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authorJaben Carsey <jaben.carsey@intel.com>2014-02-12 18:27:07 +0000
committerjcarsey <jcarsey@6f19259b-4bc3-4df7-8a09-765794883524>2014-02-12 18:27:07 +0000
commitd5b5440bf205a37c8ae0ac4b873cd976a9598326 (patch)
treedf734187cc67610a844d18ae45c239c494cb0f86 /ShellPkg/Application
parente6f3ed43400bc9d02ff3e2728579cc9f35f71405 (diff)
downloadedk2-platforms-d5b5440bf205a37c8ae0ac4b873cd976a9598326.tar.xz
ShellPkg: refactor elimination of non-replaced environment variables
This changes how non-replaced environment variables are found and eliminated from the command line. This new method makes sure that the found environment variables are not using escaped characters and that they do not stretch over quoted strings Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Jaben Carsey <jaben.carsey@intel.com> Reviewed-by: Erik Bjorge <erik.c.bjorge@intel.com> git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15242 6f19259b-4bc3-4df7-8a09-765794883524
Diffstat (limited to 'ShellPkg/Application')
-rw-r--r--ShellPkg/Application/Shell/Shell.c142
1 files changed, 108 insertions, 34 deletions
diff --git a/ShellPkg/Application/Shell/Shell.c b/ShellPkg/Application/Shell/Shell.c
index 2d5c89aadf..ba3be3f6c3 100644
--- a/ShellPkg/Application/Shell/Shell.c
+++ b/ShellPkg/Application/Shell/Shell.c
@@ -1277,6 +1277,113 @@ ShellConvertAlias(
}
/**
+ Parse for the next instance of one string within another string. Can optionally make sure that
+ the string was not escaped (^ character) per the shell specification.
+
+ @param[in] SourceString The string to search within
+ @param[in] FindString The string to look for
+ @param[in] CheckForEscapeCharacter TRUE to skip escaped instances of FinfString, otherwise will return even escaped instances
+**/
+CHAR16*
+EFIAPI
+FindNextInstance(
+ IN CONST CHAR16 *SourceString,
+ IN CONST CHAR16 *FindString,
+ IN CONST BOOLEAN CheckForEscapeCharacter
+ )
+{
+ CHAR16 *Temp;
+ if (SourceString == NULL) {
+ return (NULL);
+ }
+ Temp = StrStr(SourceString, FindString);
+
+ //
+ // If nothing found, or we dont care about escape characters
+ //
+ if (Temp == NULL || !CheckForEscapeCharacter) {
+ return (Temp);
+ }
+
+ //
+ // If we found an escaped character, try again on the remainder of the string
+ //
+ if ((Temp > (SourceString)) && *(Temp-1) == L'^') {
+ return FindNextInstance(Temp+1, FindString, CheckForEscapeCharacter);
+ }
+
+ //
+ // we found the right character
+ //
+ return (Temp);
+}
+
+/**
+ This function will eliminate unreplaced (and therefore non-found) environment variables.
+
+ @param[in,out] CmdLine The command line to update.
+**/
+EFI_STATUS
+EFIAPI
+StripUnreplacedEnvironmentVariables(
+ IN OUT CHAR16 *CmdLine
+ )
+{
+ CHAR16 *FirstPercent;
+ CHAR16 *FirstQuote;
+ CHAR16 *SecondPercent;
+ CHAR16 *SecondQuote;
+ CHAR16 *CurrentLocator;
+
+ for (CurrentLocator = CmdLine ; CurrentLocator != NULL ; ) {
+ FirstQuote = FindNextInstance(CurrentLocator, L"\"", TRUE);
+ FirstPercent = FindNextInstance(CurrentLocator, L"%", TRUE);
+ SecondPercent = FirstPercent!=NULL?FindNextInstance(FirstPercent+1, L"%", TRUE):NULL;
+ if (FirstPercent == NULL || SecondPercent == NULL) {
+ //
+ // If we ever dont have 2 % we are done.
+ //
+ break;
+ }
+
+ if (FirstQuote < FirstPercent) {
+ SecondQuote = FirstQuote!= NULL?FindNextInstance(FirstQuote+1, L"\"", TRUE):NULL;
+ //
+ // Quote is first found
+ //
+
+ if (SecondQuote < FirstPercent) {
+ //
+ // restart after the pair of "
+ //
+ CurrentLocator = SecondQuote + 1;
+ } else /* FirstPercent < SecondQuote */{
+ //
+ // Restart on the first percent
+ //
+ CurrentLocator = FirstPercent;
+ }
+ continue;
+ }
+ ASSERT(FirstPercent < FirstQuote);
+ if (SecondPercent < FirstQuote) {
+ //
+ // We need to remove from FirstPercent to SecondPercent
+ //
+ CopyMem(FirstPercent, SecondPercent + 1, StrSize(SecondPercent + 1));
+
+ //
+ // dont need to update the locator. both % characters are gone.
+ //
+ continue;
+ }
+ ASSERT(FirstQuote < SecondPercent);
+ CurrentLocator = FirstQuote;
+ }
+ return (EFI_SUCCESS);
+}
+
+/**
Function allocates a new command line and replaces all instances of environment
variable names that are correctly preset to their values.
@@ -1298,7 +1405,6 @@ ShellConvertVariables (
CHAR16 *NewCommandLine1;
CHAR16 *NewCommandLine2;
CHAR16 *Temp;
- CHAR16 *Temp2;
UINTN ItemSize;
CHAR16 *ItemTemp;
SCRIPT_FILE *CurrentScriptFile;
@@ -1391,39 +1497,7 @@ ShellConvertVariables (
//
// Remove non-existant environment variables in scripts only
//
- for (Temp = NewCommandLine1 ; Temp != NULL ; ) {
- Temp = StrStr(Temp, L"%");
- if (Temp == NULL) {
- break;
- }
- while (*(Temp - 1) == L'^') {
- Temp = StrStr(Temp + 1, L"%");
- if (Temp == NULL) {
- break;
- }
- }
- if (Temp == NULL) {
- break;
- }
-
- Temp2 = StrStr(Temp + 1, L"%");
- if (Temp2 == NULL) {
- break;
- }
- while (*(Temp2 - 1) == L'^') {
- Temp2 = StrStr(Temp2 + 1, L"%");
- if (Temp2 == NULL) {
- break;
- }
- }
- if (Temp2 == NULL) {
- break;
- }
-
- Temp2++;
- CopyMem(Temp, Temp2, StrSize(Temp2));
- }
-
+ StripUnreplacedEnvironmentVariables(NewCommandLine1);
}
//