Andrew's git - gitweb.git/blob

   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
  14#ifndef PATH_MAX
  15# define PATH_MAX 4096
  16#endif
  17
  18static const char git_usage[] =
  19        "Usage: git [--version] [--exec-path[=GIT_EXEC_PATH]] [--help] COMMAND [ ARGS ]";
  20
  21/* most gui terms set COLUMNS (although some don't export it) */
  22static int term_columns(void)
  23{
  24        char *col_string = getenv("COLUMNS");
  25        int n_cols = 0;
  26
  27        if (col_string && (n_cols = atoi(col_string)) > 0)
  28                return n_cols;
  29
  30#ifdef TIOCGWINSZ
  31        {
  32                struct winsize ws;
  33                if (!ioctl(1, TIOCGWINSZ, &ws)) {
  34                        if (ws.ws_col)
  35                                return ws.ws_col;
  36                }
  37        }
  38#endif
  39
  40        return 80;
  41}
  42
  43static void oom(void)
  44{
  45        fprintf(stderr, "git: out of memory\n");
  46        exit(1);
  47}
  48
  49static inline void mput_char(char c, unsigned int num)
  50{
  51        while(num--)
  52                putchar(c);
  53}
  54
  55static struct cmdname {
  56        size_t len;
  57        char name[1];
  58} **cmdname;
  59static int cmdname_alloc, cmdname_cnt;
  60
  61static void add_cmdname(const char *name, int len)
  62{
  63        struct cmdname *ent;
  64        if (cmdname_alloc <= cmdname_cnt) {
  65                cmdname_alloc = cmdname_alloc + 200;
  66                cmdname = realloc(cmdname, cmdname_alloc * sizeof(*cmdname));
  67                if (!cmdname)
  68                        oom();
  69        }
  70        ent = malloc(sizeof(*ent) + len);
  71        if (!ent)
  72                oom();
  73        ent->len = len;
  74        memcpy(ent->name, name, len);
  75        ent->name[len] = 0;
  76        cmdname[cmdname_cnt++] = ent;
  77}
  78
  79static int cmdname_compare(const void *a_, const void *b_)
  80{
  81        struct cmdname *a = *(struct cmdname **)a_;
  82        struct cmdname *b = *(struct cmdname **)b_;
  83        return strcmp(a->name, b->name);
  84}
  85
  86static void pretty_print_string_list(struct cmdname **cmdname, int longest)
  87{
  88        int cols = 1, rows;
  89        int space = longest + 1; /* min 1 SP between words */
  90        int max_cols = term_columns() - 1; /* don't print *on* the edge */
  91        int i, j;
  92
  93        if (space < max_cols)
  94                cols = max_cols / space;
  95        rows = (cmdname_cnt + cols - 1) / cols;
  96
  97        qsort(cmdname, cmdname_cnt, sizeof(*cmdname), cmdname_compare);
  98
  99        for (i = 0; i < rows; i++) {
 100                printf("  ");
 101
 102                for (j = 0; j < cols; j++) {
 103                        int n = j * rows + i;
 104                        int size = space;
 105                        if (n >= cmdname_cnt)
 106                                break;
 107                        if (j == cols-1 || n + rows >= cmdname_cnt)
 108                                size = 1;
 109                        printf("%-*s", size, cmdname[n]->name);
 110                }
 111                putchar('\n');
 112        }
 113}
 114
 115static void list_commands(const char *exec_path, const char *pattern)
 116{
 117        unsigned int longest = 0;
 118        char path[PATH_MAX];
 119        int dirlen;
 120        DIR *dir = opendir(exec_path);
 121        struct dirent *de;
 122
 123        if (!dir) {
 124                fprintf(stderr, "git: '%s': %s\n", exec_path, strerror(errno));
 125                exit(1);
 126        }
 127
 128        dirlen = strlen(exec_path);
 129        if (PATH_MAX - 20 < dirlen) {
 130                fprintf(stderr, "git: insanely long exec-path '%s'\n",
 131                        exec_path);
 132                exit(1);
 133        }
 134
 135        memcpy(path, exec_path, dirlen);
 136        path[dirlen++] = '/';
 137
 138        while ((de = readdir(dir)) != NULL) {
 139                struct stat st;
 140                int entlen;
 141
 142                if (strncmp(de->d_name, "git-", 4))
 143                        continue;
 144                strcpy(path+dirlen, de->d_name);
 145                if (stat(path, &st) || /* stat, not lstat */
 146                    !S_ISREG(st.st_mode) ||
 147                    !(st.st_mode & S_IXUSR))
 148                        continue;
 149
 150                entlen = strlen(de->d_name);
 151                if (4 < entlen && !strcmp(de->d_name + entlen - 4, ".exe"))
 152                        entlen -= 4;
 153
 154                if (longest < entlen)
 155                        longest = entlen;
 156
 157                add_cmdname(de->d_name + 4, entlen-4);
 158        }
 159        closedir(dir);
 160
 161        printf("git commands available in '%s'\n", exec_path);
 162        printf("----------------------------");
 163        mput_char('-', strlen(exec_path));
 164        putchar('\n');
 165        pretty_print_string_list(cmdname, longest - 4);
 166        putchar('\n');
 167}
 168
 169#ifdef __GNUC__
 170static void cmd_usage(const char *exec_path, const char *fmt, ...)
 171        __attribute__((__format__(__printf__, 2, 3), __noreturn__));
 172#endif
 173static void cmd_usage(const char *exec_path, const char *fmt, ...)
 174{
 175        if (fmt) {
 176                va_list ap;
 177
 178                va_start(ap, fmt);
 179                printf("git: ");
 180                vprintf(fmt, ap);
 181                va_end(ap);
 182                putchar('\n');
 183        }
 184        else
 185                puts(git_usage);
 186
 187        putchar('\n');
 188
 189        if(exec_path)
 190                list_commands(exec_path, "git-*");
 191
 192        exit(1);
 193}
 194
 195static void prepend_to_path(const char *dir, int len)
 196{
 197        char *path, *old_path = getenv("PATH");
 198        int path_len = len;
 199
 200        if (!old_path)
 201                old_path = "/usr/local/bin:/usr/bin:/bin";
 202
 203        path_len = len + strlen(old_path) + 1;
 204
 205        path = malloc(path_len + 1);
 206
 207        memcpy(path, dir, len);
 208        path[len] = ':';
 209        memcpy(path + len + 1, old_path, path_len - len);
 210
 211        setenv("PATH", path, 1);
 212}
 213
 214static void show_man_page(char *git_cmd)
 215{
 216        char *page;
 217
 218        if (!strncmp(git_cmd, "git", 3))
 219                page = git_cmd;
 220        else {
 221                int page_len = strlen(git_cmd) + 4;
 222
 223                page = malloc(page_len + 1);
 224                strcpy(page, "git-");
 225                strcpy(page + 4, git_cmd);
 226                page[page_len] = 0;
 227        }
 228
 229        execlp("man", "man", page, NULL);
 230}
 231
 232int main(int argc, char **argv, char **envp)
 233{
 234        char git_command[PATH_MAX + 1];
 235        char wd[PATH_MAX + 1];
 236        int i, len, show_help = 0;
 237        char *exec_path = getenv("GIT_EXEC_PATH");
 238
 239        getcwd(wd, PATH_MAX);
 240
 241        if (!exec_path)
 242                exec_path = GIT_EXEC_PATH;
 243
 244        for (i = 1; i < argc; i++) {
 245                char *arg = argv[i];
 246
 247                if (!strcmp(arg, "help")) {
 248                        show_help = 1;
 249                        continue;
 250                }
 251
 252                if (strncmp(arg, "--", 2))
 253                        break;
 254
 255                arg += 2;
 256
 257                if (!strncmp(arg, "exec-path", 9)) {
 258                        arg += 9;
 259                        if (*arg == '=')
 260                                exec_path = arg + 1;
 261                        else {
 262                                puts(exec_path);
 263                                exit(0);
 264                        }
 265                }
 266                else if (!strcmp(arg, "version")) {
 267                        printf("git version %s\n", GIT_VERSION);
 268                        exit(0);
 269                }
 270                else if (!strcmp(arg, "help"))
 271                        show_help = 1;
 272                else if (!show_help)
 273                        cmd_usage(NULL, NULL);
 274        }
 275
 276        if (i >= argc || show_help) {
 277                if (i >= argc)
 278                        cmd_usage(exec_path, NULL);
 279
 280                show_man_page(argv[i]);
 281        }
 282
 283        if (*exec_path != '/') {
 284                if (!getcwd(git_command, sizeof(git_command))) {
 285                        fprintf(stderr,
 286                                "git: cannot determine current directory\n");
 287                        exit(1);
 288                }
 289                len = strlen(git_command);
 290
 291                /* Trivial cleanup */
 292                while (!strncmp(exec_path, "./", 2)) {
 293                        exec_path += 2;
 294                        while (*exec_path == '/')
 295                                exec_path++;
 296                }
 297                snprintf(git_command + len, sizeof(git_command) - len,
 298                         "/%s", exec_path);
 299        }
 300        else
 301                strcpy(git_command, exec_path);
 302        len = strlen(git_command);
 303        prepend_to_path(git_command, len);
 304
 305        len += snprintf(git_command + len, sizeof(git_command) - len,
 306                        "/git-%s", argv[i]);
 307        if (sizeof(git_command) <= len) {
 308                fprintf(stderr, "git: command name given is too long.\n");
 309                exit(1);
 310        }
 311
 312        /* execve() can only ever return if it fails */
 313        execve(git_command, &argv[i], envp);
 314
 315        if (errno == ENOENT)
 316                cmd_usage(exec_path, "'%s' is not a git-command", argv[i]);
 317
 318        fprintf(stderr, "Failed to run command '%s': %s\n",
 319                git_command, strerror(errno));
 320
 321        return 1;
 322}