From dfbbf7f6e1b22ccf9e5a45d77ee10995577fb4fc Mon Sep 17 00:00:00 2001 From: Hiltjo Posthuma Date: Wed, 8 Mar 2023 21:20:52 +0100 Subject: [PATCH] readstdin: reduce memory-usage by duplicating the line from getline() Improves upon commit 32db2b125190d366be472ccb7cad833248696144 The getline() implementation often uses a more greedy way of allocating memory. Using this buffer directly and forcing an allocation (by setting it to NULL) would waste a bit of extra space, depending on the implementation of course. Tested on musl libc and glibc. The current glibc version allocates a minimum of 120 bytes per line. For smaller lines musl libc seems less wasteful but still wastes a few bytes per line. On a dmenu_path listing on my system the memory usage was about 350kb (old) vs 30kb (new) on Void Linux glibc. Side-note that getline() also reads NUL bytes in lines, while strdup() would read until the NUL byte. Since dmenu reads text lines either is probably fine(tm). Also rename junk to linesiz. --- dmenu.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/dmenu.c b/dmenu.c index 27b7a30..4e7df12 100644 --- a/dmenu.c +++ b/dmenu.c @@ -550,11 +550,11 @@ static void readstdin(void) { char *line = NULL; - size_t i, junk, itemsiz = 0; + size_t i, itemsiz = 0, linesiz = 0; ssize_t len; /* read each line from stdin and add it to the item list */ - for (i = 0; (len = getline(&line, &junk, stdin)) != -1; i++) { + for (i = 0; (len = getline(&line, &linesiz, stdin)) != -1; i++) { if (i + 1 >= itemsiz) { itemsiz += 256; if (!(items = realloc(items, itemsiz * sizeof(*items)))) @@ -562,9 +562,10 @@ readstdin(void) } if (line[len - 1] == '\n') line[len - 1] = '\0'; - items[i].text = line; + if (!(items[i].text = strdup(line))) + die("strdup:"); + items[i].out = 0; - line = NULL; /* next call of getline() allocates a new line */ } free(line); if (items) -- 2.11.4.GIT