From f3985622a1e68d7a9250e3a3403c33029ebc6f03 Mon Sep 17 00:00:00 2001 From: =?utf8?q?J=C3=A9r=C3=A9mie=20Galarneau?= Date: Thu, 18 Jul 2024 17:37:43 +0000 Subject: [PATCH] sessiond: manage syscall table allocation using std::vector MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Transitioning to the use of std::vector to manage the allocation and resizing of the syscall table allows us to do away with memset() of the syscall structure. The memset becomes problematic when lttng_ht_node_* becomes non-POD in a follow-up change. Change-Id: I94096782360f85ffffb0f72d188224af15e54d07 Signed-off-by: Jérémie Galarneau --- src/bin/lttng-sessiond/kernel.cpp | 1 - src/bin/lttng-sessiond/lttng-syscall.cpp | 95 ++++++------------------ src/bin/lttng-sessiond/lttng-syscall.hpp | 27 +++++-- 3 files changed, 46 insertions(+), 77 deletions(-) diff --git a/src/bin/lttng-sessiond/kernel.cpp b/src/bin/lttng-sessiond/kernel.cpp index 2d60fdca0..0fd9a6ebd 100644 --- a/src/bin/lttng-sessiond/kernel.cpp +++ b/src/bin/lttng-sessiond/kernel.cpp @@ -2228,7 +2228,6 @@ void cleanup_kernel_tracer() } kernel_tracer_status = nonstd::nullopt; - free(syscall_table); } bool kernel_tracer_is_initialized() diff --git a/src/bin/lttng-sessiond/lttng-syscall.cpp b/src/bin/lttng-sessiond/lttng-syscall.cpp index 42eb0e7ee..598574e65 100644 --- a/src/bin/lttng-sessiond/lttng-syscall.cpp +++ b/src/bin/lttng-sessiond/lttng-syscall.cpp @@ -18,10 +18,7 @@ #include /* Global syscall table. */ -struct syscall *syscall_table; - -/* Number of entry in the syscall table. */ -static size_t syscall_table_nb_entry; +std::vector syscall_table; /* * Populate the system call table using the kernel tracer. @@ -32,11 +29,9 @@ static size_t syscall_table_nb_entry; int syscall_init_table(int tracer_fd) { int ret, fd, err; - size_t nbmem; FILE *fp; /* Syscall data from the kernel. */ size_t index = 0; - bool at_least_one_syscall = false; uint32_t bitness; char name[SYSCALL_NAME_LEN]; @@ -60,14 +55,6 @@ int syscall_init_table(int tracer_fd) goto error_fp; } - nbmem = SYSCALL_TABLE_INIT_SIZE; - syscall_table = calloc(nbmem); - if (!syscall_table) { - ret = -errno; - PERROR("syscall list zmalloc"); - goto error; - } - while (fscanf(fp, "syscall { index = %zu; \ name = %" SYSCALL_NAME_LEN_SCANF_IS_A_BROKEN_API "[^;]; \ @@ -75,56 +62,22 @@ int syscall_init_table(int tracer_fd) &index, name, &bitness) == 3) { - at_least_one_syscall = true; - if (index >= nbmem) { - struct syscall *new_list; - size_t new_nbmem; - - /* Double memory size. */ - new_nbmem = std::max(index + 1, nbmem << 1); - if (new_nbmem > (SIZE_MAX / sizeof(*new_list))) { - /* Overflow, stop everything, something went really wrong. */ - ERR("Syscall listing memory size overflow. Stopping"); - free(syscall_table); - syscall_table = nullptr; - ret = -EINVAL; - goto error; - } - - DBG("Reallocating syscall table from %zu to %zu entries", nbmem, new_nbmem); - new_list = (struct syscall *) realloc(syscall_table, - new_nbmem * sizeof(*new_list)); - if (!new_list) { - ret = -errno; - PERROR("syscall list realloc"); - goto error; - } - - /* Zero out the new memory. */ - memset(new_list + nbmem, 0, (new_nbmem - nbmem) * sizeof(*new_list)); - nbmem = new_nbmem; - syscall_table = new_list; - } - syscall_table[index].index = index; - syscall_table[index].bitness = bitness; - if (lttng_strncpy( - syscall_table[index].name, name, sizeof(syscall_table[index].name))) { - ret = -EINVAL; - free(syscall_table); - syscall_table = nullptr; + try { + syscall_table.emplace_back(index, bitness, name); + } catch (const std::bad_alloc&) { + ERR_FMT("Failed to add syscall to syscall table: table_current_element_count={}, syscall_name=`{}`", + syscall_table.size(), + name); + ret = ENOMEM; + goto error; + } catch (const lttng::invalid_argument_error& ex) { + ERR_FMT("Failed to add syscall to syscall table: table_current_element_count={}, reason=`{}`", + syscall_table.size(), + name, + ex.what()); + ret = EINVAL; goto error; } - /* - DBG("Syscall name '%s' at index %" PRIu32 " of bitness %u", - syscall_table[index].name, - syscall_table[index].index, - syscall_table[index].bitness); - */ - } - - /* Index starts at 0. */ - if (at_least_one_syscall) { - syscall_table_nb_entry = index + 1; } ret = 0; @@ -172,7 +125,7 @@ static void destroy_syscall_ht(struct lttng_ht *ht) ret = lttng_ht_del(ht, &iter); LTTNG_ASSERT(!ret); - free(ksyscall); + delete ksyscall; } } @@ -254,16 +207,16 @@ static int add_syscall_to_ht(struct lttng_ht *ht, unsigned int index, unsigned i LTTNG_ASSERT(ht); - ksyscall = zmalloc(); - if (!ksyscall) { + try { + ksyscall = new struct syscall( + syscall_index, syscall_table[index].bitness, syscall_table[index].name); + } catch (const std::bad_alloc& ex) { + ERR_FMT("Failed to allocate syscall entry when adding it to the global syscall hash table: syscall name=`{}`", + syscall_table[index].name); ret = -LTTNG_ERR_NOMEM; goto error; } - strncpy(ksyscall->name, syscall_table[index].name, sizeof(ksyscall->name)); - ksyscall->bitness = syscall_table[index].bitness; - ksyscall->index = syscall_index; - lttng_ht_node_init_str(&ksyscall->node, ksyscall->name); lttng_ht_add_unique_str(ht, &ksyscall->node); ret = 0; @@ -294,7 +247,7 @@ ssize_t syscall_table_list(struct lttng_event **_events) * them might not be valid. The count below will make sure to return the * right size of the events array. */ - events = calloc(syscall_table_nb_entry); + events = calloc(syscall_table.size()); if (!events) { PERROR("syscall table list zmalloc"); ret = -LTTNG_ERR_NOMEM; @@ -306,7 +259,7 @@ ssize_t syscall_table_list(struct lttng_event **_events) goto error; } - for (i = 0; i < syscall_table_nb_entry; i++) { + for (i = 0; i < syscall_table.size(); i++) { /* Skip empty syscalls. */ if (*syscall_table[i].name == '\0') { continue; diff --git a/src/bin/lttng-sessiond/lttng-syscall.hpp b/src/bin/lttng-sessiond/lttng-syscall.hpp index 8ba8c7ea0..877f59390 100644 --- a/src/bin/lttng-sessiond/lttng-syscall.hpp +++ b/src/bin/lttng-sessiond/lttng-syscall.hpp @@ -10,7 +10,10 @@ #include "trace-kernel.hpp" +#include #include +#include +#include #include @@ -28,18 +31,32 @@ * list. */ struct syscall { - uint32_t index; - uint32_t bitness; - char name[SYSCALL_NAME_LEN]; + syscall(std::uint32_t index_, std::uint32_t bitness_, const lttng::c_string_view name_) : + index(index_), bitness(bitness_) + { + if (lttng_strncpy(name, name_.data(), sizeof(name))) { + LTTNG_THROW_INVALID_ARGUMENT_ERROR(fmt::format( + "Invalid syscall name: name=`{}`, length={}, max_length={}", + name_.data(), + name_.len(), + sizeof(name))); + } + + lttng_ht_node_init_str(&node, name); + } + + std::uint32_t index = 0; + std::uint32_t bitness = 0; + char name[SYSCALL_NAME_LEN] = {}; /* Used by the list syscalls command. */ - struct lttng_ht_node_str node; + struct lttng_ht_node_str node = {}; }; /* * Allocated once when listing all syscalls at boot time. This is an array * indexed by the syscall index provided in the listing. */ -extern struct syscall *syscall_table; +extern std::vector syscall_table; /* Use to list kernel system calls. */ int syscall_init_table(int tracer_fd); -- 2.34.1