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 const char git_usage_string[] =
  19         "git [--version] [--exec-path[=GIT_EXEC_PATH]] [--help] COMMAND [ ARGS ]";
  20
  21 static void prepend_to_path(const char *dir, int len)
  22 {
  23         const char *old_path = getenv("PATH");
  24         char *path;
  25         int path_len = len;
  26
  27         if (!old_path)
  28                 old_path = "/usr/local/bin:/usr/bin:/bin";
  29
  30         path_len = len + strlen(old_path) + 1;
  31
  32         path = malloc(path_len + 1);
  33
  34         memcpy(path, dir, len);
  35         path[len] = ':';
  36         memcpy(path + len + 1, old_path, path_len - len);
  37
  38         setenv("PATH", path, 1);
  39 }
  40
  41 static int handle_options(const char*** argv, int* argc)
  42 {
  43         int handled = 0;
  44
  45         while (*argc > 0) {
  46                 const char *cmd = (*argv)[0];
  47                 if (cmd[0] != '-')
  48                         break;
  49
  50                 /*
  51                  * For legacy reasons, the "version" and "help"
  52                  * commands can be written with "--" prepended
  53                  * to make them look like flags.
  54                  */
  55                 if (!strcmp(cmd, "--help") || !strcmp(cmd, "--version"))
  56                         break;
  57
  58                 /*
  59                  * Check remaining flags.
  60                  */
  61                 if (!strncmp(cmd, "--exec-path", 11)) {
  62                         cmd += 11;
  63                         if (*cmd == '=')
  64                                 git_set_exec_path(cmd + 1);
  65                         else {
  66                                 puts(git_exec_path());
  67                                 exit(0);
  68                         }
  69                 } else if (!strcmp(cmd, "-p") || !strcmp(cmd, "--paginate")) {
  70                         setup_pager();
  71                 } else if (!strcmp(cmd, "--git-dir")) {
  72                         if (*argc < 1)
  73                                 return -1;
  74                         setenv("GIT_DIR", (*argv)[1], 1);
  75                         (*argv)++;
  76                         (*argc)--;
  77                 } else if (!strncmp(cmd, "--git-dir=", 10)) {
  78                         setenv("GIT_DIR", cmd + 10, 1);
  79                 } else if (!strcmp(cmd, "--bare")) {
  80                         static char git_dir[1024];
  81                         setenv("GIT_DIR", getcwd(git_dir, 1024), 1);
  82                 } else {
  83                         fprintf(stderr, "Unknown option: %s\n", cmd);
  84                         usage(git_usage_string);
  85                 }
  86
  87                 (*argv)++;
  88                 (*argc)--;
  89                 handled++;
  90         }
  91         return handled;
  92 }
  93
  94 static const char *alias_command;
  95 static char *alias_string = NULL;
  96
  97 static int git_alias_config(const char *var, const char *value)
  98 {
  99         if (!strncmp(var, "alias.", 6) && !strcmp(var + 6, alias_command)) {
 100                 alias_string = strdup(value);
 101         }
 102         return 0;
 103 }
 104
 105 static int split_cmdline(char *cmdline, const char ***argv)
 106 {
 107         int src, dst, count = 0, size = 16;
 108         char quoted = 0;
 109
 110         *argv = malloc(sizeof(char*) * size);
 111
 112         /* split alias_string */
 113         (*argv)[count++] = cmdline;
 114         for (src = dst = 0; cmdline[src];) {
 115                 char c = cmdline[src];
 116                 if (!quoted && isspace(c)) {
 117                         cmdline[dst++] = 0;
 118                         while (cmdline[++src]
 119                                         && isspace(cmdline[src]))
 120                                 ; /* skip */
 121                         if (count >= size) {
 122                                 size += 16;
 123                                 *argv = realloc(*argv, sizeof(char*) * size);
 124                         }
 125                         (*argv)[count++] = cmdline + dst;
 126                 } else if(!quoted && (c == '\'' || c == '"')) {
 127                         quoted = c;
 128                         src++;
 129                 } else if (c == quoted) {
 130                         quoted = 0;
 131                         src++;
 132                 } else {
 133                         if (c == '\\' && quoted != '\'') {
 134                                 src++;
 135                                 c = cmdline[src];
 136                                 if (!c) {
 137                                         free(*argv);
 138                                         *argv = NULL;
 139                                         return error("cmdline ends with \\");
 140                                 }
 141                         }
 142                         cmdline[dst++] = c;
 143                         src++;
 144                 }
 145         }
 146
 147         cmdline[dst] = 0;
 148
 149         if (quoted) {
 150                 free(*argv);
 151                 *argv = NULL;
 152                 return error("unclosed quote");
 153         }
 154
 155         return count;
 156 }
 157
 158 static int handle_alias(int *argcp, const char ***argv)
 159 {
 160         int nongit = 0, ret = 0, saved_errno = errno;
 161         const char *subdir;
 162         int count, option_count;
 163         const char** new_argv;
 164
 165         subdir = setup_git_directory_gently(&nongit);
 166
 167         alias_command = (*argv)[0];
 168         git_config(git_alias_config);
 169         if (alias_string) {
 170                 count = split_cmdline(alias_string, &new_argv);
 171                 option_count = handle_options(&new_argv, &count);
 172                 memmove(new_argv - option_count, new_argv,
 173                                 count * sizeof(char *));
 174                 new_argv -= option_count;
 175
 176                 if (count < 1)
 177                         die("empty alias for %s", alias_command);
 178
 179                 if (!strcmp(alias_command, new_argv[0]))
 180                         die("recursive alias: %s", alias_command);
 181
 182                 if (getenv("GIT_TRACE")) {
 183                         int i;
 184                         fprintf(stderr, "trace: alias expansion: %s =>",
 185                                 alias_command);
 186                         for (i = 0; i < count; ++i) {
 187                                 fputc(' ', stderr);
 188                                 sq_quote_print(stderr, new_argv[i]);
 189                         }
 190                         fputc('\n', stderr);
 191                         fflush(stderr);
 192                 }
 193
 194                 new_argv = realloc(new_argv, sizeof(char*) *
 195                                    (count + *argcp + 1));
 196                 /* insert after command name */
 197                 memcpy(new_argv + count, *argv + 1, sizeof(char*) * *argcp);
 198                 new_argv[count+*argcp] = NULL;
 199
 200                 *argv = new_argv;
 201                 *argcp += count - 1;
 202
 203                 ret = 1;
 204         }
 205
 206         if (subdir)
 207                 chdir(subdir);
 208
 209         errno = saved_errno;
 210
 211         return ret;
 212 }
 213
 214 const char git_version_string[] = GIT_VERSION;
 215
 216 #define NEEDS_PREFIX 1
 217 #define USE_PAGER 2
 218
 219 static void handle_internal_command(int argc, const char **argv, char **envp)
 220 {
 221         const char *cmd = argv[0];
 222         static struct cmd_struct {
 223                 const char *cmd;
 224                 int (*fn)(int, const char **, const char *);
 225                 int option;
 226         } commands[] = {
 227                 { "version", cmd_version },
 228                 { "help", cmd_help },
 229                 { "log", cmd_log, NEEDS_PREFIX | USE_PAGER },
 230                 { "whatchanged", cmd_whatchanged, NEEDS_PREFIX | USE_PAGER },
 231                 { "show", cmd_show, NEEDS_PREFIX | USE_PAGER },
 232                 { "push", cmd_push, NEEDS_PREFIX },
 233                 { "format-patch", cmd_format_patch, NEEDS_PREFIX },
 234                 { "count-objects", cmd_count_objects },
 235                 { "diff", cmd_diff, NEEDS_PREFIX },
 236                 { "grep", cmd_grep, NEEDS_PREFIX },
 237                 { "rm", cmd_rm, NEEDS_PREFIX },
 238                 { "add", cmd_add, NEEDS_PREFIX },
 239                 { "rev-list", cmd_rev_list, NEEDS_PREFIX },
 240                 { "init-db", cmd_init_db },
 241                 { "get-tar-commit-id", cmd_get_tar_commit_id },
 242                 { "upload-tar", cmd_upload_tar },
 243                 { "check-ref-format", cmd_check_ref_format },
 244                 { "ls-files", cmd_ls_files, NEEDS_PREFIX },
 245                 { "ls-tree", cmd_ls_tree, NEEDS_PREFIX },
 246                 { "tar-tree", cmd_tar_tree, NEEDS_PREFIX },
 247                 { "read-tree", cmd_read_tree, NEEDS_PREFIX },
 248                 { "commit-tree", cmd_commit_tree, NEEDS_PREFIX },
 249                 { "apply", cmd_apply },
 250                 { "show-branch", cmd_show_branch, NEEDS_PREFIX },
 251                 { "diff-files", cmd_diff_files, NEEDS_PREFIX },
 252                 { "diff-index", cmd_diff_index, NEEDS_PREFIX },
 253                 { "diff-stages", cmd_diff_stages, NEEDS_PREFIX },
 254                 { "diff-tree", cmd_diff_tree, NEEDS_PREFIX },
 255                 { "cat-file", cmd_cat_file, NEEDS_PREFIX },
 256                 { "rev-parse", cmd_rev_parse, NEEDS_PREFIX },
 257                 { "write-tree", cmd_write_tree, NEEDS_PREFIX },
 258                 { "mailsplit", cmd_mailsplit },
 259                 { "mailinfo", cmd_mailinfo },
 260                 { "stripspace", cmd_stripspace },
 261                 { "update-index", cmd_update_index, NEEDS_PREFIX },
 262                 { "update-ref", cmd_update_ref, NEEDS_PREFIX },
 263                 { "fmt-merge-msg", cmd_fmt_merge_msg, NEEDS_PREFIX },
 264                 { "prune", cmd_prune, NEEDS_PREFIX },
 265                 { "mv", cmd_mv, NEEDS_PREFIX },
 266                 { "prune-packed", cmd_prune_packed, NEEDS_PREFIX },
 267                 { "repo-config", cmd_repo_config },
 268         };
 269         int i;
 270
 271         /* Turn "git cmd --help" into "git help cmd" */
 272         if (argc > 1 && !strcmp(argv[1], "--help")) {
 273                 argv[1] = argv[0];
 274                 argv[0] = cmd = "help";
 275         }
 276
 277         for (i = 0; i < ARRAY_SIZE(commands); i++) {
 278                 struct cmd_struct *p = commands+i;
 279                 const char *prefix;
 280                 if (strcmp(p->cmd, cmd))
 281                         continue;
 282
 283                 prefix = NULL;
 284                 if (p->option & NEEDS_PREFIX)
 285                         prefix = setup_git_directory();
 286                 if (p->option & USE_PAGER)
 287                         setup_pager();
 288                 if (getenv("GIT_TRACE")) {
 289                         int i;
 290                         fprintf(stderr, "trace: built-in: git");
 291                         for (i = 0; i < argc; ++i) {
 292                                 fputc(' ', stderr);
 293                                 sq_quote_print(stderr, argv[i]);
 294                         }
 295                         putc('\n', stderr);
 296                         fflush(stderr);
 297                 }
 298
 299                 exit(p->fn(argc, argv, prefix));
 300         }
 301 }
 302
 303 int main(int argc, const char **argv, char **envp)
 304 {
 305         const char *cmd = argv[0];
 306         char *slash = strrchr(cmd, '/');
 307         const char *exec_path = NULL;
 308         int done_alias = 0;
 309
 310         /*
 311          * Take the basename of argv[0] as the command
 312          * name, and the dirname as the default exec_path
 313          * if it's an absolute path and we don't have
 314          * anything better.
 315          */
 316         if (slash) {
 317                 *slash++ = 0;
 318                 if (*cmd == '/')
 319                         exec_path = cmd;
 320                 cmd = slash;
 321         }
 322
 323         /*
 324          * "git-xxxx" is the same as "git xxxx", but we obviously:
 325          *
 326          *  - cannot take flags in between the "git" and the "xxxx".
 327          *  - cannot execute it externally (since it would just do
 328          *    the same thing over again)
 329          *
 330          * So we just directly call the internal command handler, and
 331          * die if that one cannot handle it.
 332          */
 333         if (!strncmp(cmd, "git-", 4)) {
 334                 cmd += 4;
 335                 argv[0] = cmd;
 336                 handle_internal_command(argc, argv, envp);
 337                 die("cannot handle %s internally", cmd);
 338         }
 339
 340         /* Look for flags.. */
 341         argv++;
 342         argc--;
 343         handle_options(&argv, &argc);
 344         if (argc > 0) {
 345                 if (!strncmp(argv[0], "--", 2))
 346                         argv[0] += 2;
 347         } else {
 348                 /* Default command: "help" */
 349                 argv[0] = "help";
 350                 argc = 1;
 351         }
 352         cmd = argv[0];
 353
 354         /*
 355          * We search for git commands in the following order:
 356          *  - git_exec_path()
 357          *  - the path of the "git" command if we could find it
 358          *    in $0
 359          *  - the regular PATH.
 360          */
 361         if (exec_path)
 362                 prepend_to_path(exec_path, strlen(exec_path));
 363         exec_path = git_exec_path();
 364         prepend_to_path(exec_path, strlen(exec_path));
 365
 366         while (1) {
 367                 /* See if it's an internal command */
 368                 handle_internal_command(argc, argv, envp);
 369
 370                 /* .. then try the external ones */
 371                 execv_git_cmd(argv);
 372
 373                 /* It could be an alias -- this works around the insanity
 374                  * of overriding "git log" with "git show" by having
 375                  * alias.log = show
 376                  */
 377                 if (done_alias || !handle_alias(&argc, &argv))
 378                         break;
 379                 done_alias = 1;
 380         }
 381
 382         if (errno == ENOENT)
 383                 help_unknown_cmd(cmd);
 384
 385         fprintf(stderr, "Failed to run command '%s': %s\n",
 386                 cmd, strerror(errno));
 387
 388         return 1;
 389 }