prepare_{git,shell}_cmd: use argv_array

These functions transform an existing argv into one suitable
for exec-ing or spawning via git or a shell. We can use an
argv_array in each to avoid dealing with manual counting and
allocation.

This also makes the memory allocation more clear and fixes
some leaks. In prepare_shell_cmd, we would sometimes
allocate a new string with "$@" in it and sometimes not,
meaning the caller could not correctly free it. On the
non-Windows side, we are in a child process which will
exec() or exit() immediately, so the leak isn't a big deal.
On Windows, though, we use spawn() from the parent process,
and leak a string for each shell command we run. On top of
that, the Windows code did not free the allocated argv array
at all (but does for the prepare_git_cmd case!).

By switching both of these functions to write into an
argv_array, we can consistently free the result as
appropriate.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/exec_cmd.c b/exec_cmd.c
index e85f0fd..cf442a9 100644 (file)
--- a/exec_cmd.c
+++ b/exec_cmd.c
@@ -1,6 +1,7 @@
 #include "cache.h"
 #include "exec_cmd.h"
 #include "quote.h"
+#include "argv-array.h"
 #define MAX_ARGS       32
 
 static const char *argv_exec_path;
@@ -107,32 +108,25 @@ void setup_path(void)
        strbuf_release(&new_path);
 }
 
-const char **prepare_git_cmd(const char **argv)
+const char **prepare_git_cmd(struct argv_array *out, const char **argv)
 {
-       int argc;
-       const char **nargv;
-
-       for (argc = 0; argv[argc]; argc++)
-               ; /* just counting */
-       nargv = xmalloc(sizeof(*nargv) * (argc + 2));
-
-       nargv[0] = "git";
-       for (argc = 0; argv[argc]; argc++)
-               nargv[argc + 1] = argv[argc];
-       nargv[argc + 1] = NULL;
-       return nargv;
+       argv_array_push(out, "git");
+       argv_array_pushv(out, argv);
+       return out->argv;
 }
 
 int execv_git_cmd(const char **argv) {
-       const char **nargv = prepare_git_cmd(argv);
-       trace_argv_printf(nargv, "trace: exec:");
+       struct argv_array nargv = ARGV_ARRAY_INIT;
+
+       prepare_git_cmd(&nargv, argv);
+       trace_argv_printf(nargv.argv, "trace: exec:");
 
        /* execvp() can only ever return if it fails */
-       sane_execvp("git", (char **)nargv);
+       sane_execvp("git", (char **)nargv.argv);
 
        trace_printf("trace: exec failed: %s\n", strerror(errno));
 
-       free(nargv);
+       argv_array_clear(&nargv);
        return -1;
 }
 

diff --git a/exec_cmd.h b/exec_cmd.h
index 93b0c02..1f6b433 100644 (file)
--- a/exec_cmd.h
+++ b/exec_cmd.h
@@ -1,11 +1,13 @@
 #ifndef GIT_EXEC_CMD_H
 #define GIT_EXEC_CMD_H
 
+struct argv_array;
+
 extern void git_set_argv_exec_path(const char *exec_path);
 extern const char *git_extract_argv0_path(const char *path);
 extern const char *git_exec_path(void);
 extern void setup_path(void);
-extern const char **prepare_git_cmd(const char **argv);
+extern const char **prepare_git_cmd(struct argv_array *out, const char **argv);
 extern int execv_git_cmd(const char **argv); /* NULL terminated */
 LAST_ARG_MUST_BE_NULL
 extern int execl_git_cmd(const char *cmd, ...);

diff --git a/run-command.c b/run-command.c
index 13fa452..171cbaa 100644 (file)
--- a/run-command.c
+++ b/run-command.c
@@ -158,50 +158,41 @@ int sane_execvp(const char *file, char * const argv[])
        return -1;
 }
 
-static const char **prepare_shell_cmd(const char **argv)
+static const char **prepare_shell_cmd(struct argv_array *out, const char **argv)
 {
-       int argc, nargc = 0;
-       const char **nargv;
-
-       for (argc = 0; argv[argc]; argc++)
-               ; /* just counting */
-       /* +1 for NULL, +3 for "sh -c" plus extra $0 */
-       nargv = xmalloc(sizeof(*nargv) * (argc + 1 + 3));
-
-       if (argc < 1)
+       if (!argv[0])
                die("BUG: shell command is empty");
 
        if (strcspn(argv[0], "|&;<>()$`\\\"' \t\n*?[#~=%") != strlen(argv[0])) {
 #ifndef GIT_WINDOWS_NATIVE
-               nargv[nargc++] = SHELL_PATH;
+               argv_array_push(out, SHELL_PATH);
 #else
-               nargv[nargc++] = "sh";
+               argv_array_push(out, "sh");
 #endif
-               nargv[nargc++] = "-c";
-
-               if (argc < 2)
-                       nargv[nargc++] = argv[0];
-               else {
-                       struct strbuf arg0 = STRBUF_INIT;
-                       strbuf_addf(&arg0, "%s \"$@\"", argv[0]);
-                       nargv[nargc++] = strbuf_detach(&arg0, NULL);
-               }
-       }
+               argv_array_push(out, "-c");
 
-       for (argc = 0; argv[argc]; argc++)
-               nargv[nargc++] = argv[argc];
-       nargv[nargc] = NULL;
+               /*
+                * If we have no extra arguments, we do not even need to
+                * bother with the "$@" magic.
+                */
+               if (!argv[1])
+                       argv_array_push(out, argv[0]);
+               else
+                       argv_array_pushf(out, "%s \"$@\"", argv[0]);
+       }
 
-       return nargv;
+       argv_array_pushv(out, argv);
+       return out->argv;
 }
 
 #ifndef GIT_WINDOWS_NATIVE
 static int execv_shell_cmd(const char **argv)
 {
-       const char **nargv = prepare_shell_cmd(argv);
-       trace_argv_printf(nargv, "trace: exec:");
-       sane_execvp(nargv[0], (char **)nargv);
-       free(nargv);
+       struct argv_array nargv = ARGV_ARRAY_INIT;
+       prepare_shell_cmd(&nargv, argv);
+       trace_argv_printf(nargv.argv, "trace: exec:");
+       sane_execvp(nargv.argv[0], (char **)nargv.argv);
+       argv_array_clear(&nargv);
        return -1;
 }
 #endif
@@ -455,6 +446,7 @@ fail_pipe:
 {
        int fhin = 0, fhout = 1, fherr = 2;
        const char **sargv = cmd->argv;
+       struct argv_array nargv = ARGV_ARRAY_INIT;
 
        if (cmd->no_stdin)
                fhin = open("/dev/null", O_RDWR);
@@ -480,9 +472,9 @@ fail_pipe:
                fhout = dup(cmd->out);
 
        if (cmd->git_cmd)
-               cmd->argv = prepare_git_cmd(cmd->argv);
+               cmd->argv = prepare_git_cmd(&nargv, cmd->argv);
        else if (cmd->use_shell)
-               cmd->argv = prepare_shell_cmd(cmd->argv);
+               cmd->argv = prepare_shell_cmd(&nargv, cmd->argv);
 
        cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, (char**) cmd->env,
                        cmd->dir, fhin, fhout, fherr);
@@ -492,9 +484,7 @@ fail_pipe:
        if (cmd->clean_on_exit && cmd->pid >= 0)
                mark_child_for_cleanup(cmd->pid);
 
-       if (cmd->git_cmd)
-               free(cmd->argv);
-
+       argv_array_clear(&nargv);
        cmd->argv = sargv;
        if (fhin != 0)
                close(fhin);