Merge #6084 from justinmk/fix-coverity-155968

coverity/155968: resource leak

3 files changed, 28 insertions, 36 deletions

diff --git a/src/nvim/globals.h b/src/nvim/globals.h
index 696bdf586f..20a00e1d9c 100644
--- a/src/nvim/globals.h
+++ b/src/nvim/globals.h
@@ -13,10 +13,6 @@
 #include "nvim/types.h"
 #include "nvim/event/loop.h"
 
-/*
- * definition of global variables
- */
-
 #define IOSIZE         (1024+1)          // file I/O and sprintf buffer size
 
 #define MAX_MCO        6                 // maximum value for 'maxcombine'
@@ -25,11 +21,8 @@
 # define MSG_BUF_CLEN  (MSG_BUF_LEN / 6) // cell length (worst case: utf-8
                                          // takes 6 bytes for one cell)
 
-/*
- * Maximum length of a path (for non-unix systems) Make it a bit long, to stay
- * on the safe side.  But not too long to put on the stack.
- * TODO(metrix78): Move this to os_defs.h
- */
+// Maximum length of a file path.  Make it a bit long, to stay
+// on the safe side.  But not too long to put on the stack.
 #ifndef MAXPATHL
 # ifdef MAXPATHLEN
 #  define MAXPATHL  MAXPATHLEN
@@ -108,12 +101,9 @@ typedef enum {
  * They may have different values when the screen wasn't (re)allocated yet
  * after setting Rows or Columns (e.g., when starting up).
  */
-
-#define DFLT_COLS       80              /* default value for 'columns' */
-#define DFLT_ROWS       24              /* default value for 'lines' */
-
+#define DFLT_COLS       80              // default value for 'columns'
+#define DFLT_ROWS       24              // default value for 'lines'
 EXTERN long Rows INIT(= DFLT_ROWS);     // nr of rows in the screen
-
 EXTERN long Columns INIT(= DFLT_COLS);  // nr of columns in the screen
 
 /*
@@ -889,9 +879,11 @@ EXTERN int swap_exists_action INIT(= SEA_NONE);
 EXTERN int swap_exists_did_quit INIT(= FALSE);
 /* Selected "quit" at the dialog. */
 
-EXTERN char_u IObuff[IOSIZE];       /* sprintf's are done in this buffer */
-EXTERN char_u NameBuff[MAXPATHL];   /* buffer for expanding file names */
-EXTERN char_u msg_buf[MSG_BUF_LEN]; /* small buffer for messages */
+EXTERN char_u IObuff[IOSIZE];               ///< Buffer for sprintf, I/O, etc.
+EXTERN char_u NameBuff[MAXPATHL];           ///< Buffer for expanding file names
+EXTERN char_u msg_buf[MSG_BUF_LEN];         ///< Small buffer for messages
+EXTERN char os_buf[MAX(MAXPATHL, IOSIZE)];  ///< Buffer for the os/ layer
+
 
 /* When non-zero, postpone redrawing. */
 EXTERN int RedrawingDisabled INIT(= 0);
diff --git a/src/nvim/os/env.c b/src/nvim/os/env.c
index 5a3c1ef2c8..1697d5edb2 100644
--- a/src/nvim/os/env.c
+++ b/src/nvim/os/env.c
@@ -164,11 +164,11 @@ static char_u   *homedir = NULL;
 
 void init_homedir(void)
 {
-  // In case we are called a second time (when 'encoding' changes).
+  // In case we are called a second time.
   xfree(homedir);
   homedir = NULL;
 
-  char_u *var = (char_u *)os_getenv("HOME");
+  const char *var = os_getenv("HOME");
 
 #ifdef WIN32
   // Typically, $HOME is not defined on Windows, unless the user has
@@ -182,10 +182,10 @@ void init_homedir(void)
         homepath = "\\";
     }
     if (homedrive != NULL && strlen(homedrive) + strlen(homepath) < MAXPATHL) {
-      snprintf((char *)NameBuff, MAXPATHL, "%s%s", homedrive, homepath);
-      if (NameBuff[0] != NUL) {
-        var = NameBuff;
-        vim_setenv("HOME", (char *)NameBuff);
+      snprintf(os_buf, MAXPATHL, "%s%s", homedrive, homepath);
+      if (os_buf[0] != NUL) {
+        var = os_buf;
+        vim_setenv("HOME", os_buf);
       }
     }
   }
@@ -195,17 +195,16 @@ void init_homedir(void)
 #ifdef UNIX
     // Change to the directory and get the actual path.  This resolves
     // links.  Don't do it when we can't return.
-    if (os_dirname(NameBuff, MAXPATHL) == OK
-        && os_chdir((char *)NameBuff) == 0) {
-      if (!os_chdir((char *)var) && os_dirname(IObuff, IOSIZE) == OK) {
-        var = IObuff;
+    if (os_dirname((char_u *)os_buf, MAXPATHL) == OK && os_chdir(os_buf) == 0) {
+      if (!os_chdir(var) && os_dirname(IObuff, IOSIZE) == OK) {
+        var = (char *)IObuff;
       }
-      if (os_chdir((char *)NameBuff) != 0) {
+      if (os_chdir(os_buf) != 0) {
         EMSG(_(e_prev_dir));
       }
     }
 #endif
-    homedir = vim_strsave(var);
+    homedir = vim_strsave((char_u *)var);
   }
 }
 
@@ -870,11 +869,12 @@ bool os_setenv_append_path(const char *fname)
     return false;
   }
   const char *tail = (char *)path_tail_with_sep((char_u *)fname);
-  const char *dir = (char *)vim_strnsave((char_u *)fname,
-                                         (size_t)(tail - fname));
+  size_t dirlen = (size_t)(tail - fname);
+  assert(tail >= fname && dirlen + 1 < sizeof(os_buf));
+  xstrlcpy(os_buf, fname, dirlen + 1);
   const char *path = os_getenv("PATH");
   const size_t pathlen = path ? strlen(path) : 0;
-  const size_t newlen = pathlen + strlen(dir) + 2;
+  const size_t newlen = pathlen + dirlen + 2;
   if (newlen < MAX_ENVPATHLEN) {
     char *temp = xmalloc(newlen);
     if (pathlen == 0) {
@@ -883,7 +883,7 @@ bool os_setenv_append_path(const char *fname)
       xstrlcpy(temp, path, newlen);
       xstrlcat(temp, ENV_SEPSTR, newlen);
     }
-    xstrlcat(temp, dir, newlen);
+    xstrlcat(temp, os_buf, newlen);
     os_setenv("PATH", temp, 1);
     xfree(temp);
     return true;
diff --git a/src/nvim/os/fs.c b/src/nvim/os/fs.c
index 097c672887..e930561234 100644
--- a/src/nvim/os/fs.c
+++ b/src/nvim/os/fs.c
@@ -275,8 +275,8 @@ static bool is_executable(const char *name)
 static bool is_executable_ext(char *name, const char *pathext)
   FUNC_ATTR_NONNULL_ALL
 {
-  xstrlcpy((char *)NameBuff, name, sizeof(NameBuff));
-  char *buf_end = xstrchrnul((char *)NameBuff, '\0');
+  xstrlcpy(os_buf, name, sizeof(os_buf));
+  char *buf_end = xstrchrnul(os_buf, '\0');
   for (const char *ext = pathext; *ext; ext++) {
     // Skip the extension if there is no suffix after a '.'.
     if (ext[0] == '.' && (ext[1] == '\0' || ext[1] == ENV_SEPCHAR)) {
@@ -287,7 +287,7 @@ static bool is_executable_ext(char *name, const char *pathext)
     const char *ext_end = xstrchrnul(ext, ENV_SEPCHAR);
     STRLCPY(buf_end, ext, ext_end - ext + 1);
 
-    if (is_executable((char *)NameBuff)) {
+    if (is_executable(os_buf)) {
       return true;
     }