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kusmakusma
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contrib: add win32 credential-helper
Since the Windows port of Git expects binary pipes, we need to make sure the helper-end also sets up binary pipes. Side-step CRLF-issue in test to make it pass. Signed-off-by: Erik Faye-Lund <kusmabite@gmail.com>
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‎contrib/credential/wincred/Makefile

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all: git-credential-wincred.exe
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CC = gcc
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RM = rm -f
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CFLAGS = -O2 -Wall
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git-credential-wincred.exe : git-credential-wincred.c
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$(LINK.c) $^ $(LOADLIBES) $(LDLIBS) -o $@

‎contrib/credential/wincred/git-credential-wincred.c

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/*
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* A git credential helper that interface with Windows' Credential Manager
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*
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*/
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#include <windows.h>
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#include <stdio.h>
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#include <io.h>
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#include <fcntl.h>
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/* common helpers */
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static void die(const char *err, ...)
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{
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char msg[4096];
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va_list params;
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va_start(params, err);
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vsnprintf(msg, sizeof(msg), err, params);
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fprintf(stderr, "%s\n", msg);
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va_end(params);
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exit(1);
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}
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static void *xmalloc(size_t size)
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{
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void *ret = malloc(size);
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if (!ret && !size)
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ret = malloc(1);
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if (!ret)
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die("Out of memory");
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return ret;
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}
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static char *xstrdup(const char *str)
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{
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char *ret = strdup(str);
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if (!ret)
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die("Out of memory");
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return ret;
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}
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/* MinGW doesn't have wincred.h, so we need to define stuff */
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typedef struct _CREDENTIAL_ATTRIBUTEW {
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LPWSTR Keyword;
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DWORD Flags;
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DWORD ValueSize;
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LPBYTE Value;
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} CREDENTIAL_ATTRIBUTEW, *PCREDENTIAL_ATTRIBUTEW;
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typedef struct _CREDENTIALW {
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DWORD Flags;
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DWORD Type;
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LPWSTR TargetName;
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LPWSTR Comment;
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FILETIME LastWritten;
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DWORD CredentialBlobSize;
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LPBYTE CredentialBlob;
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DWORD Persist;
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DWORD AttributeCount;
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PCREDENTIAL_ATTRIBUTEW Attributes;
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LPWSTR TargetAlias;
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LPWSTR UserName;
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} CREDENTIALW, *PCREDENTIALW;
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#define CRED_TYPE_GENERIC 1
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#define CRED_PERSIST_LOCAL_MACHINE 2
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#define CRED_MAX_ATTRIBUTES 64
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typedef BOOL (WINAPI *CredWriteWT)(PCREDENTIALW, DWORD);
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typedef BOOL (WINAPI *CredUnPackAuthenticationBufferWT)(DWORD, PVOID, DWORD,
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LPWSTR, DWORD *, LPWSTR, DWORD *, LPWSTR, DWORD *);
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typedef BOOL (WINAPI *CredEnumerateWT)(LPCWSTR, DWORD, DWORD *,
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PCREDENTIALW **);
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typedef BOOL (WINAPI *CredPackAuthenticationBufferWT)(DWORD, LPWSTR, LPWSTR,
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PBYTE, DWORD *);
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typedef VOID (WINAPI *CredFreeT)(PVOID);
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typedef BOOL (WINAPI *CredDeleteWT)(LPCWSTR, DWORD, DWORD);
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static HMODULE advapi, credui;
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static CredWriteWT CredWriteW;
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static CredUnPackAuthenticationBufferWT CredUnPackAuthenticationBufferW;
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static CredEnumerateWT CredEnumerateW;
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static CredPackAuthenticationBufferWT CredPackAuthenticationBufferW;
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static CredFreeT CredFree;
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static CredDeleteWT CredDeleteW;
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static void load_cred_funcs(void)
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{
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/* load DLLs */
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advapi = LoadLibrary("advapi32.dll");
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credui = LoadLibrary("credui.dll");
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if (!advapi || !credui)
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die("failed to load DLLs");
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/* get function pointers */
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CredWriteW = (CredWriteWT)GetProcAddress(advapi, "CredWriteW");
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CredUnPackAuthenticationBufferW = (CredUnPackAuthenticationBufferWT)
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GetProcAddress(credui, "CredUnPackAuthenticationBufferW");
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CredEnumerateW = (CredEnumerateWT)GetProcAddress(advapi,
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"CredEnumerateW");
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CredPackAuthenticationBufferW = (CredPackAuthenticationBufferWT)
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GetProcAddress(credui, "CredPackAuthenticationBufferW");
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CredFree = (CredFreeT)GetProcAddress(advapi, "CredFree");
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CredDeleteW = (CredDeleteWT)GetProcAddress(advapi, "CredDeleteW");
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if (!CredWriteW || !CredUnPackAuthenticationBufferW ||
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!CredEnumerateW || !CredPackAuthenticationBufferW || !CredFree ||
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!CredDeleteW)
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die("failed to load functions");
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}
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static char target_buf[1024];
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static char *protocol, *host, *path, *username;
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static WCHAR *wusername, *password, *target;
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static void write_item(const char *what, WCHAR *wbuf)
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{
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char *buf;
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int len = WideCharToMultiByte(CP_UTF8, 0, wbuf, -1, NULL, 0, NULL,
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FALSE);
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buf = xmalloc(len);
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if (!WideCharToMultiByte(CP_UTF8, 0, wbuf, -1, buf, len, NULL, FALSE))
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die("WideCharToMultiByte failed!");
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printf("%s=", what);
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fwrite(buf, 1, len - 1, stdout);
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putchar('\n');
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free(buf);
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}
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static int match_attr(const CREDENTIALW *cred, const WCHAR *keyword,
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const char *want)
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{
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int i;
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if (!want)
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return 1;
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for (i = 0; i < cred->AttributeCount; ++i)
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if (!wcscmp(cred->Attributes[i].Keyword, keyword))
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return !strcmp((const char *)cred->Attributes[i].Value,
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want);
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return 0; /* not found */
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}
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static int match_cred(const CREDENTIALW *cred)
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{
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return (!wusername || !wcscmp(wusername, cred->UserName)) &&
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match_attr(cred, L"git_protocol", protocol) &&
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match_attr(cred, L"git_host", host) &&
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match_attr(cred, L"git_path", path);
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}
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static void get_credential(void)
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{
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WCHAR *user_buf, *pass_buf;
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DWORD user_buf_size = 0, pass_buf_size = 0;
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CREDENTIALW **creds, *cred = NULL;
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DWORD num_creds;
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int i;
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if (!CredEnumerateW(L"git:*", 0, &num_creds, &creds))
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return;
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/* search for the first credential that matches username */
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for (i = 0; i < num_creds; ++i)
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if (match_cred(creds[i])) {
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cred = creds[i];
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break;
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}
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if (!cred)
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return;
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CredUnPackAuthenticationBufferW(0, cred->CredentialBlob,
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cred->CredentialBlobSize, NULL, &user_buf_size, NULL, NULL,
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NULL, &pass_buf_size);
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user_buf = xmalloc(user_buf_size * sizeof(WCHAR));
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pass_buf = xmalloc(pass_buf_size * sizeof(WCHAR));
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if (!CredUnPackAuthenticationBufferW(0, cred->CredentialBlob,
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cred->CredentialBlobSize, user_buf, &user_buf_size, NULL, NULL,
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pass_buf, &pass_buf_size))
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die("CredUnPackAuthenticationBuffer failed");
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CredFree(creds);
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/* zero-terminate (sizes include zero-termination) */
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user_buf[user_buf_size - 1] = L'\0';
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pass_buf[pass_buf_size - 1] = L'\0';
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write_item("username", user_buf);
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write_item("password", pass_buf);
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free(user_buf);
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free(pass_buf);
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}
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static void write_attr(CREDENTIAL_ATTRIBUTEW *attr, const WCHAR *keyword,
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const char *value)
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{
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attr->Keyword = (LPWSTR)keyword;
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attr->Flags = 0;
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attr->ValueSize = strlen(value) + 1; /* store zero-termination */
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attr->Value = (LPBYTE)value;
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}
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static void store_credential(void)
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{
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CREDENTIALW cred;
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BYTE *auth_buf;
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DWORD auth_buf_size = 0;
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CREDENTIAL_ATTRIBUTEW attrs[CRED_MAX_ATTRIBUTES];
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if (!wusername || !password)
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return;
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/* query buffer size */
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CredPackAuthenticationBufferW(0, wusername, password,
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NULL, &auth_buf_size);
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auth_buf = xmalloc(auth_buf_size);
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if (!CredPackAuthenticationBufferW(0, wusername, password,
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auth_buf, &auth_buf_size))
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die("CredPackAuthenticationBuffer failed");
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cred.Flags = 0;
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cred.Type = CRED_TYPE_GENERIC;
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cred.TargetName = target;
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cred.Comment = L"saved by git-credential-wincred";
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cred.CredentialBlobSize = auth_buf_size;
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cred.CredentialBlob = auth_buf;
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cred.Persist = CRED_PERSIST_LOCAL_MACHINE;
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cred.AttributeCount = 2;
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cred.Attributes = attrs;
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cred.TargetAlias = NULL;
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cred.UserName = wusername;
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write_attr(attrs, L"git_protocol", protocol);
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write_attr(attrs + 1, L"git_host", host);
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if (path) {
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write_attr(attrs + 2, L"git_path", path);
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cred.AttributeCount++;
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}
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if (!CredWriteW(&cred, 0))
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die("CredWrite failed");
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}
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static void erase_credential(void)
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{
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CREDENTIALW **creds;
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DWORD num_creds;
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int i;
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if (!CredEnumerateW(L"git:*", 0, &num_creds, &creds))
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return;
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for (i = 0; i < num_creds; ++i) {
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if (match_cred(creds[i]))
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CredDeleteW(creds[i]->TargetName, creds[i]->Type, 0);
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}
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CredFree(creds);
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}
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static WCHAR *utf8_to_utf16_dup(const char *str)
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{
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int wlen = MultiByteToWideChar(CP_UTF8, 0, str, -1, NULL, 0);
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WCHAR *wstr = xmalloc(sizeof(WCHAR) * wlen);
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MultiByteToWideChar(CP_UTF8, 0, str, -1, wstr, wlen);
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return wstr;
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}
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static void read_credential(void)
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{
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char buf[1024];
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while (fgets(buf, sizeof(buf), stdin)) {
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char *v;
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if (!strcmp(buf, "\n"))
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break;
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buf[strlen(buf)-1] = '\0';
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v = strchr(buf, '=');
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if (!v)
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die("bad input: %s", buf);
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*v++ = '\0';
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if (!strcmp(buf, "protocol"))
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protocol = xstrdup(v);
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else if (!strcmp(buf, "host"))
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host = xstrdup(v);
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else if (!strcmp(buf, "path"))
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path = xstrdup(v);
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else if (!strcmp(buf, "username")) {
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username = xstrdup(v);
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wusername = utf8_to_utf16_dup(v);
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} else if (!strcmp(buf, "password"))
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password = utf8_to_utf16_dup(v);
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else
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die("unrecognized input");
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}
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}
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int main(int argc, char *argv[])
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{
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const char *usage =
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"Usage: git credential-wincred <get|store|erase>\n";
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if (!argv[1])
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die(usage);
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/* git use binary pipes to avoid CRLF-issues */
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_setmode(_fileno(stdin), _O_BINARY);
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_setmode(_fileno(stdout), _O_BINARY);
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read_credential();
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load_cred_funcs();
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if (!protocol || !host)
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return 0;
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/* prepare 'target', the unique key for the credential */
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strncat(target_buf, "git:", sizeof(target_buf));
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strncat(target_buf, protocol, sizeof(target_buf));
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strncat(target_buf, "://", sizeof(target_buf));
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if (username) {
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strncat(target_buf, username, sizeof(target_buf));
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strncat(target_buf, "@", sizeof(target_buf));
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}
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strncat(target_buf, host, sizeof(target_buf));
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if (path) {
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strncat(target_buf, "/", sizeof(target_buf));
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strncat(target_buf, path, sizeof(target_buf));
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}
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target = utf8_to_utf16_dup(target_buf);
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if (!strcmp(argv[1], "get"))
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get_credential();
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else if (!strcmp(argv[1], "store"))
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store_credential();
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else if (!strcmp(argv[1], "erase"))
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erase_credential();
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/* otherwise, ignore unknown action */
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return 0;
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}

‎t/lib-credential.sh

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read_chunk >expect-stdout &&
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read_chunk >expect-stderr &&
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test-credential "$@" <stdin >stdout 2>stderr &&
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if test_have_prereq MINGW
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then
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dos2unix -q stderr
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fi &&
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test_cmp expect-stdout stdout &&
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test_cmp expect-stderr stderr
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}

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