On Windows the environment variable PATH contains a semicolon-separated
list of directories to search for, in order, when looking for the
location of a binary to run. get_path_split() parses it and returns an
array of string copies, which is iterated by path_lookup(), which in
turn passes each entry to lookup_prog().
Change lookup_prog() to take the directory name as a length-limited
string instead of as a NUL-terminated one and parse PATH directly in
path_lookup(). This avoids memory allocations, simplifying the code.
Helped-by: Johannes Sixt <j6t@xxxxxxxx>
Signed-off-by: Rene Scharfe <l.s.r@xxxxxx>
---
Rebased against Junio's master, fixed string overrun. Can hold and
resubmit in a few months if it gets in the way right now.
compat/mingw.c | 91 +++++++++++++++-------------------------------------------
1 file changed, 23 insertions(+), 68 deletions(-)
diff --git a/compat/mingw.c b/compat/mingw.c
index 3fbfda5978..c6134f7c81 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -941,64 +941,14 @@ static const char *parse_interpreter(const char *cmd)
}
/*
- * Splits the PATH into parts.
- */
-static char **get_path_split(void)
-{
- char *p, **path, *envpath = mingw_getenv("PATH");
- int i, n = 0;
-
- if (!envpath || !*envpath)
- return NULL;
-
- envpath = xstrdup(envpath);
- p = envpath;
- while (p) {
- char *dir = p;
- p = strchr(p, ';');
- if (p) *p++ = '\0';
- if (*dir) { /* not earlier, catches series of ; */
- ++n;
- }
- }
- if (!n)
- return NULL;
-
- ALLOC_ARRAY(path, n + 1);
- p = envpath;
- i = 0;
- do {
- if (*p)
- path[i++] = xstrdup(p);
- p = p+strlen(p)+1;
- } while (i < n);
- path[i] = NULL;
-
- free(envpath);
-
- return path;
-}
-
-static void free_path_split(char **path)
-{
- char **p = path;
-
- if (!path)
- return;
-
- while (*p)
- free(*p++);
- free(path);
-}
-
-/*
* exe_only means that we only want to detect .exe files, but not scripts
* (which do not have an extension)
*/
-static char *lookup_prog(const char *dir, const char *cmd, int isexe, int exe_only)
+static char *lookup_prog(const char *dir, int dirlen, const char *cmd,
+ int isexe, int exe_only)
{
char path[MAX_PATH];
- snprintf(path, sizeof(path), "%s/%s.exe", dir, cmd);
+ snprintf(path, sizeof(path), "%.*s\\%s.exe", dirlen, dir, cmd);
if (!isexe && access(path, F_OK) == 0)
return xstrdup(path);
@@ -1013,17 +963,29 @@ static char *lookup_prog(const char *dir, const char *cmd, int isexe, int exe_on
* Determines the absolute path of cmd using the split path in path.
* If cmd contains a slash or backslash, no lookup is performed.
*/
-static char *path_lookup(const char *cmd, char **path, int exe_only)
+static char *path_lookup(const char *cmd, int exe_only)
{
+ const char *path;
char *prog = NULL;
int len = strlen(cmd);
int isexe = len >= 4 && !strcasecmp(cmd+len-4, ".exe");
if (strchr(cmd, '/') || strchr(cmd, '\\'))
- prog = xstrdup(cmd);
+ return xstrdup(cmd);
+
+ path = mingw_getenv("PATH");
+ if (!path)
+ return NULL;
- while (!prog && *path)
- prog = lookup_prog(*path++, cmd, isexe, exe_only);
+ while (!prog) {
+ const char *sep = strchrnul(path, ';');
+ int dirlen = sep - path;
+ if (dirlen)
+ prog = lookup_prog(path, dirlen, cmd, isexe, exe_only);
+ if (!*sep)
+ break;
+ path = sep + 1;
+ }
return prog;
}
@@ -1190,8 +1152,7 @@ pid_t mingw_spawnvpe(const char *cmd, const char **argv, char **deltaenv,
int fhin, int fhout, int fherr)
{
pid_t pid;
- char **path = get_path_split();
- char *prog = path_lookup(cmd, path, 0);
+ char *prog = path_lookup(cmd, 0);
if (!prog) {
errno = ENOENT;
@@ -1202,7 +1163,7 @@ pid_t mingw_spawnvpe(const char *cmd, const char **argv, char **deltaenv,
if (interpr) {
const char *argv0 = argv[0];
- char *iprog = path_lookup(interpr, path, 1);
+ char *iprog = path_lookup(interpr, 1);
argv[0] = prog;
if (!iprog) {
errno = ENOENT;
@@ -1220,21 +1181,18 @@ pid_t mingw_spawnvpe(const char *cmd, const char **argv, char **deltaenv,
fhin, fhout, fherr);
free(prog);
}
- free_path_split(path);
return pid;
}
static int try_shell_exec(const char *cmd, char *const *argv)
{
const char *interpr = parse_interpreter(cmd);
- char **path;
char *prog;
int pid = 0;
if (!interpr)
return 0;
- path = get_path_split();
- prog = path_lookup(interpr, path, 1);
+ prog = path_lookup(interpr, 1);
if (prog) {
int argc = 0;
const char **argv2;
@@ -1253,7 +1211,6 @@ static int try_shell_exec(const char *cmd, char *const *argv)
free(prog);
free(argv2);
}
- free_path_split(path);
return pid;
}
@@ -1275,8 +1232,7 @@ int mingw_execv(const char *cmd, char *const *argv)
int mingw_execvp(const char *cmd, char *const *argv)
{
- char **path = get_path_split();
- char *prog = path_lookup(cmd, path, 0);
+ char *prog = path_lookup(cmd, 0);
if (prog) {
mingw_execv(prog, argv);
@@ -1284,7 +1240,6 @@ int mingw_execvp(const char *cmd, char *const *argv)
} else
errno = ENOENT;
- free_path_split(path);
return -1;
}
--
2.12.1.windows.1