From 7f96b1d8147b164bc7c8ce119aeea5fed6ceecb7 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Wed, 22 Jan 2014 13:06:04 +0100 Subject: [PATCH] bus: extend memfd api so that we can label memfds for debugging purposes --- src/libsystemd/libsystemd.sym | 1 + src/libsystemd/sd-bus/sd-memfd.c | 117 +++++++++++++++++++-- src/libsystemd/sd-bus/test-bus-memfd.c | 10 +- src/libsystemd/sd-bus/test-bus-zero-copy.c | 4 +- src/systemd/sd-memfd.h | 9 +- 5 files changed, 124 insertions(+), 17 deletions(-) diff --git a/src/libsystemd/libsystemd.sym b/src/libsystemd/libsystemd.sym index 951166afa..7798fac34 100644 --- a/src/libsystemd/libsystemd.sym +++ b/src/libsystemd/libsystemd.sym @@ -215,6 +215,7 @@ global: sd_memfd_get_sealed; sd_memfd_get_size; sd_memfd_set_size; + sd_memfd_get_name; /* sd-event functions */ sd_event_default; diff --git a/src/libsystemd/sd-bus/sd-memfd.c b/src/libsystemd/sd-bus/sd-memfd.c index 112c95fb4..913be2086 100644 --- a/src/libsystemd/sd-bus/sd-memfd.c +++ b/src/libsystemd/sd-bus/sd-memfd.c @@ -23,22 +23,26 @@ #include #include #include +#include #include "util.h" #include "kdbus.h" #include "sd-memfd.h" +#include "sd-bus.h" struct sd_memfd { int fd; FILE *f; }; -_public_ int sd_memfd_new(sd_memfd **m) { - struct kdbus_cmd_memfd_make cmd = { - .size = sizeof(struct kdbus_cmd_memfd_make), - }; +_public_ int sd_memfd_new(const char *name, sd_memfd **m) { + + struct kdbus_cmd_memfd_make *cmd; + struct kdbus_item *item; _cleanup_close_ int kdbus = -1; + _cleanup_free_ char *g = NULL; + size_t sz, l; sd_memfd *n; assert_return(m, -EINVAL); @@ -47,16 +51,64 @@ _public_ int sd_memfd_new(sd_memfd **m) { if (kdbus < 0) return -errno; - if (ioctl(kdbus, KDBUS_CMD_MEMFD_NEW, &cmd) < 0) + if (name) { + /* The kernel side is pretty picky about the character + * set here, let's do the usual bus escaping to deal + * with that. */ + + g = sd_bus_label_escape(name); + if (!g) + return -ENOMEM; + + name = g; + + } else { + char pr[17] = {}; + + /* If no name is specified we generate one. We include + * a hint indicating our library implementation, and + * add the thread name to it */ + + assert_se(prctl(PR_GET_NAME, (unsigned long) pr) >= 0); + + if (isempty(pr)) + name = "sd"; + else { + _cleanup_free_ char *e = NULL; + + e = sd_bus_label_escape(pr); + if (!e) + return -ENOMEM; + + g = strappend("sd-", e); + if (!g) + return -ENOMEM; + + name = g; + } + } + + l = strlen(name); + sz = ALIGN8(offsetof(struct kdbus_cmd_memfd_make, items)) + + ALIGN8(offsetof(struct kdbus_item, str)) + + l + 1; + cmd = alloca0(sz); + cmd->size = sz; + item = cmd->items; + item->size = ALIGN8(offsetof(struct kdbus_item, str)) + l + 1; + item->type = KDBUS_ITEM_MEMFD_NAME; + memcpy(item->str, name, l + 1); + + if (ioctl(kdbus, KDBUS_CMD_MEMFD_NEW, cmd) < 0) return -errno; n = new0(struct sd_memfd, 1); if (!n) { - close_nointr_nofail(cmd.fd); + close_nointr_nofail(cmd->fd); return -ENOMEM; } - n->fd = cmd.fd; + n->fd = cmd->fd; *m = n; return 0; } @@ -195,11 +247,11 @@ _public_ int sd_memfd_set_size(sd_memfd *m, uint64_t sz) { return r; } -_public_ int sd_memfd_new_and_map(sd_memfd **m, size_t sz, void **p) { +_public_ int sd_memfd_new_and_map(const char *name, sd_memfd **m, size_t sz, void **p) { sd_memfd *n; int r; - r = sd_memfd_new(&n); + r = sd_memfd_new(name, &n); if (r < 0) return r; @@ -218,3 +270,50 @@ _public_ int sd_memfd_new_and_map(sd_memfd **m, size_t sz, void **p) { *m = n; return 0; } + +_public_ int sd_memfd_get_name(sd_memfd *m, char **name) { + char path[sizeof("/proc/self/fd/") + DECIMAL_STR_MAX(int)], buf[FILENAME_MAX+1], *e; + const char *delim, *end; + _cleanup_free_ char *n = NULL; + ssize_t k; + + assert_return(m, -EINVAL); + assert_return(name, -EINVAL); + + sprintf(path, "/proc/self/fd/%i", m->fd); + + k = readlink(path, buf, sizeof(buf)); + if (k < 0) + return -errno; + + if ((size_t) k >= sizeof(buf)) + return -E2BIG; + + buf[k] = 0; + + delim = strstr(buf, ":["); + if (!delim) + return -EIO; + + delim = strchr(delim + 2, ':'); + if (!delim) + return -EIO; + + delim++; + + end = strchr(delim, ']'); + if (!end) + return -EIO; + + n = strndup(delim, end - delim); + if (!n) + return -ENOMEM; + + e = sd_bus_label_unescape(n); + if (!e) + return -ENOMEM; + + *name = e; + + return 0; +} diff --git a/src/libsystemd/sd-bus/test-bus-memfd.c b/src/libsystemd/sd-bus/test-bus-memfd.c index b9d6a250c..f7197ed09 100644 --- a/src/libsystemd/sd-bus/test-bus-memfd.c +++ b/src/libsystemd/sd-bus/test-bus-memfd.c @@ -30,7 +30,7 @@ int main(int argc, char *argv[]) { sd_memfd *m; - char *s; + char *s, *name; uint64_t sz; int r, fd; FILE *f; @@ -40,10 +40,16 @@ int main(int argc, char *argv[]) { log_set_max_level(LOG_DEBUG); - r = sd_memfd_new(&m); + r = sd_memfd_new(NULL, &m); if (r == -ENOENT) return EXIT_TEST_SKIP; + assert_se(r >= 0); + + assert_se(sd_memfd_get_name(m, &name) >= 0); + log_info("name: %s", name); + free(name); + r = sd_memfd_map(m, 0, 12, (void**) &s); assert_se(r >= 0); diff --git a/src/libsystemd/sd-bus/test-bus-zero-copy.c b/src/libsystemd/sd-bus/test-bus-zero-copy.c index 5ad8ed54b..a2239acaa 100644 --- a/src/libsystemd/sd-bus/test-bus-zero-copy.c +++ b/src/libsystemd/sd-bus/test-bus-zero-copy.c @@ -93,7 +93,7 @@ int main(int argc, char *argv[]) { memset(p+1, 'L', FIRST_ARRAY-2); p[FIRST_ARRAY-1] = '>'; - r = sd_memfd_new_and_map(&f, STRING_SIZE, (void**) &s); + r = sd_memfd_new_and_map(NULL, &f, STRING_SIZE, (void**) &s); assert_se(r >= 0); s[0] = '<'; @@ -112,7 +112,7 @@ int main(int argc, char *argv[]) { sd_memfd_free(f); - r = sd_memfd_new_and_map(&f, SECOND_ARRAY, (void**) &p); + r = sd_memfd_new_and_map(NULL, &f, SECOND_ARRAY, (void**) &p); assert_se(r >= 0); p[0] = '<'; diff --git a/src/systemd/sd-memfd.h b/src/systemd/sd-memfd.h index f4ef8f102..76cb8751c 100644 --- a/src/systemd/sd-memfd.h +++ b/src/systemd/sd-memfd.h @@ -32,16 +32,15 @@ _SD_BEGIN_DECLARATIONS; typedef struct sd_memfd sd_memfd; -int sd_memfd_new(sd_memfd **m); +int sd_memfd_new(const char *name, sd_memfd **m); +int sd_memfd_new_and_map(const char *name, sd_memfd **m, size_t sz, void **p); int sd_memfd_make(int fd, sd_memfd **m); -int sd_memfd_new_and_map(sd_memfd **m, size_t sz, void **p); - void sd_memfd_free(sd_memfd *m); int sd_memfd_get_fd(sd_memfd *m); -int sd_memfd_get_file(sd_memfd *m, FILE **f); int sd_memfd_dup_fd(sd_memfd *n); +int sd_memfd_get_file(sd_memfd *m, FILE **f); int sd_memfd_map(sd_memfd *m, uint64_t offset, size_t size, void **p); @@ -51,6 +50,8 @@ int sd_memfd_get_sealed(sd_memfd *m); int sd_memfd_get_size(sd_memfd *m, uint64_t *sz); int sd_memfd_set_size(sd_memfd *m, uint64_t sz); +int sd_memfd_get_name(sd_memfd *m, char **name); + _SD_END_DECLARATIONS; #endif -- 2.30.2