git
175                  * commands or a command in the COMMAND_DIR
176                  */
177                 die("Run with no arguments or with -c cmd");
178         }
179
180         prog = xstrdup(argv[2]);
181         if (!strncmp(prog, "git", 3) && isspace(prog[3]))
182                 /* Accept "git foo" as if the caller said "git-foo". */
183                 prog[3] = '-';
184
185         for (cmd = cmd_list ; cmd->name ; cmd++) {
186                 int len = strlen(cmd->name);
187                 char *arg;
188                 if (strncmp(cmd->name, prog, len))
189                         continue;
190                 arg = NULL;
191                 switch (prog[len]) {
192                 case '\0':
193                         arg = NULL;
194                         break;
195                 case ' ':
196                         arg = prog + len + 1;
197                         break;
198                 default:
199                         continue;
200                 }
201                 exit(cmd->exec(cmd->name, arg));
202         }
203
204         cd_to_homedir();
205         count = split_cmdline(prog, &user_argv);
206         if (count >= 0) {
207                 if (is_valid_cmd_name(user_argv[0])) {
208                         prog = make_cmd(user_argv[0]);
209                         user_argv[0] = prog;
210                         execv(user_argv[0], (char *const *) user_argv);
211                 }
212                 free(prog);
213                 free(user_argv);
214                 die("unrecognized command '%s'", argv[2]);
215         } else {
216                 free(prog);
217                 die("invalid command format '%s': %s", argv[2],
218                     split_cmdline_strerror(count));
219         }
220 }