[groff] 13/35: [groff]: Refactor to be more careful with memory.

[G. Branden Robinson]

gbranden pushed a commit to branch master
in repository groff.

commit 751e5d4304d629544b4fe0f4b484a073df24b59f
Author: G. Branden Robinson <g.branden.robinson@gmail.com>
AuthorDate: Mon Jun 20 10:57:21 2022 -0500

    [groff]: Refactor to be more careful with memory.
    
    * src/roff/groff/groff.cpp: Refactor to be more meticulous with memory.
      Add globals `saved_path`, `groff_bin_path`, and `groff_font` to store
      pointers into the process environment returned by `putenv()`; once
      used, they need to remain valid for the lifetime of the program.
    
      (xstrdup): Add `strdup()` wrapper: dies if `strdup()` fails.
    
      (main): Split nested `strsave()` and `xputenv()` (until recently
      `putenv()`) calls.  Free duplicate strings prior to exit.
---
 ChangeLog                | 11 +++++++++++
 src/roff/groff/groff.cpp | 38 ++++++++++++++++++++++++++++++--------
 2 files changed, 41 insertions(+), 8 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 79efbb4c..b3dcfa46 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2022-06-20  G. Branden Robinson <g.branden.robinson@gmail.com>
+
+       * src/roff/groff/groff.cpp: Refactor to be more meticulous with
+       memory.  Add globals `saved_path`, `groff_bin_path`, and
+       `groff_font` to store pointers into the process environment
+       returned by `putenv()`; once used, they need to remain valid for
+       the lifetime of the program.
+       (xstrdup): Add `strdup()` wrapper: dies if `strdup()` fails.
+       (main): Split nested `strsave()` and `xputenv()` (until recently
+       `putenv()`) calls.  Free duplicate strings prior to exit.
+
 2022-06-19  G. Branden Robinson <g.branden.robinson@gmail.com>
 
        * src/roff/groff/groff.cpp (main): Rename temporary variable to
diff --git a/src/roff/groff/groff.cpp b/src/roff/groff/groff.cpp
index 32525f43..1ab80711 100644
--- a/src/roff/groff/groff.cpp
+++ b/src/roff/groff/groff.cpp
@@ -97,6 +97,9 @@ char *spooler = 0 /* nullptr */;
 char *postdriver = 0 /* nullptr */;
 char *predriver = 0 /* nullptr */;
 bool need_postdriver = true;
+char *saved_path = 0 /* nullptr */;
+char *groff_bin_path = 0 /* nullptr */;
+char *groff_font_path = 0 /* nullptr */;
 
 possible_command commands[NCOMMANDS];
 
@@ -110,6 +113,15 @@ const char *xbasename(const char *);
 void usage(FILE *stream);
 void help();
 
+static char *xstrdup(const char *s) {
+  if (0 /* nullptr */ == s)
+    return const_cast<char *>(s);
+  char *str = strdup(s);
+  if (0 /* nullptr */ == str)
+    fatal("unable to copy string: %1", strerror(errno));
+  return str;
+}
+
 static void xputenv(const char *s) {
   if (putenv(const_cast<char *>(s)) != 0)
     fatal("unable to write to environment: %1", strerror(errno));
@@ -471,7 +483,8 @@ int main(int argc, char **argv)
       e += fontpath;
     }
     e += '\0';
-    xputenv(strsave(e.contents()));
+    groff_font_path = xstrdup(e.contents());
+    xputenv(groff_font_path);
   }
   {
     // we save the original path in GROFF_PATH__ and put it into the
@@ -482,7 +495,8 @@ int main(int argc, char **argv)
     if (path && *path)
       g += path;
     g += '\0';
-    xputenv(strsave(g.contents()));
+    saved_path = xstrdup(g.contents());
+    xputenv(saved_path);
     char *binpath = getenv("GROFF_BIN_PATH");
     string f = "PATH";
     f += '=';
@@ -497,13 +511,21 @@ int main(int argc, char **argv)
       f += path;
     }
     f += '\0';
-    xputenv(strsave(f.contents()));
+    groff_bin_path = xstrdup(f.contents());
+    xputenv(groff_bin_path);
   }
   if (Vflag)
     print_commands(Vflag == 1 ? stdout : stderr);
   if (Vflag == 1)
     exit(EXIT_SUCCESS);
-  return run_commands(vflag);
+  int status = run_commands(vflag);
+  free(spooler);
+  free(predriver);
+  free(postdriver);
+  free(saved_path);
+  free(groff_bin_path);
+  free(groff_font_path);
+  exit(status);
 }
 
 const char *xbasename(const char *s)
@@ -535,7 +557,7 @@ void handle_unknown_desc_command(const char *command, const 
char *arg,
     if (arg == 0 /* nullptr */)
       error("'print' directive requires an argument");
     else
-      spooler = strsave(arg);
+      spooler = xstrdup(arg);
   }
   if (strcmp(command, "prepro") == 0) {
     if (arg == 0 /* nullptr */)
@@ -547,7 +569,7 @@ void handle_unknown_desc_command(const char *command, const 
char *arg,
                " program name required", arg);
          return;
        }
-      predriver = strsave(arg);
+      predriver = xstrdup(arg);
     }
   }
   if (strcmp(command, "postpro") == 0) {
@@ -560,7 +582,7 @@ void handle_unknown_desc_command(const char *command, const 
char *arg,
                " program name required", arg);
          return;
        }
-      postdriver = strsave(arg);
+      postdriver = xstrdup(arg);
     }
   }
 }
@@ -602,7 +624,7 @@ possible_command::~possible_command()
 void possible_command::set_name(const char *s)
 {
   free(name);
-  name = strsave(s);
+  name = xstrdup(s);
 }
 
 void possible_command::clear_name()