Fix const-correctness issues uncovered by gcc -Wwrite-strings

* defs.h (struct xlat): Add const qualifier to the field of
type "char *".
(set_sortby, qualify, printnum, printnum_int): Add const qualifier to
arguments of type "char *".
* count.c (set_sortby): Add const qualifier to the argument and
automatic variable of type "char *".
* desc.c (decode_select): Add const qualifier to automatic variables of
type "char *".
* ioctlsort.c (struct ioctlent): Add const qualifier to fields of
type "char *".
(main):  Add const qualifier to argv.
* process.c (printargv): Add const qualifier to the argument and
automatic variable of type "char *".
(printargc) Add const qualifier to argument of type "char *".
* signal.c (sprintsigmask, parse_sigset_t): Add const qualifier to
arguments of type "char *".
* strace.c (progname): Add const qualifier.
(detach): Add const qualifier to automatic variable of type "char *".
* stream.c (struct strbuf): Add const qualifier to the field of
type "char *".
* syscall.c (struct qual_options): Add const qualifier to fields of
type "char *".
(qual_syscall, qual_fault, qual_desc, lookup_class): Add const qualifier
to arguments of type "char *".
(qual_signal): Add const qualifier to the argument of type "char *",
avoid modification of constant argument.
(qualify): Likewise.
* util.c (printflags): Add const qualifier to automatic variable of
type "char *".
(printnum, printnum_int): Add const qualifier to arguments of
type "char *".

count.c

@@ -131,7 +131,7 @@ static int (*sortfun)();
 static struct timeval overhead = { -1, -1 };
 
 void
-set_sortby(char *sortby)
+set_sortby(const char *sortby)
 {
 	if (strcmp(sortby, "time") == 0)
 		sortfun = time_cmp;
@@ -161,7 +161,7 @@ call_summary_pers(FILE *outf)
 	int     call_cum, error_cum;
 	struct timeval tv_cum, dtv;
 	double  percent;
-	char   *dashes = "-------------------------";
+	const char *dashes = "-------------------------";
 	char    error_str[16];
 	int    *sorted_count = calloc(sizeof(int), nsyscalls);
 

defs.h

@@ -424,7 +424,7 @@ struct tcb {
 
 struct xlat {
 	int val;
-	char *str;
+	const char *str;
 };
 
 extern const struct xlat open_mode_flags[];
@@ -488,9 +488,9 @@ extern void expand_tcbtab(void);
 
 #define alloctcb(pid)	alloc_tcb((pid), 1)
 
-extern void set_sortby(char *);
+extern void set_sortby(const char *);
 extern void set_overhead(int);
-extern void qualify(char *);
+extern void qualify(const char *);
 extern int get_scno(struct tcb *);
 extern long known_scno(struct tcb *);
 extern long do_ptrace(int request, struct tcb *tcp, void *addr, void *data);
@@ -509,8 +509,8 @@ extern int upeek(struct tcb *, long, long *);
 extern void dumpiov(struct tcb *, int, long);
 extern void dumpstr(struct tcb *, long, int);
 extern void printstr(struct tcb *, long, int);
-extern void printnum(struct tcb *, long, char *);
-extern void printnum_int(struct tcb *, long, char *);
+extern void printnum(struct tcb *, long, const char *);
+extern void printnum_int(struct tcb *, long, const char *);
 extern void printpath(struct tcb *, long);
 extern void printpathn(struct tcb *, long, int);
 extern void printtv_bitness(struct tcb *, long, enum bitness_t, int);

desc.c

@@ -490,7 +490,7 @@ decode_select(struct tcb *tcp, long *args, enum bitness_t bitness)
 			       & -sizeof(long));
 	fd_set *fds;
 	static char outstr[1024];
-	char *sep;
+	const char *sep;
 	long arg;
 
 	if (entering(tcp)) {
@@ -529,7 +529,7 @@ decode_select(struct tcb *tcp, long *args, enum bitness_t bitness)
 	else
 	{
 		unsigned int cumlen = 0;
-		char *sep = "";
+		const char *sep = "";
 
 		if (syserror(tcp))
 			return 0;

ioctlsort.c

@@ -36,8 +36,8 @@
 #endif
 
 struct ioctlent {
-	char *doth;
-	char *symbol;
+	const char *doth;
+	const char *symbol;
 	unsigned long code;
 };
 
@@ -56,9 +56,7 @@ const void *b;
 }
 
 int
-main(argc, argv)
-int argc;
-char *argv[];
+main(int argc, const char *argv[])
 {
 	int i;
 

process.c

@@ -1630,16 +1630,14 @@ struct tcb *tcp;
 
 
 static void
-printargv(tcp, addr)
-struct tcb *tcp;
-long addr;
+printargv(struct tcb *tcp, long addr)
 {
 	union {
 		unsigned int p32;
 		unsigned long p64;
 		char data[sizeof(long)];
 	} cp;
-	char *sep;
+	const char *sep;
 	int n = 0;
 
 	cp.p64 = 1;
@@ -1662,10 +1660,7 @@ long addr;
 }
 
 static void
-printargc(fmt, tcp, addr)
-char *fmt;
-struct tcb *tcp;
-long addr;
+printargc(const char *fmt, struct tcb *tcp, long addr)
 {
 	int count;
 	char *cp;

signal.c

@@ -315,7 +315,8 @@ sprintsigmask(const char *str, sigset_t *mask, int rt)
 {
 	int i, nsigs;
 	int maxsigs;
-	char *format, *s;
+	const char *format;
+	char *s;
 	static char outstr[8 * sizeof(sigset_t) * 8];
 
 	strcpy(outstr, str);
@@ -785,7 +786,7 @@ int verbose;
 #ifdef LINUX
 
 static void
-parse_sigset_t (const char *str, sigset_t *set)
+parse_sigset_t(const char *str, sigset_t *set)
 {
 	const char *p;
 	unsigned int digit;
@@ -832,7 +833,7 @@ int sig;
 	int sfd;
 	char sname[32];
 	char buf[2048];
-	char *s;
+	const char *s;
 	int i;
 	sigset_t ignored, caught;
 #endif

strace.c

@@ -117,7 +117,7 @@ FILE *outf;
 static int curcol;
 struct tcb **tcbtab;
 unsigned int nprocs, tcbtabsize;
-char *progname;
+const char *progname;
 extern char **environ;
 
 static int detach(struct tcb *tcp, int sig);
@@ -531,7 +531,7 @@ startup_child (char **argv)
 		strcpy(pathname, filename);
 #endif /* USE_DEBUGGING_EXEC */
 	else {
-		char *path;
+		const char *path;
 		int m, n, len;
 
 		for (path = getenv("PATH"); path && *path; path += m) {

stream.c

@@ -57,7 +57,7 @@
 struct strbuf {
 	int     maxlen;                 /* no. of bytes in buffer */
 	int     len;                    /* no. of bytes returned */
-	char    *buf;                   /* pointer to data */
+	const char *buf;                /* pointer to data */
 };
 #define MORECTL 1
 #define MOREDATA 2

syscall.c

@@ -238,9 +238,9 @@ static int qual_syscall(), qual_signal(), qual_fault(), qual_desc();
 
 static const struct qual_options {
 	int bitflag;
-	char *option_name;
-	int (*qualify)();
-	char *argument_name;
+	const char *option_name;
+	int (*qualify)(const char *, const struct qual_options *, int);
+	const char *argument_name;
 } qual_options[] = {
 	{ QUAL_TRACE,	"trace",	qual_syscall,	"system call"	},
 	{ QUAL_TRACE,	"t",		qual_syscall,	"system call"	},
@@ -299,10 +299,7 @@ qualify_one(n, opt, not, pers)
 }
 
 static int
-qual_syscall(s, opt, not)
-	char *s;
-	const struct qual_options *opt;
-	int not;
+qual_syscall(const char *s, const struct qual_options *opt, int not)
 {
 	int i;
 	int rc = -1;
@@ -340,10 +337,7 @@ qual_syscall(s, opt, not)
 }
 
 static int
-qual_signal(s, opt, not)
-	char *s;
-	const struct qual_options *opt;
-	int not;
+qual_signal(const char *s, const struct qual_options *opt, int not)
 {
 	int i;
 	char buf[32];
@@ -359,12 +353,10 @@ qual_signal(s, opt, not)
 		return -1;
 	strcpy(buf, s);
 	s = buf;
-	for (i = 0; s[i]; i++)
-		s[i] = toupper((unsigned char)(s[i]));
-	if (strncmp(s, "SIG", 3) == 0)
+	if (strncasecmp(s, "SIG", 3) == 0)
 		s += 3;
 	for (i = 0; i <= NSIG; i++)
-		if (strcmp(s, signame(i) + 3) == 0) {
+		if (strcasecmp(s, signame(i) + 3) == 0) {
 			qualify_one(i, opt, not, -1);
 			return 0;
 		}
@@ -372,19 +364,13 @@ qual_signal(s, opt, not)
 }
 
 static int
-qual_fault(s, opt, not)
-	char *s;
-	const struct qual_options *opt;
-	int not;
+qual_fault(const char *s, const struct qual_options *opt, int not)
 {
 	return -1;
 }
 
 static int
-qual_desc(s, opt, not)
-	char *s;
-	const struct qual_options *opt;
-	int not;
+qual_desc(const char *s, const struct qual_options *opt, int not)
 {
 	if (isdigit((unsigned char)*s)) {
 		int desc = atoi(s);
@@ -397,8 +383,7 @@ qual_desc(s, opt, not)
 }
 
 static int
-lookup_class(s)
-	char *s;
+lookup_class(const char *s)
 {
 	if (strcmp(s, "file") == 0)
 		return TRACE_FILE;
@@ -416,12 +401,12 @@ lookup_class(s)
 }
 
 void
-qualify(s)
-char *s;
+qualify(const char *s)
 {
 	const struct qual_options *opt;
 	int not;
-	char *p;
+	char *copy;
+	const char *p;
 	int i, n;
 
 	opt = &qual_options[0];
@@ -451,7 +436,13 @@ char *s;
 	for (i = 0; i < MAX_QUALS; i++) {
 		qualify_one(i, opt, !not, -1);
 	}
-	for (p = strtok(s, ","); p; p = strtok(NULL, ",")) {
+	if (!strchr(s, ','))
+		return;
+	if (!(copy = strdup(s))) {
+		fprintf(stderr, "out of memory\n");
+		exit(1);
+	}
+	for (p = strtok(copy, ","); p; p = strtok(NULL, ",")) {
 		if (opt->bitflag == QUAL_TRACE && (n = lookup_class(p)) > 0) {
 			for (i = 0; i < nsyscalls0; i++)
 				if (sysent0[i].sys_flags & n)
@@ -477,6 +468,7 @@ char *s;
 			exit(1);
 		}
 	}
+	free(copy);
 	return;
 }
 

util.c

@@ -340,13 +340,10 @@ sprintflags(const char *prefix, const struct xlat *xlat, int flags)
 }
 
 int
-printflags(xlat, flags, dflt)
-const struct xlat *xlat;
-int flags;
-const char *dflt;
+printflags(const struct xlat *xlat, int flags, const char *dflt)
 {
 	int n;
-	char *sep;
+	const char *sep;
 
 	if (flags == 0 && xlat->val == 0) {
 		tprintf("%s", xlat->str);
@@ -383,10 +380,7 @@ const char *dflt;
 }
 
 void
-printnum(tcp, addr, fmt)
-struct tcb *tcp;
-long addr;
-char *fmt;
+printnum(struct tcb *tcp, long addr, const char *fmt)
 {
 	long num;
 
@@ -404,10 +398,7 @@ char *fmt;
 }
 
 void
-printnum_int(tcp, addr, fmt)
-struct tcb *tcp;
-long addr;
-char *fmt;
+printnum_int(struct tcb *tcp, long addr, const char *fmt)
 {
 	int num;