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                 { "check-ref-format", cmd_check_ref_format }
  55         };
  56         int i;
  57
  58         /* Turn "git cmd --help" into "git help cmd" */
  59         if (argc > 1 && !strcmp(argv[1], "--help")) {
  60                 argv[1] = argv[0];
  61                 argv[0] = cmd = "help";
  62         }
  63
  64         for (i = 0; i < ARRAY_SIZE(commands); i++) {
  65                 struct cmd_struct *p = commands+i;
  66                 if (strcmp(p->cmd, cmd))
  67                         continue;
  68                 exit(p->fn(argc, argv, envp));
  69         }
  70 }
  71
  72 int main(int argc, const char **argv, char **envp)
  73 {
  74         const char *cmd = argv[0];
  75         char *slash = strrchr(cmd, '/');
  76         char git_command[PATH_MAX + 1];
  77         const char *exec_path = NULL;
  78
  79         /*
  80          * Take the basename of argv[0] as the command
  81          * name, and the dirname as the default exec_path
  82          * if it's an absolute path and we don't have
  83          * anything better.
  84          */
  85         if (slash) {
  86                 *slash++ = 0;
  87                 if (*cmd == '/')
  88                         exec_path = cmd;
  89                 cmd = slash;
  90         }
  91
  92         /*
  93          * "git-xxxx" is the same as "git xxxx", but we obviously:
  94          *
  95          *  - cannot take flags in between the "git" and the "xxxx".
  96          *  - cannot execute it externally (since it would just do
  97          *    the same thing over again)
  98          *
  99          * So we just directly call the internal command handler, and
 100          * die if that one cannot handle it.
 101          */
 102         if (!strncmp(cmd, "git-", 4)) {
 103                 cmd += 4;
 104                 argv[0] = cmd;
 105                 handle_internal_command(argc, argv, envp);
 106                 die("cannot handle %s internally", cmd);
 107         }
 108
 109         /* Default command: "help" */
 110         cmd = "help";
 111
 112         /* Look for flags.. */
 113         while (argc > 1) {
 114                 cmd = *++argv;
 115                 argc--;
 116
 117                 if (strncmp(cmd, "--", 2))
 118                         break;
 119
 120                 cmd += 2;
 121
 122                 /*
 123                  * For legacy reasons, the "version" and "help"
 124                  * commands can be written with "--" prepended
 125                  * to make them look like flags.
 126                  */
 127                 if (!strcmp(cmd, "help"))
 128                         break;
 129                 if (!strcmp(cmd, "version"))
 130                         break;
 131
 132                 /*
 133                  * Check remaining flags (which by now must be
 134                  * "--exec-path", but maybe we will accept
 135                  * other arguments some day)
 136                  */
 137                 if (!strncmp(cmd, "exec-path", 9)) {
 138                         cmd += 9;
 139                         if (*cmd == '=') {
 140                                 git_set_exec_path(cmd + 1);
 141                                 continue;
 142                         }
 143                         puts(git_exec_path());
 144                         exit(0);
 145                 }
 146                 cmd_usage(0, NULL, NULL);
 147         }
 148         argv[0] = cmd;
 149
 150         /*
 151          * We search for git commands in the following order:
 152          *  - git_exec_path()
 153          *  - the path of the "git" command if we could find it
 154          *    in $0
 155          *  - the regular PATH.
 156          */
 157         if (exec_path)
 158                 prepend_to_path(exec_path, strlen(exec_path));
 159         exec_path = git_exec_path();
 160         prepend_to_path(exec_path, strlen(exec_path));
 161
 162         /* See if it's an internal command */
 163         handle_internal_command(argc, argv, envp);
 164
 165         /* .. then try the external ones */
 166         execv_git_cmd(argv);
 167
 168         if (errno == ENOENT)
 169                 cmd_usage(0, exec_path, "'%s' is not a git-command", cmd);
 170
 171         fprintf(stderr, "Failed to run command '%s': %s\n",
 172                 git_command, strerror(errno));
 173
 174         return 1;
 175 }