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                 { "fmt-patch", cmd_format_patch },
  51                 { "count-objects", cmd_count_objects },
  52                 { "diff", cmd_diff },
  53                 { "grep", cmd_grep },
  54         };
  55         int i;
  56
  57         /* Turn "git cmd --help" into "git help cmd" */
  58         if (argc > 1 && !strcmp(argv[1], "--help")) {
  59                 argv[1] = argv[0];
  60                 argv[0] = cmd = "help";
  61         }
  62
  63         for (i = 0; i < ARRAY_SIZE(commands); i++) {
  64                 struct cmd_struct *p = commands+i;
  65                 if (strcmp(p->cmd, cmd))
  66                         continue;
  67                 exit(p->fn(argc, argv, envp));
  68         }
  69 }
  70
  71 int main(int argc, const char **argv, char **envp)
  72 {
  73         const char *cmd = argv[0];
  74         char *slash = strrchr(cmd, '/');
  75         char git_command[PATH_MAX + 1];
  76         const char *exec_path = NULL;
  77
  78         /*
  79          * Take the basename of argv[0] as the command
  80          * name, and the dirname as the default exec_path
  81          * if it's an absolute path and we don't have
  82          * anything better.
  83          */
  84         if (slash) {
  85                 *slash++ = 0;
  86                 if (*cmd == '/')
  87                         exec_path = cmd;
  88                 cmd = slash;
  89         }
  90
  91         /*
  92          * "git-xxxx" is the same as "git xxxx", but we obviously:
  93          *
  94          *  - cannot take flags in between the "git" and the "xxxx".
  95          *  - cannot execute it externally (since it would just do
  96          *    the same thing over again)
  97          *
  98          * So we just directly call the internal command handler, and
  99          * die if that one cannot handle it.
 100          */
 101         if (!strncmp(cmd, "git-", 4)) {
 102                 cmd += 4;
 103                 argv[0] = cmd;
 104                 handle_internal_command(argc, argv, envp);
 105                 die("cannot handle %s internally", cmd);
 106         }
 107
 108         /* Default command: "help" */
 109         cmd = "help";
 110
 111         /* Look for flags.. */
 112         while (argc > 1) {
 113                 cmd = *++argv;
 114                 argc--;
 115
 116                 if (strncmp(cmd, "--", 2))
 117                         break;
 118
 119                 cmd += 2;
 120
 121                 /*
 122                  * For legacy reasons, the "version" and "help"
 123                  * commands can be written with "--" prepended
 124                  * to make them look like flags.
 125                  */
 126                 if (!strcmp(cmd, "help"))
 127                         break;
 128                 if (!strcmp(cmd, "version"))
 129                         break;
 130
 131                 /*
 132                  * Check remaining flags (which by now must be
 133                  * "--exec-path", but maybe we will accept
 134                  * other arguments some day)
 135                  */
 136                 if (!strncmp(cmd, "exec-path", 9)) {
 137                         cmd += 9;
 138                         if (*cmd == '=') {
 139                                 git_set_exec_path(cmd + 1);
 140                                 continue;
 141                         }
 142                         puts(git_exec_path());
 143                         exit(0);
 144                 }
 145                 cmd_usage(0, NULL, NULL);
 146         }
 147         argv[0] = cmd;
 148
 149         /*
 150          * We search for git commands in the following order:
 151          *  - git_exec_path()
 152          *  - the path of the "git" command if we could find it
 153          *    in $0
 154          *  - the regular PATH.
 155          */
 156         if (exec_path)
 157                 prepend_to_path(exec_path, strlen(exec_path));
 158         exec_path = git_exec_path();
 159         prepend_to_path(exec_path, strlen(exec_path));
 160
 161         /* See if it's an internal command */
 162         handle_internal_command(argc, argv, envp);
 163
 164         /* .. then try the external ones */
 165         execv_git_cmd(argv);
 166
 167         if (errno == ENOENT)
 168                 cmd_usage(0, exec_path, "'%s' is not a git-command", cmd);
 169
 170         fprintf(stderr, "Failed to run command '%s': %s\n",
 171                 git_command, strerror(errno));
 172
 173         return 1;
 174 }