git

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#include "git-compat-util.h"
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#include "abspath.h"
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#include "environment.h"
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#include "exec-cmd.h"
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#include "gettext.h"
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#include "path.h"
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#include "run-command.h"
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#include "strvec.h"
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#include "trace.h"
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#include "trace2.h"
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#if defined(RUNTIME_PREFIX)
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#if defined(HAVE_NS_GET_EXECUTABLE_PATH)
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#include <mach-o/dyld.h>
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#endif
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#if defined(HAVE_BSD_KERN_PROC_SYSCTL)
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#include <sys/param.h>
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#include <sys/types.h>
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#include <sys/sysctl.h>
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#endif
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#endif /* RUNTIME_PREFIX */
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#define MAX_ARGS 32
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static const char *system_prefix(void);
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#ifdef RUNTIME_PREFIX
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/**
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 * When using a runtime prefix, Git dynamically resolves paths relative to its
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 * executable.
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 *
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 * The method for determining the path of the executable is highly
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 * platform-specific.
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 */
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/**
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 * Path to the current Git executable. Resolved on startup by
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 * 'git_resolve_executable_dir'.
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 */
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static const char *executable_dirname;
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static const char *system_prefix(void)
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{
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	static const char *prefix;
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	assert(executable_dirname);
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	assert(is_absolute_path(executable_dirname));
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	if (!prefix &&
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	    !(prefix = strip_path_suffix(executable_dirname, GIT_EXEC_PATH)) &&
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	    !(prefix = strip_path_suffix(executable_dirname, BINDIR)) &&
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	    !(prefix = strip_path_suffix(executable_dirname, "git"))) {
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		prefix = FALLBACK_RUNTIME_PREFIX;
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		trace_printf("RUNTIME_PREFIX requested, "
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				"but prefix computation failed.  "
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				"Using static fallback '%s'.\n", prefix);
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	}
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	return prefix;
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}
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/*
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 * Resolves the executable path from argv[0], only if it is absolute.
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 *
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 * Returns 0 on success, -1 on failure.
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 */
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static int git_get_exec_path_from_argv0(struct strbuf *buf, const char *argv0)
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{
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	const char *slash;
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	if (!argv0 || !*argv0)
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		return -1;
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	slash = find_last_dir_sep(argv0);
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	if (slash) {
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		trace_printf("trace: resolved executable path from argv0: %s\n",
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			     argv0);
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		strbuf_add_absolute_path(buf, argv0);
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		return 0;
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	}
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	return -1;
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}
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#ifdef PROCFS_EXECUTABLE_PATH
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/*
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 * Resolves the executable path by examining a procfs symlink.
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 *
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 * Returns 0 on success, -1 on failure.
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 */
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static int git_get_exec_path_procfs(struct strbuf *buf)
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{
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	if (strbuf_realpath(buf, PROCFS_EXECUTABLE_PATH, 0)) {
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		trace_printf(
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			"trace: resolved executable path from procfs: %s\n",
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			buf->buf);
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		return 0;
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	}
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	return -1;
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}
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#endif /* PROCFS_EXECUTABLE_PATH */
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#ifdef HAVE_BSD_KERN_PROC_SYSCTL
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/*
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 * Resolves the executable path using KERN_PROC_PATHNAME BSD sysctl.
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 *
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 * Returns 0 on success, -1 on failure.
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 */
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static int git_get_exec_path_bsd_sysctl(struct strbuf *buf)
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{
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	int mib[4];
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	char path[MAXPATHLEN];
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	size_t cb = sizeof(path);
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	mib[0] = CTL_KERN;
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	mib[1] = KERN_PROC;
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	mib[2] = KERN_PROC_PATHNAME;
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	mib[3] = -1;
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	if (!sysctl(mib, 4, path, &cb, NULL, 0)) {
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		trace_printf(
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			"trace: resolved executable path from sysctl: %s\n",
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			path);
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		strbuf_addstr(buf, path);
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		return 0;
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	}
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	return -1;
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}
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#endif /* HAVE_BSD_KERN_PROC_SYSCTL */
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#ifdef HAVE_NS_GET_EXECUTABLE_PATH
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/*
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 * Resolves the executable path by querying Darwin application stack.
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 *
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 * Returns 0 on success, -1 on failure.
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 */
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static int git_get_exec_path_darwin(struct strbuf *buf)
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{
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	char path[PATH_MAX];
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	uint32_t size = sizeof(path);
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	if (!_NSGetExecutablePath(path, &size)) {
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		trace_printf(
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			"trace: resolved executable path from Darwin stack: %s\n",
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			path);
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		strbuf_addstr(buf, path);
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		return 0;
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	}
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	return -1;
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}
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#endif /* HAVE_NS_GET_EXECUTABLE_PATH */
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#ifdef HAVE_WPGMPTR
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/*
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 * Resolves the executable path by using the global variable _wpgmptr.
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 *
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 * Returns 0 on success, -1 on failure.
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 */
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static int git_get_exec_path_wpgmptr(struct strbuf *buf)
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{
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	int len = wcslen(_wpgmptr) * 3 + 1;
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	strbuf_grow(buf, len);
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	len = xwcstoutf(buf->buf, _wpgmptr, len);
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	if (len < 0)
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		return -1;
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	buf->len += len;
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	return 0;
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}
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#endif /* HAVE_WPGMPTR */
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/*
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 * Resolves the absolute path of the current executable.
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 *
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 * Returns 0 on success, -1 on failure.
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 */
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static int git_get_exec_path(struct strbuf *buf, const char *argv0)
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{
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	/*
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	 * Identifying the executable path is operating system specific.
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	 * Selectively employ all available methods in order of preference,
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	 * preferring highly-available authoritative methods over
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	 * selectively-available or non-authoritative methods.
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	 *
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	 * All cases fall back on resolving against argv[0] if there isn't a
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	 * better functional method. However, note that argv[0] can be
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	 * used-supplied on many operating systems, and is not authoritative
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	 * in those cases.
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	 *
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	 * Each of these functions returns 0 on success, so evaluation will stop
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	 * after the first successful method.
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	 */
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	if (
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#ifdef HAVE_BSD_KERN_PROC_SYSCTL
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		git_get_exec_path_bsd_sysctl(buf) &&
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#endif /* HAVE_BSD_KERN_PROC_SYSCTL */
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#ifdef HAVE_NS_GET_EXECUTABLE_PATH
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		git_get_exec_path_darwin(buf) &&
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#endif /* HAVE_NS_GET_EXECUTABLE_PATH */
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#ifdef PROCFS_EXECUTABLE_PATH
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		git_get_exec_path_procfs(buf) &&
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#endif /* PROCFS_EXECUTABLE_PATH */
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#ifdef HAVE_WPGMPTR
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		git_get_exec_path_wpgmptr(buf) &&
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#endif /* HAVE_WPGMPTR */
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		git_get_exec_path_from_argv0(buf, argv0)) {
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		return -1;
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	}
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	if (strbuf_normalize_path(buf)) {
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		trace_printf("trace: could not normalize path: %s\n", buf->buf);
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		return -1;
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	}
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	trace2_cmd_path(buf->buf);
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	return 0;
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}
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void git_resolve_executable_dir(const char *argv0)
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{
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	struct strbuf buf = STRBUF_INIT;
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	char *resolved;
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	const char *slash;
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	if (git_get_exec_path(&buf, argv0)) {
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		trace_printf(
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			"trace: could not determine executable path from: %s\n",
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			argv0);
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		strbuf_release(&buf);
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		return;
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	}
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	resolved = strbuf_detach(&buf, NULL);
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	slash = find_last_dir_sep(resolved);
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	if (slash)
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		resolved[slash - resolved] = '\0';
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	executable_dirname = resolved;
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	trace_printf("trace: resolved executable dir: %s\n",
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		     executable_dirname);
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}
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#else
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/*
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 * When not using a runtime prefix, Git uses a hard-coded path.
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 */
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static const char *system_prefix(void)
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{
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	return FALLBACK_RUNTIME_PREFIX;
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}
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/*
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 * This is called during initialization, but No work needs to be done here when
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 * runtime prefix is not being used.
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 */
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void git_resolve_executable_dir(const char *argv0 UNUSED)
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{
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}
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#endif /* RUNTIME_PREFIX */
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char *system_path(const char *path)
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{
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	struct strbuf d = STRBUF_INIT;
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	if (is_absolute_path(path))
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		return xstrdup(path);
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	strbuf_addf(&d, "%s/%s", system_prefix(), path);
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	return strbuf_detach(&d, NULL);
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}
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static const char *exec_path_value;
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void git_set_exec_path(const char *exec_path)
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{
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	exec_path_value = exec_path;
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	/*
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	 * Propagate this setting to external programs.
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	 */
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	setenv(EXEC_PATH_ENVIRONMENT, exec_path, 1);
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}
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/* Returns the highest-priority location to look for git programs. */
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const char *git_exec_path(void)
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{
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	if (!exec_path_value) {
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		const char *env = getenv(EXEC_PATH_ENVIRONMENT);
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		if (env && *env)
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			exec_path_value = xstrdup(env);
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		else
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			exec_path_value = system_path(GIT_EXEC_PATH);
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	}
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	return exec_path_value;
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}
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static void add_path(struct strbuf *out, const char *path)
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{
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	if (path && *path) {
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		strbuf_add_absolute_path(out, path);
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		strbuf_addch(out, PATH_SEP);
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	}
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}
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void setup_path(void)
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{
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	const char *exec_path = git_exec_path();
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	const char *old_path = getenv("PATH");
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	struct strbuf new_path = STRBUF_INIT;
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	git_set_exec_path(exec_path);
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	add_path(&new_path, exec_path);
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	if (old_path)
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		strbuf_addstr(&new_path, old_path);
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	else
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		strbuf_addstr(&new_path, _PATH_DEFPATH);
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	setenv("PATH", new_path.buf, 1);
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	strbuf_release(&new_path);
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}
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const char **prepare_git_cmd(struct strvec *out, const char **argv)
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{
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	strvec_push(out, "git");
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	strvec_pushv(out, argv);
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	return out->v;
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}
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int execv_git_cmd(const char **argv)
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{
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	struct strvec nargv = STRVEC_INIT;
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	prepare_git_cmd(&nargv, argv);
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	trace_argv_printf(nargv.v, "trace: exec:");
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	/* execvp() can only ever return if it fails */
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	sane_execvp("git", (char **)nargv.v);
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	trace_printf("trace: exec failed: %s\n", strerror(errno));
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	strvec_clear(&nargv);
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	return -1;
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}
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int execl_git_cmd(const char *cmd, ...)
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{
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	int argc;
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	const char *argv[MAX_ARGS + 1];
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	const char *arg;
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	va_list param;
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	va_start(param, cmd);
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	argv[0] = cmd;
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	argc = 1;
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	while (argc < MAX_ARGS) {
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		arg = argv[argc++] = va_arg(param, char *);
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		if (!arg)
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			break;
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	}
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	va_end(param);
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	if (MAX_ARGS <= argc)
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		return error(_("too many args to run %s"), cmd);
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	argv[argc] = NULL;
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	return execv_git_cmd(argv);
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}
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