/* * Top users/processes display for Unix * Version 3 * * This program may be freely redistributed, * but this entire comment MUST remain intact. * * Copyright (c) 1984, 1989, William LeFebvre, Rice University * Copyright (c) 1989, 1990, 1992, William LeFebvre, Northwestern University */ /* * This file contains the routines that display information on the screen. * Each section of the screen has two routines: one for initially writing * all constant and dynamic text, and one for only updating the text that * changes. The prefix "i_" is used on all the "initial" routines and the * prefix "u_" is used for all the "updating" routines. * * ASSUMPTIONS: * None of the "i_" routines use any of the termcap capabilities. * In this way, those routines can be safely used on terminals that * have minimal (or nonexistant) terminal capabilities. * * The routines are called in this order: *_loadave, i_timeofday, * *_procstates, *_cpustates, *_memory, *_message, *_header, * *_process, u_endscreen. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "screen.h" /* interface to screen package */ #include "layout.h" /* defines for screen position layout */ #include "display.h" #include "top.h" #include "machine.h" /* we should eliminate this!!! */ #include "utils.h" #ifdef DEBUG FILE *debug; #endif static int lmpid = 0; static int last_hi = 0; /* used in u_process and u_endscreen */ static int lastline = 0; #define lineindex(l) ((l)*screen_width) /* things initialized by display_init and used thruout */ /* buffer of proc information lines for display updating */ static char *screenbuf = NULL; static const char * const *procstate_names; static const char * const *cpustate_names; static const char * const *memory_names; static const char * const *arc_names; static const char * const *carc_names; static const char * const *swap_names; static int num_procstates; static int num_cpustates; static int num_memory; static int num_swap; static int *lprocstates; static int *lcpustates; static int *lmemory; static int *lswap; static int num_cpus; static int *cpustate_columns; static int cpustate_total_length; static int cpustates_column; static enum { OFF, ON, ERASE } header_status = ON; static void summary_format(char *, int *, const char * const *); static void line_update(char *, char *, int, int); static int setup_buffer_bufsiz = 0; static char * setup_buffer(char *, int); int x_lastpid = 10; int y_lastpid = 0; int x_loadave = 33; int x_loadave_nompid = 15; int y_loadave = 0; int x_procstate = 0; int y_procstate = 1; int x_brkdn = 15; int y_brkdn = 1; int x_mem = 5; int y_mem = 3; int x_arc = 5; int y_arc = 4; int x_carc = 5; int y_carc = 5; int x_swap = 6; int y_swap = 4; int y_message = 5; int x_header = 0; int y_header = 6; int x_idlecursor = 0; int y_idlecursor = 5; int y_procs = 7; int y_cpustates = 2; int Header_lines = 7; int display_resize(void) { int lines; /* first, deallocate any previous buffer that may have been there */ if (screenbuf != NULL) { free(screenbuf); } /* calculate the current dimensions */ /* if operating in "dumb" mode, we only need one line */ lines = smart_terminal ? screen_length - Header_lines : 1; if (lines < 0) lines = 0; /* now, allocate space for the screen buffer */ screenbuf = calloc(lines, screen_width); if (screenbuf == NULL) { /* oops! */ return(-1); } /* return number of lines available */ /* for dumb terminals, pretend like we can show any amount */ return(smart_terminal ? lines : Largest); } int display_updatecpus(struct statics *statics) { int lines; int i; /* call resize to do the dirty work */ lines = display_resize(); if (pcpu_stats) num_cpus = statics->ncpus; else num_cpus = 1; cpustates_column = 5; /* CPU: */ if (num_cpus > 1) { cpustates_column += 1 + digits(num_cpus); /* CPU #: */ } /* fill the "last" array with all -1s, to insure correct updating */ for (i = 0; i < num_cpustates * num_cpus; ++i) { lcpustates[i] = -1; } return(lines); } int display_init(struct statics * statics) { int lines; const char * const *pp; int *ip; int i; lines = display_updatecpus(statics); /* only do the rest if we need to */ if (lines > -1) { /* save pointers and allocate space for names */ procstate_names = statics->procstate_names; num_procstates = 8; assert(num_procstates > 0); lprocstates = calloc(num_procstates, sizeof(int)); cpustate_names = statics->cpustate_names; swap_names = statics->swap_names; num_swap = 7; assert(num_swap > 0); lswap = calloc(num_swap, sizeof(int)); num_cpustates = CPUSTATES; assert(num_cpustates > 0); lcpustates = calloc(num_cpustates * sizeof(int), statics->ncpus); cpustate_columns = calloc(num_cpustates, sizeof(int)); memory_names = statics->memory_names; num_memory = 7; assert(num_memory > 0); lmemory = calloc(num_memory, sizeof(int)); arc_names = statics->arc_names; carc_names = statics->carc_names; /* calculate starting columns where needed */ cpustate_total_length = 0; pp = cpustate_names; ip = cpustate_columns; while (*pp != NULL) { *ip++ = cpustate_total_length; if ((i = strlen(*pp++)) > 0) { cpustate_total_length += i + 8; } } } /* return number of lines available */ return(lines); } void i_loadave(int mpid, double avenrun[]) { int i; /* i_loadave also clears the screen, since it is first */ top_clear(); /* mpid == -1 implies this system doesn't have an _mpid */ if (mpid != -1) { printf("last pid: %5d; ", mpid); } printf("load averages"); for (i = 0; i < 3; i++) { printf("%c %5.2f", i == 0 ? ':' : ',', avenrun[i]); } lmpid = mpid; } void u_loadave(int mpid, double *avenrun) { int i; if (mpid != -1) { /* change screen only when value has really changed */ if (mpid != lmpid) { Move_to(x_lastpid, y_lastpid); printf("%5d", mpid); lmpid = mpid; } /* i remembers x coordinate to move to */ i = x_loadave; } else { i = x_loadave_nompid; } /* move into position for load averages */ Move_to(i, y_loadave); /* display new load averages */ /* we should optimize this and only display changes */ for (i = 0; i < 3; i++) { printf("%s%5.2f", i == 0 ? "" : ", ", avenrun[i]); } } void i_timeofday(time_t *tod) { /* * Display the current time. * "ctime" always returns a string that looks like this: * * Sun Sep 16 01:03:52 1973 * 012345678901234567890123 * 1 2 * * We want indices 11 thru 18 (length 8). */ if (smart_terminal) { Move_to(screen_width - 8, 0); } else { fputs(" ", stdout); } #ifdef DEBUG { char *foo; foo = ctime(tod); fputs(foo, stdout); } #endif printf("%-8.8s\n", &(ctime(tod)[11])); lastline = 1; } static int ltotal = 0; static char *procstates_buffer = NULL; /* * *_procstates(total, brkdn, names) - print the process summary line * * Assumptions: cursor is at the beginning of the line on entry * lastline is valid */ void i_procstates(int total, int *brkdn) { int i; procstates_buffer = setup_buffer(procstates_buffer, 0); /* write current number of processes and remember the value */ printf("%d %s:", total, ps.thread ? "threads" : "processes"); ltotal = total; /* put out enough spaces to get to column 15 */ i = digits(total); while (i++ < (ps.thread ? 6 : 4)) { putchar(' '); } /* format and print the process state summary */ summary_format(procstates_buffer, brkdn, procstate_names); fputs(procstates_buffer, stdout); /* save the numbers for next time */ memcpy(lprocstates, brkdn, num_procstates * sizeof(int)); } void u_procstates(int total, int *brkdn) { static char *new = NULL; int i; new = setup_buffer(new, 0); /* update number of processes only if it has changed */ if (ltotal != total) { /* move and overwrite */ if (x_procstate == 0) { Move_to(x_procstate, y_procstate); } else { /* cursor is already there...no motion needed */ assert(lastline == 1); } printf("%d", total); /* if number of digits differs, rewrite the label */ if (digits(total) != digits(ltotal)) { printf(" %s:", ps.thread ? "threads" : "processes"); /* put out enough spaces to get to column 15 */ i = digits(total); while (i++ < (ps.thread ? 6 : 4)) { putchar(' '); } /* cursor may end up right where we want it!!! */ } /* save new total */ ltotal = total; } /* see if any of the state numbers has changed */ if (memcmp(lprocstates, brkdn, num_procstates * sizeof(int)) != 0) { /* format and update the line */ summary_format(new, brkdn, procstate_names); line_update(procstates_buffer, new, x_brkdn, y_brkdn); memcpy(lprocstates, brkdn, num_procstates * sizeof(int)); } } void i_cpustates(int *states) { int i = 0; int value; const char * const *names; const char *thisname; int *hstates = states; int cpu; for (cpu = 0; cpu < num_cpus; cpu++) { names = cpustate_names; /* print tag and bump lastline */ if (num_cpus == 1) printf("\nCPU: "); else { value = printf("\nCPU %d: ", cpu); while (value++ <= cpustates_column) printf(" "); } lastline++; /* now walk thru the names and print the line */ while ((thisname = *names++) != NULL) { if (*thisname != '\0') { /* retrieve the value and remember it */ value = *states++; /* if percentage is >= 1000, print it as 100% */ printf((value >= 1000 ? "%s%4.0f%% %s" : "%s%4.1f%% %s"), (i++ % num_cpustates) == 0 ? "" : ", ", ((float)value)/10., thisname); } } } /* copy over values into "last" array */ states = hstates; memcpy(lcpustates, states, num_cpustates * sizeof(int) * num_cpus); } void u_cpustates(int *states) { int value; const char * const *names; const char *thisname; int *hstates = states; int *lp; int *colp; int cpu; for (cpu = 0; cpu < num_cpus; cpu++) { names = cpustate_names; Move_to(cpustates_column, y_cpustates + cpu); lastline = y_cpustates + cpu; lp = lcpustates + (cpu * num_cpustates); colp = cpustate_columns; /* we could be much more optimal about this */ while ((thisname = *names++) != NULL) { if (*thisname != '\0') { /* did the value change since last time? */ if (*lp != *states) { /* yes, move and change */ Move_to(cpustates_column + *colp, y_cpustates + cpu); lastline = y_cpustates + cpu; /* retrieve value and remember it */ value = *states; /* if percentage is >= 1000, print it as 100% */ printf((value >= 1000 ? "%4.0f" : "%4.1f"), ((double)value)/10.); /* remember it for next time */ *lp = value; } } /* increment and move on */ lp++; states++; colp++; } } states = hstates; } void z_cpustates(void) { int i = 0; const char * const *names; const char *thisname; int cpu, value; for (cpu = 0; cpu < num_cpus; cpu++) { names = cpustate_names; /* show tag and bump lastline */ if (num_cpus == 1) printf("\nCPU: "); else { value = printf("\nCPU %d: ", cpu); while (value++ <= cpustates_column) printf(" "); } lastline++; while ((thisname = *names++) != NULL) { if (*thisname != '\0') { printf("%s %% %s", (i++ % num_cpustates) == 0 ? "" : ", ", thisname); } } } /* fill the "last" array with all -1s, to insure correct updating */ for (i = 0; i < num_cpustates * num_cpus; ++i) { lcpustates[i] = -1; } } /* * *_memory(stats) - print "Memory: " followed by the memory summary string * * Assumptions: cursor is on "lastline" * for i_memory ONLY: cursor is on the previous line */ static char *memory_buffer = NULL; void i_memory(int *stats) { memory_buffer = setup_buffer(memory_buffer, 0); fputs("\nMem: ", stdout); lastline++; /* format and print the memory summary */ summary_format(memory_buffer, stats, memory_names); fputs(memory_buffer, stdout); } void u_memory(int *stats) { static char *new = NULL; new = setup_buffer(new, 0); /* format the new line */ summary_format(new, stats, memory_names); line_update(memory_buffer, new, x_mem, y_mem); } /* * *_arc(stats) - print "ARC: " followed by the ARC summary string * * Assumptions: cursor is on "lastline" * for i_arc ONLY: cursor is on the previous line */ static char *arc_buffer = NULL; void i_arc(int *stats) { arc_buffer = setup_buffer(arc_buffer, 0); if (arc_names == NULL) return; fputs("\nARC: ", stdout); lastline++; /* format and print the memory summary */ summary_format(arc_buffer, stats, arc_names); fputs(arc_buffer, stdout); } void u_arc(int *stats) { static char *new = NULL; new = setup_buffer(new, 0); if (arc_names == NULL) return; /* format the new line */ summary_format(new, stats, arc_names); line_update(arc_buffer, new, x_arc, y_arc); } /* * *_carc(stats) - print "Compressed ARC: " followed by the summary string * * Assumptions: cursor is on "lastline" * for i_carc ONLY: cursor is on the previous line */ static char *carc_buffer = NULL; void i_carc(int *stats) { carc_buffer = setup_buffer(carc_buffer, 0); if (carc_names == NULL) return; fputs("\n ", stdout); lastline++; /* format and print the memory summary */ summary_format(carc_buffer, stats, carc_names); fputs(carc_buffer, stdout); } void u_carc(int *stats) { static char *new = NULL; new = setup_buffer(new, 0); if (carc_names == NULL) return; /* format the new line */ summary_format(new, stats, carc_names); line_update(carc_buffer, new, x_carc, y_carc); } /* * *_swap(stats) - print "Swap: " followed by the swap summary string * * Assumptions: cursor is on "lastline" * for i_swap ONLY: cursor is on the previous line */ static char *swap_buffer = NULL; void i_swap(int *stats) { swap_buffer = setup_buffer(swap_buffer, 0); if (swap_names == NULL) return; fputs("\nSwap: ", stdout); lastline++; /* format and print the swap summary */ summary_format(swap_buffer, stats, swap_names); fputs(swap_buffer, stdout); } void u_swap(int *stats) { static char *new = NULL; new = setup_buffer(new, 0); if (swap_names == NULL) return; /* format the new line */ summary_format(new, stats, swap_names); line_update(swap_buffer, new, x_swap, y_swap); } /* * *_message() - print the next pending message line, or erase the one * that is there. * * Note that u_message is (currently) the same as i_message. * * Assumptions: lastline is consistent */ /* * i_message is funny because it gets its message asynchronously (with * respect to screen updates). */ #define NEXT_MSG_ADDLEN 5 static char *next_msg = NULL; static int msglen = 0; /* Invariant: msglen is always the length of the message currently displayed on the screen (even when next_msg doesn't contain that message). */ void i_message(void) { next_msg = setup_buffer(next_msg, NEXT_MSG_ADDLEN); while (lastline < y_message) { fputc('\n', stdout); lastline++; } if (next_msg[0] != '\0') { top_standout(next_msg); msglen = strlen(next_msg); next_msg[0] = '\0'; } else if (msglen > 0) { (void) clear_eol(msglen); msglen = 0; } } void u_message(void) { i_message(); } static int header_length; /* * Trim a header string to the current display width and return a newly * allocated area with the trimmed header. */ char * trim_header(const char *text) { char *s; int width; s = NULL; width = screen_width; header_length = strlen(text); if (header_length >= width) { s = strndup(text, width); if (s == NULL) return (NULL); } return (s); } /* * *_header(text) - print the header for the process area * * Assumptions: cursor is on the previous line and lastline is consistent */ void i_header(const char *text) { char *s; s = trim_header(text); if (s != NULL) text = s; if (header_status == ON) { putchar('\n'); fputs(text, stdout); lastline++; } else if (header_status == ERASE) { header_status = OFF; } free(s); } void u_header(const char *text __unused) { if (header_status == ERASE) { putchar('\n'); lastline++; clear_eol(header_length); header_status = OFF; } } /* * *_process(line, thisline) - print one process line * * Assumptions: lastline is consistent */ void i_process(int line, char *thisline) { char *p; char *base; /* make sure we are on the correct line */ while (lastline < y_procs + line) { putchar('\n'); lastline++; } /* truncate the line to conform to our current screen width */ int len = strlen(thisline); if (screen_width < len) { thisline[screen_width] = '\0'; } /* write the line out */ fputs(thisline, stdout); /* copy it in to our buffer */ base = smart_terminal ? screenbuf + lineindex(line) : screenbuf; p = stpcpy(base, thisline); /* zero fill the rest of it */ if (p - base < screen_width) { memset(p, 0, screen_width - (p - base)); } } void u_process(int line, char *newline) { char *optr; int screen_line = line + Header_lines; char *bufferline; /* remember a pointer to the current line in the screen buffer */ bufferline = &screenbuf[lineindex(line)]; /* truncate the line to conform to our current screen width */ int len = strlen(newline); if (screen_width < len) { newline[screen_width] = '\0'; } /* is line higher than we went on the last display? */ if (line >= last_hi) { /* yes, just ignore screenbuf and write it out directly */ /* get positioned on the correct line */ if (screen_line - lastline == 1) { putchar('\n'); lastline++; } else { Move_to(0, screen_line); lastline = screen_line; } /* now write the line */ fputs(newline, stdout); /* copy it in to the buffer */ optr = stpcpy(bufferline, newline); /* zero fill the rest of it */ if (optr - bufferline < screen_width) { memset(optr, 0, screen_width - (optr - bufferline)); } } else { line_update(bufferline, newline, 0, line + Header_lines); } } void u_endscreen(int hi) { int screen_line = hi + Header_lines; int i; if (smart_terminal) { if (hi < last_hi) { /* need to blank the remainder of the screen */ /* but only if there is any screen left below this line */ if (lastline + 1 < screen_length) { /* efficiently move to the end of currently displayed info */ if (screen_line - lastline < 5) { while (lastline < screen_line) { putchar('\n'); lastline++; } } else { Move_to(0, screen_line); lastline = screen_line; } if (clear_to_end) { /* we can do this the easy way */ putcap(clear_to_end); } else { /* use clear_eol on each line */ i = hi; while ((void) clear_eol(strlen(&screenbuf[lineindex(i++)])), i < last_hi) { putchar('\n'); } } } } last_hi = hi; /* move the cursor to a pleasant place */ Move_to(x_idlecursor, y_idlecursor); lastline = y_idlecursor; } else { /* separate this display from the next with some vertical room */ fputs("\n\n", stdout); } } void display_header(int t) { if (t) { header_status = ON; } else if (header_status == ON) { header_status = ERASE; } } void new_message(int type, const char *msgfmt, ...) { va_list args; size_t i; va_start(args, msgfmt); /* first, format the message */ vsnprintf(next_msg, setup_buffer_bufsiz + NEXT_MSG_ADDLEN, msgfmt, args); va_end(args); if (msglen > 0) { /* message there already -- can we clear it? */ if (!overstrike) { /* yes -- write it and clear to end */ i = strlen(next_msg); if ((type & MT_delayed) == 0) { if (type & MT_standout) { top_standout(next_msg); } else { fputs(next_msg, stdout); } clear_eol(msglen - i); msglen = i; next_msg[0] = '\0'; } } } else { if ((type & MT_delayed) == 0) { if (type & MT_standout) { top_standout(next_msg); } else { fputs(next_msg, stdout); } msglen = strlen(next_msg); next_msg[0] = '\0'; } } } void clear_message(void) { if (clear_eol(msglen) == 1) { putchar('\r'); } } int readline(char *buffer, int size, int numeric) { char *ptr = buffer; char ch; char cnt = 0; char maxcnt = 0; /* allow room for null terminator */ size -= 1; /* read loop */ while ((fflush(stdout), read(0, ptr, 1) > 0)) { /* newline means we are done */ if ((ch = *ptr) == '\n' || ch == '\r') { break; } /* handle special editing characters */ if (ch == ch_kill) { /* kill line -- account for overstriking */ if (overstrike) { msglen += maxcnt; } /* return null string */ *buffer = '\0'; putchar('\r'); return(-1); } else if (ch == ch_erase) { /* erase previous character */ if (cnt <= 0) { /* none to erase! */ putchar('\7'); } else { fputs("\b \b", stdout); ptr--; cnt--; } } /* check for character validity and buffer overflow */ else if (cnt == size || (numeric && !isdigit(ch)) || !isprint(ch)) { /* not legal */ putchar('\7'); } else { /* echo it and store it in the buffer */ putchar(ch); ptr++; cnt++; if (cnt > maxcnt) { maxcnt = cnt; } } } /* all done -- null terminate the string */ *ptr = '\0'; /* account for the extra characters in the message area */ /* (if terminal overstrikes, remember the furthest they went) */ msglen += overstrike ? maxcnt : cnt; /* return either inputted number or string length */ putchar('\r'); return(cnt == 0 ? -1 : numeric ? atoi(buffer) : cnt); } /* internal support routines */ static void summary_format(char *str, int *numbers, const char * const *names) { char *p; int num; const char *thisname; char rbuf[6]; /* format each number followed by its string */ p = str; while ((thisname = *names++) != NULL) { /* get the number to format */ num = *numbers++; /* display only non-zero numbers */ if (num > 0) { /* is this number in kilobytes? */ if (thisname[0] == 'K') { /* yes: format it as a memory value */ p = stpcpy(p, format_k(num)); /* skip over the K, since it was included by format_k */ p = stpcpy(p, thisname+1); } /* is this number a ratio? */ else if (thisname[0] == ':') { (void) snprintf(rbuf, sizeof(rbuf), "%.2f", (float)*(numbers - 2) / (float)num); p = stpcpy(p, rbuf); p = stpcpy(p, thisname); } else { p = stpcpy(p, itoa(num)); p = stpcpy(p, thisname); } } /* ignore negative numbers, but display corresponding string */ else if (num < 0) { p = stpcpy(p, thisname); } } /* if the last two characters in the string are ", ", delete them */ p -= 2; if (p >= str && p[0] == ',' && p[1] == ' ') { *p = '\0'; } } static void line_update(char *old, char *new, int start, int line) { int ch; int diff; int newcol = start + 1; int lastcol = start; char cursor_on_line = false; char *current; /* compare the two strings and only rewrite what has changed */ current = old; #ifdef DEBUG fprintf(debug, "line_update, starting at %d\n", start); fputs(old, debug); fputc('\n', debug); fputs(new, debug); fputs("\n-\n", debug); #endif /* start things off on the right foot */ /* this is to make sure the invariants get set up right */ if ((ch = *new++) != *old) { if (line - lastline == 1 && start == 0) { putchar('\n'); } else { Move_to(start, line); } cursor_on_line = true; putchar(ch); *old = ch; lastcol = start + 1; } old++; /* * main loop -- check each character. If the old and new aren't the * same, then update the display. When the distance from the * current cursor position to the new change is small enough, * the characters that belong there are written to move the * cursor over. * * Invariants: * lastcol is the column where the cursor currently is sitting * (always one beyond the end of the last mismatch). */ do /* yes, a do...while */ { if ((ch = *new++) != *old) { /* new character is different from old */ /* make sure the cursor is on top of this character */ diff = newcol - lastcol; if (diff > 0) { /* some motion is required--figure out which is shorter */ if (diff < 6 && cursor_on_line) { /* overwrite old stuff--get it out of the old buffer */ printf("%.*s", diff, ¤t[lastcol-start]); } else { /* use cursor addressing */ Move_to(newcol, line); cursor_on_line = true; } /* remember where the cursor is */ lastcol = newcol + 1; } else { /* already there, update position */ lastcol++; } /* write what we need to */ if (ch == '\0') { /* at the end--terminate with a clear-to-end-of-line */ (void) clear_eol(strlen(old)); } else { /* write the new character */ putchar(ch); } /* put the new character in the screen buffer */ *old = ch; } /* update working column and screen buffer pointer */ newcol++; old++; } while (ch != '\0'); /* zero out the rest of the line buffer -- MUST BE DONE! */ diff = screen_width - newcol; if (diff > 0) { memset(old, 0, diff); } /* remember where the current line is */ if (cursor_on_line) { lastline = line; } } void i_uptime(struct timeval *bt, time_t *tod) { time_t uptime; int days, hrs, mins, secs; if (bt->tv_sec != -1) { uptime = *tod - bt->tv_sec; days = uptime / 86400; uptime %= 86400; hrs = uptime / 3600; uptime %= 3600; mins = uptime / 60; secs = uptime % 60; /* * Display the uptime. */ if (smart_terminal) { Move_to((screen_width - 24) - (days > 9 ? 1 : 0), 0); } else { fputs(" ", stdout); } printf(" up %d+%02d:%02d:%02d", days, hrs, mins, secs); } } void i_battery(int nbat, int batt) { if (nbat > 0) { printf("; battery: %d%%", batt); } } #define SETUPBUFFER_MIN_SCREENWIDTH 80 #define SETUPBUFFER_REQUIRED_ADDBUFSIZ 2 static char * setup_buffer(char *buffer, int addlen) { size_t len, old_len; char *new_buffer; setup_buffer_bufsiz = screen_width; if (setup_buffer_bufsiz < SETUPBUFFER_MIN_SCREENWIDTH) { setup_buffer_bufsiz = SETUPBUFFER_MIN_SCREENWIDTH; } len = setup_buffer_bufsiz + addlen + SETUPBUFFER_REQUIRED_ADDBUFSIZ; new_buffer = calloc(len, sizeof(char)); if (new_buffer == NULL) { errx(4, "can't allocate sufficient memory"); } if (buffer != NULL) { old_len = strlen(buffer); memcpy(new_buffer, buffer, old_len < len - 1 ? old_len : len - 1); free(buffer); } return new_buffer; }