diff options
Diffstat (limited to 'git.c')
| -rw-r--r-- | git.c | 229 |
1 files changed, 229 insertions, 0 deletions
@@ -0,0 +1,229 @@ +#include <stdio.h> +#include <unistd.h> +#include <stdlib.h> +#include <string.h> +#include <errno.h> +#include <limits.h> +#include <stdarg.h> +#include <glob.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 ]"; + +struct string_list { + size_t len; + char *str; + struct string_list *next; +}; + +/* 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 inline void mput_char(char c, unsigned int num) +{ + while(num--) + putchar(c); +} + +static void pretty_print_string_list(struct string_list *list, 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 */ + + if (space < max_cols) + cols = max_cols / space; + + while (list) { + int c; + printf(" "); + + for (c = cols; c && list; list = list->next) { + printf("%s", list->str); + + if (--c) + mput_char(' ', space - list->len); + } + putchar('\n'); + } +} + +static void list_commands(const char *exec_path, const char *pattern) +{ + struct string_list *list = NULL, *tail = NULL; + unsigned int longest = 0, i; + glob_t gl; + + if (chdir(exec_path) < 0) { + printf("git: '%s': %s\n", exec_path, strerror(errno)); + exit(1); + } + + i = glob(pattern, 0, NULL, &gl); + switch(i) { + case GLOB_NOSPACE: + puts("Out of memory when running glob()"); + exit(2); + case GLOB_ABORTED: + printf("'%s': Read error: %s\n", exec_path, strerror(errno)); + exit(2); + case GLOB_NOMATCH: + printf("No git commands available in '%s'.\n", exec_path); + printf("Do you need to specify --exec-path or set GIT_EXEC_PATH?\n"); + exit(1); + } + + for (i = 0; i < gl.gl_pathc; i++) { + int len = strlen(gl.gl_pathv[i] + 4); + + if (access(gl.gl_pathv[i], X_OK)) + continue; + + if (longest < len) + longest = len; + + if (!tail) + tail = list = malloc(sizeof(struct string_list)); + else { + tail->next = malloc(sizeof(struct string_list)); + tail = tail->next; + } + tail->len = len; + tail->str = gl.gl_pathv[i] + 4; + tail->next = NULL; + } + + printf("git commands available in '%s'\n", exec_path); + printf("----------------------------"); + mput_char('-', strlen(exec_path)); + putchar('\n'); + pretty_print_string_list(list, longest); + 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 = "/bin:/usr/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); +} + +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) + usage(exec_path, NULL); + + /* allow relative paths, but run with exact */ + if (chdir(exec_path)) { + printf("git: '%s': %s\n", exec_path, strerror(errno)); + exit (1); + } + + getcwd(git_command, sizeof(git_command)); + chdir(wd); + + 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; +} |