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                 { "grep", cmd_grep },
  50         };
  51         int i;
  52
  53         /* Turn "git cmd --help" into "git help cmd" */
  54         if (argc > 1 && !strcmp(argv[1], "--help")) {
  55                 argv[1] = argv[0];
  56                 argv[0] = cmd = "help";
  57         }
  58
  59         for (i = 0; i < ARRAY_SIZE(commands); i++) {
  60                 struct cmd_struct *p = commands+i;
  61                 if (strcmp(p->cmd, cmd))
  62                         continue;
  63                 exit(p->fn(argc, argv, envp));
  64         }
  65 }
  66
  67 int main(int argc, const char **argv, char **envp)
  68 {
  69         const char *cmd = argv[0];
  70         char *slash = strrchr(cmd, '/');
  71         char git_command[PATH_MAX + 1];
  72         const char *exec_path = NULL;
  73
  74         /*
  75          * Take the basename of argv[0] as the command
  76          * name, and the dirname as the default exec_path
  77          * if it's an absolute path and we don't have
  78          * anything better.
  79          */
  80         if (slash) {
  81                 *slash++ = 0;
  82                 if (*cmd == '/')
  83                         exec_path = cmd;
  84                 cmd = slash;
  85         }
  86
  87         /*
  88          * "git-xxxx" is the same as "git xxxx", but we obviously:
  89          *
  90          *  - cannot take flags in between the "git" and the "xxxx".
  91          *  - cannot execute it externally (since it would just do
  92          *    the same thing over again)
  93          *
  94          * So we just directly call the internal command handler, and
  95          * die if that one cannot handle it.
  96          */
  97         if (!strncmp(cmd, "git-", 4)) {
  98                 cmd += 4;
  99                 argv[0] = cmd;
 100                 handle_internal_command(argc, argv, envp);
 101                 die("cannot handle %s internally", cmd);
 102         }
 103
 104         /* Default command: "help" */
 105         cmd = "help";
 106
 107         /* Look for flags.. */
 108         while (argc > 1) {
 109                 cmd = *++argv;
 110                 argc--;
 111
 112                 if (strncmp(cmd, "--", 2))
 113                         break;
 114
 115                 cmd += 2;
 116
 117                 /*
 118                  * For legacy reasons, the "version" and "help"
 119                  * commands can be written with "--" prepended
 120                  * to make them look like flags.
 121                  */
 122                 if (!strcmp(cmd, "help"))
 123                         break;
 124                 if (!strcmp(cmd, "version"))
 125                         break;
 126
 127                 /*
 128                  * Check remaining flags (which by now must be
 129                  * "--exec-path", but maybe we will accept
 130                  * other arguments some day)
 131                  */
 132                 if (!strncmp(cmd, "exec-path", 9)) {
 133                         cmd += 9;
 134                         if (*cmd == '=') {
 135                                 git_set_exec_path(cmd + 1);
 136                                 continue;
 137                         }
 138                         puts(git_exec_path());
 139                         exit(0);
 140                 }
 141                 cmd_usage(0, NULL, NULL);
 142         }
 143         argv[0] = cmd;
 144
 145         /*
 146          * We search for git commands in the following order:
 147          *  - git_exec_path()
 148          *  - the path of the "git" command if we could find it
 149          *    in $0
 150          *  - the regular PATH.
 151          */
 152         if (exec_path)
 153                 prepend_to_path(exec_path, strlen(exec_path));
 154         exec_path = git_exec_path();
 155         prepend_to_path(exec_path, strlen(exec_path));
 156
 157         /* See if it's an internal command */
 158         handle_internal_command(argc, argv, envp);
 159
 160         /* .. then try the external ones */
 161         execv_git_cmd(argv);
 162
 163         if (errno == ENOENT)
 164                 cmd_usage(0, exec_path, "'%s' is not a git-command", cmd);
 165
 166         fprintf(stderr, "Failed to run command '%s': %s\n",
 167                 git_command, strerror(errno));
 168
 169         return 1;
 170 }