Exec git programs without using PATH.
[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 #include <sys/ioctl.h>
12 #include "git-compat-util.h"
13 #include "exec_cmd.h"
14
15 #ifndef PATH_MAX
16 # define PATH_MAX 4096
17 #endif
18
19 static const char git_usage[] =
20 "Usage: git [--version] [--exec-path[=GIT_EXEC_PATH]] [--help] COMMAND [ ARGS ]";
21
22 /* most gui terms set COLUMNS (although some don't export it) */
23 static int term_columns(void)
24 {
25 char *col_string = getenv("COLUMNS");
26 int n_cols = 0;
27
28 if (col_string && (n_cols = atoi(col_string)) > 0)
29 return n_cols;
30
31 #ifdef TIOCGWINSZ
32 {
33 struct winsize ws;
34 if (!ioctl(1, TIOCGWINSZ, &ws)) {
35 if (ws.ws_col)
36 return ws.ws_col;
37 }
38 }
39 #endif
40
41 return 80;
42 }
43
44 static void oom(void)
45 {
46 fprintf(stderr, "git: out of memory\n");
47 exit(1);
48 }
49
50 static inline void mput_char(char c, unsigned int num)
51 {
52 while(num--)
53 putchar(c);
54 }
55
56 static struct cmdname {
57 size_t len;
58 char name[1];
59 } **cmdname;
60 static int cmdname_alloc, cmdname_cnt;
61
62 static void add_cmdname(const char *name, int len)
63 {
64 struct cmdname *ent;
65 if (cmdname_alloc <= cmdname_cnt) {
66 cmdname_alloc = cmdname_alloc + 200;
67 cmdname = realloc(cmdname, cmdname_alloc * sizeof(*cmdname));
68 if (!cmdname)
69 oom();
70 }
71 ent = malloc(sizeof(*ent) + len);
72 if (!ent)
73 oom();
74 ent->len = len;
75 memcpy(ent->name, name, len);
76 ent->name[len] = 0;
77 cmdname[cmdname_cnt++] = ent;
78 }
79
80 static int cmdname_compare(const void *a_, const void *b_)
81 {
82 struct cmdname *a = *(struct cmdname **)a_;
83 struct cmdname *b = *(struct cmdname **)b_;
84 return strcmp(a->name, b->name);
85 }
86
87 static void pretty_print_string_list(struct cmdname **cmdname, int longest)
88 {
89 int cols = 1, rows;
90 int space = longest + 1; /* min 1 SP between words */
91 int max_cols = term_columns() - 1; /* don't print *on* the edge */
92 int i, j;
93
94 if (space < max_cols)
95 cols = max_cols / space;
96 rows = (cmdname_cnt + cols - 1) / cols;
97
98 qsort(cmdname, cmdname_cnt, sizeof(*cmdname), cmdname_compare);
99
100 for (i = 0; i < rows; i++) {
101 printf(" ");
102
103 for (j = 0; j < cols; j++) {
104 int n = j * rows + i;
105 int size = space;
106 if (n >= cmdname_cnt)
107 break;
108 if (j == cols-1 || n + rows >= cmdname_cnt)
109 size = 1;
110 printf("%-*s", size, cmdname[n]->name);
111 }
112 putchar('\n');
113 }
114 }
115
116 static void list_commands(const char *exec_path, const char *pattern)
117 {
118 unsigned int longest = 0;
119 char path[PATH_MAX];
120 int dirlen;
121 DIR *dir = opendir(exec_path);
122 struct dirent *de;
123
124 if (!dir) {
125 fprintf(stderr, "git: '%s': %s\n", exec_path, strerror(errno));
126 exit(1);
127 }
128
129 dirlen = strlen(exec_path);
130 if (PATH_MAX - 20 < dirlen) {
131 fprintf(stderr, "git: insanely long exec-path '%s'\n",
132 exec_path);
133 exit(1);
134 }
135
136 memcpy(path, exec_path, dirlen);
137 path[dirlen++] = '/';
138
139 while ((de = readdir(dir)) != NULL) {
140 struct stat st;
141 int entlen;
142
143 if (strncmp(de->d_name, "git-", 4))
144 continue;
145 strcpy(path+dirlen, de->d_name);
146 if (stat(path, &st) || /* stat, not lstat */
147 !S_ISREG(st.st_mode) ||
148 !(st.st_mode & S_IXUSR))
149 continue;
150
151 entlen = strlen(de->d_name);
152 if (4 < entlen && !strcmp(de->d_name + entlen - 4, ".exe"))
153 entlen -= 4;
154
155 if (longest < entlen)
156 longest = entlen;
157
158 add_cmdname(de->d_name + 4, entlen-4);
159 }
160 closedir(dir);
161
162 printf("git commands available in '%s'\n", exec_path);
163 printf("----------------------------");
164 mput_char('-', strlen(exec_path));
165 putchar('\n');
166 pretty_print_string_list(cmdname, longest - 4);
167 putchar('\n');
168 }
169
170 #ifdef __GNUC__
171 static void cmd_usage(const char *exec_path, const char *fmt, ...)
172 __attribute__((__format__(__printf__, 2, 3), __noreturn__));
173 #endif
174 static void cmd_usage(const char *exec_path, const char *fmt, ...)
175 {
176 if (fmt) {
177 va_list ap;
178
179 va_start(ap, fmt);
180 printf("git: ");
181 vprintf(fmt, ap);
182 va_end(ap);
183 putchar('\n');
184 }
185 else
186 puts(git_usage);
187
188 putchar('\n');
189
190 if(exec_path)
191 list_commands(exec_path, "git-*");
192
193 exit(1);
194 }
195
196 static void prepend_to_path(const char *dir, int len)
197 {
198 char *path, *old_path = getenv("PATH");
199 int path_len = len;
200
201 if (!old_path)
202 old_path = "/usr/local/bin:/usr/bin:/bin";
203
204 path_len = len + strlen(old_path) + 1;
205
206 path = malloc(path_len + 1);
207
208 memcpy(path, dir, len);
209 path[len] = ':';
210 memcpy(path + len + 1, old_path, path_len - len);
211
212 setenv("PATH", path, 1);
213 }
214
215 static void show_man_page(char *git_cmd)
216 {
217 char *page;
218
219 if (!strncmp(git_cmd, "git", 3))
220 page = git_cmd;
221 else {
222 int page_len = strlen(git_cmd) + 4;
223
224 page = malloc(page_len + 1);
225 strcpy(page, "git-");
226 strcpy(page + 4, git_cmd);
227 page[page_len] = 0;
228 }
229
230 execlp("man", "man", page, NULL);
231 }
232
233 int main(int argc, char **argv, char **envp)
234 {
235 char git_command[PATH_MAX + 1];
236 char wd[PATH_MAX + 1];
237 int i, show_help = 0;
238 const char *exec_path;
239
240 getcwd(wd, PATH_MAX);
241
242 for (i = 1; i < argc; i++) {
243 char *arg = argv[i];
244
245 if (!strcmp(arg, "help")) {
246 show_help = 1;
247 continue;
248 }
249
250 if (strncmp(arg, "--", 2))
251 break;
252
253 arg += 2;
254
255 if (!strncmp(arg, "exec-path", 9)) {
256 arg += 9;
257 if (*arg == '=') {
258 exec_path = arg + 1;
259 git_set_exec_path(exec_path);
260 } else {
261 puts(git_exec_path());
262 exit(0);
263 }
264 }
265 else if (!strcmp(arg, "version")) {
266 printf("git version %s\n", GIT_VERSION);
267 exit(0);
268 }
269 else if (!strcmp(arg, "help"))
270 show_help = 1;
271 else if (!show_help)
272 cmd_usage(NULL, NULL);
273 }
274
275 if (i >= argc || show_help) {
276 if (i >= argc)
277 cmd_usage(git_exec_path(), NULL);
278
279 show_man_page(argv[i]);
280 }
281
282 exec_path = git_exec_path();
283 prepend_to_path(exec_path, strlen(exec_path));
284
285 execv_git_cmd(argv + i);
286
287 if (errno == ENOENT)
288 cmd_usage(exec_path, "'%s' is not a git-command", argv[i]);
289
290 fprintf(stderr, "Failed to run command '%s': %s\n",
291 git_command, strerror(errno));
292
293 return 1;
294 }