C implementation of the 'git' program, take two.
[git/git.git] / git.c
... / ...
CommitLineData
1#include <stdio.h>
2#include <unistd.h>
3#include <stdlib.h>
4#include <string.h>
5#include <errno.h>
6#include <limits.h>
7#include <stdarg.h>
8#include <glob.h>
9
10#ifndef PATH_MAX
11# define PATH_MAX 4096
12#endif
13
14static const char git_usage[] =
15 "Usage: git [--version] [--exec-path[=GIT_EXEC_PATH]] [--help] COMMAND [ ARGS ]";
16
17struct string_list {
18 size_t len;
19 char *str;
20 struct string_list *next;
21};
22
23/* most gui terms set COLUMNS (although some don't export it) */
24static 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
35static inline void mput_char(char c, unsigned int num)
36{
37 while(num--)
38 putchar(c);
39}
40
41static void pretty_print_string_list(struct string_list *list, int longest)
42{
43 int cols = 1;
44 int space = longest + 1; /* min 1 SP between words */
45 int max_cols = term_columns() - 1; /* don't print *on* the edge */
46
47 if (space < max_cols)
48 cols = max_cols / space;
49
50 while (list) {
51 int c;
52 printf(" ");
53
54 for (c = cols; c && list; list = list->next) {
55 printf("%s", list->str);
56
57 if (--c)
58 mput_char(' ', space - list->len);
59 }
60 putchar('\n');
61 }
62}
63
64static void list_commands(const char *exec_path, const char *pattern)
65{
66 struct string_list *list = NULL, *tail = NULL;
67 unsigned int longest = 0, i;
68 glob_t gl;
69
70 if (chdir(exec_path) < 0) {
71 printf("git: '%s': %s\n", exec_path, strerror(errno));
72 exit(1);
73 }
74
75 i = glob(pattern, 0, NULL, &gl);
76 switch(i) {
77 case GLOB_NOSPACE:
78 puts("Out of memory when running glob()");
79 exit(2);
80 case GLOB_ABORTED:
81 printf("'%s': Read error: %s\n", exec_path, strerror(errno));
82 exit(2);
83 case GLOB_NOMATCH:
84 printf("No git commands available in '%s'.\n", exec_path);
85 printf("Do you need to specify --exec-path or set GIT_EXEC_PATH?\n");
86 exit(1);
87 }
88
89 for (i = 0; i < gl.gl_pathc; i++) {
90 int len = strlen(gl.gl_pathv[i] + 4);
91
92 if (access(gl.gl_pathv[i], X_OK))
93 continue;
94
95 if (longest < len)
96 longest = len;
97
98 if (!tail)
99 tail = list = malloc(sizeof(struct string_list));
100 else {
101 tail->next = malloc(sizeof(struct string_list));
102 tail = tail->next;
103 }
104 tail->len = len;
105 tail->str = gl.gl_pathv[i] + 4;
106 tail->next = NULL;
107 }
108
109 printf("git commands available in '%s'\n", exec_path);
110 printf("----------------------------");
111 mput_char('-', strlen(exec_path));
112 putchar('\n');
113 pretty_print_string_list(list, longest);
114 putchar('\n');
115}
116
117#ifdef __GNUC__
118static void usage(const char *exec_path, const char *fmt, ...)
119 __attribute__((__format__(__printf__, 2, 3), __noreturn__));
120#endif
121static void usage(const char *exec_path, const char *fmt, ...)
122{
123 if (fmt) {
124 va_list ap;
125
126 va_start(ap, fmt);
127 printf("git: ");
128 vprintf(fmt, ap);
129 va_end(ap);
130 putchar('\n');
131 }
132 else
133 puts(git_usage);
134
135 putchar('\n');
136
137 if(exec_path)
138 list_commands(exec_path, "git-*");
139
140 exit(1);
141}
142
143static void prepend_to_path(const char *dir, int len)
144{
145 char *path, *old_path = getenv("PATH");
146 int path_len = len;
147
148 if (!old_path)
149 old_path = "/bin:/usr/bin:.";
150
151 path_len = len + strlen(old_path) + 1;
152
153 path = malloc(path_len + 1);
154 path[path_len + 1] = '\0';
155
156 memcpy(path, dir, len);
157 path[len] = ':';
158 memcpy(path + len + 1, old_path, path_len - len);
159
160 setenv("PATH", path, 1);
161}
162
163int main(int argc, char **argv, char **envp)
164{
165 char git_command[PATH_MAX + 1];
166 char wd[PATH_MAX + 1];
167 int i, len, show_help = 0;
168 char *exec_path = getenv("GIT_EXEC_PATH");
169
170 getcwd(wd, PATH_MAX);
171
172 if (!exec_path)
173 exec_path = GIT_EXEC_PATH;
174
175 for (i = 1; i < argc; i++) {
176 char *arg = argv[i];
177
178 if (strncmp(arg, "--", 2))
179 break;
180
181 arg += 2;
182
183 if (!strncmp(arg, "exec-path", 9)) {
184 arg += 9;
185 if (*arg == '=')
186 exec_path = arg + 1;
187 else {
188 puts(exec_path);
189 exit(0);
190 }
191 }
192 else if (!strcmp(arg, "version")) {
193 printf("git version %s\n", GIT_VERSION);
194 exit(0);
195 }
196 else if (!strcmp(arg, "help"))
197 show_help = 1;
198 else if (!show_help)
199 usage(NULL, NULL);
200 }
201
202 if (i >= argc || show_help)
203 usage(exec_path, NULL);
204
205 /* allow relative paths, but run with exact */
206 if (chdir(exec_path)) {
207 printf("git: '%s': %s\n", exec_path, strerror(errno));
208 exit (1);
209 }
210
211 getcwd(git_command, sizeof(git_command));
212 chdir(wd);
213
214 len = strlen(git_command);
215 prepend_to_path(git_command, len);
216
217 strncat(&git_command[len], "/git-", sizeof(git_command) - len);
218 len += 5;
219 strncat(&git_command[len], argv[i], sizeof(git_command) - len);
220
221 if (access(git_command, X_OK))
222 usage(exec_path, "'%s' is not a git-command", argv[i]);
223
224 /* execve() can only ever return if it fails */
225 execve(git_command, &argv[i], envp);
226 printf("Failed to run command '%s': %s\n", git_command, strerror(errno));
227
228 return 1;
229}