diff options
Diffstat (limited to 'git.c')
| -rw-r--r-- | git.c | 298 |
1 files changed, 298 insertions, 0 deletions
@@ -0,0 +1,298 @@ +#include <stdio.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <dirent.h> +#include <unistd.h> +#include <stdlib.h> +#include <string.h> +#include <errno.h> +#include <limits.h> +#include <stdarg.h> + +#ifndef PATH_MAX +# define PATH_MAX 4096 +#endif + +static const char git_usage[] = + "Usage: git [--version] [--exec-path[=GIT_EXEC_PATH]] [--help] COMMAND [ ARGS ]"; + +/* most gui terms set COLUMNS (although some don't export it) */ +static int term_columns(void) +{ + char *col_string = getenv("COLUMNS"); + int n_cols = 0; + + if (col_string && (n_cols = atoi(col_string)) > 0) + return n_cols; + + return 80; +} + +static void oom(void) +{ + fprintf(stderr, "git: out of memory\n"); + exit(1); +} + +static inline void mput_char(char c, unsigned int num) +{ + while(num--) + putchar(c); +} + +static struct cmdname { + size_t len; + char name[1]; +} **cmdname; +static int cmdname_alloc, cmdname_cnt; + +static void add_cmdname(const char *name, int len) +{ + struct cmdname *ent; + if (cmdname_alloc <= cmdname_cnt) { + cmdname_alloc = cmdname_alloc + 200; + cmdname = realloc(cmdname, cmdname_alloc * sizeof(*cmdname)); + if (!cmdname) + oom(); + } + ent = malloc(sizeof(*ent) + len); + if (!ent) + oom(); + ent->len = len; + memcpy(ent->name, name, len); + ent->name[len] = 0; + cmdname[cmdname_cnt++] = ent; +} + +static int cmdname_compare(const void *a_, const void *b_) +{ + struct cmdname *a = *(struct cmdname **)a_; + struct cmdname *b = *(struct cmdname **)b_; + return strcmp(a->name, b->name); +} + +static void pretty_print_string_list(struct cmdname **cmdname, int longest) +{ + int cols = 1; + int space = longest + 1; /* min 1 SP between words */ + int max_cols = term_columns() - 1; /* don't print *on* the edge */ + int i; + + if (space < max_cols) + cols = max_cols / space; + + qsort(cmdname, cmdname_cnt, sizeof(*cmdname), cmdname_compare); + + for (i = 0; i < cmdname_cnt; ) { + int c; + printf(" "); + + for (c = cols; c && i < cmdname_cnt; i++) { + printf("%s", cmdname[i]->name); + + if (--c) + mput_char(' ', space - cmdname[i]->len); + } + putchar('\n'); + } +} + +static void list_commands(const char *exec_path, const char *pattern) +{ + unsigned int longest = 0; + char path[PATH_MAX]; + int dirlen; + DIR *dir = opendir(exec_path); + struct dirent *de; + + if (!dir) { + fprintf(stderr, "git: '%s': %s\n", exec_path, strerror(errno)); + exit(1); + } + + dirlen = strlen(exec_path); + if (PATH_MAX - 20 < dirlen) { + fprintf(stderr, "git: insanely long exec-path '%s'\n", + exec_path); + exit(1); + } + + memcpy(path, exec_path, dirlen); + path[dirlen++] = '/'; + + while ((de = readdir(dir)) != NULL) { + struct stat st; + int entlen; + + if (strncmp(de->d_name, "git-", 4)) + continue; + strcpy(path+dirlen, de->d_name); + if (stat(path, &st) || /* stat, not lstat */ + !S_ISREG(st.st_mode) || + !(st.st_mode & S_IXUSR)) + continue; + + entlen = strlen(de->d_name); + if (4 < entlen && !strcmp(de->d_name + entlen - 4, ".exe")) + entlen -= 4; + + if (longest < entlen) + longest = entlen; + + add_cmdname(de->d_name + 4, entlen-4); + } + closedir(dir); + + printf("git commands available in '%s'\n", exec_path); + printf("----------------------------"); + mput_char('-', strlen(exec_path)); + putchar('\n'); + pretty_print_string_list(cmdname, longest - 4); + putchar('\n'); +} + +#ifdef __GNUC__ +static void usage(const char *exec_path, const char *fmt, ...) + __attribute__((__format__(__printf__, 2, 3), __noreturn__)); +#endif +static void usage(const char *exec_path, const char *fmt, ...) +{ + if (fmt) { + va_list ap; + + va_start(ap, fmt); + printf("git: "); + vprintf(fmt, ap); + va_end(ap); + putchar('\n'); + } + else + puts(git_usage); + + putchar('\n'); + + if(exec_path) + list_commands(exec_path, "git-*"); + + exit(1); +} + +static void prepend_to_path(const char *dir, int len) +{ + char *path, *old_path = getenv("PATH"); + int path_len = len; + + if (!old_path) + old_path = "/usr/local/bin:/usr/bin:/bin"; + + path_len = len + strlen(old_path) + 1; + + path = malloc(path_len + 1); + path[path_len + 1] = '\0'; + + memcpy(path, dir, len); + path[len] = ':'; + memcpy(path + len + 1, old_path, path_len - len); + + setenv("PATH", path, 1); +} + +static void show_man_page(char *git_cmd) +{ + char *page; + + if (!strncmp(git_cmd, "git", 3)) + page = git_cmd; + else { + int page_len = strlen(git_cmd) + 4; + + page = malloc(page_len + 1); + strcpy(page, "git-"); + strcpy(page + 4, git_cmd); + page[page_len] = 0; + } + + execlp("man", "man", page, NULL); +} + +int main(int argc, char **argv, char **envp) +{ + char git_command[PATH_MAX + 1]; + char wd[PATH_MAX + 1]; + int i, len, show_help = 0; + char *exec_path = getenv("GIT_EXEC_PATH"); + + getcwd(wd, PATH_MAX); + + if (!exec_path) + exec_path = GIT_EXEC_PATH; + + for (i = 1; i < argc; i++) { + char *arg = argv[i]; + + if (strncmp(arg, "--", 2)) + break; + + arg += 2; + + if (!strncmp(arg, "exec-path", 9)) { + arg += 9; + if (*arg == '=') + exec_path = arg + 1; + else { + puts(exec_path); + exit(0); + } + } + else if (!strcmp(arg, "version")) { + printf("git version %s\n", GIT_VERSION); + exit(0); + } + else if (!strcmp(arg, "help")) + show_help = 1; + else if (!show_help) + usage(NULL, NULL); + } + + if (i >= argc || show_help) { + if (i >= argc) + usage(exec_path, NULL); + + show_man_page(argv[i]); + } + + if (*exec_path != '/') { + if (!getcwd(git_command, sizeof(git_command))) { + fprintf(stderr, + "git: cannot determine current directory"); + exit(1); + } + len = strlen(git_command); + + /* Trivial cleanup */ + while (!strncmp(exec_path, "./", 2)) { + exec_path += 2; + while (*exec_path == '/') + *exec_path++; + } + snprintf(git_command + len, sizeof(git_command) - len, + "/%s", exec_path); + } + else + strcpy(git_command, exec_path); + len = strlen(git_command); + prepend_to_path(git_command, len); + + strncat(&git_command[len], "/git-", sizeof(git_command) - len); + len += 5; + strncat(&git_command[len], argv[i], sizeof(git_command) - len); + + if (access(git_command, X_OK)) + usage(exec_path, "'%s' is not a git-command", argv[i]); + + /* execve() can only ever return if it fails */ + execve(git_command, &argv[i], envp); + printf("Failed to run command '%s': %s\n", git_command, strerror(errno)); + + return 1; +} |