vi: make status line less confusing when we open non-readable files,

require rood to use w! when saving non-writable files.
Patch by Natanael Copa <natanael.copa@gmail.com>

update_ro_status                                       -      73     +73
edit_file                                            819     822      +3
colon                                               3440    3425     -15
.rodata                                           128090  128058     -32
file_insert                                          288     235     -53
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 1/3 up/down: 76/-100)           Total: -24 bytes
   text    data     bss     dec     hex filename
 673344    2740   13968  690052   a8784 busybox_old
 673320    2740   13968  690028   a876c busybox_unstripped

1 files changed, 40 insertions, 59 deletions

diff --git a/editors/vi.c b/editors/vi.c
index 01d45e50e..fda29acfb 100644
--- a/editors/vi.c
+++ b/editors/vi.c
@@ -229,7 +229,12 @@ static int mysleep(int);	// sleep for 'h' 1/100 seconds
 static char readit(void);       // read (maybe cursor) key from stdin
 static char get_one_char(void); // read 1 char from stdin
 static int file_size(const char *);   // what is the byte size of "fn"
-static int file_insert(char *, char *, int);
+static int file_insert(char *, char *);
+#if ENABLE_FEATURE_VI_READONLY
+static void update_ro_status(const char *);
+#else
+static ALWAYS_INLINE void update_ro_status(const char *name) {}
+#endif
 static int file_write(char *, char *, char *);
 static void place_cursor(int, int, int);
 static void screen_erase(void);
@@ -419,8 +424,9 @@ static void edit_file(char * fn)
         new_text(size);         // get a text[] buffer
         screenbegin = dot = end = text;
         if (fn != 0) {
-                ch = file_insert(fn, text, cnt);
-        }
+                ch = file_insert(fn, text);
+                update_ro_status(fn);
+        } 
         if (ch < 1) {
                 char_insert(text, '\n');        // start empty buf with dummy line
         }
@@ -654,7 +660,6 @@ static void colon(char * buf)
         char *fn, cmd[MAX_LINELEN], args[MAX_LINELEN];
         int i, l, li, ch, b, e;
         int useforce = FALSE, forced = FALSE;
-        struct stat st_buf;
 
         // :3154        // if (-e line 3154) goto it  else stay put
         // :4,33w! foo  // write a portion of buffer to file "foo"
@@ -758,6 +763,7 @@ static void colon(char * buf)
                 dot_skip_over_ws();
         } else if (strncasecmp(cmd, "edit", i) == 0) {  // Edit a file
                 int sr;
+                struct stat st_buf;
                 sr= 0;
                 // don't edit, if the current file has been modified
                 if (file_modified && ! useforce) {
@@ -809,7 +815,8 @@ static void colon(char * buf)
                 screenbegin = dot = end = text;
 
                 // insert new file
-                ch = file_insert(fn, text, file_size(fn));
+                ch = file_insert(fn, text);
+                update_ro_status(fn);
 
                 if (ch < 1) {
                         // start empty buf with dummy line
@@ -937,25 +944,15 @@ static void colon(char * buf)
                 // read after current line- unless user said ":0r foo"
                 if (b != 0)
                         q = next_line(q);
-#if ENABLE_FEATURE_VI_READONLY
-                l = readonly;                   // remember current files' status
-#endif
-                ch = file_insert(fn, q, file_size(fn));
-#if ENABLE_FEATURE_VI_READONLY
-                readonly = l;
-#endif
+                ch = file_insert(fn, q);
                 if (ch < 0)
                         goto vc1;       // nothing was inserted
                 // how many lines in text[]?
                 li = count_lines(q, q + ch - 1);
                 psb("\"%s\""
-#if ENABLE_FEATURE_VI_READONLY
-                        "%s"
-#endif
+                        USE_FEATURE_VI_READONLY("%s")
                         " %dL, %dC", fn,
-#if ENABLE_FEATURE_VI_READONLY
-                        ((vi_readonly || readonly) ? " [Read only]" : ""),
-#endif
+                        USE_FEATURE_VI_READONLY(((vi_readonly || readonly) ? " [Read only]" : ""),)
                         li, ch);
                 if (ch > 0) {
                         // if the insert is before "dot" then we need to update
@@ -2399,37 +2396,22 @@ static char *get_input_line(const char * prompt) // get input line- use "status
 static int file_size(const char * fn) // what is the byte size of "fn"
 {
         struct stat st_buf;
-        int cnt, sr;
+        int cnt;
 
-        if (!fn || !fn[0])
-                return -1;
         cnt = -1;
-        sr = stat(fn, &st_buf); // see if file exists
-        if (sr >= 0) {
+        if (fn && fn[0] && stat(fn, &st_buf) == 0)      // see if file exists
                 cnt = (int) st_buf.st_size;
-        }
         return cnt;
 }
 
-static int file_insert(char * fn, char * p, int size)
+static int file_insert(char * fn, char * p) 
 {
-        int fd, cnt;
-
-        cnt = -1;
-#if ENABLE_FEATURE_VI_READONLY
-        readonly = FALSE;
-#endif
-        if (!fn || !fn[0]) {
-                psbs("No filename given");
-                goto fi0;
-        }
-        if (size == 0) {
-                // OK- this is just a no-op
-                cnt = 0;
-                goto fi0;
-        }
+        int cnt = -1;
+        int fd, size;
+        
+        size = file_size(fn);
         if (size < 0) {
-                psbs("Trying to insert a negative number (%d) of characters", size);
+                psbs("File does not exist");
                 goto fi0;
         }
         if (p < text || p > end) {
@@ -2437,25 +2419,11 @@ static int file_insert(char * fn, char * p, int size)
                 goto fi0;
         }
 
-        // see if we can open the file
-#if ENABLE_FEATURE_VI_READONLY
-        if (vi_readonly) goto fi1;              // do not try write-mode
-#endif
-        fd = open(fn, O_RDWR);                  // assume read & write
+        // read file to buffer
+        fd = open(fn, O_RDONLY);
         if (fd < 0) {
-                // could not open for writing- maybe file is read only
-#if ENABLE_FEATURE_VI_READONLY
- fi1:
-#endif
-                fd = open(fn, O_RDONLY);        // try read-only
-                if (fd < 0) {
-                        psbs("\"%s\" %s", fn, "cannot open file");
-                        goto fi0;
-                }
-#if ENABLE_FEATURE_VI_READONLY
-                // got the file- read-only
-                readonly = TRUE;
-#endif
+                psbs("\"%s\" %s", fn, "cannot open file");
+                goto fi0;
         }
         p = text_hole_make(p, size);
         cnt = read(fd, p, size);
@@ -2475,6 +2443,19 @@ static int file_insert(char * fn, char * p, int size)
         return cnt;
 }
 
+#if ENABLE_FEATURE_VI_READONLY
+static void update_ro_status(const char *fn)
+{
+        struct stat sb;
+        if (stat(fn, &sb) == 0) {
+                readonly = vi_readonly || (access(fn, W_OK) < 0) ||
+                        /* root will always have access()
+                         * so we check fileperms too */
+                        !(sb.st_mode & (S_IWUSR | S_IWGRP | S_IWOTH));
+        }
+}
+#endif
+
 static int file_write(char * fn, char * first, char * last)
 {
         int fd, cnt, charcnt;