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