X-Git-Url: https://git.distorted.org.uk/u/mdw/putty/blobdiff_plain/57356d6317f6f33dd622711d305c4579df63b269..39934deb5202149f98198c111a35c21cb4d0d0f8:/misc.c diff --git a/misc.c b/misc.c index 6b2f9e68..474bf024 100644 --- a/misc.c +++ b/misc.c @@ -1,3 +1,7 @@ +/* + * Platform-independent routines shared between all PuTTY programs. + */ + #include #include #include @@ -11,9 +15,12 @@ char *dupstr(const char *s) { - int len = strlen(s); - char *p = smalloc(len + 1); - strcpy(p, s); + char *p = NULL; + if (s) { + int len = strlen(s); + p = snewn(len + 1, char); + strcpy(p, s); + } return p; } @@ -34,7 +41,7 @@ char *dupcat(const char *s1, ...) } va_end(ap); - p = smalloc(len + 1); + p = snewn(len + 1, char); strcpy(p, s1); q = p + strlen(p); @@ -54,13 +61,46 @@ char *dupcat(const char *s1, ...) /* * Do an sprintf(), but into a custom-allocated buffer. * - * Irritatingly, we don't seem to be able to do this portably using - * vsnprintf(), because there appear to be issues with re-using the - * same va_list for two calls, and the excellent C99 va_copy is not - * yet widespread. Bah. Instead I'm going to do a horrid, horrid - * hack, in which I trawl the format string myself, work out the - * maximum length of each format component, and resize the buffer - * before printing it. + * Currently I'm doing this via vsnprintf. This has worked so far, + * but it's not good, because: + * + * - vsnprintf is not available on all platforms. There's an ifdef + * to use `_vsnprintf', which seems to be the local name for it + * on Windows. Other platforms may lack it completely, in which + * case it'll be time to rewrite this function in a totally + * different way. + * + * - technically you can't reuse a va_list like this: it is left + * unspecified whether advancing a va_list pointer modifies its + * value or something it points to, so on some platforms calling + * vsnprintf twice on the same va_list might fail hideously. It + * would be better to use the `va_copy' macro mandated by C99, + * but that too is not yet ubiquitous. + * + * The only `properly' portable solution I can think of is to + * implement my own format string scanner, which figures out an + * upper bound for the length of each formatting directive, + * allocates the buffer as it goes along, and calls sprintf() to + * actually process each directive. If I ever need to actually do + * this, some caveats: + * + * - It's very hard to find a reliable upper bound for + * floating-point values. %f, in particular, when supplied with + * a number near to the upper or lower limit of representable + * numbers, could easily take several hundred characters. It's + * probably feasible to predict this statically using the + * constants in , or even to predict it dynamically by + * looking at the exponent of the specific float provided, but + * it won't be fun. + * + * - Don't forget to _check_, after calling sprintf, that it's + * used at most the amount of space we had available. + * + * - Fault any formatting directive we don't fully understand. The + * aim here is to _guarantee_ that we never overflow the buffer, + * because this is a security-critical function. If we see a + * directive we don't know about, we should panic and die rather + * than run any risk. */ char *dupprintf(const char *fmt, ...) { @@ -76,7 +116,7 @@ char *dupvprintf(const char *fmt, va_list ap) char *buf; int len, size; - buf = smalloc(512); + buf = snewn(512, char); size = 512; while (1) { @@ -97,8 +137,31 @@ char *dupvprintf(const char *fmt, va_list ap) * buffer wasn't big enough, so we enlarge it a bit and hope. */ size += 512; } - buf = srealloc(buf, size); + buf = sresize(buf, size, char); + } +} + +/* + * Read an entire line of text from a file. Return a buffer + * malloced to be as big as necessary (caller must free). + */ +char *fgetline(FILE *fp) +{ + char *ret = snewn(512, char); + int size = 512, len = 0; + while (fgets(ret + len, size - len, fp)) { + len += strlen(ret + len); + if (ret[len-1] == '\n') + break; /* got a newline, we're done */ + size = len + 512; + ret = sresize(ret, size, char); + } + if (len == 0) { /* first fgets returned NULL */ + sfree(ret); + return NULL; } + ret[len] = '\0'; + return ret; } /* ---------------------------------------------------------------------- @@ -174,9 +237,11 @@ int bufchain_size(bufchain *ch) return ch->buffersize; } -void bufchain_add(bufchain *ch, void *data, int len) +void bufchain_add(bufchain *ch, const void *data, int len) { - char *buf = (char *)data; + const char *buf = (const char *)data; + + if (len == 0) return; ch->buffersize += len; @@ -190,7 +255,7 @@ void bufchain_add(bufchain *ch, void *data, int len) while (len > 0) { int grainlen = min(len, BUFFER_GRANULE); struct bufchain_granule *newbuf; - newbuf = smalloc(sizeof(struct bufchain_granule)); + newbuf = snew(struct bufchain_granule); newbuf->bufpos = 0; newbuf->buflen = grainlen; memcpy(newbuf->buf, buf, grainlen); @@ -266,225 +331,10 @@ void bufchain_fetch(bufchain *ch, void *data, int len) */ #ifdef MINEFIELD -/* - * Minefield - a Windows equivalent for Electric Fence - */ - -#define PAGESIZE 4096 - -/* - * Design: - * - * We start by reserving as much virtual address space as Windows - * will sensibly (or not sensibly) let us have. We flag it all as - * invalid memory. - * - * Any allocation attempt is satisfied by committing one or more - * pages, with an uncommitted page on either side. The returned - * memory region is jammed up against the _end_ of the pages. - * - * Freeing anything causes instantaneous decommitment of the pages - * involved, so stale pointers are caught as soon as possible. - */ - -static int minefield_initialised = 0; -static void *minefield_region = NULL; -static long minefield_size = 0; -static long minefield_npages = 0; -static long minefield_curpos = 0; -static unsigned short *minefield_admin = NULL; -static void *minefield_pages = NULL; - -static void minefield_admin_hide(int hide) -{ - int access = hide ? PAGE_NOACCESS : PAGE_READWRITE; - VirtualProtect(minefield_admin, minefield_npages * 2, access, NULL); -} - -static void minefield_init(void) -{ - int size; - int admin_size; - int i; - - for (size = 0x40000000; size > 0; size = ((size >> 3) * 7) & ~0xFFF) { - minefield_region = VirtualAlloc(NULL, size, - MEM_RESERVE, PAGE_NOACCESS); - if (minefield_region) - break; - } - minefield_size = size; - - /* - * Firstly, allocate a section of that to be the admin block. - * We'll need a two-byte field for each page. - */ - minefield_admin = minefield_region; - minefield_npages = minefield_size / PAGESIZE; - admin_size = (minefield_npages * 2 + PAGESIZE - 1) & ~(PAGESIZE - 1); - minefield_npages = (minefield_size - admin_size) / PAGESIZE; - minefield_pages = (char *) minefield_region + admin_size; - - /* - * Commit the admin region. - */ - VirtualAlloc(minefield_admin, minefield_npages * 2, - MEM_COMMIT, PAGE_READWRITE); - - /* - * Mark all pages as unused (0xFFFF). - */ - for (i = 0; i < minefield_npages; i++) - minefield_admin[i] = 0xFFFF; - - /* - * Hide the admin region. - */ - minefield_admin_hide(1); - - minefield_initialised = 1; -} - -static void minefield_bomb(void) -{ - div(1, *(int *) minefield_pages); -} - -static void *minefield_alloc(int size) -{ - int npages; - int pos, lim, region_end, region_start; - int start; - int i; - - npages = (size + PAGESIZE - 1) / PAGESIZE; - - minefield_admin_hide(0); - - /* - * Search from current position until we find a contiguous - * bunch of npages+2 unused pages. - */ - pos = minefield_curpos; - lim = minefield_npages; - while (1) { - /* Skip over used pages. */ - while (pos < lim && minefield_admin[pos] != 0xFFFF) - pos++; - /* Count unused pages. */ - start = pos; - while (pos < lim && pos - start < npages + 2 && - minefield_admin[pos] == 0xFFFF) - pos++; - if (pos - start == npages + 2) - break; - /* If we've reached the limit, reset the limit or stop. */ - if (pos >= lim) { - if (lim == minefield_npages) { - /* go round and start again at zero */ - lim = minefield_curpos; - pos = 0; - } else { - minefield_admin_hide(1); - return NULL; - } - } - } - - minefield_curpos = pos - 1; - - /* - * We have npages+2 unused pages starting at start. We leave - * the first and last of these alone and use the rest. - */ - region_end = (start + npages + 1) * PAGESIZE; - region_start = region_end - size; - /* FIXME: could align here if we wanted */ - - /* - * Update the admin region. - */ - for (i = start + 2; i < start + npages + 1; i++) - minefield_admin[i] = 0xFFFE; /* used but no region starts here */ - minefield_admin[start + 1] = region_start % PAGESIZE; - - minefield_admin_hide(1); - - VirtualAlloc((char *) minefield_pages + region_start, size, - MEM_COMMIT, PAGE_READWRITE); - return (char *) minefield_pages + region_start; -} - -static void minefield_free(void *ptr) -{ - int region_start, i, j; - - minefield_admin_hide(0); - - region_start = (char *) ptr - (char *) minefield_pages; - i = region_start / PAGESIZE; - if (i < 0 || i >= minefield_npages || - minefield_admin[i] != region_start % PAGESIZE) - minefield_bomb(); - for (j = i; j < minefield_npages && minefield_admin[j] != 0xFFFF; j++) { - minefield_admin[j] = 0xFFFF; - } - - VirtualFree(ptr, j * PAGESIZE - region_start, MEM_DECOMMIT); - - minefield_admin_hide(1); -} - -static int minefield_get_size(void *ptr) -{ - int region_start, i, j; - - minefield_admin_hide(0); - - region_start = (char *) ptr - (char *) minefield_pages; - i = region_start / PAGESIZE; - if (i < 0 || i >= minefield_npages || - minefield_admin[i] != region_start % PAGESIZE) - minefield_bomb(); - for (j = i; j < minefield_npages && minefield_admin[j] != 0xFFFF; j++); - - minefield_admin_hide(1); - - return j * PAGESIZE - region_start; -} - -static void *minefield_c_malloc(size_t size) -{ - if (!minefield_initialised) - minefield_init(); - return minefield_alloc(size); -} - -static void minefield_c_free(void *p) -{ - if (!minefield_initialised) - minefield_init(); - minefield_free(p); -} - -/* - * realloc _always_ moves the chunk, for rapid detection of code - * that assumes it won't. - */ -static void *minefield_c_realloc(void *p, size_t size) -{ - size_t oldsize; - void *q; - if (!minefield_initialised) - minefield_init(); - q = minefield_alloc(size); - oldsize = minefield_get_size(p); - memcpy(q, p, (oldsize < size ? oldsize : size)); - minefield_free(p); - return q; -} - -#endif /* MINEFIELD */ +void *minefield_c_malloc(size_t size); +void minefield_c_free(void *p); +void *minefield_c_realloc(void *p, size_t size); +#endif #ifdef MALLOC_LOG static FILE *fp = NULL; @@ -591,29 +441,9 @@ void safefree(void *ptr) */ #ifdef DEBUG -static FILE *debug_fp = NULL; -static int debug_got_console = 0; - -static void dputs(char *buf) -{ - DWORD dw; - - if (!debug_got_console) { - AllocConsole(); - debug_got_console = 1; - } - if (!debug_fp) { - debug_fp = fopen("debug.log", "w"); - } - - WriteFile(GetStdHandle(STD_OUTPUT_HANDLE), buf, strlen(buf), &dw, - NULL); - fputs(buf, debug_fp); - fflush(debug_fp); -} - +extern void dputs(char *); /* defined in per-platform *misc.c */ -void dprintf(char *fmt, ...) +void debug_printf(char *fmt, ...) { char *buf; va_list ap; @@ -633,7 +463,7 @@ void debug_memdump(void *buf, int len, int L) char foo[17]; if (L) { int delta; - dprintf("\t%d (0x%x) bytes:\n", len, len); + debug_printf("\t%d (0x%x) bytes:\n", len, len); delta = 15 & (int) p; p -= delta; len += delta; @@ -641,14 +471,14 @@ void debug_memdump(void *buf, int len, int L) for (; 0 < len; p += 16, len -= 16) { dputs(" "); if (L) - dprintf("%p: ", p); + debug_printf("%p: ", p); strcpy(foo, "................"); /* sixteen dots */ for (i = 0; i < 16 && i < len; ++i) { if (&p[i] < (unsigned char *) buf) { dputs(" "); /* 3 spaces */ foo[i] = ' '; } else { - dprintf("%c%02.2x", + debug_printf("%c%02.2x", &p[i] != (unsigned char *) buf && i % 4 ? '.' : ' ', p[i] ); @@ -657,7 +487,7 @@ void debug_memdump(void *buf, int len, int L) } } foo[i] = '\0'; - dprintf("%*s%s\n", (16 - i) * 3 + 2, "", foo); + debug_printf("%*s%s\n", (16 - i) * 3 + 2, "", foo); } }