mm: rcu-protected get_mm_exe_file()

[linux-2.6-block.git] / lib / string_helpers.c

diff --git a/lib/string_helpers.c b/lib/string_helpers.c
index 8f8c4417f22865d9ffb274700540b37f1a17bd93..1826c7407258f235e97becea57b260584658d128 100644 (file)
--- a/lib/string_helpers.c
+++ b/lib/string_helpers.c
@@ -239,29 +239,21 @@ int string_unescape(char *src, char *dst, size_t size, unsigned int flags)
 }
 EXPORT_SYMBOL(string_unescape);
 
-static int escape_passthrough(unsigned char c, char **dst, size_t *osz)
+static bool escape_passthrough(unsigned char c, char **dst, char *end)
 {
        char *out = *dst;
 
-       if (*osz < 1)
-               return -ENOMEM;
-
-       *out++ = c;
-
-       *dst = out;
-       *osz -= 1;
-
-       return 1;
+       if (out < end)
+               *out = c;
+       *dst = out + 1;
+       return true;
 }
 
-static int escape_space(unsigned char c, char **dst, size_t *osz)
+static bool escape_space(unsigned char c, char **dst, char *end)
 {
        char *out = *dst;
        unsigned char to;
 
-       if (*osz < 2)
-               return -ENOMEM;
-
        switch (c) {
        case '\n':
                to = 'n';
@@ -279,26 +271,25 @@ static int escape_space(unsigned char c, char **dst, size_t *osz)
                to = 'f';
                break;
        default:
-               return 0;
+               return false;
        }
 
-       *out++ = '\\';
-       *out++ = to;
+       if (out < end)
+               *out = '\\';
+       ++out;
+       if (out < end)
+               *out = to;
+       ++out;
 
        *dst = out;
-       *osz -= 2;
-
-       return 1;
+       return true;
 }
 
-static int escape_special(unsigned char c, char **dst, size_t *osz)
+static bool escape_special(unsigned char c, char **dst, char *end)
 {
        char *out = *dst;
        unsigned char to;
 
-       if (*osz < 2)
-               return -ENOMEM;
-
        switch (c) {
        case '\\':
                to = '\\';
@@ -310,71 +301,78 @@ static int escape_special(unsigned char c, char **dst, size_t *osz)
                to = 'e';
                break;
        default:
-               return 0;
+               return false;
        }
 
-       *out++ = '\\';
-       *out++ = to;
+       if (out < end)
+               *out = '\\';
+       ++out;
+       if (out < end)
+               *out = to;
+       ++out;
 
        *dst = out;
-       *osz -= 2;
-
-       return 1;
+       return true;
 }
 
-static int escape_null(unsigned char c, char **dst, size_t *osz)
+static bool escape_null(unsigned char c, char **dst, char *end)
 {
        char *out = *dst;
 
-       if (*osz < 2)
-               return -ENOMEM;
-
        if (c)
-               return 0;
+               return false;
 
-       *out++ = '\\';
-       *out++ = '0';
+       if (out < end)
+               *out = '\\';
+       ++out;
+       if (out < end)
+               *out = '0';
+       ++out;
 
        *dst = out;
-       *osz -= 2;
-
-       return 1;
+       return true;
 }
 
-static int escape_octal(unsigned char c, char **dst, size_t *osz)
+static bool escape_octal(unsigned char c, char **dst, char *end)
 {
        char *out = *dst;
 
-       if (*osz < 4)
-               return -ENOMEM;
-
-       *out++ = '\\';
-       *out++ = ((c >> 6) & 0x07) + '0';
-       *out++ = ((c >> 3) & 0x07) + '0';
-       *out++ = ((c >> 0) & 0x07) + '0';
+       if (out < end)
+               *out = '\\';
+       ++out;
+       if (out < end)
+               *out = ((c >> 6) & 0x07) + '0';
+       ++out;
+       if (out < end)
+               *out = ((c >> 3) & 0x07) + '0';
+       ++out;
+       if (out < end)
+               *out = ((c >> 0) & 0x07) + '0';
+       ++out;
 
        *dst = out;
-       *osz -= 4;
-
-       return 1;
+       return true;
 }
 
-static int escape_hex(unsigned char c, char **dst, size_t *osz)
+static bool escape_hex(unsigned char c, char **dst, char *end)
 {
        char *out = *dst;
 
-       if (*osz < 4)
-               return -ENOMEM;
-
-       *out++ = '\\';
-       *out++ = 'x';
-       *out++ = hex_asc_hi(c);
-       *out++ = hex_asc_lo(c);
+       if (out < end)
+               *out = '\\';
+       ++out;
+       if (out < end)
+               *out = 'x';
+       ++out;
+       if (out < end)
+               *out = hex_asc_hi(c);
+       ++out;
+       if (out < end)
+               *out = hex_asc_lo(c);
+       ++out;
 
        *dst = out;
-       *osz -= 4;
-
-       return 1;
+       return true;
 }
 
 /**
@@ -426,19 +424,17 @@ static int escape_hex(unsigned char c, char **dst, size_t *osz)
  * it if needs.
  *
  * Return:
- * The amount of the characters processed to the destination buffer, or
- * %-ENOMEM if the size of buffer is not enough to put an escaped character is
- * returned.
- *
- * Even in the case of error @dst pointer will be updated to point to the byte
- * after the last processed character.
+ * The total size of the escaped output that would be generated for
+ * the given input and flags. To check whether the output was
+ * truncated, compare the return value to osz. There is room left in
+ * dst for a '\0' terminator if and only if ret < osz.
  */
-int string_escape_mem(const char *src, size_t isz, char **dst, size_t osz,
+int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz,
                      unsigned int flags, const char *esc)
 {
-       char *out = *dst, *p = out;
+       char *p = dst;
+       char *end = p + osz;
        bool is_dict = esc && *esc;
-       int ret = 0;
 
        while (isz--) {
                unsigned char c = *src++;
@@ -458,55 +454,26 @@ int string_escape_mem(const char *src, size_t isz, char **dst, size_t osz,
                    (is_dict && !strchr(esc, c))) {
                        /* do nothing */
                } else {
-                       if (flags & ESCAPE_SPACE) {
-                               ret = escape_space(c, &p, &osz);
-                               if (ret < 0)
-                                       break;
-                               if (ret > 0)
-                                       continue;
-                       }
-
-                       if (flags & ESCAPE_SPECIAL) {
-                               ret = escape_special(c, &p, &osz);
-                               if (ret < 0)
-                                       break;
-                               if (ret > 0)
-                                       continue;
-                       }
-
-                       if (flags & ESCAPE_NULL) {
-                               ret = escape_null(c, &p, &osz);
-                               if (ret < 0)
-                                       break;
-                               if (ret > 0)
-                                       continue;
-                       }
+                       if (flags & ESCAPE_SPACE && escape_space(c, &p, end))
+                               continue;
+
+                       if (flags & ESCAPE_SPECIAL && escape_special(c, &p, end))
+                               continue;
+
+                       if (flags & ESCAPE_NULL && escape_null(c, &p, end))
+                               continue;
 
                        /* ESCAPE_OCTAL and ESCAPE_HEX always go last */
-                       if (flags & ESCAPE_OCTAL) {
-                               ret = escape_octal(c, &p, &osz);
-                               if (ret < 0)
-                                       break;
+                       if (flags & ESCAPE_OCTAL && escape_octal(c, &p, end))
                                continue;
-                       }
-                       if (flags & ESCAPE_HEX) {
-                               ret = escape_hex(c, &p, &osz);
-                               if (ret < 0)
-                                       break;
+
+                       if (flags & ESCAPE_HEX && escape_hex(c, &p, end))
                                continue;
-                       }
                }
 
-               ret = escape_passthrough(c, &p, &osz);
-               if (ret < 0)
-                       break;
+               escape_passthrough(c, &p, end);
        }
 
-       *dst = p;
-
-       if (ret < 0)
-               return ret;
-
-       return p - out;
+       return p - dst;
 }
 EXPORT_SYMBOL(string_escape_mem);