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                 { "check-ref-format", cmd_check_ref_format },
  56                 { "ls-files", cmd_ls_files },
  57                 { "ls-tree", cmd_ls_tree },
  58                 { "tar-tree", cmd_tar_tree }
  59         };
  60         int i;
  61
  62         /* Turn "git cmd --help" into "git help cmd" */
  63         if (argc > 1 && !strcmp(argv[1], "--help")) {
  64                 argv[1] = argv[0];
  65                 argv[0] = cmd = "help";
  66         }
  67
  68         for (i = 0; i < ARRAY_SIZE(commands); i++) {
  69                 struct cmd_struct *p = commands+i;
  70                 if (strcmp(p->cmd, cmd))
  71                         continue;
  72                 exit(p->fn(argc, argv, envp));
  73         }
  74 }
  75
  76 int main(int argc, const char **argv, char **envp)
  77 {
  78         const char *cmd = argv[0];
  79         char *slash = strrchr(cmd, '/');
  80         char git_command[PATH_MAX + 1];
  81         const char *exec_path = NULL;
  82
  83         /*
  84          * Take the basename of argv[0] as the command
  85          * name, and the dirname as the default exec_path
  86          * if it's an absolute path and we don't have
  87          * anything better.
  88          */
  89         if (slash) {
  90                 *slash++ = 0;
  91                 if (*cmd == '/')
  92                         exec_path = cmd;
  93                 cmd = slash;
  94         }
  95
  96         /*
  97          * "git-xxxx" is the same as "git xxxx", but we obviously:
  98          *
  99          *  - cannot take flags in between the "git" and the "xxxx".
 100          *  - cannot execute it externally (since it would just do
 101          *    the same thing over again)
 102          *
 103          * So we just directly call the internal command handler, and
 104          * die if that one cannot handle it.
 105          */
 106         if (!strncmp(cmd, "git-", 4)) {
 107                 cmd += 4;
 108                 argv[0] = cmd;
 109                 handle_internal_command(argc, argv, envp);
 110                 die("cannot handle %s internally", cmd);
 111         }
 112
 113         /* Default command: "help" */
 114         cmd = "help";
 115
 116         /* Look for flags.. */
 117         while (argc > 1) {
 118                 cmd = *++argv;
 119                 argc--;
 120
 121                 if (strncmp(cmd, "--", 2))
 122                         break;
 123
 124                 cmd += 2;
 125
 126                 /*
 127                  * For legacy reasons, the "version" and "help"
 128                  * commands can be written with "--" prepended
 129                  * to make them look like flags.
 130                  */
 131                 if (!strcmp(cmd, "help"))
 132                         break;
 133                 if (!strcmp(cmd, "version"))
 134                         break;
 135
 136                 /*
 137                  * Check remaining flags (which by now must be
 138                  * "--exec-path", but maybe we will accept
 139                  * other arguments some day)
 140                  */
 141                 if (!strncmp(cmd, "exec-path", 9)) {
 142                         cmd += 9;
 143                         if (*cmd == '=') {
 144                                 git_set_exec_path(cmd + 1);
 145                                 continue;
 146                         }
 147                         puts(git_exec_path());
 148                         exit(0);
 149                 }
 150                 cmd_usage(0, NULL, NULL);
 151         }
 152         argv[0] = cmd;
 153
 154         /*
 155          * We search for git commands in the following order:
 156          *  - git_exec_path()
 157          *  - the path of the "git" command if we could find it
 158          *    in $0
 159          *  - the regular PATH.
 160          */
 161         if (exec_path)
 162                 prepend_to_path(exec_path, strlen(exec_path));
 163         exec_path = git_exec_path();
 164         prepend_to_path(exec_path, strlen(exec_path));
 165
 166         /* See if it's an internal command */
 167         handle_internal_command(argc, argv, envp);
 168
 169         /* .. then try the external ones */
 170         execv_git_cmd(argv);
 171
 172         if (errno == ENOENT)
 173                 cmd_usage(0, exec_path, "'%s' is not a git-command", cmd);
 174
 175         fprintf(stderr, "Failed to run command '%s': %s\n",
 176                 git_command, strerror(errno));
 177
 178         return 1;
 179 }