win32: code shrink popen(3)

- Replace the half-baked code to quote the command passed to
  popen(3) with a call to quote_arg().

- Where the command to be run is a non-overridden applet in the
  current binary pass the path to the binary to CreateProcess()
  instead of adding '--busybox' to the command.

Saves 128-136 bytes.

1 files changed, 13 insertions, 40 deletions

diff --git a/win32/popen.c b/win32/popen.c
index 79433a27b..69c913b70 100644
--- a/win32/popen.c
+++ b/win32/popen.c
@@ -115,10 +115,8 @@ FILE *mingw_popen(const char *cmd, const char *mode)
         pipe_data *p;
         FILE *fptr = NULL;
         int fd;
-        int len, count;
-        char *cmd_buff = NULL;
-        const char *s;
-        char *t;
+        char *arg, *cmd_buff;
+        const char *exe = NULL;
 
         if ( cmd == NULL || *cmd == '\0' || mode == NULL ||
                         (*mode != 'r' && *mode != 'w') ) {
@@ -130,43 +128,21 @@ FILE *mingw_popen(const char *cmd, const char *mode)
                 return NULL;
         }
 
-        /* count double quotes */
-        count = 0;
-        for ( s=cmd; *s; ++s ) {
-                if ( *s == '"' ) {
-                        ++count;
-                }
-        }
-
-        len = strlen(bb_busybox_exec_path) + strlen(cmd) + 32 + count;
-        if ( (cmd_buff=malloc(len)) == NULL ) {
-                return NULL;
-        }
-        cmd_buff[0] = '\0';
-
 #if ENABLE_FEATURE_PREFER_APPLETS && NUM_APPLETS > 1
         if (find_applet_by_name("sh") >= 0) {
-                sprintf(cmd_buff, "%s --busybox ", bb_busybox_exec_path);
+                exe = bb_busybox_exec_path;
         }
 #endif
-        strcat(cmd_buff, "sh -c \"");
-
-        /* escape double quotes */
-        for ( s=cmd,t=cmd_buff+strlen(cmd_buff); *s; ++s ) {
-                if ( *s == '"' ) {
-                        *t++ = '\\';
-                }
-                *t++ = *s;
-        }
-        *t++ = '"';
-        *t = '\0';
+        arg = quote_arg(cmd);
+        cmd_buff = xasprintf("sh -c %s", arg);
 
         /* Create the pipe */
-        if ((fd=mingw_popen_internal(p, NULL, cmd_buff, mode, -1, NULL)) != -1) {
+        if ((fd=mingw_popen_internal(p, exe, cmd_buff, mode, -1, NULL)) != -1) {
                 fptr = _fdopen(fd, *mode == 'r' ? "rb" : "wb");
         }
 
         free(cmd_buff);
+        free(arg);
 
         return fptr;
 }
@@ -311,7 +287,8 @@ int mingw_pclose(FILE *fp)
  * file; with mode "r" and a decompressor in open_transformer. */
 pid_t mingw_fork_compressor(int fd, const char *compressor, const char *mode)
 {
-        char *cmd, *exe = NULL;
+        char *cmd, *freeme = NULL;
+        const char *exe = NULL;
         int fd1;
         pid_t pid;
 
@@ -323,25 +300,21 @@ pid_t mingw_fork_compressor(int fd, const char *compressor, const char *mode)
                 && !(mode[0] == 'w' && index_in_strings("lzma\0xz\0", compressor) >= 0)
 # endif
                 ) {
-                // shared format string
-                cmd = xasprintf("%s --busybox %s -cf -", bb_busybox_exec_path,
-                                        compressor);
+                exe = bb_busybox_exec_path;
         } else {
                 // Look up compressor on PATH
-                exe = find_first_executable(compressor);
+                exe = freeme = find_first_executable(compressor);
                 if (exe == NULL)
                         bb_perror_msg_and_die("can't execute '%s'", compressor);
-                cmd = xasprintf("%s --busybox %s -cf -" + 13, compressor);
         }
-#else
-        cmd = xasprintf("%s -cf -", compressor);
 #endif
+        cmd = xasprintf("%s -cf -", compressor);
 
         if ((fd1 = mingw_popen_fd(exe, cmd, mode, fd, &pid)) == -1)
                 bb_perror_msg_and_die("can't execute '%s'", compressor);
 
         free(cmd);
-        free(exe);
+        free(freeme);
         xmove_fd(fd1, fd);
         return pid;
 }