git-svn: minor cleanups, extra error-checking
[git] / git.c
1 #include <stdio.h>
2 #include <sys/types.h>
3 #include <sys/stat.h>
4 #include <dirent.h>
5 #include <unistd.h>
6 #include <stdlib.h>
7 #include <string.h>
8 #include <errno.h>
9 #include <limits.h>
10 #include <stdarg.h>
11 #include "git-compat-util.h"
12 #include "exec_cmd.h"
13 #include "cache.h"
14
15 #include "builtin.h"
16
17 static void prepend_to_path(const char *dir, int len)
18 {
19         char *path, *old_path = getenv("PATH");
20         int path_len = len;
21
22         if (!old_path)
23                 old_path = "/usr/local/bin:/usr/bin:/bin";
24
25         path_len = len + strlen(old_path) + 1;
26
27         path = malloc(path_len + 1);
28
29         memcpy(path, dir, len);
30         path[len] = ':';
31         memcpy(path + len + 1, old_path, path_len - len);
32
33         setenv("PATH", path, 1);
34 }
35
36 static const char *alias_command;
37 static char *alias_string = NULL;
38
39 static int git_alias_config(const char *var, const char *value)
40 {
41         if (!strncmp(var, "alias.", 6) && !strcmp(var + 6, alias_command)) {
42                 alias_string = strdup(value);
43         }
44         return 0;
45 }
46
47 static int split_cmdline(char *cmdline, const char ***argv)
48 {
49         int src, dst, count = 0, size = 16;
50         char quoted = 0;
51
52         *argv = malloc(sizeof(char*) * size);
53
54         /* split alias_string */
55         (*argv)[count++] = cmdline;
56         for (src = dst = 0; cmdline[src];) {
57                 char c = cmdline[src];
58                 if (!quoted && isspace(c)) {
59                         cmdline[dst++] = 0;
60                         while (cmdline[++src]
61                                         && isspace(cmdline[src]))
62                                 ; /* skip */
63                         if (count >= size) {
64                                 size += 16;
65                                 *argv = realloc(*argv, sizeof(char*) * size);
66                         }
67                         (*argv)[count++] = cmdline + dst;
68                 } else if(!quoted && (c == '\'' || c == '"')) {
69                         quoted = c;
70                         src++;
71                 } else if (c == quoted) {
72                         quoted = 0;
73                         src++;
74                 } else {
75                         if (c == '\\' && quoted != '\'') {
76                                 src++;
77                                 c = cmdline[src];
78                                 if (!c) {
79                                         free(*argv);
80                                         *argv = NULL;
81                                         return error("cmdline ends with \\");
82                                 }
83                         }
84                         cmdline[dst++] = c;
85                         src++;
86                 }
87         }
88
89         cmdline[dst] = 0;
90
91         if (quoted) {
92                 free(*argv);
93                 *argv = NULL;
94                 return error("unclosed quote");
95         }
96
97         return count;
98 }
99
100 static int handle_alias(int *argcp, const char ***argv)
101 {
102         int nongit = 0, ret = 0;
103         const char *subdir;
104
105         subdir = setup_git_directory_gently(&nongit);
106         if (!nongit) {
107                 int count;
108                 const char** new_argv;
109
110                 alias_command = (*argv)[0];
111                 git_config(git_alias_config);
112                 if (alias_string) {
113
114                         count = split_cmdline(alias_string, &new_argv);
115
116                         if (count < 1)
117                                 die("empty alias for %s", alias_command);
118
119                         if (!strcmp(alias_command, new_argv[0]))
120                                 die("recursive alias: %s", alias_command);
121
122                         /* insert after command name */
123                         if (*argcp > 1) {
124                                 new_argv = realloc(new_argv, sizeof(char*) *
125                                                 (count + *argcp - 1));
126                                 memcpy(new_argv + count, *argv, sizeof(char*) *
127                                                 (*argcp - 1));
128                         }
129
130                         *argv = new_argv;
131                         *argcp += count - 1;
132
133                         ret = 1;
134                 }
135         }
136
137         if (subdir)
138                 chdir(subdir);
139
140         return ret;
141 }
142
143 const char git_version_string[] = GIT_VERSION;
144
145 static void handle_internal_command(int argc, const char **argv, char **envp)
146 {
147         const char *cmd = argv[0];
148         static struct cmd_struct {
149                 const char *cmd;
150                 int (*fn)(int, const char **, char **);
151         } commands[] = {
152                 { "version", cmd_version },
153                 { "help", cmd_help },
154                 { "log", cmd_log },
155                 { "whatchanged", cmd_whatchanged },
156                 { "show", cmd_show },
157                 { "push", cmd_push },
158                 { "format-patch", cmd_format_patch },
159                 { "count-objects", cmd_count_objects },
160                 { "diff", cmd_diff },
161                 { "grep", cmd_grep },
162                 { "rm", cmd_rm },
163                 { "add", cmd_add },
164                 { "rev-list", cmd_rev_list },
165                 { "init-db", cmd_init_db },
166                 { "get-tar-commit-id", cmd_get_tar_commit_id },
167                 { "upload-tar", cmd_upload_tar },
168                 { "check-ref-format", cmd_check_ref_format },
169                 { "ls-files", cmd_ls_files },
170                 { "ls-tree", cmd_ls_tree },
171                 { "tar-tree", cmd_tar_tree },
172                 { "read-tree", cmd_read_tree },
173                 { "commit-tree", cmd_commit_tree },
174                 { "apply", cmd_apply },
175                 { "show-branch", cmd_show_branch },
176                 { "diff-files", cmd_diff_files },
177                 { "diff-index", cmd_diff_index },
178                 { "diff-stages", cmd_diff_stages },
179                 { "diff-tree", cmd_diff_tree },
180                 { "cat-file", cmd_cat_file },
181                 { "rev-parse", cmd_rev_parse }
182         };
183         int i;
184
185         /* Turn "git cmd --help" into "git help cmd" */
186         if (argc > 1 && !strcmp(argv[1], "--help")) {
187                 argv[1] = argv[0];
188                 argv[0] = cmd = "help";
189         }
190
191         for (i = 0; i < ARRAY_SIZE(commands); i++) {
192                 struct cmd_struct *p = commands+i;
193                 if (strcmp(p->cmd, cmd))
194                         continue;
195                 exit(p->fn(argc, argv, envp));
196         }
197 }
198
199 int main(int argc, const char **argv, char **envp)
200 {
201         const char *cmd = argv[0];
202         char *slash = strrchr(cmd, '/');
203         char git_command[PATH_MAX + 1];
204         const char *exec_path = NULL;
205         int done_alias = 0;
206
207         /*
208          * Take the basename of argv[0] as the command
209          * name, and the dirname as the default exec_path
210          * if it's an absolute path and we don't have
211          * anything better.
212          */
213         if (slash) {
214                 *slash++ = 0;
215                 if (*cmd == '/')
216                         exec_path = cmd;
217                 cmd = slash;
218         }
219
220         /*
221          * "git-xxxx" is the same as "git xxxx", but we obviously:
222          *
223          *  - cannot take flags in between the "git" and the "xxxx".
224          *  - cannot execute it externally (since it would just do
225          *    the same thing over again)
226          *
227          * So we just directly call the internal command handler, and
228          * die if that one cannot handle it.
229          */
230         if (!strncmp(cmd, "git-", 4)) {
231                 cmd += 4;
232                 argv[0] = cmd;
233                 handle_internal_command(argc, argv, envp);
234                 die("cannot handle %s internally", cmd);
235         }
236
237         /* Default command: "help" */
238         cmd = "help";
239
240         /* Look for flags.. */
241         while (argc > 1) {
242                 cmd = *++argv;
243                 argc--;
244
245                 if (strncmp(cmd, "--", 2))
246                         break;
247
248                 cmd += 2;
249
250                 /*
251                  * For legacy reasons, the "version" and "help"
252                  * commands can be written with "--" prepended
253                  * to make them look like flags.
254                  */
255                 if (!strcmp(cmd, "help"))
256                         break;
257                 if (!strcmp(cmd, "version"))
258                         break;
259
260                 /*
261                  * Check remaining flags (which by now must be
262                  * "--exec-path", but maybe we will accept
263                  * other arguments some day)
264                  */
265                 if (!strncmp(cmd, "exec-path", 9)) {
266                         cmd += 9;
267                         if (*cmd == '=') {
268                                 git_set_exec_path(cmd + 1);
269                                 continue;
270                         }
271                         puts(git_exec_path());
272                         exit(0);
273                 }
274                 cmd_usage(0, NULL, NULL);
275         }
276         argv[0] = cmd;
277
278         /*
279          * We search for git commands in the following order:
280          *  - git_exec_path()
281          *  - the path of the "git" command if we could find it
282          *    in $0
283          *  - the regular PATH.
284          */
285         if (exec_path)
286                 prepend_to_path(exec_path, strlen(exec_path));
287         exec_path = git_exec_path();
288         prepend_to_path(exec_path, strlen(exec_path));
289
290         while (1) {
291                 /* See if it's an internal command */
292                 handle_internal_command(argc, argv, envp);
293
294                 /* .. then try the external ones */
295                 execv_git_cmd(argv);
296
297                 /* It could be an alias -- this works around the insanity
298                  * of overriding "git log" with "git show" by having
299                  * alias.log = show
300                  */
301                 if (done_alias || !handle_alias(&argc, &argv))
302                         break;
303                 done_alias = 1;
304         }
305
306         if (errno == ENOENT)
307                 cmd_usage(0, exec_path, "'%s' is not a git-command", cmd);
308
309         fprintf(stderr, "Failed to run command '%s': %s\n",
310                 git_command, strerror(errno));
311
312         return 1;
313 }