ee5048aaaa2f814f00a6a3fb937bf0d15e46f50c
[git/git.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
12 #ifndef PATH_MAX
13 # define PATH_MAX 4096
14 #endif
15
16 #ifdef NO_SETENV
17 extern int gitsetenv(const char *, const char *, int);
18 #endif
19
20 static const char git_usage[] =
21 "Usage: git [--version] [--exec-path[=GIT_EXEC_PATH]] [--help] COMMAND [ ARGS ]";
22
23 /* most gui terms set COLUMNS (although some don't export it) */
24 static int term_columns(void)
25 {
26 char *col_string = getenv("COLUMNS");
27 int n_cols = 0;
28
29 if (col_string && (n_cols = atoi(col_string)) > 0)
30 return n_cols;
31
32 return 80;
33 }
34
35 static void oom(void)
36 {
37 fprintf(stderr, "git: out of memory\n");
38 exit(1);
39 }
40
41 static inline void mput_char(char c, unsigned int num)
42 {
43 while(num--)
44 putchar(c);
45 }
46
47 static struct cmdname {
48 size_t len;
49 char name[1];
50 } **cmdname;
51 static int cmdname_alloc, cmdname_cnt;
52
53 static void add_cmdname(const char *name, int len)
54 {
55 struct cmdname *ent;
56 if (cmdname_alloc <= cmdname_cnt) {
57 cmdname_alloc = cmdname_alloc + 200;
58 cmdname = realloc(cmdname, cmdname_alloc * sizeof(*cmdname));
59 if (!cmdname)
60 oom();
61 }
62 ent = malloc(sizeof(*ent) + len);
63 if (!ent)
64 oom();
65 ent->len = len;
66 memcpy(ent->name, name, len);
67 ent->name[len] = 0;
68 cmdname[cmdname_cnt++] = ent;
69 }
70
71 static int cmdname_compare(const void *a_, const void *b_)
72 {
73 struct cmdname *a = *(struct cmdname **)a_;
74 struct cmdname *b = *(struct cmdname **)b_;
75 return strcmp(a->name, b->name);
76 }
77
78 static void pretty_print_string_list(struct cmdname **cmdname, int longest)
79 {
80 int cols = 1;
81 int space = longest + 1; /* min 1 SP between words */
82 int max_cols = term_columns() - 1; /* don't print *on* the edge */
83 int i;
84
85 if (space < max_cols)
86 cols = max_cols / space;
87
88 qsort(cmdname, cmdname_cnt, sizeof(*cmdname), cmdname_compare);
89
90 for (i = 0; i < cmdname_cnt; ) {
91 int c;
92 printf(" ");
93
94 for (c = cols; c && i < cmdname_cnt; i++) {
95 printf("%s", cmdname[i]->name);
96
97 if (--c)
98 mput_char(' ', space - cmdname[i]->len);
99 }
100 putchar('\n');
101 }
102 }
103
104 static void list_commands(const char *exec_path, const char *pattern)
105 {
106 unsigned int longest = 0;
107 char path[PATH_MAX];
108 int dirlen;
109 DIR *dir = opendir(exec_path);
110 struct dirent *de;
111
112 if (!dir) {
113 fprintf(stderr, "git: '%s': %s\n", exec_path, strerror(errno));
114 exit(1);
115 }
116
117 dirlen = strlen(exec_path);
118 if (PATH_MAX - 20 < dirlen) {
119 fprintf(stderr, "git: insanely long exec-path '%s'\n",
120 exec_path);
121 exit(1);
122 }
123
124 memcpy(path, exec_path, dirlen);
125 path[dirlen++] = '/';
126
127 while ((de = readdir(dir)) != NULL) {
128 struct stat st;
129 int entlen;
130
131 if (strncmp(de->d_name, "git-", 4))
132 continue;
133 strcpy(path+dirlen, de->d_name);
134 if (stat(path, &st) || /* stat, not lstat */
135 !S_ISREG(st.st_mode) ||
136 !(st.st_mode & S_IXUSR))
137 continue;
138
139 entlen = strlen(de->d_name);
140 if (4 < entlen && !strcmp(de->d_name + entlen - 4, ".exe"))
141 entlen -= 4;
142
143 if (longest < entlen)
144 longest = entlen;
145
146 add_cmdname(de->d_name + 4, entlen-4);
147 }
148 closedir(dir);
149
150 printf("git commands available in '%s'\n", exec_path);
151 printf("----------------------------");
152 mput_char('-', strlen(exec_path));
153 putchar('\n');
154 pretty_print_string_list(cmdname, longest - 4);
155 putchar('\n');
156 }
157
158 #ifdef __GNUC__
159 static void usage(const char *exec_path, const char *fmt, ...)
160 __attribute__((__format__(__printf__, 2, 3), __noreturn__));
161 #endif
162 static void usage(const char *exec_path, const char *fmt, ...)
163 {
164 if (fmt) {
165 va_list ap;
166
167 va_start(ap, fmt);
168 printf("git: ");
169 vprintf(fmt, ap);
170 va_end(ap);
171 putchar('\n');
172 }
173 else
174 puts(git_usage);
175
176 putchar('\n');
177
178 if(exec_path)
179 list_commands(exec_path, "git-*");
180
181 exit(1);
182 }
183
184 static void prepend_to_path(const char *dir, int len)
185 {
186 char *path, *old_path = getenv("PATH");
187 int path_len = len;
188
189 if (!old_path)
190 old_path = "/usr/local/bin:/usr/bin:/bin";
191
192 path_len = len + strlen(old_path) + 1;
193
194 path = malloc(path_len + 1);
195
196 memcpy(path, dir, len);
197 path[len] = ':';
198 memcpy(path + len + 1, old_path, path_len - len);
199
200 setenv("PATH", path, 1);
201 }
202
203 static void show_man_page(char *git_cmd)
204 {
205 char *page;
206
207 if (!strncmp(git_cmd, "git", 3))
208 page = git_cmd;
209 else {
210 int page_len = strlen(git_cmd) + 4;
211
212 page = malloc(page_len + 1);
213 strcpy(page, "git-");
214 strcpy(page + 4, git_cmd);
215 page[page_len] = 0;
216 }
217
218 execlp("man", "man", page, NULL);
219 }
220
221 int main(int argc, char **argv, char **envp)
222 {
223 char git_command[PATH_MAX + 1];
224 char wd[PATH_MAX + 1];
225 int i, len, show_help = 0;
226 char *exec_path = getenv("GIT_EXEC_PATH");
227
228 getcwd(wd, PATH_MAX);
229
230 if (!exec_path)
231 exec_path = GIT_EXEC_PATH;
232
233 for (i = 1; i < argc; i++) {
234 char *arg = argv[i];
235
236 if (strncmp(arg, "--", 2))
237 break;
238
239 arg += 2;
240
241 if (!strncmp(arg, "exec-path", 9)) {
242 arg += 9;
243 if (*arg == '=')
244 exec_path = arg + 1;
245 else {
246 puts(exec_path);
247 exit(0);
248 }
249 }
250 else if (!strcmp(arg, "version")) {
251 printf("git version %s\n", GIT_VERSION);
252 exit(0);
253 }
254 else if (!strcmp(arg, "help"))
255 show_help = 1;
256 else if (!show_help)
257 usage(NULL, NULL);
258 }
259
260 if (i >= argc || show_help) {
261 if (i >= argc)
262 usage(exec_path, NULL);
263
264 show_man_page(argv[i]);
265 }
266
267 if (*exec_path != '/') {
268 if (!getcwd(git_command, sizeof(git_command))) {
269 fprintf(stderr,
270 "git: cannot determine current directory");
271 exit(1);
272 }
273 len = strlen(git_command);
274
275 /* Trivial cleanup */
276 while (!strncmp(exec_path, "./", 2)) {
277 exec_path += 2;
278 while (*exec_path == '/')
279 exec_path++;
280 }
281 snprintf(git_command + len, sizeof(git_command) - len,
282 "/%s", exec_path);
283 }
284 else
285 strcpy(git_command, exec_path);
286 len = strlen(git_command);
287 prepend_to_path(git_command, len);
288
289 len += snprintf(git_command + len, sizeof(git_command) - len,
290 "/git-%s", argv[i]);
291 if (sizeof(git_command) <= len) {
292 fprintf(stderr, "git: command name given is too long.\n");
293 exit(1);
294 }
295
296 /* execve() can only ever return if it fails */
297 execve(git_command, &argv[i], envp);
298
299 if (errno == ENOENT)
300 usage(exec_path, "'%s' is not a git-command", argv[i]);
301
302 fprintf(stderr, "Failed to run command '%s': %s\n",
303 git_command, strerror(errno));
304
305 return 1;
306 }