git/exec-cmd.c
D Harithamma 987bbcd088 exec_cmd: RUNTIME_PREFIX on z/OS systems
Enable Git to resolve its own binary location using __getprogramdir
and getprogname.

Since /proc is not a mandatory filesystem on z/OS, we cannot rely on the
git_get_exec_path_procfs method to determine Git's executable path. To
address this, we have implemented git_get_exec_path_zos, which resolves
the executable path by extracting it from the current program's
directory and filename.

Signed-off-by: D Harithamma <harithamma.d@ibm.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-08-22 08:58:46 -07:00

397 lines
8.6 KiB
C

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