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