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
  14 #include "builtin.h"
  15
  16 static void prepend_to_path(const char *dir, int len)
  17 {
  18         char *path, *old_path = getenv("PATH");
  19         int path_len = len;
  20
  21         if (!old_path)
  22                 old_path = "/usr/local/bin:/usr/bin:/bin";
  23
  24         path_len = len + strlen(old_path) + 1;
  25
  26         path = malloc(path_len + 1);
  27
  28         memcpy(path, dir, len);
  29         path[len] = ':';
  30         memcpy(path + len + 1, old_path, path_len - len);
  31
  32         setenv("PATH", path, 1);
  33 }
  34
  35 const char git_version_string[] = GIT_VERSION;
  36
  37 static void handle_internal_command(int argc, const char **argv, char **envp)
  38 {
  39         const char *cmd = argv[0];
  40         static struct cmd_struct {
  41                 const char *cmd;
  42                 int (*fn)(int, const char **, char **);
  43         } commands[] = {
  44                 { "version", cmd_version },
  45                 { "help", cmd_help },
  46                 { "log", cmd_log },
  47                 { "whatchanged", cmd_whatchanged },
  48                 { "show", cmd_show },
  49                 { "push", cmd_push },
  50                 { "count-objects", cmd_count_objects },
  51                 { "diff", cmd_diff },
  52                 { "grep", cmd_grep },
  53                 { "rev-list", cmd_rev_list },
  54                 { "init-db", cmd_init_db },
  55                 { "tar-tree", cmd_tar_tree },
  56                 { "upload-tar", cmd_upload_tar },
  57                 { "check-ref-format", cmd_check_ref_format },
  58                 { "ls-files", cmd_ls_files },
  59                 { "ls-tree", cmd_ls_tree },
  60                 { "tar-tree", cmd_tar_tree },
  61                 { "read-tree", cmd_read_tree },
  62                 { "commit-tree", cmd_commit_tree },
  63                 { "apply", cmd_apply },
  64                 { "show-branch", cmd_show_branch },
  65                 { "diff-files", cmd_diff_files },
  66                 { "diff-index", cmd_diff_index },
  67                 { "diff-stages", cmd_diff_stages },
  68                 { "diff-tree", cmd_diff_tree }
  69         };
  70         int i;
  71
  72         /* Turn "git cmd --help" into "git help cmd" */
  73         if (argc > 1 && !strcmp(argv[1], "--help")) {
  74                 argv[1] = argv[0];
  75                 argv[0] = cmd = "help";
  76         }
  77
  78         for (i = 0; i < ARRAY_SIZE(commands); i++) {
  79                 struct cmd_struct *p = commands+i;
  80                 if (strcmp(p->cmd, cmd))
  81                         continue;
  82                 exit(p->fn(argc, argv, envp));
  83         }
  84 }
  85
  86 int main(int argc, const char **argv, char **envp)
  87 {
  88         const char *cmd = argv[0];
  89         char *slash = strrchr(cmd, '/');
  90         char git_command[PATH_MAX + 1];
  91         const char *exec_path = NULL;
  92
  93         /*
  94          * Take the basename of argv[0] as the command
  95          * name, and the dirname as the default exec_path
  96          * if it's an absolute path and we don't have
  97          * anything better.
  98          */
  99         if (slash) {
 100                 *slash++ = 0;
 101                 if (*cmd == '/')
 102                         exec_path = cmd;
 103                 cmd = slash;
 104         }
 105
 106         /*
 107          * "git-xxxx" is the same as "git xxxx", but we obviously:
 108          *
 109          *  - cannot take flags in between the "git" and the "xxxx".
 110          *  - cannot execute it externally (since it would just do
 111          *    the same thing over again)
 112          *
 113          * So we just directly call the internal command handler, and
 114          * die if that one cannot handle it.
 115          */
 116         if (!strncmp(cmd, "git-", 4)) {
 117                 cmd += 4;
 118                 argv[0] = cmd;
 119                 handle_internal_command(argc, argv, envp);
 120                 die("cannot handle %s internally", cmd);
 121         }
 122
 123         /* Default command: "help" */
 124         cmd = "help";
 125
 126         /* Look for flags.. */
 127         while (argc > 1) {
 128                 cmd = *++argv;
 129                 argc--;
 130
 131                 if (strncmp(cmd, "--", 2))
 132                         break;
 133
 134                 cmd += 2;
 135
 136                 /*
 137                  * For legacy reasons, the "version" and "help"
 138                  * commands can be written with "--" prepended
 139                  * to make them look like flags.
 140                  */
 141                 if (!strcmp(cmd, "help"))
 142                         break;
 143                 if (!strcmp(cmd, "version"))
 144                         break;
 145
 146                 /*
 147                  * Check remaining flags (which by now must be
 148                  * "--exec-path", but maybe we will accept
 149                  * other arguments some day)
 150                  */
 151                 if (!strncmp(cmd, "exec-path", 9)) {
 152                         cmd += 9;
 153                         if (*cmd == '=') {
 154                                 git_set_exec_path(cmd + 1);
 155                                 continue;
 156                         }
 157                         puts(git_exec_path());
 158                         exit(0);
 159                 }
 160                 cmd_usage(0, NULL, NULL);
 161         }
 162         argv[0] = cmd;
 163
 164         /*
 165          * We search for git commands in the following order:
 166          *  - git_exec_path()
 167          *  - the path of the "git" command if we could find it
 168          *    in $0
 169          *  - the regular PATH.
 170          */
 171         if (exec_path)
 172                 prepend_to_path(exec_path, strlen(exec_path));
 173         exec_path = git_exec_path();
 174         prepend_to_path(exec_path, strlen(exec_path));
 175
 176         /* See if it's an internal command */
 177         handle_internal_command(argc, argv, envp);
 178
 179         /* .. then try the external ones */
 180         execv_git_cmd(argv);
 181
 182         if (errno == ENOENT)
 183                 cmd_usage(0, exec_path, "'%s' is not a git-command", cmd);
 184
 185         fprintf(stderr, "Failed to run command '%s': %s\n",
 186                 git_command, strerror(errno));
 187
 188         return 1;
 189 }