From 2e52a44546db246b89817711efec6b046c06d453 Mon Sep 17 00:00:00 2001 From: Marc-Antoine Perennou Date: Fri, 22 Nov 2013 08:29:29 +0100 Subject: [PATCH 2/5] MEDIUM: add haproxy-systemd-wrapper Currently, to reload haproxy configuration, you have to use "-sf". There is a problem with this way of doing things. First of all, in the systemd world, reload commands should be "oneshot" ones, which means they should not be the new main process but rather a tool which makes a call to it and then exits. With the current approach, the reload command is the new main command and moreover, it makes the previous one exit. Systemd only tracks the main program, seeing it ending, it assumes it either finished or failed, and kills everything remaining as a grabage collector. We then end up with no haproxy running at all. This patch adds wrapper around haproxy, no changes at all have been made into it, so it's not intrusive and doesn't change anything for other hosts. What this wrapper does is basically launching haproxy as a child, listen to the SIGUSR2 (not to conflict with haproxy itself) signal, and spawing a new haproxy with "-sf" as a child to relay the first one. Signed-off-by: Marc-Antoine Perennou --- .gitignore | 1 + Makefile | 16 +++++- src/haproxy-systemd-wrapper.c | 114 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 129 insertions(+), 2 deletions(-) create mode 100644 src/haproxy-systemd-wrapper.c diff --git a/.gitignore b/.gitignore index 83d84083ca3e..ec1545a7a3df 100644 --- a/.gitignore +++ b/.gitignore @@ -12,6 +12,7 @@ src/*.o *.log* *.trace* haproxy-* +!src/*.c make-* dlmalloc.c 00*.patch diff --git a/Makefile b/Makefile index 57692fe51ba6..6bb231a0213a 100644 --- a/Makefile +++ b/Makefile @@ -519,7 +519,7 @@ all: @echo @exit 1 else -all: haproxy +all: haproxy haproxy-systemd-wrapper endif OBJS = src/haproxy.o src/sessionhash.o src/base64.o src/protocols.o \ @@ -537,12 +537,17 @@ EBTREE_OBJS = $(EBTREE_DIR)/ebtree.o \ $(EBTREE_DIR)/ebmbtree.o $(EBTREE_DIR)/ebsttree.o \ $(EBTREE_DIR)/ebimtree.o $(EBTREE_DIR)/ebistree.o +WRAPPER_OBJS = src/haproxy-systemd-wrapper.o + # Not used right now LIB_EBTREE = $(EBTREE_DIR)/libebtree.a haproxy: $(OBJS) $(OPTIONS_OBJS) $(EBTREE_OBJS) $(LD) $(LDFLAGS) -o $@ $^ $(LDOPTS) +haproxy-systemd-wrapper: $(WRAPPER_OBJS) + $(LD) $(LDFLAGS) -o $@ $^ $(LDOPTS) + $(LIB_EBTREE): $(EBTREE_OBJS) $(AR) rv $@ $^ @@ -562,6 +567,11 @@ src/haproxy.o: src/haproxy.c -DBUILD_OPTIONS='"$(strip $(BUILD_OPTIONS))"' \ -c -o $@ $< +src/haproxy-systemd-wrapper.o: src/haproxy-systemd-wrapper.c + $(CC) $(COPTS) \ + -DSBINDIR='"$(strip $(SBINDIR))"' \ + -c -o $@ $< + src/dlmalloc.o: $(DLMALLOC_SRC) $(CC) $(COPTS) -DDEFAULT_MMAP_THRESHOLD=$(DLMALLOC_THRES) -c -o $@ $< @@ -575,9 +585,10 @@ install-doc: install -m 644 doc/$$x.txt $(DESTDIR)$(DOCDIR) ; \ done -install-bin: haproxy +install-bin: haproxy haproxy-systemd-wrapper install -d $(DESTDIR)$(SBINDIR) install haproxy $(DESTDIR)$(SBINDIR) + install haproxy-systemd-wrapper $(DESTDIR)$(SBINDIR) install: install-bin install-man install-doc @@ -586,6 +597,7 @@ clean: for dir in . src include/* doc ebtree; do rm -f $$dir/*~ $$dir/*.rej $$dir/core; done rm -f haproxy-$(VERSION).tar.gz haproxy-$(VERSION)$(SUBVERS).tar.gz rm -f haproxy-$(VERSION) nohup.out gmon.out + rm -f haproxy-systemd-wrapper tags: find src include \( -name '*.c' -o -name '*.h' \) -print0 | \ diff --git a/src/haproxy-systemd-wrapper.c b/src/haproxy-systemd-wrapper.c new file mode 100644 index 000000000000..596801591b9e --- /dev/null +++ b/src/haproxy-systemd-wrapper.c @@ -0,0 +1,114 @@ +/* + * Wrapper to make haproxy systemd-compliant. + * + * Copyright 2013 Marc-Antoine Perennou + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +static pid_t pid = 0; +static char *pid_file = "/run/haproxy.pid"; +static int main_argc; +static char **main_argv; + +static pid_t spawn_haproxy(char **pid_strv, int nb_pid) +{ + pid_t pid = fork(); + if (!pid) { + /* 3 for "haproxy -Ds -sf" */ + char **argv = calloc(4 + main_argc + nb_pid + 1, sizeof(char *)); + int i; + int argno = 0; + argv[argno++] = SBINDIR"/haproxy"; + for (i = 0; i < main_argc; ++i) + argv[argno++] = main_argv[i]; + argv[argno++] = "-Ds"; + if (nb_pid > 0) { + argv[argno++] = "-sf"; + for (i = 0; i < nb_pid; ++i) + argv[argno++] = pid_strv[i]; + } + argv[argno] = NULL; + execv(argv[0], argv); + exit(0); + } + return pid; +} + +static int read_pids(char ***pid_strv) +{ + FILE *f = fopen(pid_file, "r"); + int read = 0, allocated = 8; + char pid_str[10]; + + if (!f) + return 0; + + *pid_strv = malloc(allocated * sizeof(char *)); + while (1 == fscanf(f, "%s\n", pid_str)) { + if (read == allocated) { + allocated *= 2; + *pid_strv = realloc(*pid_strv, allocated * sizeof(char *)); + } + (*pid_strv)[read++] = strdup(pid_str); + } + + fclose(f); + + return read; +} + +static void signal_handler(int signum __attribute__((unused))) +{ + int i; + char **pid_strv = NULL; + int nb_pid = read_pids(&pid_strv); + + pid = spawn_haproxy(pid_strv, nb_pid); + + for (i = 0; i < nb_pid; ++i) + free(pid_strv[i]); + free(pid_strv); +} + +static void init(int argc, char **argv) +{ + while (argc > 1) { + if (**argv == '-') { + char *flag = *argv + 1; + --argc; ++argv; + if (*flag == 'p') + pid_file = *argv; + } + --argc; ++argv; + } +} + +int main(int argc, char **argv) +{ + --argc; ++argv; + main_argc = argc; + main_argv = argv; + + init(argc, argv); + + signal(SIGUSR2, &signal_handler); + + pid = spawn_haproxy(NULL, 0); + while (-1 != waitpid(pid, NULL, 0) || errno == EINTR); + + return EXIT_SUCCESS; +} -- 1.8.4