It's hard to believe but there are systems out there that are so sparse with memory that they can't afford 1MiB of RAM to read a file into. Use mmap when possible and fall back to reading into an allocated buffer otherwise. Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> --- common/imd.c | 6 ++++- scripts/bareboximd.c | 53 ++++++++++++++++++++++++++++---------------- 2 files changed, 39 insertions(+), 20 deletions(-) diff --git a/common/imd.c b/common/imd.c index aff3b00b6b..e1d5733c6b 100644 --- a/common/imd.c +++ b/common/imd.c @@ -17,6 +17,10 @@ int imd_command_setenv(const char *variable_name, const char *value) return -ENOSYS; } #endif +static inline void read_file_2_free(void *buf) +{ + free(buf); +} #endif /* @@ -542,6 +546,6 @@ int imd_command(int argc, char *argv[]) ret = 0; out: - free(buf); + read_file_2_free(buf); return ret; } diff --git a/scripts/bareboximd.c b/scripts/bareboximd.c index 9558c77d1a..c3dcb4dcf0 100644 --- a/scripts/bareboximd.c +++ b/scripts/bareboximd.c @@ -15,6 +15,7 @@ #include <stdarg.h> #include <linux/err.h> #include <linux/kernel.h> +#include <sys/mman.h> #include "../include/image-metadata.h" @@ -96,29 +97,35 @@ static int read_file_2(const char *filename, size_t *size, void **outbuf, size_t goto close; } - buf = malloc(max_size); - if (!buf) { - fprintf(stderr, "Cannot allocate memory\n"); - ret = -ENOMEM; - goto close; - } + buf = mmap(NULL, max_size, PROT_READ, MAP_SHARED, fd, 0); + if (buf == MAP_FAILED ) { + buf = malloc(max_size); + if (!buf) { + fprintf(stderr, "Cannot allocate memory\n"); + ret = -ENOMEM; + goto close; + } - *outbuf = buf; - while (*size < max_size) { - rsize = read(fd, buf, max_size-*size); - if (rsize == 0) { - ret = -EIO; - goto free; - } else if (rsize < 0) { - if (errno == EAGAIN) - continue; - else { + *outbuf = buf; + + while (*size < max_size) { + rsize = read(fd, buf, max_size - *size); + if (rsize == 0) { + ret = -EIO; + goto free; + } + + if (rsize < 0) { ret = -errno; goto free; } - } /* ret > 0 */ - buf += rsize; - *size += rsize; + + buf += rsize; + *size += rsize; + } + } else { + *outbuf = buf; + *size = max_size; } ret = 0; @@ -131,6 +138,14 @@ close: return ret; } +static inline void read_file_2_free(void *buf) +{ + /* + * Can't free() here because buffer might be mmapped. No need + * to do anything as we are exitting in a moment anyway. + */ +} + static unsigned long simple_strtoul(const char *cp, char **endp, unsigned int base) { return strtoul(cp, endp, base); -- 2.29.2 _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox