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 #include "quote.h"
  15
  16 #include "builtin.h"
  17
  18 static void prepend_to_path(const char *dir, int len)
  19 {
  20         const char *old_path = getenv("PATH");
  21         char *path;
  22         int path_len = len;
  23
  24         if (!old_path)
  25                 old_path = "/usr/local/bin:/usr/bin:/bin";
  26
  27         path_len = len + strlen(old_path) + 1;
  28
  29         path = malloc(path_len + 1);
  30
  31         memcpy(path, dir, len);
  32         path[len] = ':';
  33         memcpy(path + len + 1, old_path, path_len - len);
  34
  35         setenv("PATH", path, 1);
  36 }
  37
  38 static int handle_options(const char*** argv, int* argc)
  39 {
  40         int handled = 0;
  41
  42         while (*argc > 0) {
  43                 const char *cmd = (*argv)[0];
  44                 if (cmd[0] != '-')
  45                         break;
  46
  47                 /*
  48                  * For legacy reasons, the "version" and "help"
  49                  * commands can be written with "--" prepended
  50                  * to make them look like flags.
  51                  */
  52                 if (!strcmp(cmd, "--help") || !strcmp(cmd, "--version"))
  53                         break;
  54
  55                 /*
  56                  * Check remaining flags.
  57                  */
  58                 if (!strncmp(cmd, "--exec-path", 11)) {
  59                         cmd += 11;
  60                         if (*cmd == '=')
  61                                 git_set_exec_path(cmd + 1);
  62                         else {
  63                                 puts(git_exec_path());
  64                                 exit(0);
  65                         }
  66                 } else if (!strcmp(cmd, "-p") || !strcmp(cmd, "--paginate")) {
  67                         setup_pager();
  68                 } else if (!strcmp(cmd, "--git-dir")) {
  69                         if (*argc < 1)
  70                                 return -1;
  71                         setenv("GIT_DIR", (*argv)[1], 1);
  72                         (*argv)++;
  73                         (*argc)--;
  74                 } else if (!strncmp(cmd, "--git-dir=", 10)) {
  75                         setenv("GIT_DIR", cmd + 10, 1);
  76                 } else if (!strcmp(cmd, "--bare")) {
  77                         static char git_dir[1024];
  78                         setenv("GIT_DIR", getcwd(git_dir, 1024), 1);
  79                 } else {
  80                         fprintf(stderr, "Unknown option: %s\n", cmd);
  81                         cmd_usage(0, NULL, NULL);
  82                 }
  83
  84                 (*argv)++;
  85                 (*argc)--;
  86                 handled++;
  87         }
  88         return handled;
  89 }
  90
  91 static const char *alias_command;
  92 static char *alias_string = NULL;
  93
  94 static int git_alias_config(const char *var, const char *value)
  95 {
  96         if (!strncmp(var, "alias.", 6) && !strcmp(var + 6, alias_command)) {
  97                 alias_string = strdup(value);
  98         }
  99         return 0;
 100 }
 101
 102 static int split_cmdline(char *cmdline, const char ***argv)
 103 {
 104         int src, dst, count = 0, size = 16;
 105         char quoted = 0;
 106
 107         *argv = malloc(sizeof(char*) * size);
 108
 109         /* split alias_string */
 110         (*argv)[count++] = cmdline;
 111         for (src = dst = 0; cmdline[src];) {
 112                 char c = cmdline[src];
 113                 if (!quoted && isspace(c)) {
 114                         cmdline[dst++] = 0;
 115                         while (cmdline[++src]
 116                                         && isspace(cmdline[src]))
 117                                 ; /* skip */
 118                         if (count >= size) {
 119                                 size += 16;
 120                                 *argv = realloc(*argv, sizeof(char*) * size);
 121                         }
 122                         (*argv)[count++] = cmdline + dst;
 123                 } else if(!quoted && (c == '\'' || c == '"')) {
 124                         quoted = c;
 125                         src++;
 126                 } else if (c == quoted) {
 127                         quoted = 0;
 128                         src++;
 129                 } else {
 130                         if (c == '\\' && quoted != '\'') {
 131                                 src++;
 132                                 c = cmdline[src];
 133                                 if (!c) {
 134                                         free(*argv);
 135                                         *argv = NULL;
 136                                         return error("cmdline ends with \\");
 137                                 }
 138                         }
 139                         cmdline[dst++] = c;
 140                         src++;
 141                 }
 142         }
 143
 144         cmdline[dst] = 0;
 145
 146         if (quoted) {
 147                 free(*argv);
 148                 *argv = NULL;
 149                 return error("unclosed quote");
 150         }
 151
 152         return count;
 153 }
 154
 155 static int handle_alias(int *argcp, const char ***argv)
 156 {
 157         int nongit = 0, ret = 0, saved_errno = errno;
 158         const char *subdir;
 159         int count, option_count;
 160         const char** new_argv;
 161
 162         subdir = setup_git_directory_gently(&nongit);
 163
 164         alias_command = (*argv)[0];
 165         git_config(git_alias_config);
 166         if (alias_string) {
 167                 count = split_cmdline(alias_string, &new_argv);
 168                 option_count = handle_options(&new_argv, &count);
 169                 memmove(new_argv - option_count, new_argv,
 170                                 count * sizeof(char *));
 171                 new_argv -= option_count;
 172
 173                 if (count < 1)
 174                         die("empty alias for %s", alias_command);
 175
 176                 if (!strcmp(alias_command, new_argv[0]))
 177                         die("recursive alias: %s", alias_command);
 178
 179                 if (getenv("GIT_TRACE")) {
 180                         int i;
 181                         fprintf(stderr, "trace: alias expansion: %s =>",
 182                                 alias_command);
 183                         for (i = 0; i < count; ++i) {
 184                                 fputc(' ', stderr);
 185                                 sq_quote_print(stderr, new_argv[i]);
 186                         }
 187                         fputc('\n', stderr);
 188                         fflush(stderr);
 189                 }
 190
 191                 new_argv = realloc(new_argv, sizeof(char*) *
 192                                    (count + *argcp + 1));
 193                 /* insert after command name */
 194                 memcpy(new_argv + count, *argv + 1, sizeof(char*) * *argcp);
 195                 new_argv[count+*argcp] = NULL;
 196
 197                 *argv = new_argv;
 198                 *argcp += count - 1;
 199
 200                 ret = 1;
 201         }
 202
 203         if (subdir)
 204                 chdir(subdir);
 205
 206         errno = saved_errno;
 207
 208         return ret;
 209 }
 210
 211 const char git_version_string[] = GIT_VERSION;
 212
 213 #define NEEDS_PREFIX 1
 214
 215 static void handle_internal_command(int argc, const char **argv, char **envp)
 216 {
 217         const char *cmd = argv[0];
 218         static struct cmd_struct {
 219                 const char *cmd;
 220                 int (*fn)(int, const char **, const char *);
 221                 int prefix;
 222         } commands[] = {
 223                 { "version", cmd_version },
 224                 { "help", cmd_help },
 225                 { "log", cmd_log, NEEDS_PREFIX },
 226                 { "whatchanged", cmd_whatchanged, NEEDS_PREFIX },
 227                 { "show", cmd_show, NEEDS_PREFIX },
 228                 { "push", cmd_push },
 229                 { "format-patch", cmd_format_patch, NEEDS_PREFIX },
 230                 { "count-objects", cmd_count_objects },
 231                 { "diff", cmd_diff, NEEDS_PREFIX },
 232                 { "grep", cmd_grep, NEEDS_PREFIX },
 233                 { "rm", cmd_rm, NEEDS_PREFIX },
 234                 { "add", cmd_add, NEEDS_PREFIX },
 235                 { "rev-list", cmd_rev_list, NEEDS_PREFIX },
 236                 { "init-db", cmd_init_db },
 237                 { "get-tar-commit-id", cmd_get_tar_commit_id },
 238                 { "upload-tar", cmd_upload_tar },
 239                 { "check-ref-format", cmd_check_ref_format },
 240                 { "ls-files", cmd_ls_files, NEEDS_PREFIX },
 241                 { "ls-tree", cmd_ls_tree, NEEDS_PREFIX },
 242                 { "tar-tree", cmd_tar_tree, NEEDS_PREFIX },
 243                 { "read-tree", cmd_read_tree, NEEDS_PREFIX },
 244                 { "commit-tree", cmd_commit_tree, NEEDS_PREFIX },
 245                 { "apply", cmd_apply },
 246                 { "show-branch", cmd_show_branch, NEEDS_PREFIX },
 247                 { "diff-files", cmd_diff_files, NEEDS_PREFIX },
 248                 { "diff-index", cmd_diff_index, NEEDS_PREFIX },
 249                 { "diff-stages", cmd_diff_stages, NEEDS_PREFIX },
 250                 { "diff-tree", cmd_diff_tree, NEEDS_PREFIX },
 251                 { "cat-file", cmd_cat_file, NEEDS_PREFIX },
 252                 { "rev-parse", cmd_rev_parse, NEEDS_PREFIX },
 253                 { "write-tree", cmd_write_tree, NEEDS_PREFIX },
 254                 { "mailsplit", cmd_mailsplit },
 255                 { "mailinfo", cmd_mailinfo },
 256                 { "stripspace", cmd_stripspace },
 257                 { "update-index", cmd_update_index, NEEDS_PREFIX },
 258                 { "update-ref", cmd_update_ref, NEEDS_PREFIX },
 259                 { "fmt-merge-msg", cmd_fmt_merge_msg, NEEDS_PREFIX },
 260                 { "prune", cmd_prune, NEEDS_PREFIX },
 261                 { "mv", cmd_mv, NEEDS_PREFIX },
 262         };
 263         int i;
 264
 265         /* Turn "git cmd --help" into "git help cmd" */
 266         if (argc > 1 && !strcmp(argv[1], "--help")) {
 267                 argv[1] = argv[0];
 268                 argv[0] = cmd = "help";
 269         }
 270
 271         for (i = 0; i < ARRAY_SIZE(commands); i++) {
 272                 struct cmd_struct *p = commands+i;
 273                 const char *prefix;
 274                 if (strcmp(p->cmd, cmd))
 275                         continue;
 276
 277                 prefix = NULL;
 278                 if (p->prefix)
 279                         prefix = setup_git_directory();
 280                 if (getenv("GIT_TRACE")) {
 281                         int i;
 282                         fprintf(stderr, "trace: built-in: git");
 283                         for (i = 0; i < argc; ++i) {
 284                                 fputc(' ', stderr);
 285                                 sq_quote_print(stderr, argv[i]);
 286                         }
 287                         putc('\n', stderr);
 288                         fflush(stderr);
 289                 }
 290
 291                 exit(p->fn(argc, argv, prefix));
 292         }
 293 }
 294
 295 int main(int argc, const char **argv, char **envp)
 296 {
 297         const char *cmd = argv[0];
 298         char *slash = strrchr(cmd, '/');
 299         const char *exec_path = NULL;
 300         int done_alias = 0;
 301
 302         /*
 303          * Take the basename of argv[0] as the command
 304          * name, and the dirname as the default exec_path
 305          * if it's an absolute path and we don't have
 306          * anything better.
 307          */
 308         if (slash) {
 309                 *slash++ = 0;
 310                 if (*cmd == '/')
 311                         exec_path = cmd;
 312                 cmd = slash;
 313         }
 314
 315         /*
 316          * "git-xxxx" is the same as "git xxxx", but we obviously:
 317          *
 318          *  - cannot take flags in between the "git" and the "xxxx".
 319          *  - cannot execute it externally (since it would just do
 320          *    the same thing over again)
 321          *
 322          * So we just directly call the internal command handler, and
 323          * die if that one cannot handle it.
 324          */
 325         if (!strncmp(cmd, "git-", 4)) {
 326                 cmd += 4;
 327                 argv[0] = cmd;
 328                 handle_internal_command(argc, argv, envp);
 329                 die("cannot handle %s internally", cmd);
 330         }
 331
 332         /* Look for flags.. */
 333         argv++;
 334         argc--;
 335         handle_options(&argv, &argc);
 336         if (argc > 0) {
 337                 if (!strncmp(argv[0], "--", 2))
 338                         argv[0] += 2;
 339         } else {
 340                 /* Default command: "help" */
 341                 argv[0] = "help";
 342                 argc = 1;
 343         }
 344         cmd = argv[0];
 345
 346         /*
 347          * We search for git commands in the following order:
 348          *  - git_exec_path()
 349          *  - the path of the "git" command if we could find it
 350          *    in $0
 351          *  - the regular PATH.
 352          */
 353         if (exec_path)
 354                 prepend_to_path(exec_path, strlen(exec_path));
 355         exec_path = git_exec_path();
 356         prepend_to_path(exec_path, strlen(exec_path));
 357
 358         while (1) {
 359                 /* See if it's an internal command */
 360                 handle_internal_command(argc, argv, envp);
 361
 362                 /* .. then try the external ones */
 363                 execv_git_cmd(argv);
 364
 365                 /* It could be an alias -- this works around the insanity
 366                  * of overriding "git log" with "git show" by having
 367                  * alias.log = show
 368                  */
 369                 if (done_alias || !handle_alias(&argc, &argv))
 370                         break;
 371                 done_alias = 1;
 372         }
 373
 374         if (errno == ENOENT)
 375                 cmd_usage(0, exec_path, "'%s' is not a git-command", cmd);
 376
 377         fprintf(stderr, "Failed to run command '%s': %s\n",
 378                 cmd, strerror(errno));
 379
 380         return 1;
 381 }