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