Add more out of memory checks (re: 18529b88) (#192)

The referenced commit neglected to add checks for strdup() calls.
That calls malloc() as well, and is used a lot.

This commit switches to another strategy: it adds wrapper functions
for all the allocation macros that check if the allocation
succeeded, so those checks don't need to be done manually.

src/cmd/ksh93/include/defs.h,
src/cmd/ksh93/sh/init.c:
- Add sh_malloc(), sh_realloc(), sh_calloc(), sh_strdup(),
  sh_memdup() wrapper functions with success checks. Call nospace()
  to error out if allocation fails.
- Update new_of() macro to use sh_malloc().
- Define new sh_newof() macro to replace newof(); it uses
  sh_realloc().

All other changed files:
- Replace the relevant calls with the wrappers.
- Remove now-redundant success checks from 18529b88.
- The ERROR_PANIC error message calls are updated to inclusive-or
  ERROR_SYSTEM into the exit code argument, so libast's error()
  appends the human-readable version of errno in square brackets.
  See src/lib/libast/man/error.3

src/cmd/ksh93/edit/history.c:
- Include "defs.h" to get access to the wrappers even if KSHELL is
  not defined.
- Since we're here, fix a compile error that occurred with KSHELL
  undefined by updating the type definition of hist_fname[] to
  match that of history.h.

src/cmd/ksh93/bltins/enum.c:
- To get access to sh_newof(), include "defs.h" instead of
  <shell.h> (note that "defs.h" includes <shell.h> itself).

src/cmd/ksh93/Mamfile:
- enum.c: depend on defs.h instead of shell.h.
- enum.o: add an -I. flag in the compiler invocation so that defs.h
  can find its subsequent includes.

src/cmd/builtin/pty.c:
- Define one outofmemory() function and call that instead of
  repeating the error message call.
- outofmemory() never returns, so remove superfluous exit handling.

Co-authored-by: Martijn Dekker <martijn@inlv.org>

src/cmd/ksh93/edit/edit.c

@@ -761,11 +761,7 @@ void	ed_setup(register Edit_t *ep, int fd, int reedit)
 		/* can't use output buffer when reading from stderr */
 		static char *buff;
 		if(!buff)
-		{
-			buff = (char*)malloc(MAXLINE);
-			if(!buff)
-				sh_outofmemory();
-		}
+			buff = (char*)sh_malloc(MAXLINE);
 		ep->e_outbase = ep->e_outptr = buff;
 		ep->e_outlast = ep->e_outptr + MAXLINE;
 		return;
@@ -1885,7 +1881,7 @@ void	ed_histlist(Edit_t *ep,int n)
 
 void	*ed_open(Shell_t *shp)
 {
-	Edit_t *ed = newof(0,Edit_t,1,0);
+	Edit_t *ed = sh_newof(0,Edit_t,1,0);
 	ed->sh = shp;
 	strcpy(ed->e_macro,"_??");
 	return((void*)ed);

src/cmd/ksh93/edit/emacs.c

@@ -196,7 +196,7 @@ int ed_emacsread(void *context, int fd,char *buff,int scend, int reedit)
 	memset(Screen,0,sizeof(Screen));
 	if(!ep)
 	{
-		ep = ed->e_emacs = newof(0,Emacs_t,1,0);
+		ep = ed->e_emacs = sh_newof(0,Emacs_t,1,0);
 		ep->ed = ed;
 		ep->prevdirection =  1;
 		location.hist_command =  -5;
@@ -220,9 +220,7 @@ int ed_emacsread(void *context, int fd,char *buff,int scend, int reedit)
 #endif /* SHOPT_MULTIBYTE */
 	if(!kstack)
 	{
-		kstack = (genchar*)malloc(CHARSIZE*MAXLINE);
-		if(!kstack)
-			sh_outofmemory();
+		kstack = (genchar*)sh_malloc(CHARSIZE*MAXLINE);
 		kstack[0] = '\0';
 	}
 	drawbuff = out;

src/cmd/ksh93/edit/hexpand.c

@@ -73,7 +73,7 @@ static char *parse_subst(const char *s, struct subst *sb)
 	/* init "new" with empty string */
 	if(sb->str[1])
 		free(sb->str[1]);
-	sb->str[1] = strdup("");
+	sb->str[1] = sh_strdup("");
 
 	/* get delimiter */
 	del = *s;
@@ -91,7 +91,7 @@ static char *parse_subst(const char *s, struct subst *sb)
 				stakputc('\0');
 				if(sb->str[n])
 					free(sb->str[n]);
-				sb->str[n] = strdup(stakptr(off));
+				sb->str[n] = sh_strdup(stakptr(off));
 				stakseek(off);
 			}
 			n++;
@@ -241,7 +241,7 @@ int hist_expand(const char *ln, char **xp)
 			cp++;
 			n = staktell(); /* terminate string and dup */
 			stakputc('\0');
-			cc = strdup(stakptr(0));
+			cc = sh_strdup(stakptr(0));
 			stakseek(n); /* remove null byte again */
 			ref = sfopen(ref, cc, "s"); /* open as file */
 			n = 0; /* skip history file referencing */
@@ -587,7 +587,7 @@ getsel:
 				{
 					/* preset old with match from !?string? */
 					if(!sb.str[0] && wm)
-						sb.str[0] = strdup(sfsetbuf(wm, (Void_t*)1, 0));
+						sb.str[0] = sh_strdup(sfsetbuf(wm, (Void_t*)1, 0));
 					cp = parse_subst(cp, &sb);
 				}
 
@@ -713,7 +713,7 @@ done:
 
 	/* error? */
 	if(staktell() && !(flag & HIST_ERROR))
-		*xp = strdup(stakfreeze(1));
+		*xp = sh_strdup(stakfreeze(1));
 
 	/* restore shell stack */
 	if(off)

src/cmd/ksh93/edit/history.c

@@ -75,8 +75,8 @@
 #include	"FEATURE/time"
 #include	<error.h>
 #include	<ls.h>
+#include	"defs.h"
 #if KSHELL
-#   include	"defs.h"
 #   include	"variables.h"
 #   include	"path.h"
 #   include	"builtins.h"
@@ -87,7 +87,6 @@
 #include	"history.h"
 
 #if !KSHELL
-#   define new_of(type,x)	((type*)malloc((unsigned)sizeof(type)+(x)))
 #   define NIL(type)		((type)0)
 #   define path_relative(s,x)	(s,x)
 #   ifdef __STDC__
@@ -98,7 +97,7 @@
 #   define e_unknown	 	"unknown"
 #   define sh_translate(x)	(x)
     char login_sh =		0;
-    char hist_fname[] =		"/.history";
+    const char hist_fname[] =	"/.history";
 #endif	/* KSHELL */
 
 #ifndef O_BINARY
@@ -145,7 +144,7 @@ static History_t *hist_ptr;
 		else
 			cp = "unknown";
 	}
-	logname = strdup(cp);
+	logname = sh_strdup(cp);
 	if((acctfd=sh_open(acctfile,
 		O_BINARY|O_WRONLY|O_APPEND|O_CREAT,S_IRUSR|S_IWUSR))>=0 &&
 	    (unsigned)acctfd < 10)
@@ -306,11 +305,7 @@ retry:
 	else
 		maxlines = HIST_DFLT;
 	for(histmask=16;histmask <= maxlines; histmask <<=1 );
-	if(!(hp=new_of(History_t,(--histmask)*sizeof(off_t))))
-	{
-		close(fd);
-		return(0);
-	}
+	hp = new_of(History_t,(--histmask)*sizeof(off_t));
 	shgd->hist_ptr = hist_ptr = hp;
 	hp->histshell = (void*)shp;
 	hp->histsize = maxlines;
@@ -320,7 +315,7 @@ retry:
 	hp->histind = 1;
 	hp->histcmds[1] = 2;
 	hp->histcnt = 2;
-	hp->histname = strdup(histname);
+	hp->histname = sh_strdup(histname);
 	hp->histdisc = hist_disc;
 	if(hsize==0)
 	{
@@ -395,7 +390,7 @@ retry:
 			if(fd>=0)
 			{
 				fcntl(fd,F_SETFD,FD_CLOEXEC);
-				hp->tty = strdup(isatty(2)?ttyname(2):"notty");
+				hp->tty = sh_strdup(isatty(2)?ttyname(2):"notty");
 				hp->auditfp = sfnew((Sfio_t*)0,NULL,-1,fd,SF_WRITE);
 			}
 		}
@@ -471,9 +466,7 @@ static History_t* hist_trim(History_t *hp, int n)
 		int fd;
 		char *last, *name=hist_old->histname;
 		close(sffileno(hist_old->histfp));
-		tmpname = (char*)malloc(strlen(name)+14);
-		if(!tmpname)
-			sh_outofmemory();
+		tmpname = (char*)sh_malloc(strlen(name)+14);
 		if(last = strrchr(name,'/'))
 		{
 			*last = 0;

src/cmd/ksh93/edit/vi.c

@@ -231,10 +231,8 @@ int ed_viread(void *context, int fd, register char *shbuf, int nchar, int reedit
 #endif /* SHOPT_RAWONLY */
 	if(!vp)
 	{
-		ed->e_vi = vp =  newof(0,Vi_t,1,0);
-		vp->lastline = (genchar*)malloc(MAXLINE*CHARSIZE);
-		if(!vp->lastline)
-			sh_outofmemory();
+		ed->e_vi = vp = sh_newof(0,Vi_t,1,0);
+		vp->lastline = (genchar*)sh_malloc(MAXLINE*CHARSIZE);
 		vp->direction = -1;
 		vp->ed = ed;
 	}
@@ -383,17 +381,9 @@ int ed_viread(void *context, int fd, register char *shbuf, int nchar, int reedit
 	window[0] = '\0';
 
 	if(!yankbuf)
-	{
-		yankbuf = (genchar*)malloc(MAXLINE*CHARSIZE);
-		if(!yankbuf)
-			sh_outofmemory();
-	}
+		yankbuf = (genchar*)sh_malloc(MAXLINE*CHARSIZE);
 	if(!vp->lastline)
-	{
-		vp->lastline = (genchar*)malloc(MAXLINE*CHARSIZE);
-		if(!vp->lastline)
-			sh_outofmemory();
-	}
+		vp->lastline = (genchar*)sh_malloc(MAXLINE*CHARSIZE);
 	if( vp->last_cmd == '\0' )
 	{
 		/*** first time for this shell ***/