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less: make it a bit more resistant against statusline corruption.

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less: "examine" command will not bomb out on bad file name now

less_main                                           1663    1694     +31
examine_file                                          87     114     +27
less_getch                                           138     160     +22
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 3/0 up/down: 80/0)               Total: 80 bytes
   text    data     bss     dec     hex filename
 798368     740    7484  806592   c4ec0 busybox_old
 798470     740    7484  806694   c4f26 busybox_unstripped
This commit is contained in:
Denis Vlasenko 2008-02-23 11:54:37 +00:00
parent 33196372be
commit d2172c04e6
1 changed files with 20 additions and 11 deletions
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31
miscutils/less.c
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@ -706,13 +706,16 @@ static ssize_t getch_nowait(char* input, int sz)
/* Grab a character from input without requiring the return key. If the /* Grab a character from input without requiring the return key. If the
* character is ASCII \033, get more characters and assign certain sequences * character is ASCII \033, get more characters and assign certain sequences
* special return codes. Note that this function works best with raw input. */ * special return codes. Note that this function works best with raw input. */
static int less_getch(void) static int less_getch(int pos)
{ {
unsigned char input[16]; unsigned char input[16];
unsigned i; unsigned i;
again: again:
less_gets_pos = pos;
memset(input, 0, sizeof(input)); memset(input, 0, sizeof(input));
getch_nowait(input, sizeof(input)); getch_nowait(input, sizeof(input));
less_gets_pos = -1;
/* Detect escape sequences (i.e. arrow keys) and handle /* Detect escape sequences (i.e. arrow keys) and handle
* them accordingly */ * them accordingly */
@ -777,12 +780,17 @@ static void examine_file(void)
char *new_fname; char *new_fname;
print_statusline("Examine: "); print_statusline("Examine: ");
new_fname = less_gets(sizeof("Examine: ")-1); new_fname = less_gets(sizeof("Examine: ") - 1);
if (!new_fname[0]) { if (!new_fname[0]) {
free(new_fname);
status_print(); status_print();
err:
free(new_fname);
return; return;
} }
if (access(new_fname, R_OK) != 0) {
print_statusline("Cannot read this file");
goto err;
}
free(filename); free(filename);
filename = new_fname; filename = new_fname;
/* files start by = argv. why we assume that argv is infinitely long?? /* files start by = argv. why we assume that argv is infinitely long??
@ -838,7 +846,7 @@ static void colon_process(void)
/* Clear the current line and print a prompt */ /* Clear the current line and print a prompt */
print_statusline(" :"); print_statusline(" :");
keypress = less_getch(); keypress = less_getch(2);
switch (keypress) { switch (keypress) {
case 'd': case 'd':
remove_current_file(); remove_current_file();
@ -971,7 +979,7 @@ static void regex_process(void)
static void number_process(int first_digit) static void number_process(int first_digit)
{ {
int i = 1; int i;
int num; int num;
char num_input[sizeof(int)*4]; /* more than enough */ char num_input[sizeof(int)*4]; /* more than enough */
char keypress; char keypress;
@ -983,8 +991,9 @@ static void number_process(int first_digit)
printf(":%c", first_digit); printf(":%c", first_digit);
/* Receive input until a letter is given */ /* Receive input until a letter is given */
i = 1;
while (i < sizeof(num_input)-1) { while (i < sizeof(num_input)-1) {
num_input[i] = less_getch(); num_input[i] = less_getch(i + 1);
if (!num_input[i] || !isdigit(num_input[i])) if (!num_input[i] || !isdigit(num_input[i]))
break; break;
bb_putchar(num_input[i]); bb_putchar(num_input[i]);
@ -1043,7 +1052,7 @@ static void flag_change(void)
clear_line(); clear_line();
bb_putchar('-'); bb_putchar('-');
keypress = less_getch(); keypress = less_getch(1);
switch (keypress) { switch (keypress) {
case 'M': case 'M':
@ -1068,7 +1077,7 @@ static void show_flag_status(void)
clear_line(); clear_line();
bb_putchar('_'); bb_putchar('_');
keypress = less_getch(); keypress = less_getch(1);
switch (keypress) { switch (keypress) {
case 'M': case 'M':
@ -1127,7 +1136,7 @@ static void add_mark(void)
int letter; int letter;
print_statusline("Mark: "); print_statusline("Mark: ");
letter = less_getch(); letter = less_getch(sizeof("Mark: ") - 1);
if (isalpha(letter)) { if (isalpha(letter)) {
/* If we exceed 15 marks, start overwriting previous ones */ /* If we exceed 15 marks, start overwriting previous ones */
@ -1148,7 +1157,7 @@ static void goto_mark(void)
int i; int i;
print_statusline("Go to mark: "); print_statusline("Go to mark: ");
letter = less_getch(); letter = less_getch(sizeof("Go to mark: ") - 1);
clear_line(); clear_line();
if (isalpha(letter)) { if (isalpha(letter)) {
@ -1385,7 +1394,7 @@ int less_main(int argc, char **argv)
reinitialize(); reinitialize();
while (1) { while (1) {
keypress = less_getch(); keypress = less_getch(-1); /* -1: do not position cursor */
keypress_process(keypress); keypress_process(keypress);
} }
} }